Patent Description:
Papilloma virus (PV) belongs to the Papillomaviridae Family and causes papillomas in humans, cattle, dogs, and rabbits. One of its members, human papilloma virus (HPV), is a non-enveloped DNA virus. The genome of this virus is a double-stranded closed circular DNA, about <NUM>-8kb in size, with <NUM> open reading frames, which can be divided into three regions according to their functions: (<NUM>) early region (E), about <NUM>. 5kb, encoding E1, E2, E4-E7, a total of <NUM> non-structural proteins related to viral replication, transcription and transformation; (<NUM>) late region (L), about <NUM>. 5kb, encoding the major capsid protein L1 and the minor capsid protein L2; (<NUM>) long regulatory region (LCR), which is located between the end of the L region and the beginning of the E region, is about <NUM>-<NUM> bp long and does not encode any protein, serving as DNA replication and expression regulatory elements.

The L1 proteins and the L2 proteins are synthesized late in the HPV infection cycle. The L1 protein is the major capsid protein and has a molecular weight of <NUM>-<NUM> kDa. The L2 protein is the minor capsid protein. <NUM> L1 protein-pentamers form the outer shell of the icosahedral HPV particle (<NUM>-<NUM> in diameter), which encloses closed circular double-stranded DNA. The L2 protein is located on the inner side of the L1 protein (Structure of Small Virus-like Particles Assembled from the L1 Protein of Human Papillomavirus <NUM> <NPL>).

The ORF of the L1 protein, the most conserved gene in the PV genome, can be used to identify new PV types. A new PV type is identified if its complete genome is cloned and its L1 ORF DNA sequence differs from the closest known PV type by more than <NUM>%. Homologies with differences between <NUM>% and <NUM>% are defined as different subtypes, and differences of less than <NUM>% are defined as different variants of the same subtype (<NPL>).

At late stages of HPV infection, newly synthesized L1 proteins in the cytoplasm are transported to the nucleus of terminally differentiated keratin where, together with L2 proteins, package the replicated HPV genomic DNA to form infectious viruses (<NPL>). This suggests that nuclear import of the L1 protein plays a very important role in HPV infection and production. The ability of the virus to enter the nucleus is determined by the nuclear localization signal (NLS) at the C-terminus of the HPV L1 protein, the NLS is characterized by its abundance of basic amino acids (<NPL>).

<NUM> high-risk (HR) HPV types can lead to cancers of cervix, anus, penis, vagina, vulva and oropharynx, among which HPV-<NUM> and HPV-<NUM> are by far the most common causes of cancers, accounting for approximately <NUM>% of cervical cancers, and the other HR-HPV types (Types <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>) cause the rest. HPV-<NUM> accounts for approximately <NUM>% of HPV-positive oropharyngeal cancers (OPCs). The persistent low-risk genotypes HPV-<NUM> and HPV-<NUM> cause most anogenital warts and respiratory papillomas, but are rarely associated with cancers (<NPL>).

The L1 protein can be recombinantly expressed by poxvirus, baculovirus, or yeast systems and then self-assembles to form virus-like particles (VLP) containing approximately <NUM> L1 proteins, similar to the virus capsid. VLP has no indication. VLP induces neutralizing antibodies in inoculated animals and protects experimental animals from subsequent attack by infectious viruses. Thus, VLP appears to be an excellent candidate for papilloma virus vaccines (<NPL>).

Glaxo's CERVARIX®, a bivalent recombinant HPV vaccine, contains HPV Type <NUM> recombinant L1 protein and HPV Type <NUM> recombinant L1 protein. The L1 protein is obtained by expression of a recombinant baculovirus expression vector system in insect cells of the nocturnal moth (Trichoplusia ni). The L1 protein self-assembles into virus-like particles for the prevention of cervical cancer, Grade <NUM> or <NUM> cervical intraepithelial neoplasia and adenocarcinoma in situ caused by HPV Types <NUM> and <NUM>, and Grade <NUM> cervical intraepithelial neoplasia (oncogenic) in women aged <NUM>-<NUM> years (https://www. gov/downloads/BiologicsBloodVaccines/Vaccines/ApprovedProducts/UCM18 <NUM>.

GARDASIL® is a human papilloma virus quadrivalent (Types <NUM>, <NUM>, <NUM> and <NUM>) recombinant vaccine from Merck for the prevention of cervical cancer, genital warts (condyloma acuminata) and precancerous or proliferative abnormal lesions caused by HPV Types <NUM>, <NUM>, <NUM> and <NUM> in girls and women aged <NUM>-<NUM> years; and for the prevention of anal cancer, genital warts (condyloma acuminatum) and pre-cancerous or abnormal developmental lesions caused by HPV Types <NUM>, <NUM>, <NUM>, and <NUM> in boys and men aged <NUM>-<NUM> (https://www. gov/vaccines-blood-biologics/vaccines/gardasil).

GARDASIL®<NUM> is a nine-valent recombinant human papilloma virus vaccine from Merck that contains virus-like particles of L1 proteins of HPV Types <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, the L1 protein is produced by fermentation of Saccharomyces cerevisiae and self-assembles into VLP. It is used in girls and women aged <NUM>-<NUM> years for the prevention of cervical cancer, vulvar cancer, vaginal cancer and anal cancer caused by HPV Types <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, genital warts (condyloma acuminata) caused by HPV Types <NUM> and <NUM>, and precancerous or proliferative abnormalities caused by HPV Types <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>; and in boys and men aged <NUM>-<NUM> years for the prevention of anal cancer caused by HPV Types <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, genital warts (condyloma acuminatum) caused by HPV Types <NUM> and <NUM> and pre-cancerous or developmentally abnormal lesions caused by HPV Types <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> (https://www. gov/vaccines-blood-biologics/vaccines /gardasil-<NUM>).

The instruction for GARDASIL®<NUM> announced that HPV Types <NUM> and <NUM> are the cause of about <NUM>% of cervical cancers, with the remaining <NUM>% of cases attributed to Types <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, therefor GARDASIL®<NUM> prevents <NUM>% of cervical cancers (https://www. gov/ BiologicsBloodVaccines/Vaccines/ApprovedProducts/ucm426445.

Industrial production of virus-like particles is critical to HPV vaccine development. The common systems for producing virus-like particles are mainly classified into the eukaryotic expression system and the prokaryotic expression system.

Commonly used eukaryotic expression systems include poxvirus expression systems, insect baculovirus expression systems, and yeast expression systems. The HPV L1 protein expressed in eukaryotic expression systems can be spontaneously assembled to virus-like particles as its natural conformation is less disrupted, but the yield thereof is low. The HPV L1 protein expressed in prokaryotic expression systems, mainly E. coli expression systems, is of high yields but mostly in the form of inclusion bodies, this form of protein can not be easily purified thus makes the production process complicated.

Therefore, there is still a need to obtain high yields of HPV virus-like particles.

The invention relates to aspects disclosed in the appended claims.

In one aspect, the present invention provides a chimeric human papillomavirus (HPV) L1 protein comprising, from its N-terminus to C-terminus orientation,.

wherein the chimeric human papillomavirus L1 protein has the immunogenicity of the L1 protein of the first human papillomavirus type.

In one embodiment, the C-terminus of said N-terminal fragment is connected to the N-terminus of said C-terminal fragment directly or via a linker.

The linker does not affect the immunogenicity of said N-terminal fragment and does not affect the expression level or solubility of the protein. In one embodiment, said N-terminal fragment and said C-terminal fragment are connected via a linker comprising <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> amino acids. In one embodiment, the linker is an artificial sequence. In another embodiment, the linker is a naturally occurring sequence in the HPV L1 protein. In another embodiment, the linker may be a partial sequence of the HPV Type <NUM> L1 protein. In another embodiment, the linker may be a partial sequence of the HPV Type <NUM> L1 protein.

In one embodiment, within the range of plus or minus <NUM> amino acid positions of the connection point when the C-terminus of said N-terminal fragment is connected to the N-terminus of said C-terminal fragment, there presents the following continuous amino acid sequence: RKFL; preferably, within the range of plus or minus <NUM> amino acid positions of the connection point, there presents the following continuous amino acid sequence: LGRKFL.

In one aspect, the present invention provides a papilloma virus-like particle, comprising a chimeric papilloma virus L1 protein as previously described. In one embodiment, the papilloma virus-like particle is the HPV virus-like particle, and in one embodiment, the HPV virus-like particle is the icosahedron comprising <NUM> pentamers of said chimeric HPV L1 protein. In one embodiment, the HPV virus-like particle has correctly formed disulfide bonds and thus has a good natural conformation. In one embodiment, the HPV virus-like particles self-assemble in an in vivo expression system.

In one aspect, the present invention provides an immunogenic composition for the prevention of papilloma virus-related disease or infections, comprising papilloma virus-like particles and adjuvants as previously described. Said prevention may be considered as a treatment and they can be used interchangeably.

In one aspect, the present invention provides an isolated polynucleotide encoding a chimeric papilloma virus L1 protein as previously described. In one embodiment, the polynucleotide is a codon-optimized polynucleotide for varieties of expression systems. In one embodiment, the polynucleotide is a codon-optimized polynucleotide for an insect baculovirus expression system.

In one aspect, the present invention provides a vector, comprising a polynucleotide as previously described. In one embodiment, the vector is a baculovirus vector. In one embodiment, the vector may be a transfer vector for a baculovirus expression system. In another embodiment, the vector may be an expression vector for a baculovirus expression system. In another embodiment, the vector may be a recombinant vector for the baculovirus expression system.

In one aspect, the present invention provides a baculovirus, comprising a polynucleotide as previously described.

In one aspect, the present invention provides a host cell, comprising the polynucleotide, the vector, or the baculovirus as previously described. In one embodiment, the host cell is an insect cell, preferably, said insect cell is selected from Sf9 cells, Sf21 cells, Hi5 cells and S2 cells.

In one aspect, the present invention provides a method for preparing papilloma virus-like particles as previously described, comprising: culturing the host cells as previously described to express said chimeric papilloma virus L1 proteins which is assembled into virus-like particles; and purifying said papilloma virus-like particles.

In one embodiment, the host cells are insect cells. In one embodiment, the host cells are Hi5 cells. In one embodiment, the chimeric papilloma L1 proteins are chimeric HPV L1 proteins that self-assemble into HPV virus-like particles in host cells. In one embodiment, the chimeric HPV L1 proteins self-assemble into HPV virus-like particles in host cells having an icosahedron comprising <NUM> pentamers of said chimeric HPV L1 proteins. In one embodiment, the HPV virus-like particles have correctly formed disulfide bonds and thus have a good natural conformation.

In one embodiment, the purification is carried out using cation exchange chromatography. In one embodiment, the purification is carried out using strong cation exchange chromatography. In another embodiment, the purification is carried out using weak cation exchange chromatography. In one embodiment, the purification is carried out using a combination of multiple cation exchange chromatography. In one embodiment, the purification is carried out using HS strong cation exchange chromatography. In another embodiment, the purification is carried out using MMA ion exchange chromatography. In another embodiment, purification is performed using HS-MMA two-step chromatography.

Papillomavirus L1 proteins expressed by eukaryotic expression systems can spontaneously assemble to virus-like particles, but the low expression level make them not suitable for mass production.

The sequences of the L1 proteins of each HPV type can be easily obtained from https://www. For a given HPV type, the L1 protein can be derived from different strains, thus the amino acid sequence thereof may have multiple versions, any version of the natural sequence can be used in the present invention. It is possible that the sequence of the HPV L1 protein of a given type used during the conception and design of the present invention may differ from the sequence used in the following examples, but such differences do not affect the decisions and conclusions of the inventors.

It is generally accepted by those of skill in the art that the C-terminus of the L1 protein does not contain major neutralizing antigenic epitope and therefore attempts have been made to increase expression by truncating the C-terminus of the HPV L1 protein, for example Glaxo's US patent <CIT>, in which the C-terminus of the HPV16 L1 protein is truncated by <NUM>-<NUM> amino acids, preferably <NUM> amino acids, states that the yield of VLP is increased by many-fold, preferably at least by <NUM> folds, and in particular by about <NUM> to <NUM> folds. Inspired by this, the inventors attempted to truncate the C-terminus of HPV <NUM> L1 protein by <NUM> amino acids and named the truncated protein as HPV <NUM> L1 (<NUM>-<NUM>). The protein is in high expression level but poor solubility, and is difficult to be extract and purified (see Comparative Example).

The poor solubility of the protein due to this truncation may be due to the deletion of the nuclear localization sequence located at the C-terminus, but the present invention is not binding to this speculation. During research and production, the inventor discovered that HPV Type <NUM> L1 protein, HPV Type <NUM> L1 protein, HPV Type <NUM> L1 protein, HPV Type <NUM> L1 protein and HPV Type <NUM> L1 protein have better expression levels and solubility than other HPV types L1 proteins. Inspired by the discovery, the inventors replaced the C-terminus of specific HPV types L1 proteins that are less extractable or less soluble with the C-terminus of specific HPV types L1 protein having better expression levels and solubility. That is, the inventors have constructed a chimeric protein: comprising, in the N-terminus to C-terminus orientation, an N-terminal fragment derived from L1 protein of the first papilloma virus type (e.g. HPV L1 protein), which provides the immunogenicity of the first papilloma virus type (e.g. HPV), and a C-terminal fragment derived from L1 protein of the second papilloma virus type (e.g. HPV L1 protein), which provides the features of better expression levels and solubility. These two fragments can be connected directly or via a linker.

The length of the N-terminal fragment of the HPV L1 protein appropriate for maintaining the immunogenicity of the L1 protein of the first HPV type and ensuring the formation of VLP is determined. The following reports relate to epitope studies of common HPV types.

Sunanda Baidya et al. reported that the epitopes of the L1 protein 48EEYDLQFIFQLCKITLTA65, 45RHGEEYDLQFIFQLCKITLTA65, 63LPDPNKF69, 79PETQRLVWAC88, 36PVPGQYDA43, 77YNPETQRLVWAC88, 188DTGYGAMD195, 36PVPGQYDATK45, 45KQDIPKVSAYQYRVFRV61, 130RDNVSVDYKQTQLCI144 and 49YSRHVEEYDLQFIF62 can be used as tools for designing HPV <NUM> and <NUM> vaccines (see Epitope design of L1 protein for vaccine production against Human Papilloma Virus types <NUM> and <NUM>, <NPL>).

Katharina Slupetzky et al. reported that the regions near aa <NUM>-<NUM> and <NUM>-<NUM> of HPV-<NUM> contribute to the neutralization epitopes and that the latter is the immunodominant site (see Chimeric papilloma virus-like particles expressing a foreign epitope on capsid surface loops, <NPL>).

Brooke Bishop et al. prepared the following three variants of the HPV <NUM>, <NUM>, <NUM> and <NUM> L1 proteins: deletion of <NUM> amino acids at its N terminus, deletion of α4 (corresponding to amino acid residues <NUM>-<NUM> of HPV <NUM>), and deletion of <NUM> amino acids at its C terminus respectively, and reported that the former two could not be assembled into VLP, but this phenomenon has not been reported in the latter one (Crystal Structures of Four Types of Human Papillomavirus L1 Capsid Proteins <NPL>). Each the α-helix, β-fold sheets and Loop Region of each type of HPV L1 protein can be conveniently determined by sequence analysis software commonly used in the field. Wherein the α-helix regions contains the α1 Region, α2 Region, α3 Region, α4 Region and α5 Region.

The inventors performed sequence alignments of L1 proteins of <NUM> HPV types (Types <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>) and then performed secondary structure prediction according to the literature cited above (<NPL>), the results of which are shown below, where the part between the downward-pointing arrows corresponds to the regions which had been deleted for preparing the variants in that literature. <IMG>
<IMG>.

In addition to the methods used by the inventors for sequence alignments, protein secondary structure prediction software that can be used for prediction includes, but is not limited to:.

In one aspect of the disclosure, the inventors determine the length of the N-terminal fragment of the HPV L1 protein derived from the first type in the following manner: the natural sequence of the L1 protein is truncated within its α5 region and nearby regions thereof, with the sequence from its N-terminus to the newly generated C-terminus within the α5 region retained. Such a truncated sequence ensures that it has the immunogenicity of the first type and is capable of forming VLP.

The N-terminal fragment of the HPV L1 protein derived from the first type can be further modified as long as it retains the immunogenicity of the first type and is capable of forming VLP.

The length of the C-terminal fragment of the HPV L1 protein derived from the second type is determined in the following manner: The natural sequence of the L1 protein is truncated within its α5 region and nearby regions thereof, then the sequence from the newly generated N-terminus within its α5 region to the C-terminus is retained. Such a truncated sequence does not have the major neutralizing antigenic epitope so that does not interfere with the immunogenicity of the resulting chimeric protein.

The C-terminal fragment of the HPV L1 protein derived from the second type can be further mutated, deleted and/or added, preferably retaining at least one of its nuclear localization sequences. Yang et al. predicted the nuclear localization sequences of <NUM> HPV subtypes (<NPL>). The nuclear localization sequences of each type of HPV L1 protein can be conveniently determined by sequence analysis software commonly used in the field.

The above-described connection of the N-terminal fragment to the C-terminal fragment occurs at the newly generated C-terminus of the former and at the newly generated N-terminus of the latter. This can be a direct connection or a connection via a linker. The site where the connection occurs is defined as the origin coordinate, the N-terminal side of the origin is regarded as minus while the C-terminal side as plus.

The following shows the sequence of amino acids <NUM>-<NUM> of the HPV6 L1 protein and the corresponding sequences of L1 proteins of other HPV types. These sequence overlap with their α5 region respectively. It can be seen these sequences are highly similar. The numbers in brackets indicate the positions of the last amino acid residue of the listed sequences, where for HPV Type <NUM>, an additional <NUM> amino acids are present at the N-terminus of the L1 protein of some HPV Type <NUM> strains, while at the N-terminus of the L1 protein of other HPV Type <NUM> strains, the said additional <NUM> amino acids are not present, therefore the number is indicated as (<NUM>)+<NUM>.

HPV59 DLDQFPLGRKFLLQLGA(<NUM>) RPKPTIGPRKRAAPAPTSTPSPKRVKRRKSSRK wherein RKR at positions <NUM>-<NUM> and KRVKRRK at positions <NUM>-<NUM> are nuclear localization sequences.

In one aspect disclosed herein, the inventors have completed C-terminus substitutions of L1 proteins between different HPV types by taking advantage of sequence similarity of the α5 region and nearby regions between the HPV types.

In a preferred aspect, the inventors have noted that L1 protein of each HPV type has a tetrapeptide RKFL or, more advantageously, a hexapeptide LGRKFL, at a similar position. The inventors have skillfully exploited this highly conserved sequence to locate the chimeric protein connection point at any amino acid position within this oligopeptide. On one hand, the sequence starting from the N-terminus of the chimeric protein to RKFL or LGRKFL is identical to the sequence of the N-terminal fragment derived from L1 protein of the first HPV type, while on the other hand, the sequence starting from RKFL or LGRKFL to the C-terminus of the chimeric protein is identical to the sequence of the C-terminal fragment derived from L1 protein of the second type.

The chimeric protein thus produced maintains a high degree of similarity to the natural HPV L1 protein, and it can be expected to perform well in production and even in medical or prophylactic procedures thereafter.

It will be understandable for those skilled in the art that there are different strains with different natural sequences of a given HPV type, chimeric proteins constructed using different strains also fall within the scope of the present invention.

It will be understandable for those skilled in the art that because of the high degree of similarity between L1 protein of different HPV types, if, during the construction of the chimeric proteins, the N-terminal fragment derived from L1 protein of the first HPV type is extended by more amino acid residues towards the C-terminus, or the C-terminal fragment derived from L1 protein of the second HPV type is extended by more amino acid residues towards the N-terminus, it is also possible to form chimeric proteins that are structurally identical to the present invention due to identical or similar amino acids at the corresponding sites. The chimeric proteins thus formed also fall within the scope of the present invention.

It will be understandable for those skilled in the art that on the basis of the chimeric proteins of the above described embodiments, variants of the chimeric proteins may be formed by mutations, deletions and/or additions of amino acid residues. These variants are likely to have the immunogenicity of L1 protein of the first HPV type, can form VLP, and have a good yield and solubility. The chimeric proteins such formed also fall within the scope of the present invention.

The expression systems commonly used for producing virus-like particles are classified into eukaryotic expression systems and prokaryotic expression systems. The papilloma virus L proteins expressed by the eukaryotic expression systems can spontaneously assemble into viral-like particles, but have the disadvantage of low expression level thus are not suitable for mass production. The papilloma virus L protein expressed by the prokaryotic expression system requires in vitro processing to obtain virus-like particles because of often destroyed natural conformation, and has low yield , being difficult to be used in industrialization.

The present invention modifies the C-terminus of the L protein of the papilloma virus (e.g. human papilloma virus), for example by replacing it with the C-terminal fragment of HPV Type <NUM> L1 protein, HPV Type <NUM> L1 protein, HPV Type <NUM> L1 protein, HPV Type <NUM> L1 protein or HPV Type <NUM> L1 protein, thus can be used in expression systems (e.g. host cells, e.g. insect cells) to improve the expression level and the solubility of the papilloma virus L protein in expression systems (for example, host cells, e.g. insect cells). This can be used for the mass production of vaccines such as HPV vaccines.

The inventors found that the HPV Type <NUM> L1 protein, the HPV Type <NUM> L1 protein, the HPV Type <NUM> L1 protein, the HPV Type <NUM> L1 protein and the HPV Type <NUM> L1 protein have increased expression level and increased solubility compared to L1 proteins of other HPV types, and that said increased protein expression level and increased solubility was found to be depend on the C-terminal sequence of said HPV L1 protein. Among <NUM> HPV Type L1 proteins, most of them have nuclear localization sequences at the C-termini, and the C-terminal sequences have some similarities.

For papilloma virus L proteins that are currently inexpressible, very low in expression level or insoluble after expression, replacement of their C-terminal fragments with C-terminal fragments of the HPV Type <NUM> L1 protein, HPV Type <NUM> L1 protein, HPV Type <NUM> L1 protein, HPV Type <NUM> L1 protein or HPV Type <NUM> L1 protein makes it possible for soluble expression and subsequent purification. This strategy can be used for the mass production of polyvalent vaccines (e.g. HPV vaccines), making it possible to provide more comprehensive protection against a wide range of papilloma virus infections, especially HPV.

There needs to increase the expression level and the solubility of the HPV L1 protein in insect cells for mass production purpose. In addition, the virus-like particles assembled by the HPV L protein lack good conformation in yeast cells due to failure to form correct disulphide bonds.

For the HPV L1 proteins that are poorly expressed and insoluble in insect cells, a significant increase in expression level and solubility can be resulted after the modification of its C-terminal fragment into the C-terminal fragment of the HPV Type <NUM> or <NUM> L1 protein, thus they could be used for mass production of HPV vaccines.

For HPV L1 proteins that are better expressed and better soluble in insect cells compared to L1 proteins of other HPV types, such as HPV Type <NUM> protein, HPV Type <NUM> L1 protein, HPV Type <NUM> L1 protein, etc., there are needs to further improve the expression level and the solubility in order to achieve mass production of vaccines. In the present invention, for example, after modifying the C-terminal fragment of the HPV Type <NUM> L1 protein to the C-terminal fragment of the HPV Type <NUM> L1 protein, the expression level and the solubility of the modified chimeric HPV Type <NUM> protein are improved, which is conducive to the mass production of HPV vaccines.

To sum up, the chimeric HPV L1 proteins showed much higher expression level and solubility in insect cells compared to the unmodified HPV L1 protein. It can be used for the mass production of HPV vaccines. In addition, the chimeric HPV L1 proteins can correctly form disulfide bonds thus be assembled into HPV virus-like particles with good conformations in insect cells. This can improve the immunogenicity of HPV virus-like particles and trigger better immune responses.

Unless otherwise stated, all technical and scientific terms used herein have the meanings normally understood by a person of ordinary skill in the art to which the invention belongs. For the convenience of understanding the present invention, the following terms are cited below for their ordinary meaning.

When used herein and in the attached claims, the singular forms "a/an", "another" and "said/the" include the plural designations of the objects unless the context clearly indicates otherwise. Unless otherwise expressly stated, the terms "include/comprise/have", "for example", etc. are intended to convey inclusion rather than limitation.

The term "immunogenicity" refers to the ability of a substance, for example a protein or a peptide, to trigger an immune response, i.e. the ability to trigger the production of antibodies, in particular the ability to trigger humoral- or cell-mediated response.

The term "antibody" refers to an immunoglobulin molecule that binds an antigen. Antibodies may be polyclonal mixtures or monoclonal. Antibodies may be intact immunoglobulins of natural origin or of recombinant origin or may be immunoreactive portions of intact immunoglobulins. Antibodies may be present in a variety of forms including, for example, Fv, Fab', F(ab')<NUM> and as single chains.

The term "antigenicity" refers to the ability of a substance, for example a protein or a peptide, to trigger the production of antibodies that bind specifically to it.

The term "epitope" includes any protein determinant cluster that specifically binds to an antibody or T-cell receptor. Epitope determinants typically consist of chemically active surface groups (e.g. amino acids or sugar side chains, or combinations thereof) of the molecule and typically have specific three-dimensional structural characteristics as well as specific charge characteristics.

The terms "subtype" or "type" are used interchangeably herein to refer to genetic variant of virus that allows it can be recognized by the immune system as distinct antigen from type to type. For example, HPV <NUM> is immunologically distinguishable from HPV <NUM>.

The term "HPV L1 protein", as used herein, the term "HPV" and "human papilloma virus" refer to envelope-free double-stranded DNA viruses of the Papillomavirus family. Their genomes are circular and approximately <NUM> kilobase pairs in size. Most HPVs encode eight major proteins, six in the "early" region (E1-E2) and two in the "late" region (L1 (major capsid protein) and L2 (minor capsid protein)). Over <NUM> HPV types have been identified and they are labelled by numbers (e.g. HPV-<NUM>, HPV-<NUM>, etc.).

The term "HPV" or "HPV virus" refers to papilloma viruses of the Papillomaviridae Family, which are envelope-free DNA viruses with a double-stranded closed circular DNA genome of approximately <NUM> kb in size that is usually classified into three regions: (i) the early region (E ), which contains six open reading frames E1, E2, E4-E7, encoding non-structural proteins related to viral replication, transcription and transformation, as well as open reading frames E3 and E8; (ii) the late region (L), which contains reading frames encoding the major capsid protein L1 and the minor capsid protein L2; and (iii) the long regulatory region (LCR), which does not encode any proteins but has the origin of replication and multiple transcription factor binding sites.

The terms "HPV L1 protein" and "HPV L2 protein" refer to proteins encoded by the late region (L) of the HPV gene and synthesized late in the HPV infection cycle. The L2 protein is the minor capsid protein. <NUM> L1 pentamers form the outer shell of the icosahedral HPV particles, which encloses the closed circular double-stranded DNA microchromosome.

The term "virus-like particle" refers to a hollow particle containing one or plurality of structural proteins of a virus, without viral nucleic acids.

"HPV pseudovirus" is an ideal model for in vitro neutralization of HPV, by taking advantages of the non-specific nucleic acid encapsulation property of HPV VLP, HPV pseudoviru is formed by wrapping free DNA or introducing an exogenous plasmid into a VLP composed of intracellularly-expressed HPV L1 and L2.

The "pseudovirus neutralization assay" is a method for evaluating the neutralizing activity of antibodies. After incubation of immunized animal serum with a certain amount of pseudovirus and then infection of the cells, the amount of the cells decreases when serum neutralizing antibodies increases, showing a linear negative correlation in a certain range. The neutralizing activity of antibodies in serum can therefore be assessed by measuring changes in the amounts of cells.

The term "fragment thereof" or "variant thereof" refers to a deletion, insertion and/or substitution of nucleotides or amino acids sequence of the present invention. Preferably, the fragment or variant of the polypeptide provided by the present invention is capable of triggering the humoral- and/or the cellular-immune response in animals or humans.

The term "chimeric" means that sequences of polypeptides or nucleotides derived from different parental molecules are connected together by -CO-NH- or <NUM>', <NUM>'-phosphodiester bonds, respectively. Preferably, they are not spaced by additional linker sequences, but are directly adjacent to each other.

The term "truncation" refers to the removal of one or plurality of amino acids from the N- and/or C-terminus of a polypeptide or the deletion of one or plurality of amino acids from the interior of a polypeptide.

The term "nuclear localization sequence" refers to an amino acid sequence that directs the protein into the nucleus. In some HPV L1 proteins, two tight clusters of basic residues (i.e. nuclear localization sequences) (e.g. one is KRKR, KRKK, KRKRK, KRKKRK, KRVKRRK, etc. and the other is KR, RKR, KRK, etc.) have a spacer region of <NUM>-<NUM> amino acids between them. The above clusters of basic residues belong to nuclear localization sequences. In some other HPV L1 proteins, the nuclear localization sequence is a tight cluster of basic residues formed by arginines and/or lysines. Nuclear localization sequences include, but are not limited to, examples of clusters of basic residues as described above.

The term "functional variant" refers to a version of a polypeptide or a protein that retains the desired activities or characteristics after truncation, mutation, deletion and/or addition.

"Sequence identity" between two sequences of polypeptides or nucleic acids indicates the number of identical residues between said sequences as a percentage of the total number of residues, and is calculated based on the size of the smaller one of the compared molecules. When calculating the percentage identity, the sequences being compared are matched in such a way as to produce the maximum match between the sequences, with the vacant positions (if present) in the match being resolved by a specific algorithm. Preferred computer program methods for determining identity between two sequences include, but are not limited to, GCG program packages including GAP, BLASTP, BLASTN and FASTA (<NPL>). The above programs are publicly available from the National Center of Biotechnology Information (NCBI) and other sources. The well-known Smith Waterman Algorithm can also be used to determine the identity.

Non-critical amino acids can be conservatively substituted without affecting the normal function of the protein. Conservative substitution means replacing amino acids with chemically or functionally similar amino acids. Tables for conservative substitutions that provide similar amino acids are well known in the art. By way of example, in some embodiments, the groups of amino acids provided in Tables <NUM>-<NUM> are considered to be conservative substitutions for each other.

The term "amino acids" refers to the twenty common naturally occurring amino acids. Naturally occurring amino acids include alanine (Ala; A), arginine (Arg; R), asparagine (Asn; N), aspartic acid (Asp; D), cysteine (Cys; C), glutamic acid (Glu; E), glutamine (Gln; Q), glycine (Gly; G), histidine (His; H), isoleucine (Ile; I), leucine (Leu; L), lysine (Lys; K), methionine (Met; M), phenylalanine (Phe; F), proline (Pro; P), serine (Ser; S), threonine (Thr; T), tryptophan (Trp; W), tyrosine (Tyr; Y) and valine (Val; V).

The term "adjuvant" refers to a compound or mixture that enhances immune responses. In particular, a vaccine may comprise an adjuvant. Adjuvants for use in the present invention may include, but are not limited to, one or plurality of the following: mineral-containing adjuvant compositions, oil-emulsion adjuvants, saponin adjuvant formulations, derivatives of bacteria or microbes.

The term "vector" refers to a nucleic acid molecule capable of proliferating another nucleic acid connected to it. The term includes vectors as self-replicating nucleic acid structures and as vectors integrated into the genome of host cells into which the vector has been introduced. Certain vectors are capable of directing the expression of nucleic acids to which such vectors are operatively connected.

The term "host cell" refers to a cell into which an exogenous nucleic acid has been introduced, as well as to the progeny of such a cell. Host cells include "transformants" (or "transformed cells"), "transfectants" (or "transfected cells") or "infectants" (or "infected cells"), each of which includes primary transformed, transfected or infected cells and the progeny derived from them. Such progeny may not be identical to the parental cells in terms of nucleic acid content and may contain mutations.

The administration amount is preferably a "prophylactically effective amount" (herein the prophylaxis may be considered as treatment and the two may be used interchangeably), which is sufficient to show benefit to the individual.

The HPV6 L1 gene with the KpnI and XbaI cleavage sites at both ends of the synthesized sequences was synthesized by Thermo Fisher [formerly Invitrogen (Shanghai) Trading Co. ], its sequence is shown in SEQ ID NO: <NUM>. The plasmid pcDNA3-HPV6-L1 comprising the nucleotide sequence encoding amino acid <NUM>-<NUM> of HPV6 L1 was obtained by ligating the synthesized gene fragment with pcDNA3 vector (distributor: Thermo Fisher) at KpnI and XbaI cleavage sites.

The obtained pcDNA3-HPV6-L1 plasmid was subjected to double enzyme digestion with KpnI and XbaI to obtain a gene fragment of HPV6 L1 (<NUM>-<NUM>). The fragment was then ligated with the KpnI / XbaI double digested pFastBac™<NUM> vector (distributor: Thermo Fisher) to obtain a rod vector containing the HPV6 L1 (<NUM>-<NUM>) gene fragment, named as pFB-HPV6 L1.

The HPV33 L1 gene with the Kpn I and XbaI cleavage sites at both ends of the synthesized sequences was synthesized by Thermo Fisher [formerly Invitrogen (Shanghai) Trading Co. ), its sequence is shown as SEQ ID NO: <NUM>. The plasmid pcDNA3-HPV33-L1 comprising the nucleotide sequence encoding amino acids <NUM>-<NUM> of HPV33 L1 was obtained by ligating the synthesized gene fragment with pcDNA3 vector (distributor: Thermo Fisher) at Kpn I and XbaI cleavage sites.

The pcDNA3-HPV33-L1 plasmid was subjected to double enzyme digestion with KpnI and XbaI to obtain a fragment of the HPV33 L1 (<NUM>-<NUM>) gene. The fragment was then ligated to the KpnI and XbaI double digested pFastBac™<NUM> vector (distributor: Thermo Fisher) to obtain a rod vector containing the HPV33 L1 (<NUM>-<NUM>) gene fragment, named as pFB-HPV33 L1.

Chimeric gene with HPV6 L1 C-terminus substituted with HPV33 L1 C-terminus: the constructed recombinant plasmid pFB-HPV6 L1 was used as the gene template to amplify a <NUM> bp gene fragment using primers F1 and R1, the primer sequence F1 is shown in SEQ ID No: <NUM> and R1 is shown in SEQ ID No: <NUM>.

This gene fragment contains a fragment encoding amino acids <NUM>-<NUM> of HPV6 L1, <NUM> bases overlapping with the gene fragment encoding amino acids <NUM>-<NUM> of HPV33 L1, and a fragment of the KpnI digest site (GGTAC^C), the amplified sequence is shown in SEQ ID No: <NUM>.

PCR amplification parameters: pre-denaturation at <NUM> for <NUM>; denaturation at <NUM> for <NUM>, annealing at <NUM> for <NUM>, <NUM> kb/<NUM> at <NUM>, for <NUM> cycles; extension at <NUM> for <NUM>; end at <NUM>.

The recombinant plasmid pFB-HPV33 L1 was used as the gene template to amplify a gene fragment of <NUM> bp in length using primers F2 and R2, the primer sequence of F2 is shown in SEQ ID No: <NUM> and the primer sequence of R2 is shown in SEQ ID No: <NUM>.

This gene fragment contains a gene fragment encoding <NUM> C-terminal amino acids (<NUM>-<NUM>) of HPV33 L1, a <NUM> bp base overlapping with the gene fragment encoding the C-terminus of amino acids <NUM>-<NUM> of HPV6 L1 and the XbaI (T^CTAGA) digest site, the amplified sequence is shown in SEQ ID No: <NUM>.

The ligating primers were F1 and R2, and the fragments amplified using the above primers (amplified fragments of F1 and R1, amplified fragments of F2 and R2) were used as templates.

PCR ligating parameters: pre-denaturation at <NUM> for <NUM>; denaturation at <NUM> for <NUM>, annealing at <NUM> for <NUM>, <NUM> for <NUM> kb/<NUM>, for <NUM> cycles; denaturation at <NUM> for <NUM>, annealing at <NUM> for <NUM>, <NUM> for <NUM> kb/<NUM>, for <NUM> cycles; extension at <NUM> for <NUM>; end at <NUM>.

The final result was SEQ ID NO: <NUM>, a nucleotide sequence encoding amino acids <NUM>-<NUM> of HPV6 L1 and <NUM> C-terminal amino acids of HPV33 L1(aa <NUM>-<NUM>), with KpnI and XbaI cleavage sites at both ends (hereafter referred to as the ligating sequence).

The recombinant plasmid pFB-HPV6 L1: 33C was obtained by double digesting the pFastBac™<NUM> vector and the ligating sequence fragment with KpnI+XbaI enzymes and cloning the ligating sequence into the pFastBac™<NUM> vector to obtain pFB-HPV6 L1: 33C, which is a chimeric gene with the C-terminus of HPV6 L1 substituted by the C-terminus of HPV33 L1.

The experimental methods and procedures were the same as in Example <NUM>, see Appendix <NUM> for relevant sequences.

The experimental method and procedure were the same as in Example <NUM>, see Appendix <NUM> for relevant sequences.

The HPV39 L1 gene with the KpnI and XbaI cleavage sites at both ends of the synthesized sequences was synthesized by Thermo Fisher [formerly Invitrogen (Shanghai) Trading Co. ), its sequence is shown as SEQ ID NO: <NUM>. The plasmid pcDNA3-HPV39-L1 containing a nucleotide sequence encoding amino acids <NUM>-<NUM> of HPV39 L1 was obtained by ligating the synthesized gene fragment with pcDNA3 vector (distributor: Thermo Fisher) at Kpn I and XbaI cleavage sites.

The pcDNA3-HPV39-L1 plasmid was subjected to double digestion with KpnI and XbaI to obtain a fragment of the HPV39 L1 (<NUM>-<NUM>) gene. The fragment was then ligated to the KpnI and XbaI double digested pFastBac™<NUM> vector (distributor: Thermo Fisher) to obtain a rod vector containing the HPV39 L1 (<NUM>-<NUM>) gene fragment, named as pFB-HPV39 L1.

The HPV59L1 gene was synthesized by Thermo Fisher [formerly Invitrogen (Shanghai) Trading Co. ) to obtain plasmid pcDNA3-HPV59-L1 containing the nucleotide sequence encoding amino acids <NUM>-<NUM> of HPV59L1.

The pcDNA3-HPV59-L1 plasmid was double digested with KpnI and XbaI to obtain a fragment of the HPV59L1 (<NUM>-<NUM>) gene. The fragment was then ligated to the KpnI / XbaI double digested pFastBac™<NUM> vector (distributor: Thermo Fisher) to obtain a rod vector containing the HPV59L1 (<NUM>-<NUM>) gene fragment, named as pFB-HPV59L1.

Chimeric gene with HPV39 L1 C-terminus substituted with HPV59L1 C-terminus: The constructed recombinant plasmid pFB-HPV39 L1 was used as the gene template to amplify a <NUM> bp gene fragment using primers F1 and R1, the primer sequence F1 is shown in SEQ ID No: <NUM> and the primer sequence R1 is shown in SEQ ID No: <NUM>.

This fragment contains a fragment encoding amino acids <NUM>-<NUM> of HPV39 L1, a <NUM>-base overlapping with a fragment encoding amino acids <NUM>-<NUM> of HPV59L1 and a segment of the KpnI digest site (GGTAC^C), the amplified sequence is shown in SEQ ID No: <NUM>.

The recombinant plasmid pFB-HPV59L1 was used as the gene template to amplify a gene fragment of <NUM> bp in length using primers F2 and R2. The primer sequence F2 is shown in SEQ ID No: <NUM> and R2 is shown in SEQ ID No: <NUM>.

This gene fragment contains a gene fragment encoding <NUM> C-terminal amino acids (<NUM>-<NUM>) of the HPV59L1, a <NUM> bp base overlapping with the gene fragment encoding amino acids <NUM>-<NUM> of HPV39 L1 and the XbaI (T^CTAGA) digest site, and the amplified sequence is shown in SEQ ID No: <NUM>.

PCR amplification parameters: pre-denaturation at <NUM> for <NUM>; denaturation at <NUM> for <NUM>, annealing at <NUM> for <NUM>, <NUM> kb/<NUM> at <NUM> for <NUM> cycles; extension at <NUM> for <NUM>; end at <NUM>.

The ligating primers were F1 and R2, and the fragments amplified by using the above primers (F1 and R1 amplified fragments, F2 and R2 amplified fragments) were used as templates.

The final result was SEQ ID NO: <NUM>, a nucleotide sequence encoding amino acids <NUM>-<NUM> of HPV39 L1 and <NUM> C-terminal amino acids of HPV59L1(<NUM>-<NUM>) with KpnI and XbaI enzyme cleavage sites at both ends (hereafter referred to as the ligating sequence).

The recombinant plasmid pFB-HPV39 L1: 59C was obtained by double digesting the pFastBac™<NUM> vector and the ligating sequence fragment with KpnI+XbaI enzymes and the ligating sequence was cloned into the pFastBac™<NUM> vector o obtain pFB-HPV39 L1: 59C, which is a chimeric gene with the C-terminus of HPV39 L1 substituted by the C-terminus of HPV59L1.

The recombinant plasmid of pFB-HPV6 L1: 33C constructed in Example <NUM> was identified and sequenced to be correct, and was transformed into DH10Bac bacteria competent cells (Bac-to-Bac® kit, purchased from Thermo Fisher), incubated at <NUM> for proliferation, and incubated in a flat dish for streak culture. White colonies was selected, incubated overnight. The bacterial culture was collected and the recombinant baculovirus DNA was extracted using alkaline lysis method.

The recombinant baculovirus DNA was transfected into insect cells SF9 using a cationic transfection reagent (purchased from Sino Biological) to package the recombinant baculovirus virulent strains. The procedure was as follows:.

Virus supernatant was collected after visible lesions were observed in the transfected cells, typically after <NUM>-<NUM> days of culturing. The viral supernatant, i.e., the P1 generation virus strain of HPV6 L1: 33C is collected aseptically with a pipette. SF9 cells, at a density of <NUM> × <NUM><NUM> cells/mL, were infected using P1 generation virus strain of HPV6 L1: 33C at a ratio of <NUM>: <NUM> (V/V), cultured at <NUM> for <NUM> days, and centrifuged at <NUM> ± <NUM> for <NUM> at room temperature. The collected virus supernatant was the P2 generation virus and could be used for infecting the host cells and production.

The experimental methods and procedures were the same as in Example <NUM>.

The experimental methods and procedures were the same as those of Example <NUM>.

High Five cells were infected with baculovirus containing the HPV6 L1: 33C recombinant gene obtained in Example <NUM> at a ratio of <NUM>: <NUM> (V/V), and the cell precipitate was collected by centrifugation at <NUM> ± <NUM> at room temperature. The cells were broken up by sonication at low temperature for <NUM>, centrifuged at ><NUM>,<NUM> for <NUM> and the supernatant was collected for SDS-PAGE. Lane <NUM>: Marker (The marker is a mixture of <NUM> purified proteins with molecular weights ranging from <NUM> kDa to <NUM> kDa, produced by Thermo Scientific); Lane <NUM>: cell lysate; Lane <NUM>: supernatant of the lysate collected by centrifugation.

The result is shown in <FIG>. The HPV6 L1: 33C L1 protein prepared by this method has a yield of ><NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV11 L1: 33C L1 protein prepared by this method has a yield of ><NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV 16L1: 33C L1 protein prepared by this method has a yield of > <NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV18 L1: 33C L1 protein prepared method has a yield of > <NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV31 L1: 33C L1 protein prepared by this method has a yield of ><NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV35 L1: 33C L1 protein prepared by this method has a yield of ><NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV39 L1: 59C L1 protein prepared by this method has a yield of ><NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV45 L1: 33C L1 protein prepared by this method has a yield of ><NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV51 L1: 33C L1 protein prepared by this method has a yield of ><NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV52 L1: 33C L1 protein prepared by this method has a yield of ><NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV56 L1: 33C L1 protein prepared by this method has a yield of ><NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The result is shown in <FIG>. The HPV58 L1: 33C L1 protein prepared by this method has a yield of ><NUM>/L and a protein size of approximate <NUM> KD, which can be used for mass production.

The HPV6 L1: 33C virus-like particles were purified by a two-step chromatography method, i.e. HS-MMA method, the supernatant collected in Example <NUM> was purified, and finally, high purity virus-like particles were obtained.

Medium: POROS® <NUM> HS strong cation exchange media produced by Thermo Fisher was used.

Medium volume: <NUM> of media volume, <NUM>/min of linear flow rate.

Chromatography conditions: equilibration buffer (pH <NUM>, the salt concentration is <NUM> phosphate, <NUM> NaCl); wash buffer (the salt concentration is <NUM> phosphate, <NUM> NaCl, pH <NUM>).

The chromatography column was first equilibrated with <NUM> CV of equilibration buffer and then the sample was loaded. After loading, the column was then eluted with <NUM> CV of equilibration buffer and wash buffer, respectively, to remove the protein impurities.

Elution conditions: a <NUM> phosphate buffer containing <NUM> arginine hydrochloride, pH <NUM>, with an elution salt concentration being of <NUM> NaCl, was used.

Medium: MMA ion exchange media produced by Bestchrom (Shanghai) Biosciences Co. , Ltd was used.

Medium volume: media volume is150 mL, while linear flow rate is <NUM>/min.

Chromatography conditions: equilibration buffer: <NUM> PB, <NUM> NaCl, pH <NUM>. The chromatography column was first equilibrated with <NUM> CV equilibration buffer and then the sample was loaded. After loading, protein impurities were rinsed off with <NUM> CV equilibration buffer and then the target protein was eluted with elution buffer and collected.

Elution conditions: <NUM> NaAC, <NUM> NaCl, <NUM>% Tween <NUM>, pH <NUM>.

<NUM>µL sample was taken for transmission electron microscopy. The sample was fixed onto a carbon coated copper grid for <NUM>, the rest liquid was absorbed off with filter paper, and then stained twice with phosphotungstic acid (Beijing Electron Microscopy China Technology Co. , concentration <NUM>%, pH <NUM>) for <NUM> seconds each time, the rest staining solution was absorbed off with filter paper, left the sample for drying, then performed transmission electron microscopy observation. The transmission electron microscope (Brand: Hitachi, Model No.: H-<NUM>) was 80KV with a magnification of <NUM>,000x.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV6 L1: 33C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV11 L1: 33C can form uniform-sized virus-like particles, with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV 16L1: 33C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV18 L1: 33C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV31 L1: 33C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminally modified HPV35 L1: 33C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV39 L1: 59C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV45 L1: 33C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV51 L1: 33C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV52 L1: 33C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV56 L1: 33C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

The electron microscopy observation is shown in <FIG>. As can be seen in <FIG>, the C-terminal-modified HPV58 L1: 33C can form uniform-sized virus-like particles with an average diameter of approximate <NUM>.

As HPV is difficult to be cultured in vitro and has a strong host specificity, it is difficult to be reproduced in organisms other than humans, thus there is a lack of suitable animal models. Therefore, there is a need to establish suitable and effective in vitro neutralization experimental models for the evaluation of vaccine immunoprotectivity.

HPV pseudovirus is an ideal model for HPV in vitro neutralization: Thanks to the HPV VLP's characteristic of non-specifically encapsulating nucleic acids, HPV pseudovirus can be formed from the VLPs, composed of HPV L1 and L2 expressed in cells, by encapsulating free DNA or introducing exogenous plasmid.

The immunogenicity of immunized animal serum samples was analyzed by pseudovirus neutralization assay. The animal immunized with HPV6 virus-like particles can produce neutralizing antibodies against HPV6 which can neutralize HPV6 pseudovirus. When the immunized animal serum is incubated with a certain amount of pseudovirus and then infects cells, the number of cells capable of expressing GFP fluorescence decreases when neutralization antibodies in the serum increases, showing a linear negative correlation in a certain range, so the neutralizing activity of antibodies in the serum can be evaluated by detecting the change in the number of cells expressing GFP.

Construction method of pseudovirus: The HPV6 pCMV3-<NUM>-HPV6 L1+L2 (L1 sequence was from Uniprot P69898, L2 sequence was from Uniprot Q84297) plasmid (purchased from Sino Biological) and the fluorescent plasmid (PSEU-GFP Spark, purchased from Sino Biological) were co-transfected into 293FT adherent cells (purchased from Thermo Fisher). The specific methods refer to the published literature (<NPL>. The pseudovirus supernatant was collected and aliquoted, and stored in a -<NUM> refrigerator for stock.

HPV6 L1: 33C virus-like particles were adsorpted onto aluminium phosphate adjuvant, mixed, and used to immunize mice at a dose of <NUM>µg/<NUM>µL per mouse, <NUM> mice in total. The mice were immunized with the diluted samples on Days <NUM>, <NUM> and <NUM>, with control mice immunized with blank serum. Blood was collected from the eyes of the mice on Day <NUM> and the sera were isolated for pseudovirus neutralization titers assay.

The murine serum was inactivated at <NUM> for <NUM> minutes, centrifuged at <NUM>, <NUM> mins, and the supernatant was collected for assaying. <NUM>-<NUM> hours prior to the assay, 293FT cells were inoculated at a density of <NUM>,<NUM> cells/well into <NUM>-well plates and incubated at <NUM> in a CO<NUM> incubator with <NUM>% CO<NUM>. The post-immune murine serum and blank control serum were serial diluted with neutralizing media respectively, then mixed with the HPV6 pseudovirus prepared in <NUM> at a volume ratio of <NUM>:<NUM>, incubated at <NUM>-<NUM> for <NUM> hrs. , then <NUM>µL/well of the mixture were added to 293FT cells, which had been inoculated for <NUM>-<NUM> hrs in advance. Each sample was in replicate, and blank serum control group, pseudovirus positive control group and pseudovirus negative control group were used. The cells infected by pseudovirus were incubated at <NUM> in a CO<NUM> incubator with <NUM>% CO<NUM> for <NUM>-<NUM> hrs , fluorescence scanning photographed and counted in an ELISPOT analyser (Model No.: S6 Universal-V Analyzer, Manufacturer: CTL). On the basis of the neutralization inhibition of each murine serum sample, the maximum dilution of the serum at <NUM>% neutralization inhibition was calculated for each murine serum sample according to the Reed-Muench method, i.e. the half efficacy dilution EC50.

The results of the HPV6 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV6 L1: 33C virus-like particles prepared by the present invention have good immunogenicity and can produce neutralizing antibodies with high titers in animals, which can be used to prepare into a vaccine for preventing HPV infections.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot P04012 and the L2 sequence was from Uniprot P04013.

The results of HPV11 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV11 L1: 33C virus-like particles prepared by the present invention have good immunogenicity, can produce high titers of neutralizing antibodies in animals, and can be used to prepare into a vaccine for the prevention of HPV infection.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot P03101 and the L2 sequence was from Uniprot P03107.

The results of HPV16 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV 16L1: 33C virus-like particles prepared by the present invention have good immunogenicity and can produce high titers of neutralizing antibodies in animals, which can be used to prepare into a vaccine for the prevention of HPV infection.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot Q80B70 and the L2 sequence was from Uniprot P06793.

The results of HPV18 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV18 L1: 33C virus-like particles prepared by the present invention have good immunogenicity, can produce high titers of neutralizing antibodies in animals, and can be used to prepare into a vaccine for preventing HPV infection.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot P17388 and the L2 sequence was from Uniprot P17389.

The results of HPV31 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV31 L1: 33C virus-like particles prepared by the present invention have good immunogenicity, can produce high titers of neutralizing antibodies in animals, and can be used to prepare into a vaccine for preventing HPV infection.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot P27232 and the L2 sequence was from Uniprot P27234.

The results of HPV35 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV35 L1: 33C virus-like particles prepared by the present invention have good immunogenicity, can produce high titers of neutralizing antibodies in animals, and can be used to prepare into a vaccine for preventing HPV infection.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot P24838 and the L2 sequence was from Uniprot P24839.

The results of HPV39 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV39 L1: 59C virus-like particles prepared by the present invention have good immunogenicity, can produce high titers of neutralizing antibodies in animals, and can be used to prepare into a vaccine for preventing HPV infection.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot P36741 and the L2 sequence was from Uniprot P36761.

The results of HPV45 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV45 L1: 33C virus-like particles prepared by the present invention have good immunogenicity, can produce high titers of neutralizing antibodies in animals, and can be used to prepare into a vaccine for preventing HPV infection.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot P26536 and the L2 sequence was from Uniprot P26539.

The results of HPV51 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV51 L1: 33C virus-like particles prepared by the present invention have good immunogenicity, can produce high titers of neutralizing antibodies in animals, and can be used to prepare into a vaccine for preventing HPV infection.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot Q05138 and the L2 sequence was from Uniprot F8S4U2.

The results of HPV52 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV52 L1: 33C virus-like particles prepared by the present invention have good immunogenicity, can produce high titers of neutralizing antibodies in animals, and can be used to prepare into a vaccine for preventing HPV infection.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot P36743 and the L2 sequence was from Uniprot P36765.

The results of HPV56 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV56 L1: 33C virus-like particles prepared by the present invention have good immunogenicity, can produce high titers of neutralizing antibodies in animals, and can be used to prepare into a vaccine for preventing HPV infection.

The experimental methods and procedures were the same as in Example <NUM>. The L1 sequence was from Uniprot P26535 and the L2 sequence was from Uniprot B6ZB12.

The results of HPV58 serum pseudovirus neutralization titer assay are detailed in Table <NUM>.

The above evaluation results show that the HPV58 L1: 33C virus-like particles prepared by the present invention have good immunogenicity, can produce high titers of neutralizing antibodies in animals, and can be used to prepare into a vaccine for the prevention of HPV infection.

The inventors attempted to truncate the C-terminus of HPV16L1 by <NUM> amino acids and named it HPV16L1 (<NUM>-<NUM>) (SEQ ID NO: <NUM>). However, it was found in the study that the truncated HPV16L1 (<NUM>-<NUM>) protein was highly expressed but has very poor solubility, and is difficult to extract and purify, the detailed results of expression and extraction are shown in <FIG>.

Claim 1:
A chimeric human papillomavirus (HPV) L1 protein comprising, from its N-terminus to C-terminus orientation,
a. an N-terminal fragment of an L1 protein of a first human papillomavirus type, wherein said N-terminal fragment is a fragment obtained by truncating the C-terminus of the natural sequence of said L1 protein of the first human papilloma virus type, and said N-terminal fragment maintains the immunogenicity of the L1 protein of the first human papilloma virus type, and wherein said first human papilloma virus type is selected from HPV Types <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, and said N-terminal fragment derived from said L1 protein of the first human papilloma virus type is selected from the sequence of SEQ ID No: <NUM>, SEQ ID No: <NUM>, SEQ ID No: <NUM>, SEQ ID No: <NUM>, SEQ ID No: <NUM>, SEQ ID No: <NUM>, SEQ ID No: <NUM>, SEQ ID No: <NUM>, SEQ ID No: <NUM>, SEQ ID No: <NUM>, SEQ ID No: <NUM>, and SEQ ID No: <NUM>; and
b. a C-terminal fragment of an L1 protein of a second human papillomavirus type, wherein said C-terminal fragment is a fragment obtained by truncating the N-terminus of the natural sequence of said L1 protein of the second human papilloma virus type, said L1 protein of the second human papilloma virus type has better expression level and solubility compared to the L1 proteins of other types, and said second human papilloma virus type is selected from HPV Types <NUM> and <NUM>, and said C-terminal fragment derived from L1 protein of the second human papilloma virus type is selected from the sequence of SEQ ID No: <NUM>, SEQ ID No: <NUM>, and SEQ ID No: <NUM>;
wherein the chimeric human papillomavirus L1 protein has the immunogenicity of the L1 protein of the first human papillomavirus type.