ANTI-FELINE HERPESVIRUS-1 RECOMBINANT ANTIBODY AND GENE FRAGMENT CODING FOR SAID ANTIBODY

Abstract: An anti-feline herpesvirus-1 recombinant antibody which is efficacious in treating, preventing and diagnosing feline herpesvirus-1 (FHV-1) infection, and a gene fragment useful for the preparation of the antibody. A gene fragment coding for the antibody V region bearing an FHV-1 specific avidity of a mouse monoclonal antibody having an excellent activity of neutralizing FHV-1 is obtained by constructing cells which produce the antibody. A chimeric anti-FHV-1 recombinant antibody is prepared from the above gene fragment and another gene fragment coding for a feline antibody C region.

Description: Technical Field The present invention relates to a novel feline monoclonal antibody for use in the diagnosis, treatment and prevention of feline herpes virus-1 (FHV-1) infection. More particularly, the invention relates to a felinized anti-FHV-1 recombinant antibody wherein a constant region of a mouse-type -FHV-1-neutralizing monoclonal antibody is replaced with a feline antibody constant region, and a gene fragment encoding said antibody. Background Art A cat is an animal that has been loved by humans as a pet from ancient times and, in modern times, called as Companion species, is becoming a member of a human society. On the other hand, cats have hitherto greatly contributed to humans as an experimental animal in various fields such as medicine, pharmaceutics, animal husbandry veterinary and psychology, and in recent years, the contribution of cats has further increased by the use of SPF Cats in an effectiveness assay or safety test for drugs. In any case, as a matter of course, more reliable knowledge on feline diseases, especially on infectious diseases, is increasingly needed and the establishment of methods for the diagnosis, treatment and prevention of these diseases are required. Many viral diseases of cats are known. Among them, an upper tracheal disease caused by FHV-1 is acute and shows a high lethality. For this disease, there is no specific treating drug but only a symptomatic treatment for preventing a secondary infection by the use of antibiotics, sulfonamide drugs, etc., and hence, there remains a problem in a conventional method for treatment. Hitherto, a hyperimmune serum or a serum-derived immunoglobulin have been used as a medicament for the treatment of viral diseases and have shown satisfactory results. Nowadays, however, feline serum materials are hardly available due to promotion of Be-Kind-to-Animals thought, and hence, we are in a situation that this treating method cannot be used in spite of desire to use this method. Accordingly, in place of the conventional hyperimmune serum, a monoclonal antibody X capable of neutralizing FHV-1 will possibly greatly contribute to the treatment of FHV-1 infection. Prior Art There have been established several neutralizing monoclonal antibodies against FHV-1. However, all the monoclonal antibodies established hitherto are antibodies derived from a mouse hybridoma. When these antibodies are administered to a cat as a medicament, since they are a heterologous protein, they will show weaker binding capacity to complement or immunocompetent cells having an Fc receptor present in blood than that of homo species (cat) and appear to hardly induce cell damage by "antibody + complement" or antibody-dependent cellular cytotoxicity, cell-mediated cell damage. It is known that, in addition to the action of an antibody alone, these two immune reactions are also important for prevention of FHV-1 infection and for neutralization of virus (Horimoto T. et al., Jpn. J. Vet. Sci. 51, p1025, 1989). Therefore, it is possible that the conventional mouse antibodies cannot exhibit efficacious results in a treatment. Furthermore, it is also possible that the mouse antibodies recognized as a heterologous protein cause side effects such as anaphylactic shock or serum diseases or show a shortened half-life, resulting in a decreased efficacy in treatment. Accordingly, when administered, the conventional mouse monoclonal antibodies have never been satisfactory but a felinized monoclonal antibody should have been used. Disclosure of the Invention The present inventors have established a mouse monoclonal antibody, JH2, which neutralizes a FHV-1 viral strain, have identified the nucleotide sequence of a gene encoding a variable region (V region) of said antibody, and have found a specific amino acid sequence in the V region of said antibody which is deeply involved in the neutralization of FHV-1. Then, in order to felinize this mouse type monoclonal antibody, the present inventors have constructed a vector expressing an anti-FHV-1 chimeric antibody having an FHV-1 neutralizing activity by ligating the antibody V region gene coding for the -FHV-1 neutralizing antibody with a gene fragment coding for a constant region of a feline antibody which the present inventors have previously found EP 0 417 986 A1. The inventors have expressed said vector, and have successfully obtained the anti-FHV-1 chimeric antibody. Therefore, an object of the present invention is to provide an anti-FHV-1 felinized chimeric antibody which has hitherto never been reported and is prepared by utilizing a genetic engineering technique by replacing the constant region of the mouse-type antibody with a constant region of a feline antibody, and to provide a gene fragment coding for said antibody useful for production of the same. Thus, now it becomes possible to apply an anti-FHV-1 antibody as diagnostic, treating and preventing agent which is effective against FHV-1 infection without side effects. Brief Explanation of the Drawings Figure 1 illustrates the results of an agarose gel electrophoresis of the VH and Vκ genes of the anti-FHV-1 antibody JH2 amplified by PCR. Figure 2 shows the nucleotide sequence of the VH gene obtained in Example (3) and the amino acid sequence encoded by said gene. Figure 3 shows the nucleotide sequence of the Vκ gene obtained in Example (4) and the amino acid sequence encoded by said gene. Figure 4 shows the results of a homologous comparison of the VH region between JH2 and other antibodies at the amino acid level. Figure 5 shows the results of a homologous comparison of the Vκ region between JH2 and other antibodies at the amino acid level. Figure 6 shows a restriction enzyme map of a vector expressing the H chain of an anti-FHV-1 chimeric antibody. Figure 7 shows a restriction enzyme map of a vector expressing the L chain of an anti-FHV-1 chimeric antibody. Figure 8 shows the reactivity of the chimeric antibody of the present invention with an anti-feline antibody. Figure 9 shows the binding of the chimeric antibody of the present invention to FHV-1. Figure 10 shows the effectiveness of the chimeric antibody of the present invention for cats compulsorily infected with FHV-1 K1 strain. Figure 11 shows the effectiveness of the chimeric antibody of the present invention for SPF cats compulsorily infected with FHV-1 K1 strain. Best Mode for Practicing the Invention First, the present inventors have conducted a cell fusion between lymphocytes of mice immunized with FHV-1-K1 viral particles and mouse myeloma cells in accordance with the conventional manner to prepare hybridomas. As a result of the cloning regarding the virus-neutralizing activity in the culture supernatant of hybridomas, the present inventors have successfully established an antibody-producing cell, JH2, which produces a monoclonal antibody being quite excellent in FHV-1 neutralizing activity. It is generally known that the specificity of an antibody against an antigen is based on amino acids in the variable (V) region of an antibody. Thus, the present inventors have studied the amino acids which constitute the V region of JH2. The amino acid sequence was determined by cloning a gene coding for the V region of said antibody and studying the nucleotide sequence thereof. As a result, the V region was found to have the amino acid sequence as shown in Figs. 3 and 4. Generally, there exist about 200 VH, about 10 D, and 4 JH genes in an H chain gene region of an antibody. On the other hand, there are about 200 Vκ, and 4 Jκ genes in an L(κ) chain gene region. It is known that, with differentiation of B cells, each one gene is selected from these V(D)J gene fragments and rearranged to form a gene coding for an amino acid sequence of a whole variable region. The addition of a N sequence and somatic mutations give a great number of varieties of an antibody variable region. The variable region gene of JH2 of the present invention is a unique one selected among such varieties. The CDR shown in the Figures is an important region for binding with an antigen. Also in case of JH2, it appears that the amino acid sequence of these six CDR regions binds with FHV to induce a neutralizing reaction. Especially, "Asp Gly Ala Trp Phe Pro Phe" in the H chain CDR3 was found to be an unique amino acid sequence by a homologous comparison with variable regions of other antibodies. Accordingly, the amino acids of the H chain CDR3 as well as other CDR regions of the H and L chains are considered to be closely related to the binding and neutralizing reactions with FHV-1. This has been firstly revealed by isolating the variable region gene of the JH2 antibody. Determination of the nucleotide sequence and the amino acid sequence of the JH2 antibody further enables, based on these sequences, enhancement of an antigen-binding activity and felinization of the V region itself. An antibody or a peptide having such amino acid sequence is conjectured to be useful for the treatment, diagnosis and prevention of FHV-1 infection. That is, the gene fragment coding for the V region of the antibody having a neutralizing activity against FHV-1 as provided according to the present invention has the following characteristics. In the gene fragment coding for VH or a part thereof of the antibody which specifically reacts with feline herpes virus-1 (FHV-1) the nucleotide sequence coding for CDR3 of said antibody is coding for the following amino acid sequence: A prefered gene fragment of VH having a nucleotide sequence coding for such sequence includes a gene fragment wherein the nucleotide sequences coding for CDRs 1 to 3 of said antibody are coding for the following amino acid sequences: Furthermore, by way of example, a prefered sequence of the above VH gene fragment includes a nucleotide sequence coding for the amino acid sequence described in Sequence Listing as SEQ ID NO:1, preferably amino acid positions 20 to 143 of SEQ ID NO1. A specific nucleotide sequence includes, for example, the nucleotide sequence described in the Sequence Listing as SEQ ID NO:1. On the other hand, a gene fragment coding for VL or a part thereof of the antibody which specifically reacts with feline herpes virus-1 (FHV-1) includes a gene fragment wherein the nucleotide sequences coding for CDRs 1 to 3 of said antibody are coding for the following amino acid sequences: Furthermore, by way of example, a prefered sequence of the above VL gene fragment includes a nucleotide sequence coding for the amino acid sequence described in the Sequence Listing as SEQ ID NO:2, preferably amino acid positions 21 to 127 of SEQ ID NO:2. A specific nucleotide sequence includes, for example, the nucleotide sequence described in the Sequence Listing as SEQ ID NO:2. In the meanwhile, it appears to be difficult to administer directly to cats the mouse-type antibody JH2 for treatment of FHV-1 infection in view of reduction of efficacy, side effects, shortened half-life, etc. This is because the antibody itself is a protein heterologous to cats derived from mice, and hence, one can foresee that said antibody cannot possibly bind to complement or immunocompetent cells having Fc receptor of cats, and as a result, ADCC or CDC is hardly inducible. As mentioned above, considering that these activities greatly contribute to the virus-neutralization in FHV infection, the antibody needs to have an Fc region derived from cats. Furthermore, if the antibody exhibits immunogenicity as a heterogenous protein within the living body, it is possibly cleared away quickly from the living body, which shortens the half-life or it may provoke side effects such as a serum disease. It is said that the immunogenicity of an antibody molecule is localized in the Fc region. In this sense, the Fc region preferably has an amino acid sequence of an antibody molecule derived from cats as a homologous protein. Now, the present inventors have successfully prepared a felinized JH2 antibody by replacing the constant region of the JH2 antibody with that derived from cats using genetic engineering techniques. Such a felinized antibody, i.e. an anti-FHV-1 chimeric antibody, can be prepared by ligating the feline antibody constant region gene; CH gene and CL gene to the downstream (3' site) of the above-mentioned gene coding for VH of the anti-FHV-1 antibody and the VL gene provided by the present invention to construct a structural gene of the antibody's H chain and L chain coding for said felinized antibody, i.e. felinized chimeric antibody, and expressing said structural gene in a suitable animal cell. The gene coding for such feline antibody constant region has previously been found by the present inventors (Japanese Patent First Publication No. 3-123488, Japanese Patent First Publication No. 3-201986 and Japanese Patent First Publication No. 3-72873). A nucleotide sequence of the gene coding for such feline antibody constant region includes, as a gene fragment coding for CH, that of a gene fragment coding for the amino acid sequence described in the Sequence Listing as SEQ ID NO:3. A specific nucleotide sequence of said gene includes the nucleotide sequence described in the Sequence Listing as SEQ ID NO:3. A nucleotide sequence of a gene coding for Cκ, includes that of a gene fragment coding for the amino acid sequence described in the Sequence Listing as SEQ ID NO:4. A specific nucleotide sequence of said gene includes the nucleotide sequence described in the Sequence Listing as SEQ ID NO:4. A nucleotide sequence of a gene coding for Cλ, a of said gene includes that of a gene fragment coding for the amino acid sequence described in the Sequence Listing as SEQ ID NO:5. A specific nucleotide sequence of said gene includes the nucleotide sequence described in the Sequence Listing as SEQ ID NO:5. The gene fragment coding for the V region of the antibody having a neutralizing activity against FHV-1 of the present invention, in addition to the production of the chimeric antibody comprising the mouse-derived V region and the cat-derived C region as mentioned above, can also be used for preparing a reshaped antibody in which a frame (FR) region of the V region is also replaced with that derived from an antibody of animals other than mice (in case of the present invention, derived from a feline antibody). There has not yet been reported a complete amino acid sequence of a general V region FR region of a feline antibody. However, a part of such sequence has already been reported (KEHO J.M. et al., Proc. N.A.S. 69, p2052, 1972). Based on these and the amino acid sequence of the constant region of feline antibody which the present inventors have previously found, it will be possible to prepare a suitable primer, to clone a gene coding for a feline antibody V region and to determine the amino acid sequence of said FR region. A reshaped antibody can be prepared basically in accordance with known techniques (for example, Japanese Patent First Publication No. 62-296890). The gene fragment of the present invention used therefor contains, as a part of a gene coding for the VH chain and the VL chain, at least a nucleotide sequence coding for the following amino acid sequence: Preferably, nucleic acid sequences coding for CDRs in the V region of said reshaped antibody are coding for the following amino acid sequences of the VH chain and VL chain, respectively: In addition, the present inventors have further found previously that, in preparing the reshaped antibody as mentioned above, an antibody having the excellent specificity of an original mouse monoclonal antibody can sometimes be prepared by replacing a portion of the FR region of the V region adjacent to the CDRs with that derived from mice in addition to replacement of CDRs in the V region with those derived from mice rather than replacement of CDRs alone in the V region with those derived from mice in accordance with conventional techniques. That is, by replacing a portion of the FR region of the V region as well with that derived from mice, where by reference is made to the amino acid sequence described in Fig. 2 for the VH chain and the amino acid sequence described in Fig. 3 for the VL chain, a reshaped antibody can possibly be prepared which is more excellent than the reshaped antibody in which only CDRs are replaced with those derived from mice. As mentioned above, the structural gene coding for the felinized anti-FHV-1 recombinant antibody (so called chimeric antibody) is prepared by constructing a V region structural gene for a chimeric antibody or a reshaped antibody by the use of the gene coding for the variable region of the anti-FHV-1 antibody of the present invention and ligating this structural gene with the gene coding for the constant region of feline antibody which the present inventors have previously found. The recombinant antibody of the present invention obtained by ligating this structural gene to the downstream of a suitable promotor sequence and expressing the resulting gene in an animal cell in accordance with known techniques retained an excellent neutralizing activity like the mouse-type antibody JH2. When administered to FHV-infected cats, the recombinant antibody of the present invention alleviated the disease state without any significant side effect. E. A. Emini et al. have studied the preventive effect of a monoclonal antibody against HIV infection in chimpanzees. As a result, it was found that a humanized chimeric antibody could prevent HIV infection (E. A. Emini et al., Nature, 355, p728, 1992) but the original mouse-type antibody could not (E. A. Emini et al., J. Virol., 64, p3674, 1990). It appears that this is because the latter could not induce Fc region-dependent ADCC or CDC activities and showed a shortened half-life. As for the effectiveness of FH2 antibody in FHV-infected cats found by the present inventors, it appears that the mouse-type antibody has a weak effect but the effect can be exerted only by the felinized antibody like in the above-mentioned previous case. Thus, the anti-FHV-1 chimeric antibody FH2 of the present invention can be used as a substantial medicament for the treatment and prevention of FHV-1 infection. The present invention is explained in more detail by means of the following Examples. Examples (1) Production of hybridoma cells producing FVH-1-neutralizing monoclonal antibody A culture supernatant of FL cells (feline lung cells) infected with FHV-1 was precipitated with ammonium sulfate. After dialysis, the precipitate was resuspended in phosphate buffer and administered peritoneally to a BALB/c mouse for immunization together with Freund's complete adjuvant. After two weeks, mouse lymphocytes and mouse myeloma cells (P3U1) were fused by the polyethylene glycol method to prepare hybridomas. Cloning was conducted regarding the virus neutralizing activity of culture supernatants of the hydridomas and thereby four FHV-1 neutralizing monoclonal antibody producing cells were established. The following Table 1 shows the minimum effective concentration of each monoclonal antibody necessary for neutralizing 10 TCID 50 of FHV-1. Among these monoclonal antibodies, JH2 antibody most strongly neutralized the FHV-1-K1 strain. Antibody Class Minimum effective concentration for neutralization (µg/ml) JH2 γ1,κ 0.39 JH3 γ1,κ 6.3 JH4 γ1,κ 100 JH7 γ2a,κ 6.3 (2) Isolation of the variable region gene of anti-FHV-1 antibody (JH2) Whole RNA was extracted from 1 to 0.5 x 10 7 cells (hybridomas) and purified with an oligo dT column (manufactured by Stratagene, Poly(A) Quick mRNA Purification Kit). A single-stranded cDNA was synthesized with reverse transcriptase (Takara; all reagents used for genetic engineering were those manufactured by Takara unless otherwise mentioned). Oligonucleotides as 5' primers and as 3' primers at the J region (MHJ3, MKJ124) at the leader region (MHL34, MKL104) were synthesized. The nucleotide sequences of these primers are as follows: To 20 ng of cDNA were added each 50 pmol of primers. PCR (Polymerase Chain Reaction) was conducted for 30 cycles, each cycle comprising 94°C for 1 minute, 55°C for 1 minute and 72°C for 1 minute, to amplify the variable region gene (VH, Vκ) flanked by both primers. Fig. 1 shows an agarose electrophoresis pattern of the amplified gene fragments. The size of the VH (H chain) and Vκ (L chain) genes was about 400 bp and about 400 bp, respectively, and virtually corresponded to the bands as expected. (3) Determination of the nucleotide sequence The nucleotide sequence of each gene fragment amplified in (2) was determined by the dideoxy method. The VH and Vκ gene fragments were cloned into pUC18 and the nucleotide sequences thereof was determined by the dideoxy method using Sequenase ver. 2 (manufactured by USB.). Fig. 2 shows the nucleotide sequence of the VH gene of the JH2 antibody and the amino acid sequence encoded by said gene. This gene had an open reading frame (ORF) and preserved Cys for forming a domain structure, and hence, was found to be suitable for expression. It was also found that rearrangement occurred at JH3. Then, a homology comparison was conducted for the amino acid sequence coded by this gene using GENETYX-CD (Software) as software and the data base of Gene Bank. As a result, antibodies 1 to 4 belonging to the VHIII/J606 family were found to have highly homologous VH sequences (Fig. 4). In Fig. 4, the mark (*) shows an amino acid homologous to that of other VHs and the unmarked region represents an amino acid sequence found only in JH2. Especially, the underlined portion represents a novel amino acid sequence which has hitherto never been reported and is characteristic for the JH2 antibody. Fig. 3 shows a nucleotide sequence of the Vκ gene of the JH2 antibody and the amino acid sequence encoded by said gene. Like in the case of the H chain, this gene had an ORF and preserved Cys for forming a domain structure, and hence, was found to be suitable for expression. It was also found that a rearrangement occurred at Jκ1. Fig. 5 shows the results of a homology comparison. Vκ of JH2 also showed homology with other Vκ. That is, it appeared that the underlined portion in the VH chain is specific for the JH2 antibody and is an important amino acid sequence responsible for the antigen binding activity. (4) Preparation of the anti-FHV-1 chimeric antibody genes The variable region genes amplified by PCR were ligated to the gene coding for the γ chain constant region of feline antibody CB25γ (Japanese Patent First Publication No. 3-201986) or to the gene coding for the κ chain constant region of feline antibody CEK (Japanese Patent First Publication No. 3-123488). The chicken β-actin promoter (Japanese Patent Application No. 1-309785) was used as expression promoter and the neo (Southern P.J. J. Mol. Appl. Genet., 1, 327, 1982) or dhfr gene (Stark, G. R. and Wahl, G. M., Annu. Rev. Biochem., 53, p447, 1984) as selection markers. Fig. 6 and Fig. 7 show restriction enzyme maps of the chimeric antibody H chain and L chain expression vectors prepared, respectively. (5) Preparation of stable transformants Each 10 µg of the gene coding for the chimeric antibody H chain and L(κ) chain as shown in Fig. 6 and Fig. 7 were digested with PvuI and 2 x 10 6 mouse myeloma cells P3-X63-Ag8-6.5.3 (ATCC CRL1580) were co-transfected with the digested products by using lipofectin (manufactured by BRL). The transfected cells were cultured in 5% FCS/RPMI1640 selection medium containing 0.25 x 10 -7 M methotrexate (MTX) to select drug-resistant strains (transformants). Chimeric antibody producing cells were cloned by a limiting dilution method regarding the feline IgG expressed in culture supernatant to establish an expression cell, FH2. The properties of this cell were analyzed as follows. (6) Reaction with anti-feline antibody Culture supernatants of FH2 (chimeric antibody expressing cell) and of JH2 (mouse monoclonal antibody expressing cell) were added to a microtiter plate immobilized with an anti-feline antibody (E.Y.LABS.INC) and the reaction was conducted at room temperature for 1 hour. After washing the plate, HRP-anti-feline antibody (E.Y.LABS.INC) was reacted at room temperature for 1 hour. After washing the plate again, color was developed with TMBZ and an absorbance at 450 nm was measured to analyze the reactivity with the anti-feline antibody (Fig. 8). The culture supernatant of FH2 reacted with the anti-feline antibody in a concentration-dependent manner whereas the culture supernatant of JH2 which expresses the mouse antibody did not react with the anti-feline antibody. This revealed that the chimeric antibody expressed by FE2 cells is a feline antibody. (7) Identification of chimeric antibody by SDS-PAGE The chimeric antibody was purified from the culture supernatant with Protein A (manufactured by Bio Rad, MAPS-II). The purified chimeric antibody was subjected to 12.5% SDS-PAGE and compared with a feline IgG sample (polyclonal antibody). The molecular weight of the purified antibody was determined with a prestained marker manufactured by Bio Rad. The chimeric antibody displayed bands at 5 x 10 4 for the H chain and at 2.5 x 10 4 for the L chain under reducing conditions and a band at around 1.5 x 10 5 under non-reducing conditions. This revealed that the H and L chains form a dimer of H2L2 which has the same form as that of IgG present in the cat body. (8) Reaction with FHV-1 viral particle Then, an antigen binding activity of the chimeric antibody was studied. The culture supernatant (from FH2 and JH2) was added to a microtiter plate immobilized with FHV-1-K1 (crude product obtained by ammonium sulfate precipitation). After washing the plate, it was reacted with either HRP-anti-feline antibody or HRP-anti-mouse antibody. Color was developed with TMBZ and the reactivity with FHV-1 viral particle was studied. Like the mouse antibody JH2, FE2 antibody specifically reacted with FHV-1-K1. However, the recombinant chimeric antibodies specific for other viruses (antibodies having the same feline constant region and different mouse variable regions) did not react (Fig. 9). (9) Neutralization test against FHV-1 virus Then, the neutralization activity against FHV-1 of the chimeric antibody was studied. The culture supernatant (from FH2 and JH2) was reacted with 100 TCID 50 of FHV-1 virus at 4°C for 6 hours. Thereto were added 0.25 x 10 5 CRFK cells and cultured at 37°C for 2 days. CPE (Cell Rounding) was observed and a minimum effective concentration for neutralization was determined. The results are summarized in the following Table 2. As a result, it was confirmed that FH2 antibody neutralizes FHV-1 at 1.95 µg/ml. Antibody Minimum Effective Concentration for Neutralization (µg/ml) Chimeric antibody (FH2) 1.95 Mouse antibody (JH2) 1.25 (10) Effectiveness and safety of FH2 in cats compulsorily infected with FHV Cats weighing 1.5 to 3.0 Kg were compulsorily infected with 10 4 TCID 50 of FHV-1-K1 strain through the nose. At the second day, 30 and 10 mg/Kg of FH2 was administered via the jugular vein. General clinical conditions such as weight, temperature, the amount of taking meals, the amount of drinking water and spirits, and respiratory lesions such as tears, conjunctivitis, rhinorrhea, sneeze and cough were observed with the lapse of time and scored as 0 for no symptom, 1 for light symptom, 2 for moderate symptom and 3 for severe symptom. As a result, both groups administered with 10 and 30 mg/kg alleviated the symptoms (Fig. 10). Then, SPF cats weighing 1.4 to 2.3 kg were compulsorily infected with 10 4 TCID 50 of FHV-1-K1 strain. At the second day, 30 and 10 mg/kg of FH2 were administered via the jugular vein and the clinical conditions were observed. As a result, the onset of the symptoms were inhibited in the group administered with FH2 (Fig. 11). This showed the in vivo usefulness of FH2 against FHV infection. In addition, after administration of FH2, no side effects such as diarrhea, vomiting or another shock-like symptom was observed, and hence, the safety of FH2 was confirmed. Based on the above described results, the FH2 antibody can be applied as diagnostic, treating and preventing agent effective against FHV-1 infection with no side effects. Industrial Applicability of the Invention The feline monoclonal antibody of the present invention is effective against feline herpes virus-1 infection and is applicable as diagnostic, treating and preventing agent against said disease. Sequence Listing SEQ ID NO: 1 SEQUENCE LENGTH: 429 SEQUENCE TYPE: nucleic acid STRANDEDNESS: double TOPOLOGY: linear NOLECULE TYPE: cDNA to mRNA FEATURE ORIGINAL SOURCE ORGANISM: mouse SEQUENCE SEQ ID NO: 2 SEQUENCE LENGTH: 381 SEQUENCE TYPE: nucleic acid STRANDEDNESS: double TOPOLOGY: linear NOLECULE TYPE: cDNA to mRNA FEATURE ORIGINAL SOURCE ORGANISM: mouse SEQUENCE SEQ ID NO: 3 SEQUENCE LENGTH: 1005 SEQUENCE TYPE: nucleic acid STRANDEDNESS: double TOPOLOGY: linear NOLECULE TYPE: cDNA to mRNA FEATURE ORIGINAL SOURCE ORGANISM: cat SEQUENCE SEQ ID NO: 4 SEQUENCE LENGTH: 337 SEQUENCE TYPE: nucleic acid STRANDEDNESS: double TOPOLOGY: linear NOLECULE TYPE: genomic DNA FEATURE ORIGINAL SOURCE ORGANISM: cat SEQUENCE SEQ ID NO: 5 SEQUENCE LENGTH: 318 SEQUENCE TYPE: nucleic acid STRANDEDNESS: double TOPOLOGY: linear NOLECULE TYPE: cDNA to mRNA FEATURE ORIGINAL SOURCE ORGANISM: cat SEQUENCE

Claims: A recombinant antibody prepared by a genetic engineering technique which specifically reacts with feline herpes virus-1 (FHV-1), wherein a part of the amino acid sequence of the complementarity determining region 3 (CDR3) of VH has the following amino acid sequence: The antibody of claim 1 wherein CDRs in said VH and VL have the following amino acid sequences: The antibody of claim 1 wherein said VH and VL have the amino acid sequences of amino acid positions from 20th to 143rd in SEQUENCE LISTING: SEQ ID NO:1 and of amino acid positions from 21st to 127th in SEQ ID NO:2, respectively. The antibody of claim 1 wherein the amino acid sequence of the constant region of said antibody is that derived from a feline antibody. The antibody of claim 4 wherein the amino acid sequence of the H chain constant region of said antibody is that described in SEQUENCE LISTING: SEQ ID NO:3 and the amino acid sequence of the L chain constant region of said antibody is that described in SEQUENCE LISTING: SEQ ID NO:4 or in SEQUENCE LISTING: SEQ ID NO:5. A gene fragment coding for VH or a part thereof of an antibody which specifically reacts with feline (FHV-1) in which a part of the nucleotide sequence coding for CDR3 is a nucleotide sequence coding for the following amino acid sequence: The gene fragment of claim 6 wherein the nucleotide sequences coding for CDRs 1 to 3 are nucleotide sequences coding for the following amino acid sequences, respectively: The gene fragment of claim 6 wherein the nucleotide sequence coding for VH of the antibody is a nucleotide sequence coding for the amino acid sequence described in SEQUENCE LISTING: SEQ ID NO:1. The gene fragment of claim 6 wherein the nucleotide sequence coding for VH of the antibody is the nucleotide sequence described in SEQUENCE LISTING: SEQ ID NO:1. A gene fragment coding for VL of the antibody wherein the nucleotide sequences coding for CDRs 1 to 3 are nucleotide sequences coding for the following amino acid sequences, respectively: The gene fragment of claim 10 wherein the nucleotide sequence coding for VL of the antibody is a nucleotide sequence coding for the amino acid sequence described in SEQUENCE LISTING: SEQ ID NO:2. The gene fragment of claim 10 wherein the nucleotide sequence coding for VL of the antibody is the nucleotide sequence described in SEQUENCE LISTING: SEQ ID NO:2. A recombinant gene fragment coding for H chain of a feline chimeric antibody which specifically reacts with feline herpes virus-1 (FHV-1), said gene fragment comprising the gene fragment of claim 6 to the downstream (3' site) of which a gene fragment coding for H chain constant region of a feline antibody is bound. The recombinant gene fragment of claim 13 wherein said gene fragment coding for H chain constant region of a feline antibody has a nucleotide sequence coding for the amino acid sequence described in SEQUENCE LISTING: SEQ ID NO:3. A recombinant gene fragment coding for L chain of a feline chimeric antibody which specifically reacts with feline herpes virus-1 (FHV-1), said gene fragment comprising the gene fragment of claim 10 to the downstream (3' site) of which a gene fragment coding for κ chain constant region of a feline antibody is bound. The recombinant gene fragment of claim 15 wherein said gene fragment coding for κ chain constant region of a feline antibody has a nucleotide sequence coding for the amino acid sequence described in SEQUENCE LISTING: SEQ ID NO:4. A recombinant gene fragment coding for L chain of a feline chimeric antibody which specifically reacts with feline herpes virus-1 (FHV-1), said gene fragment comprising the gene fragment of claim 10 to the downstream (3' site) of which a gene fragment coding for λ chain constant region of a feline antibody is bound. The recombinant gene fragment of claim 17 wherein said gene fragment coding for λ chain constant region of a feline antibody has a nucleotide sequence coding for the amino acid sequence described in SEQUENCE LISTING: SEQ ID NO:5. An antibody according to any one of claims 1 to 5 for use as an active therapeutic substance. The use of an antibody according to any one of claims 1 to 5 for the preparation of a composition for diagnostic or treatment of feline herpes virus-1 (FHV-1) infections. The use of a gene fragment according to any one of claims 6 to 18 for the preparation of monoclonal antibodies which specifically reacts with feline herpes virus-1 (FHV-1).

Inventors: KIMACHI KAZUHIKO, MAEDA HIROAKI, NISHIYAMA KIYOTO, TOKIYOSHI SACHIO, KIMACHI, KAZUHIKO, MAEDA, HIROAKI, NISHIYAMA, KIYOTO, TOKIYOSHI, SACHIO
Applicants: JURIDICAL FOUNDATION
Application year: 1993
Main classification: C12P21
IPC codes: C12P21, C07K16, A61P31, C12N15, A61K38, C07K14, A61K39, C12R1