Patent Application: US-11235805-A

Abstract:
the invention comprises a novel method for protecting subjects against malaria . the method of the invention involves inoculation with attenuated sporozoites , and in particular , but not limited to subcutaneous , intramuscular , intradermal , mucosal , submucosal , and cutaneous administration .

Description:
the instant invention provides a new clinically relevant and acceptable method of administering attenuated plasmodium species sporozoites that makes it practical for attenuated sporozoites to be used as a vaccine to prevent malaria in humans , mammals , avian , and other relevant species . the invention &# 39 ; s significant improvement over previously standard methods of administration , administration by intravenous injection or by the bite of infected mosquitoes , of attenuated sporozoites is that it allows for a clinically practical and safe method of administering the vaccine that provides protection comparable to the previous standard methods . administration by the bite of infected mosquitoes can never be used as a vaccine for obvious reasons , and administration by intravenous injection is a method that is not in general use for any vaccine , because it is a technically difficult method of administration , especially in young children , and it is potentially dangerous because of direct injection into the bloodstream . with the prevention , the parenteral administration maybe administered in the skin ( transcutaneous , epidermally , intradermally ), subcutaneous tissue ( subcutaneously ), muscle ( intramuscularly ), through the mucous membranes , or in the sub mucosal tissue preferably , the administration is subcutaneously , intradermally or intramuscularly . the goal of attenuation is to weaken the parasites , so that they are viable enough to invade host cells and produce new proteins , but unable to produce a replicating asexual blood stage infection that causes disease . attenuation can occur in multiple ways . for example this can occur by attenuating the parasites so that inoculated sporozoites can invade host cells , partially develop in these cells , and arrest development before reaching the stage comparable to a mature hepatic stage parasite that can rupture releasing merozoites that invade erythrocytes and cause disease . this type of attenuated parasite can be termed a metabolically active , no replicating parasite . attenuation could also occur by producing parasites that can invade and normally develop in host cells to the stage comparable to a mature hepatic stage parasite , rupture from the host cells , but be unable to develop in erythrocytes to the point required for them to cause disease . this could also occur by attenuating the parasites so that they can invade and normally develop in host cells to the stage comparable to a mature hepatic stage parasite , rupture from the host cells , but be unable to develop in erythrocytes to the point required for them to cause significant disease . this could also occur by attenuating the parasites so that sporozoites partially develop and produce new proteins , but arrest development before reaching the stage comparable to a mature hepatic stage parasite that can rupture releasing merozoites that invade erythrocytes and cause disease . while numerous methods of attenuation may be used , we have found that attenuation by irradiation is currently preferred for producing a metabolically active , no replicating parasite . attenuation of the sporozoites can be accomplished in multiple ways with multiple dosage regimens . the attenuation can be accomplished while the sporozoites are still in the mosquito , after they have been isolated from the mosquitoes and before interventions such as cryopreservation , or after they have been isolated from the mosquitoes and after interventions such as cryopreservation . the current dose of irradiation based on previous experience is generally greater than 112 , 000 rads ( cgy ) and less than 23 , 000 rads ( cgy ) for plasmodium falciparum sporozoites with 15 , 000 rads ( cgy ) being most commonly used [ 34 ]. one skilled in the art will recognize that this dosage may vary from species to species or strain to strain or with the apparatus and techniques used to irradiate the sporozoites . one skilled in the art will recognize that the irradiation can be accomplished using numerous methods , including , but not limited to gamma rays , x - rays , ultraviolet rays , or other subatomic particles such as electrons , protons , or combinations of these methods . in the future , attenuation as described in paragraph [ 39 ] above may be achieved by genetic manipulation of the parasites prior to their being introduced into the vaccine recipient . attenuation may also be achieved by treating individuals before or after exposure to sporozoites with drugs which prevent development of the parasites so that they can &# 39 ; t replicate in hepatocytes . attenuation may also be achieved by treating individuals before or after exposure to sporozoites with drugs which prevent development of the parasites so that they can &# 39 ; t replicate in erythrocytes . attenuation may also be achieved by treating the sporozoites with chemicals which attenuate the parasites . the means of administration may be any methods for inoculation other than by mosquito bite or intravenous administration , such as , but not limited to injection with a single needle and syringe , multiple needles and syringe arrays , micro - needles with one to hundreds to thousands of pores , needle less injection by ballistic techniques , and the like . the attenuated sporozoites may also be delivered by a transcutaneous patch , or on a particulate material , for example , gold beads . while it is possible to achieve a level of protection with a single inoculation , it is preferred that a series of two or more inoculations or exposures be effected . the preferred inoculants is a malaria immunization effective amount of attenuated p . falciparum or other plasmodium species sporozoites . the dosage in humans per inoculation may range from about 1 , 000 to 10 , 000 , 000 , although this may be varied depending on evaluation by the practitioner or the immunogenicity / potency of the attenuated sporozoite preparations . any plasmodium species parasite , even if altered genetically , may be used in the method of the invention . in one embodiment , the parasite is p . falciparum . in other embodiments , for example , the parasite may be p . vivax , p . ovate or p . malariae . in other embodiments it could a mixture of these parasites . in other embodiments it could be plasmodium knowlesi , p . yoelii , or other plasmodium species parasites . in one embodiment the invention provides a pharmaceutical kit comprising the attenuated sporozoites in the delivery instrument such as a syringe . in other embodiments the invention provides a kit which includes a container such as a vial , but not limited to a vial containing the frozen attenuated sporozoites , a container such as a vial containing fluid to dilute the attenuated sporozoites , and the actual delivery devices , such as a syringe and needle . in other embodiments the invention provides a kit which includes a container such as a vial , but not limited to a vial containing the freeze - dried ( lyophilized ) attenuated sporozoites , a container such as a vial containing fluid to dilute the attenuated sporozoites , and the actual delivery devices , such as a syringe and needle . in other embodiments the invention provides a kit which includes a container such as a vial , but not limited to a vial containing preserved attenuated sporozoites , a container such as a vial containing fluid to dilute the attenuated sporozoites , and the actual delivery devices , such as a syringe and needle . the invention further provides the use of parenteral administration of attenuated plasmodium species sporozoites as described herein , in the administration of a vaccine for prevention or reduction of severity of malaria . the invention provides partial , enhanced , or full protection of a human who has not previously been exposed to a malaria - causing pathogen , or has been exposed , but is not fully protected . the invention may also be used to reduce the chance of developing a malaria infection , reduce the chance of becoming ill when one ill when one is infected , reduce the severity of the illness , such as fever , when one becomes infected , reduce the concentration of parasites in the infected person , or to reduce mortality from malaria when one is exposed to malaria parasites . in many cases even partial protection is beneficial . for example , a vaccine treatment strategy that results in any of these benefits of about 30 % of a population may have a significant impact on the health of a community and of the individuals residing in the community . a vaccine is a composition of matter comprising preparations that contains an infectious agent or its components which is administered to stimulate an immune response that will protect a person from illness due to that agent . a therapeutic ( treatment ) vaccine is given after infection and is intended to reduce or arrest disease progression . a preventive ( prophylactic ) vaccine is intended to prevent initial infection . agents used in vaccines may be whole - killed ( inactive ), live - attenuated ( weakened ) or artificially manufactured . a vaccine may further comprise diluents , an adjuvant , a carrier , or combinations thereof , as would be readily understood by those in the art . a vaccine may be comprised of separate components . as used herein , separate components refer to a situation wherein the term vaccine actually comprises two discrete vaccines to be administered separately to a subject . in that sense , a vaccine - comprised of separate components maybe viewed as a kit or a package comprising separate vaccine components . for example , in the context of the instant invention , a package may comprise an attenuated sporozoite component and recombinant subunit vaccine component , including but not limited to a recombinant protein , recombinant virus , recombinant bacteria , recombinant parasite , dna vaccine , or rna vaccine . an “ effective ” immunizing dosage may range between 1000 and 10 million sporozoites , but could be lower if the immunogenicity / potency of the vaccine is increased . the vaccine may be administered on multiple occasions . an ‘ effective ’ number of inoculations may range between 1 and 6 doses within a year , and ‘ booster ’ doses in subsequent years . both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention , as claimed . moreover , the invention is not limited to the particular embodiments described , as such may , of course , vary . further , the terminology used to describe particular embodiments is not intended to be limiting , since the scope of the present invention will be limited only by its claims . with respect to ranges of values , the invention encompasses each intervening value between the upper and lower limits of the range to at least a tenth of the lower limit &# 39 ; s unit , unless the context clearly indicates otherwise . further , the invention encompasses any other stated intervening values . moreover , the invention also encompasses ranges excluding either or both of the upper and lower limits of the range , unless specifically excluded from the stated range . unless defined otherwise , the meanings of all technical and scientific terms used herein are those commonly understood by one of ordinary skill in the art to which this invention belongs . one of ordinary skill in the art will also appreciate that any methods and materials similar or equivalent to those described herein can also be used to practice or test the invention . further , all publications mentioned herein are incorporated by reference . it must be noted that , as used herein and in the appended claims , the singular forms “ a ”, “ or ”, and “ the ” include plural referents unless the context clearly dictates otherwise . thus , for example , reference to “ an attenuated sporozoite vaccine ” includes a plurality of such sporozoites and reference to “ the agent ” includes reference to one or more agents and equivalents thereof known to those skilled in the art , and so forth . further , all numbers expressing quantities of ingredients , reaction conditions , % purity , and so forth , used in the specification and claims , are modified by the term “ about ” unless otherwise indicated . accordingly , the numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties of the present invention . at the very least , and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims , each numerical parameter should at least be construed in light of the number of reported significant digits , applying ordinary rounding techniques . nonetheless , the numerical values set forth in the specific examples are reported as precisely as possible . any numerical value , however , inherently contains certain errors from the standard deviation of its experimental measurement . obviously , many modifications and variations of the present invention are possible in light of the above teachings . it is therefore to be understood that , within the scope of the appended claims , the invention many be practiced otherwise than as specifically described . the following examples further illustrate the invention . they are merely illustrative of the invention and disclose various beneficial properties of certain embodiments of the invention . these examples should not be construed as limiting the invention . a study was conducted to investigate the comparative infectivity of freshly dissected sporozoites delivered intradermally ( id ), intramuscularly ( im ), subcutaneously ( sq ) or intravenously ( iv ). it is noted that iv administration is considered to be the most reliable methods for achieving infection . methods : balb / c mice were infected with plasniodiun 7 yoelii sporozoites hand - dissected from salivary glands by id , im , sq , or iv administration . the level of infection was determined by assessing thick blood films from day 1 through day 14 after administration . the results are shown in table 1 . methods : balb / c mice infected with plasmodium yoelii sporozoites hand dissected from salivary glands by multiple routes [ intradermal ( id ), intramuscular ( im ), subcutaneous ( sq ) or intravenous ( iv )]. infection was determined by assessing thick blood films through day 14 after infection . the results are shown in table ii . table ii no . of no . of no . % group spz mice infected infected iv 100 10 10 100 20 10 9 90 4 10 3 30 id 100 10 8 80 20 10 3 30 4 10 1 10 im 100 10 7 70 20 10 3 30 4 10 1 1 sq 100 10 9 90 20 10 4 40 4 10 0 0 these data show that administration of small numbers of plasmodium yoelii sporozoites handdissected from salivary glands by the id , im , or sq routes leads to infections in mice with nearly the same efficiency as as by the iv route . since we theorize that there is a direct correlation / association between the infectivity of unirradiated sporozoites when sporozoites when administered by a particular method , and the capacity of those sporozoites when irradiated and delivered by that method to to elicit protective immunity , these data suggest that it should be feasible to successfully immunize by the id , im , and sq routes as well as by the standard iv route . protective efficacy of single dose of irradiated sporozoites administered by the intradermal , intramuscular , or intravenous routes a study was conducted to investigate the comparative protection provided by immunization with a single dose of 150 , 000 radiation attenuated sporozoites . method : balb / c mice were inoculated with a single dose of 150 , 000 radiation attenuated ( 10 , 000 rads / cgy ) p . yoelii sporozoites by the it ), im or iv routes . the sporozoites for immunization were obtained by density gradient centrifugation . the inoculated mice were challenged 10 days later by injection of 100 plasmodium yoelii sporozoites hand - dissected from salivary glands . the infections were assessed through day 14 after challenge by thick blood smear . the level of infection was evaluated on a scale of 1 + ( barely detectable ) to 4 + ( heavy infection ). the control group received no immunization inoculation . the results are shown in table iii . table iii day 14 day 4 day 4 day 5 day 5 protected / protected / level protected / level chal - group # mice challenge inf . challenge inf . lenged cont 8 0 / 8 ++++ 0 / 8 ++++ 0 / 8 iv 6 2 / 6 + 1 / 6 + 0 / 6 id 6 4 / 6 + 2 / 6 + 1 / 6 im 6 3 / 6 + 2 / 6 + 0 / 6 these data demonstrate that administration of a single dose of irradiated sporozoites by the id and im routes elicits a protective immune response that provides protection against sporozoite challenge comparable to the protection seen after administration of a single dose of irradiated sporozoites by the iv route . this finding was predicted by the infectivity demonstrated in examples 1 and 2 above . in as much as im and id methods are more easily used with large numbers of people and the administration can be carried out with much greater safety and ease than by iv administration , the present invention makes possible the effective immunization of significant populations with attenuated sporozoites in a manner more facile than heretofore demonstrated . in fact it makes it possible to conceive of for the first time a practical attenuated sporozoite vaccine . administration of the single dose of irradiated sporozoites led to a dramatic reduction of parasite burden in the the mice that were challenged , an effect thought by many malaria vaccinologists to potentially be adequate to significantly reduce morbidity and mortality of malaria in recipients . however , it did not completely protect against infection . protective efficacy of three doses of irradiated sporozoites administered by the subcutaneous or intravenous routes a study was conducted to investigate the comparative protection provided by immunization with a standard regimen of three doses of radiation attenuated plasmodium yoelii sporozoites by the id or iv routes ; a regimen expected to elicit complete protection against sporozoite challenge . method : balb / c mice were inoculated with a first dose of 50 , 000 radiation attenuated ( 10 , 000 rads / cgy ) plasmodium yoelii sporozoites by the sq or iv routes . the mice received two booster doses of 30 , 000 irradiated sporozoites ( total of 110 , 000 sporozoites divided into 3 doses ). the sporozoites for immunization were obtained by density gradient centrifugation . the inoculated mice were challenged 14 days after last booster dose with 100 plasmodium yoelii sporozoites hand - dissected from salivary glands . the infections were assessed through day 14 after challenge by thick blood smear . infection was assessed a present absent . the results are shown in table iv . table iv day 14 day 14 group no . mice prot / chal % protected control 8 0 / 8 0 iv 7 7 / 7 100 % sq 8 8 / 8 100 % the data in table iv clearly demonstrate that one can achieve 100 % protection against infection by subcutaneous administration of sporozoites ( sq ). these results were predicted by the results of studies shown in example 1 , example 2 , and example 3 , but for the first time ever demonstrated in this experiment . given the comparability in infectivity by the sq , id , and im routes ( example 2 ), it seems obvious that administration of sporozoites by those routes would provide comparable protection . the 100 % protection reported in example 4 stands in stark contrast to the 0 % protection with subcutaneous immunization of a / j mice with radiation attenuated p . berghei sporozoites reported previously [ 21 ]. as stated above we believe that our discovery was made possible by our recognition that the p . yoelii - balb / c model is more relevant to p . falciparum in humans , than is the p . berghei - a / j mouse model system . infectivity of sporozoites isolated by density gradient centrifugation as compared to by hand dissection of salivary glands when administered by the intravenous route in examples 3 and 4 , the mice were immunized by administration of if radiated sporozoites that had been isolated by density gradient centrifugation . it had been our assumption that sporozoites isolated by density gradient centrifugation of the head and thorax of the mosquitoes are less infective than are sporozoites hand - dissected from salivary glands . if that is the case , and there is a direct association between the infectivity of sporozoites and their capacity to elicit protective immunity as stated above ( paragraph [ 068 ]), then it should require far fewer sporozoites hand - dissected from salivary glands than sporozoites isolated by density gradient centrifugation to achieve protective immunity . the inventors therefore first conducted an experiment comparing the infectivity of p . yoelii sporozoites isolated by density gradient centrifugation to those isolated by hand dissection of salivary glands . method : p . yoelii sporozoites were isolated from anopheles stephensi mosquitoes by density gradient centrifugation or by hand dissection of salivary glands . balb / c mice were inoculated by intravenous injection with differing numbers of sporozoites . the infections were , assessed through day 14 after challenge by thick blood smear . infection was assessed as present or absent . the results are shown in table v . table v sporozoites isolated by hand dissection or density gradient centrifugation number of sporozoites number infected / number infected / number number challenged challenged density gradient injected hand dissection centrifugation 625 10 / 10 7 / 10 125 10 / 10 4 / 10 25 5 / 10 0 / 10 5 5 / 10 0 / 10 1 0 / 9 0 / 10 50 % infectious dose ( id 50 ) 4 . 9 433 the data in table v clearly demonstrate that sporozoites hand - dissected from salivary glands are more infective than are sporozoites isolated by density gradient centrifugation . the 50 % infectious dose is more than 80 times greater for sporozoites isolated by density gradient centrifugation . if the hypothesis is correct that the protective efficacy of a lot of attenuated sporozoites is directly associated with the infectivity of the lot of sporozoites before they were attenuated , then these data would indicate that the numbers of attenuated sporozoites required to achieve protection would be substantially less for sporozoites isolated by hand - dissection of salivary glands as compared to sporozoites isolated by density gradient centrifugation . which has been the standard way of isolating sporozoites for immunization studies in the p . yoelii - balb / e model system . protective efficacy of sporozoites isolated by density gradient centrifugation as compared to by hand dissection when administered by the intravenous route based on the results of the infectivity experiment in example 5 , a protective efficacy experiment was designed . the protective efficacy of a regimen of irradiated sporozoites isolated by density gradient centrifugation which was known based on previous experience to give 90 % protection was compared to the capacity of much lower doses of irradiated sporozoites isolated by hand dissection of salivary to achieve protective immunity . method : anopheles stephensi mosquitoes infected with p . yoelii sporozoites were irradiated with 10 , 000 rads / cgy . sporozoites were isolated by density gradient centrifugation or by hand dissection of salivary glands . balb / c mice were inoculated by intravenous injection of three doses of irradiated p . yoelii sporozoites at 2 week intervals . group i received irradiated sporozoites isolated by density gradient centrifugation ( 24 , 000 , 8 , 000 , and 8 , 000 for first , second , and third doses respectively ). groups 2 - 5 received sporozoites isolated by hand dissection of salivary glands . group 6 received no immunizations . the mice in groups 1 - 6 were challenged with 100 p . yoelii sporozoites isolated by hand - dissection of salivary glands 14 days after the third immunizing dose . the infections were assessed through day 14 after challenge by thick blood smear . infection was assessed as present or absent . the results are shown in table vi . table vi group # mice # infected % protected density gradient 9 1 88 . 8 % centrifugation 24000 , 8000 , 8000 ( 1 ) hand - dissected 10 0 100 % 18000 , 6000 , 6000 ( 2 ) hand - dissected 10 0 100 % 9000 , 3000 , 3000 ( 3 ) hand - dissected 10 0 100 % 4500 , 4500 , 4500 ( 4 ) hand - dissected 10 0 100 % 4500 , 1500 , 1500 ( 5 ) control - non - 10 10 0 % immunized mice ( 6 ) these data also support the hypothesis that the p . yoelii - balb / c model system more closely predicts what occurs in humans with p . falciparum than does the p . berghei - a / j mouse model system , in part because of the much higher infectivity of sporozoites in the p . yoelii system . humans can be fully immunized by the bite of 1000 irradiated , p . falciparum infected mosquitoes [ 34 ]. it is thought that a mosquito inoculates no more than 10 sporozoites when it feeds [ 51 ]. if that is the case , then fully immunized and protected humans are probably inoculated with only 10 , 000 sporozoites [ 50 ]. in contrast , in the p . berghei - a / j mouse model system greater than 100 , 000 sporozoites isolated from hand - dissected salivary glands were used to achieve protection by intravenous administration , and this immunizing dosage regimen provided no protection when administered subcutaneously [ 21 ]. in example 6 it is demonstrated that administration to balb / c mice of 7500 p . yoelii sporozoites isolated by hand dissection of salivary glands provided 100 % protection . the fact that balb / c mice immunized with attenuated p . yoelii sporozoites and humans immunized with attenuated p . falciparum sporozoites are protected after exposure to similar numbers of attenuated sporozoites , and a / j mice immunized with p . berghei sporozoites are immunized with more than 10 times the quantity of sporozoites , supports our hypothesis that the p . yoelii - balb / c model will be more predictive of what will occur in humans than the p . berghei a / j model system . the process of developing an effective , sustainable vaccine against infections like p . falciparum have proven to be slower , more difficult and complex than expected . there is no licensed malaria vaccine , but it is now known that immunization with radiation attenuated p . falciparum sporozoites by the bite of greater than a 1000 infected mosquitoes provides sterile protective immunity in greater than 90 % of immunized individuals for at least 10 . 5 months against multiple isolates of p . falciparum from throughout the world . one of the major obstacles to making this immunization regimen into a vaccine for humans has been the fact that it is not possible to provide a regulated vaccine to large numbers of individuals by the bite of infected mosquitoes . furthermore , work by a number of scientists indicated that excellent protection could only be achieved in the mouse model system by intravenous administration of attenuated sporozoites , a method of administration that is not in general used for vaccination , because it is technically difficult and potentially more dangerous than are standard methods of administration . because methods of administration conventionally used in humans for immunization like subcutaneous and intramuscular inoculation did not lead to adequate protective immunity in this mouse model system , it was heretofore not considered possible to develop an attenuated sporozoite vaccine for humans . utilizing a different model system than that used by previous investigators , we have discovered a method of administering sporozoites that leads to high level protection and is practical , safe , and accepted . this discovery should facilitate utilization of this method of administering attenuated sporozoites to develop and provide a practical , mass delivered attenuated sporozoite malaria vaccine . the following publications as well as those mentioned any where else in this application , are hereby specifically incorporated by reference . 1 . breman j g . ears of the hippopotamus : manifestations , determinants , and estimates of the malaria burden . am j trop med hyg 2001 ; 64 : 1 - 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3 , 1980 28 . hilleman m r . yeast recombinant hepatitis b vaccine . infection 15 ( 1 ): 3 - 7 , 1987 . 29 . ballou w r , hoffman s l , sherwood j a , hollingdale m r , neva f a , hockmeyer w t , gordon d m . safety and efficacy of a recombinant dna plasmodium falciparum sporozoite vaccine . lancet 1 ( 8545 ): 1277 - 81 , 1987 . 30 . herrington d a , clyde d f , losonsky g , cortesia m , murphy j r , davis j bager s felix a m . safety and immunogenicity in man of a synthetic peptide malaria vaccine against plasmodium falciparum sporozoites . nature 328 ( 6127 )- 257 - 9 , 1987 . 31 . nussenzweig v , nussenzweig r s . rationale for the development of an engineered sporozoite malaria vaccine . adv immunol 45 : 283 - 334 , 1989 . 32 . hoffman s l , franke e d , hollingdale m r , druilhe p . attacking the infected hepatocytes . in : hoffman s l , ed malaria vaccine development : a multi - immune response approach . washington , d . c . : asm press , pp . 35 - 75 , 1996 . 33 . hoffman s l , miller l h . perspectives on malaria vaccine development . in : hoffman s l , ed . malaria vaccine development : a multi - 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immunized volunteers recognize polymorphic sequences of the circumsporozoite protein . j immunol 151 : 489 - 99 , 1993 . 49 . butler d . mosquito production mooted as fast track to malaria vaccine . nature 435 : 437 , 2003 . 50 . luke t c , hoffman s l . rationale and plans for developing a non - replicating , metabolically active radiation attenuated plasmodium falciparum sporozoite vaccine . journal of experimental biology 206 : 3803 - 3808 , 2003 . 51 . beier , j c ., et al . quantitation of plasmodium falciparum sporozoites transmitted in vitro by experimentally infected anopheles gambiae and anopheles stephensi . am j trop med hyg 44 ( 5 ): 564 - 70 , 1991 . other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein . it is intended that the specification and examples be considered as exemplary only , with a true scope and spirit of the invention being indicated by the following claims .