THE EFFICIENCY OF VACCINE REASERCH TRANSLATION INTO CLINICAL APPLICATION WILL ULTIMATELY DEPEND UPON HOW APPROPRIATE THE ANIMAL MODEL IS USED

ANIMAL MODELS IN VACCINE Jenner, 1798, exposure to cattle Pasteur, Anthrax and rabies Chicken cholera …old stock in lab, no virulent VLps Papilloma viruses, first from bovine, canine, and rabbit…than in human

(A)Model for HOST PATHOGEN interactions 1.Analysis of disease pathogenesis, route of infection and transmission of disease 2.Study disease pathogenesis 3.Analysis of virulence factors and their role in invasion 4.Penetration 5.Identification of pathogen molecules required for infection, Than can be targeted as vaccines or drugs 1. viral surface glycoprotein's 2.Bacterial type III secretions…??? 6.Functions of host genes in context of natural infections (A)Model for HOST PATHOGEN interactions 1.Analysis of disease pathogenesis, route of infection and transmission of disease 2.Study disease pathogenesis 3.Analysis of virulence factors and their role in invasion 4.Penetration 5.Identification of pathogen molecules required for infection, Than can be targeted as vaccines or drugs 1. viral surface glycoprotein's 2.Bacterial type III secretions…??? 6.Functions of host genes in context of natural infections Applications for animal models in human vaccine development

1.Animal models can also serve to analyze specific aspects of the immune response, 2.Host immune response to pathogen the development of immune organs, the role of specific immune compartments or individual cell populations, the trafficking of immune cells following infection or vaccination, Induction of mucosal versus systemic immunity 1.Animal models can also serve to analyze specific aspects of the immune response, 2.Host immune response to pathogen the development of immune organs, the role of specific immune compartments or individual cell populations, the trafficking of immune cells following infection or vaccination, Induction of mucosal versus systemic immunity (b) HOST IMMUNE RESPONSE

Development of novel strategies for vaccine delivery including mucosal or topical application formulation, adjuvants, stabalizers Assessment of onset and duration of vaccine-induced immunity Reduction of clinical symptoms and disease transmission following infection Development of novel vaccination concepts such as in utero or maternal immunization Development of novel strategies for vaccine delivery including mucosal or topical application formulation, adjuvants, stabalizers Assessment of onset and duration of vaccine-induced immunity Reduction of clinical symptoms and disease transmission following infection Development of novel vaccination concepts such as in utero or maternal immunization animal models allow analysis of herd immunity following vaccination, transmission amongst infected and noninfected animals, studying transfer of passive immunity via the placenta, colostrum and milk animal models allow analysis of herd immunity following vaccination, transmission amongst infected and noninfected animals, studying transfer of passive immunity via the placenta, colostrum and milk © Vaccine perspective

Vaccine parameters requiring animal models. Duration of immunity Mucosal vaccination Maternal vaccination Neonatal vaccination Novel vaccine technologies Onset of immunity Therapeutic vaccines for noninfectious diseases Vaccination of the elderly Vaccine safety Vaccine parameters requiring animal models. Duration of immunity Mucosal vaccination Maternal vaccination Neonatal vaccination Novel vaccine technologies Onset of immunity Therapeutic vaccines for noninfectious diseases Vaccination of the elderly Vaccine safety

only in experimental conditions High infectivity doses Artificial routes of infection Surrogate animal models mostly mice Consistent genetic background Easy to handle Cost effective Knockouts/ conditional knockouts of MHC, TLr cyto and chemokines etc,B and T cell deficient mice,Very helpful in vaccine development The ability to adoptively transfer normal or genetically modified cells from one mouse to another helps to see immune response of vaccine and transplants mostly mice Consistent genetic background Easy to handle Cost effective Knockouts/ conditional knockouts of MHC, TLr cyto and chemokines etc,B and T cell deficient mice,Very helpful in vaccine development The ability to adoptively transfer normal or genetically modified cells from one mouse to another helps to see immune response of vaccine and transplants

This is especially important since many disease models in mice utilize artificial routes of challenge. In large animals, however, it is often possible to use the natural route of challenge therefore obtain more relevant correlates of Immune mediated protection Horses as model: Maternal immunization, Passive immunity, Adjuvants response etc Horses as model: Maternal immunization, Passive immunity, Adjuvants response etc

HOST SPECIFICITY: Receptor unavailability at natural routes of infection Listeria monocytogenes kill mice after intravenous challenge but not following oral delivery which is natural Citrobactor rodentium for enterohemorrhagic e coli is natural model Pneumovirus of mice similar to RSV (resp synctial virus), BSV is also similar For Nasal vaccines cows pigs etc as model rather than mice.. HOST SPECIFICITY: Receptor unavailability at natural routes of infection Listeria monocytogenes kill mice after intravenous challenge but not following oral delivery which is natural Citrobactor rodentium for enterohemorrhagic e coli is natural model Pneumovirus of mice similar to RSV (resp synctial virus), BSV is also similar For Nasal vaccines cows pigs etc as model rather than mice.. LIMITATIONS

THE DOSE OF INFECTION: More passages can lead to attenuation and higher dose requirement TRANSMISSION MODE: Natural shed by body fluid, feces insect bites we can do aerosolization, but less effective Challenge by exposing to infected animal …but gives variable results thus require large animals for statistical evidences of efficacy THE DOSE OF INFECTION: More passages can lead to attenuation and higher dose requirement TRANSMISSION MODE: Natural shed by body fluid, feces insect bites we can do aerosolization, but less effective Challenge by exposing to infected animal …but gives variable results thus require large animals for statistical evidences of efficacy

Host –Relevant human physiology e.g pig for skin …mucosal deliver of vaccines…. In mice develops after birth… Ethical use of animals in vaccine testing requires the closest specie requirement… –– Similar lifespan and duration of neonatal, adolescent and adult period – Receptors – Route of transmission – Duration of immune memory --Transport of antibodies across the mucosal surfaces (surface IgA) – Transfer of passive immunity via the placenta, colostrum and milk Pathogen – Similar genetic and antigenic characteristics – Similarity in virulence and pathogenesis – Similar route of entry of the pathogen in animal model – Similarity in replication and spread of the pathogen Host –Relevant human physiology e.g pig for skin …mucosal deliver of vaccines…. In mice develops after birth… Ethical use of animals in vaccine testing requires the closest specie requirement… –– Similar lifespan and duration of neonatal, adolescent and adult period – Receptors – Route of transmission – Duration of immune memory --Transport of antibodies across the mucosal surfaces (surface IgA) – Transfer of passive immunity via the placenta, colostrum and milk Pathogen – Similar genetic and antigenic characteristics – Similarity in virulence and pathogenesis – Similar route of entry of the pathogen in animal model – Similarity in replication and spread of the pathogen CRITERIA TO CONSIDER WHEN USING ANIMAL MODELS FOR VACCINE DEVELOPMENT

1.WNV ….outbreak in north America resulted in rapid approval of horse vaccines 2.Wildlife vaccination to reduce rabies 3.Food safety vaccines against ecoli 1.WNV ….outbreak in north America resulted in rapid approval of horse vaccines 2.Wildlife vaccination to reduce rabies 3.Food safety vaccines against ecoli VACCINATION OF ANIMALS IN ZOONOTIC INFECTIONS

Ensuring vaccine safety without compromising its efficacy This requires: Onset And duration of immune mediated disease PROTECTION and MEMORY after 1.Single dose 2.Both in neonates and elderly For this large animal models Ensuring vaccine safety without compromising its efficacy This requires: Onset And duration of immune mediated disease PROTECTION and MEMORY after 1.Single dose 2.Both in neonates and elderly For this large animal models Strategic use of vaccine

Pigtail macaques, Macaca nemestrinaChimps, Pan troglodytes, 1. susceptible to experimental infections with HIV 2. low levels of persistent virus but do not develop clinical manifestations of AIDS. Animal Model for HIV study

15 SIV/SHIV macaque model for AIDS Most suitable animal model Monkey species used (Asian macaques only): –Rhesus macaque (Macaca mulatta) Indian origin (export ban in India; major breeding colonies in the US) from China (imported from various breeding farms) –Cynomolgus macaque (Macaca fascicularis) from the Philippines, Mauritius, Israel, China –Pig-tailed macaque (Macaca nemestrina), only very few breeding colonies

SIV-infected Rhesus Macaques - most accepted model of HIV infection in humans Genetic proximity of humans to macaques Genetic proximity of HIV to SIV Similar receptor usage for viral entry (CD4, CCR5) A marked decline in the number of CD4+ T cells Similar clinical manifestation as in HIV-infection. Variability of disease course and viral load is similar 16 Rhsus macaquues, Macac mulatta

Depletion of CD4+ cells; particularly massive and rapid loss of memory T-cells in gut upon infection with SIVmac Opportunistic infections Neurological diseases Malignancies Depletion of CD4+ cells; particularly massive and rapid loss of memory T-cells in gut upon infection with SIVmac Opportunistic infections Neurological diseases Malignancies

HIV-infected humans:  5% Rapid progressors, progress to AIDS within 1year after infection  80% Normal progressors, within 8 years  5-8% of individuals remain infected for years, without therapy, no clinical symptoms of AIDS, called long-term non progressors (LTNPs) HIV/SIV disease course Viral load of SIV-infected macaques 18 Rapid Progressors Progressors LTNPs (6 months) (2 years) (8 years or >)