How Vaccines Work. Jerry Sadoff MD Crucell Vaccine Institute

Transcription

1 How Vaccines Work Jerry Sadoff MD Crucell Vaccine Institute

2 Questions you will be able to answer at the end of this session How do Vaccines Work? How do we develop vaccines? How do we manufacture vaccines? What is the difference between a vaccine and an ipod?

3 Vaccines work by Fooling the Immune System into thinking the body is infected

4 We Develop vaccines by discovering a surrogate or correlate of immunity

5 We Manufacture vaccines with a vector using good manufacturing practices

6 The test at the end of the session is to answer why is a vaccine different from an ipad?

7 Fooling the Immune System

8 What Happens when we are naturally infected Its a race between the immune system and the pathogen Whoever wins lives on, Whoever loses dies or the pathogen lives comfortably in us or leaves us for another host Lives on: Herpes Zoster (Shingles), TB (latency) Moves on: Colds, Measles, Influenza

9 Tools of the Immune System: Innate Immunity Primitive system senses pathogens through Toll like receptors (Bacterial LPS, Viral RNA and DNA, Bacterial Cell Wall Peptidogycan) causing release of cytokines Whole body temperature goes up fever Crude Cells brought to the area to kill pathogen and cells macrophages and PMNS, First Line of Defense, happens early within hours to days Connects to Cognate Immunity through special cell -NK cells Basis of most of our adjuvants Measure mrna in cells to study microarray chips and sequencing

10 Tools of the Immune System: Cognate Immunity Recognizes more specific pieces of proteins, carboyhydrates, lipids of pathogens (antigens) Comes up more slowly originally Thats why it takes so long to get over an infection Part of the race Comes of fast if the antigen has been seen before Therefore the cognate immune system has MEMORY

11 Tools of the Cognate Immune System: Antibodies Antibodies are proteins with a front end and back end The front end recognizes specific structure In Proteins they recognize 7 or 8 amino acids in a string (linear structure) or a shape (nonlinear) Carbohydrades usually the linkage between sugars They arent supposed to recognize self antigens The back end activates complement or interacts with cells

12 What do antibodies do? Bind bacteria and viruses and form a big mass (agglutinate) which keeps them from doing what they want Prevent them from entering cells neutralize Enter in with them into the cell (stem binding flu) and prevent RNA entry to cytoplasm Helps cells gobble virus or bacteria through Fc receptor PMN, Macrophage, ADCC Fix complement at surface of virus or bacteria which punches a hole in membrane or helps bind to cell and gobble up through complement receptor

13 How do we make antibodies B cells floating around have antibody on their surface Recognize antigen thats there or presented to them by a macrophage Take up the antigen, chew it up and present part of it on their surface T cell recognizes the part of antigen on the surface and secretes factors that make the B cell expand Follicular Helper T cells recently discovered that are critical to turning B cell into plasma cell and for memory T cell expansion

14 How do we make better antibodies Original antibody on surface of B cell came from the germ line (our genes) As the B cell is stimulated and grows mutations to the original germ line sequence occurs The better those B cell bind to antigen those clones survive and the affinity of the antibody improves : affinity maturation (key to broadly neutralizing antibodies for HIV)

15 Tools of the Cognate Immune System: T cells T cells help make antibodies and T cells can kill pathogens inside cells They can do this because they recognize a piece of the antigen that is presented on the surface of the cell in our MHC locus They represent Memory of the immune system Two Major Types CD4 and CD8

16 CD4 and CD8 T cells CD4 T cells Helper T cells that help B cells mature and make antibody Short and long lived, long lived are memory Can also kill cells infected with pathogens CD8 T cells Recognize and kill cells infected with pathogens Get close to the cell and secreted granzyme and perfulysin that activate cells to kill pathogens

17 We Develop vaccines by discovering a surrogate or correlate of immunity

18 Surrogates or Correlates If you have this thing then you will be protected when you encounter the pathogen For vaccines it means your Cognate immune system remembers it from before and gets into the battle quickly so that it can win the race Technical terms are correlates of risk and correlates of protection

19 Types of correlates From epidemiologic observations Jenner noticed that milk maids dont get Small pox From animal models Stool isolates protected monkeys from Hep B Humans challenged with cholera, shigella. malaria From the cognate immune system Antibodies passive transfer protects animals from Tetanus, diptheria, measles T cells Old people dont make as many T cells as young in Zoster

20 Influenzal Meningitis: The Relation of Age Incidence LeRoy to D. Fothergill and Bactericidal Joyce Wright Power of J Immunol 1933; 24: Blood

21 Human Immunity to the Meningococcus: The role of Humoral Antibodies I Goldschneider, E. Gotschlich and M Artenstein, JEM:129,

22 Cellular responses to CS play an important role

23 Study Regimen performed at the WRAIR Serum for humoral responses, PBMCs for cellular responses

24 Protection After Challenge Vaccine efficacy (blood smear) Log rank test ARR vs RRR, p =.46 Vaccine efficacy (PCR) Log rank test ARR vs RRR, p =.41

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26 Anti CS antibody levels in relation to 200 protection from challenge Chart Title 180 ARR P 160 ARR np 140 RRR p Axis Title RRR np SCREENING PI(D28) PII(D56) CHAL(D0) CHAL(D28) PIII(D140) PIII(D236) Axis Title

27 34.9 CS

28 Once the surrogate or correlate is suspected or known Make vaccines that induce surrogate in animals and later humans through phase I and II trials, and then Phase IIB and Phase III where efficacy endpoints validate surrogates If dont have a proven surrogate or validated animal model such as HIV then may need Phase IIB human efficacy trials If have a high incidence of disease such as rotavirus or a human model like Malaria then immunologic surrogate may not be necessary

29 How do we know which piece of the pathogen to use to make the vaccine If the immune system is directed at that piece then should be in the vaccine in a state that induces the immune response desired Types of vaccines Whole live pathogen attenuated in some way Viruses through passage in cells or genetically Killed bacteria pertussis Toxin that has been made non toxic - Tetanus Piece of Pathogen trimeric GP160 Vectored antigen - adenovectored for cellular immunity

30 PER.C6 generate stable replication-deficient adenoviral vectors ψ Plasmid 4633 TG Second expression cassette ITR L1-L3 L4 E3 L5 5Orf6 ITR 3401 E2B E2A E4 ` Cosmid PER.C6 Ad5-E1 rad35.tg 30

31 Adenoviral Vaccine Vectors Recombinant Adenovirus particles in the nucleus of a PER.C6 cell

32 Purified Recombinant Adenovirus particles

33 BCG prime Ad35 TB heterologous prime boost induces CD8 T cells in humans Ad35.TB alone BCG prime/ad35.tb boost

34 We Manufacture vaccines with a vector using good manufacturing practices

35 Good manufacturing practices Simply means we do it in a way that it can be done over and over the same for production of millions of doses A batch record is followed strictly One person does and one person watches Quality control where every deviation is investigated All problems have a root cause determined Everything is documented

36 Manufacturing Process Upstream Fermentation of bacteria or virus Downsteam Purification of vaccine away from all contaminants Fill finish Put in a bottle or other container and label

37 Development of manufacturing process Process Development Engineering runs Actual clinical trial material production Assays In process assays To release the product and say it is what it is Potency in terms of induction of protection Animal model or induction of immunologic surrogate antigen

38 Intensified Technology Decreased production volumes, increased productivity Non-intensified technology 20K L scale Intensified technology L scale 27 g/l Sanofi and Lonza Cell growth to 5 millions cells/ml Cell growth to > 150 millions cells/ml

39 why is a vaccine different from an ipad?