Phagocyte B cells B Cell Receptor Nave B cell B cells and antibodies B cell attaches to antigen cloning of daughter cells daughter cells produce antibodies
Antibodies neutralise antibodies phagocyte consumes an antibody coated virus Cytotoxic CD8 cells CD8 cells can recognise markers on the outside of infected cells CD8 destroys infected cell which stops cell from producing more virus or bacteria
Antigen presenting cells These cells can engulf invading organisms Antigens presente d to CD4 cells The foreign organism is broken up into smaller CD4 cell Analogy for the immune system
Nave and Memory B cells Nave B cell Once activated it divides many times making two types of clones The plasma cell which makes and releases large amounts of the appropriate antibody The memory B cell which can live for years
Memory B cells The existence of memory B cells means that the body can respond much more quickly CD4 and CD8 Cluster of Differentiation CD4 cells
Th1 (humoral response) Th2 (cell mediated response) Th0 (??) CD8 cells Molecules on the surface of the cells that help the T cell attach to the antigen Cytotoxic lymphocytes (CTL) CD45RA Nave cells CD45RO Memory cells
CD4 count viral load over time Viral Load CD4 Count Set Point Levels in the Bloo Below the limit of the test Seroconversion Asymptomatic Symptomatic
HIV virion Fatty (lipid bilayer) membrane Glycoprotein gp120 Protein p18 Protein p24 Reverse transcriptase enzyme Vaccine - Ideal characteristics
Prevent transmission by mucosa & injecting Excellent safety profile Single dose administration Offers protection for a long time Low cost Stability and ease of administration Works against a wide range of different strains Immune system responses
Humoral response Cell-mediated response Based on cytotoxic CD8 cells Mucosal immunity Based on antibodies and the B cells that
produce them The above but concentrated in the mucosal membranes where most transmission occurs Current trend is to aim to stimulate a sufficient HIV-specific CTL response to control or prevent HIV infection Types of vaccine Live attenuated vaccines
Defective or weakened form of the virus Previous example original smallpox vaccine, vaccinia Research in monkeys indicates may slowly lead to immune disease Inactivated or 'killed' vaccines Recombinant sub-unit envelope vaccines Recombinant vectored vaccines DNA vaccines and replicons Combination vaccines or prime and boost Types of vaccine
Live attenuated vaccines Inactivated or 'killed' vaccines Second classic technique (e.g. Dr Jonas Salk in creating the world's first successful polio vaccine) No-one has yet claimed any significant success Maybe difficult to distinguish between vaccine immune response and infection
Recombinant sub-unit envelope vaccines Recombinant vectored vaccines DNA vaccines and replicons Combination vaccines or prime and boost Types of vaccine Live attenuated vaccines Inactivated or 'killed' vaccines Recombinant sub-unit envelope vaccines
Seek to stimulate antibodies to HIV by mimicking proteins on the surface of HIV (e.g. gp120) Initial research was strain-specific and produced poor antibody responses Recently more hope Recombinant vectored vaccines DNA vaccines and replicons Combination vaccines or prime and boost Types of vaccine
Live attenuated vaccines Inactivated or 'killed' vaccines Recombinant sub-unit envelope vaccines Recombinant vectored vaccines incorporate harmless bits of HIV into established vaccines ALVAC series of vaccines are canarypox based vaccines Vaccine strains of adenovirus recombinant rabies virus vaccines
DNA vaccines and replicons Combination vaccines or prime and boost Types of vaccine Live attenuated vaccines Inactivated or 'killed' vaccines Recombinant sub-unit envelope vaccines Recombinant vectored vaccines DNA vaccines and replicons
involve HIV genetic sequences which, once injected, induce expression of HIV antigens by human cells. In the case of replicons, these sequences are wrapped in the outer coat of an unrelated virus. Combination vaccines or prime and boost
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