Immune Response Humoral Immune Response – Activation of B-Cells to produce antibodies Cell-mediated Immune Response – Activation of cytotoxic T-Cells

Active vs Passive Immunity Active immunity… via natural exposure – Relies on active production of antibodies through a pathway of steps – Can be induced through vaccination Passive immunity… transferring antibodies from one individual to another – Mother to fetus (IgG antibodies) – Mother to infant (IgA antibodies)

Humoral Immune Response Helper T-Cell – Stimulated by the excretion of cytokines by dendritic cells Recognizes the MHC 2 site and stimulates B- Cells and Cytotoxic Ts – CD4 site binds to MHC site – Entry point for HIV – Makes clones – Produces cytokines to activate immune system – Activates Cell- mediated response

Humoral Immune Response B-Cells – Activated by the helper Ts Releases cytokines to activate Bs – Recognize surface proteins and polysaccharides for antigens (pollen, venom, pet dander, …) Allergies or hypersensitivities – Strong reaction leads to anaphylactic shock » Over exaggerated response by mast cells cause acute drop in blood pressure and swelling Weaker response that T activated response – Produce antibodies and numerous clones

Cell-mediated Response Cytotoxic T-Cells activated by the helper T- Cells search out MHC 1 sites on infected cells – Bound by the CD8 surface protein Converts the cell to an active killer – Destroys the cell and searches for others Certain viruses and cancers mutate MHC 1 sites to evade the killers

Recognition of Self All cells produce surface proteins – Somatic cells proteins are recognized as self Called self-tolerance – A person with A blood type recognizes their own blood antigens as self but B surface antigens as foreign » They are similar to B surface antigens found on many common bacteria » Monitored by IgM antibodies… primary response – Rh factor is a surface antibody that produces a secondary response » Produces IgA antibodies from B-Cells – MHC sites No 2 people have the identical MHC site – Causes tissue rejection in transplantation – Recipient and donor must be close… medication is then given to suppress the secondary response

Autoimmune disease Body loses the ability of self recognition and attacks self – Lupus – Adult onset diabetes

Immunodeficiency – Inborn… genetic syndromes hallmarked by the inability to generate antibodies – Acquired… Stress HIV – Creates loss of helper Ts through entry of CD4 site with presence of a secondary co-receptor (fusin) which is a chemokine found on the surface of healthy cells » Retro virus… RNA and reverse transcriptase Makes DNA which is integrated and the lytic cycle begins