This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: 11/6/11 1 CMI Involves 1. cell mediated cytotoxicity (CD8+ T cells) 2. delayed type hypersensitivity (TDTH) 3. the production of CAF A CD8+ response that bridges Innate and Cell Mediated immunity Cell Mediated Immunity Attacks infected body cells (HIV- infected cells, OI-infected cells) Attacks foreign tissues (Host v graft disease) Attacks altered cells (cancerous cells HIV is a promoter of certain cancers) Involves T cells which mature in the thymus gland. Defects in the thymus result in problems with cell mediated immunity. Cell Mediated Immune System (CMI) Involves T Lymphocytes Often involves 2 steps Activation of a T-helper cell (TH1 subset) Followed by Activation of another cell of CMI (ex. CD8+ T cell) Effector cells are in close contact to the cells they are trying to destroy Humoral Response Activated cells (plasma cells) produce antibody Activated cells = T helper cells Immune system coordination; Destruction of infected/affected APCs Destroys altered self cells (viral infected cells, cancer cells) and transplanted tissue Activated cells are cytotoxic, called CTL Types of Cells in CMI Specific Cells CD4+ T-lymphocytes important for activation of CMI CD8+ T-lymphocytes effector cells Other cells macrophages neutrophils natural killer cells eosinophils 11/6/11 2 Cell Mediated Immunity Two Types of T lymphocytes CD4 cells usually T helper (T H ) T H 1 - activates CD8+ cells T DTH (a TH1 cell) (cytokines activate phagocytic cells, destroy intracellular bacteria/fungi) recognize Ag with class II MHC Cytokines IL-2 IFN- TNF- Biological Activity M activation delayed-type hypersensitivity Tc Activation Combats intracellular parasites, viruses and tumor cells Cytokines IL-4 IL-5 IL-6 IL-10 IL-13 Biological Activity B cell activation allergic reactions Combats extracellular organisms T H 1 subset T H 2 subset Cell Mediated Immunity Two Types of T lymphocytes CD8+ cells T cytotoxic cells (CTLs) CTLs kill altered self cells such as virally infected cells and tumor cells and cause rejection of foreign grafts Recognize Ag in class I MHC CD8 protein binds class I MHC Cell Mediated Immunity CD8+ T cells Combating Endogenous Infected cells Cell Mediated Immunity Features of T-cytotoxic cells (CTLs) A TH1 response CD8 Cells (CD8+ T-Lymphocytes) recognize antigen with Class I MHC generally do not secrete many cytokines generally have cytotoxic activity in close proximity to altered self cell destroy altered self cells intracellular parasites-virally infected cells tumor cells destroy grafted cells Antigen + class I MHC (endogenous antigen) Organism (virus) infects self cell Reproduces in cell Proteins broken down Associated with MHC 1 Expressed on cell CD8/CTLs recognize altered self cell CD8/CTLs kill altered self cell 11/6/11...
View Full Document
- Fall '11
- cells, Cytotoxic Cells, MØ