Immuno (adaptive) Flashcards
Describe Class I MHC.
-presents antigens to CD8 & T cells
-Class I = nucleated cells: leukocytes, epithelial cells, mesenchymal cells
Describe Class II MHC.
-presents antigen to CD4 & T cells
-Class II = MHC expressing cells: dendritic, macrophages, B cells -> “professional antigen-presenting cells” (APCs)
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Describe the activation of naive T cells.
-dendritic cells ALWAYS
-proliferation = specific T cell
-differentiation = effector (CD4 helper or CD8) or memory T cell (CD4 or CD8)
CD4 = activates macrophages & B cells
*CD8 = macrophage activation (kills infected target cells)
What are the steps to activate a T cell?
- Immature DC encounter antigen
- Migration to lymphoid tissue & maturation
- Antigen presented by mature DC in lymph nodes
Describe the differentiation of activated T cells.
-CD4
>Th1, Th2, Th17
>express surface molecules & secrete cytokines that activate other cells
-CD8
>cytotoxic T lymphocytes (CTLs)
>kill infected cells
Describe cell-mediated immunity response.
-CD4 Th1 cells
>cytokine secretion
>activate macrophages
>activate CTLs (CD8)
-CD8 CTLs
>apoptosis
Describe humoral immunity response.
-secretion of antibodies to eliminate antigens (OR isotope switching, affinity maturation, memory B cell)
-B cells (antigen recognition not restricted by MHC presentation like T cells)
-activated by Th cells (isotope switched, high affinity antibodies = memory B cells or plasma cells) or T-independent activation (IgM, low affinity antibodies = short lived plasma cells)
Describe the immunoglobulins in a humoral response.
-IgG = secondary responses (blood & tissues) neutralization, classical pathway, neonatal immunity, opsonization for phagocytosis, cytotoxicity, feedback inhibition of B cells
-IgM = primary responses (blood) activates classical pathway
-IgA = (mucous membranes)
-IgE = (epithelial tissue) eosinophil & mast cells
-IgD = naive B cell antigen receptor
