Chapter 4 - Immunology Flashcards
What is IL-4? what does it do?
Released by CD4 helper T. causes B-cell maturation into plasma cells
What is IL-2? what does it do?
Released by CD4 helper T. causes maturation of cytotoxic T cells.. Involved in delayed hypersensitivity. (brings in inflammatory cells by chemokine secretion)
What do Th1 helper T-cells do? examples?
predominant release of proinflammatory cytokines (IL-2, INF-gamma). Cell mediated responses
What do Th2 helper T-cells do? examples?
predominant release of anti-inflammatory cytokines (IL-4–> inhibits macrophages). Atopy and allergic responses.
What do Suppressor T cells (CD8) cells do?
regulate CD4 and CD8 cells
What to cytotoxic T cells (CD8) do?
recognize and attack non-self antigens attached to MHC- class 1 receptors (eg viral gene products)
What does an intradermal skin test look for?
cell-mediated immunity
What types of infections are associated with defects in cell-mediated immunity?
intracellular pathogens (TB, viruses)
What effect can nucleotides have on the immune response?
increase T-cell mediated immunity
What is the first step in T-cell and B-cell activation?
alloantigen binds to antigen specific receptors: TCR (t-cells) or surface IgM (B-cells).
What is the second step or costimulatory signal required for T-cell and B-cell activation?
IL-1 released by antigen presenting cell. CD-41 helper T-cells release IL-2, IL-4, and IL-5 which provide help for CD81 T cells and for B-cell activation
What does IL-4 from helper T-cells do?
stimulates B-cells to become plasma cells
What does MHC class I (A, B, and C) do? Where is it present? Structural makeup? What is it a target for?
CD8 cell activation. Its present on all nucleated cells. It is a single chain with 5 domains. Its a target for cytotoxic T-cells
What does MHC class II (DR, DP, and DQ) do? where is it located? structural makeup?
CD4 cell activation. Present on B-cells, dendrites, monocytes, and antigen presenting cells. 2 chains with 4 domains each. Activator for helper T-cells. Stimulates antibody formation.
How are viral infections recognized by immune system?
Endogenous viral proteins are produced, bound to class I MHC, go to cell surface, recognized by CD8 cytotoxic T-cells
How are bacterial infections recognized by immune system?
endocytosis, proteins bound to class II MHC molecules, go to cell surface, recognized by CD4 helper T cells–> B cells already bound to antigen are then activated by CD4 helper T-cells. They then produce the antibody to that antigen and are transformed to plamsa cells and memory B-cells
Do natural killer cells require MHC?
Do not require MHC, previous exposure, or antigen presentation. Not considered T or B. recognize lack of self MHC. Cancer surveillance
What is IgM?
Initial ab made after exposure to antigen. Largest Ab. 5 domains, 10 binding sites
What is IgG?
Most abundant antibody in the body. responsible for secondary immune response. Can cross placenta- protection in newborn period.
What is IgA?
found in secretions. Peyers patches in gut - prevents microbial adherence and invasion in gut; and in breast milk- additional immunity in newborn
What is IgD?
membrane-bound receptor on B-cells (antigen receptor)
what is IgE?
allergic reactions, parasite reactions
what antibodies are opsonins?
IgM and IgG. Fix complement. 2 IgG’s or 1 IgM
What does the variable region in an antibody do?
antigen recognition
