ABSITE Review - Immunology Flashcards
What interleukins are released by Helper T cells (CD4)?
IL-2 and IL-4
What is the function of IL-2?
Causes B-cell maturation into plasma cells
Converts lymphocytes to LAK cells by enhacing their immune response to tumor
What is the function of IL-4?
Causes maturation of cytotoxic T cells
What cytokines are released by Th1 helper T cells and which proccess are they involved?
Predominant release of pro-inflammatory cytokines (IL-2, INF-gamma)
Involved in cell-mediated responses
What cytokines are released by Th2 helper T cells and which proccess are they involved?
Predominant release of anti-inflammatory cytokines (IL-4 –> inhibits macrophages)
Involved in atopy and allergic responses
What is the function of Suppressor T cells (CD8)?
Regulate CD4 and CD8 cells
What is the function of Cytotoxic T cells (CD8)?
Recognize and attack non-self antigens attached to MHC class I receptors
Mention the letters for MHC class I and their function.
A, B and C
CD8 cell activation, single chain with 5 domains and target for cytotoxic T cells
Mention the letters for MHC class II and their function.
DR, DP and DQ
CD4 cell activation, 2 chains with 4 domains each, activator for helper T cells and stimulate antibody formation
Which MHC class is present on all nucleated cells?
MHC class I
Which MHC class is present on B cells, dendrites, monocytes and APCs?
MHC class II
What is the usual immunologic response to a viral infection?
Endogenous viral proteins produce are bound to class I MHC, go to cell surface and are recognized by CD8 cytotoxic T cells.
What is the usual immunologic response to a bacterial infection?
Endocytosis –> proteins get bound to class II MHC –> go to cell surface and are recognized by CD4 helper T cells –> B cells are activated and then produced the antibody to that antigen transforming to plasma and memory B cells
Which cells are part of the body’s natural immunosurveillance for cancer?
Natural Killer cells which usually recognize cells that lack self-MHC
Which is the largest antibody with 5 domains?
IgM
Which is the most abundant antibody in the body?
IgG - can cross placenta and provides protection in newborn period
Which is the antibody found in secretions, Peyer’s patches in gut and in breast milk?
IgA - helps prevent microbial adherence and invasion in gut
Which antibody is membrane-bound receptor on B cells?
IgD
Which antibody is involved in allergic reactions and parasite infections?
IgE
Which antibodies are opsonins and fix complement?
IgM and IgG
Which region of the antibody perform antigen recognition?
Variable region
Which region of the antibody recognized PMNs and macrophages?
Constant region
What is the major source of histamine in blood?
Basophils
What is the major source of histamine in tissue?
Mast cells
What are the three primary lymphoid organs?
Liver, bone, thymus
What are the two secondary lymphoid organs?
Spleen and Lymph nodes
What are the indications for tetanus in non-tetanus prone wounds?
Give tetanus toxoid only if patient has received < 3 doses or tetanus status unknown
What is a tetanus prone wound?
> 6 hours old; obvious contamination and devitalized tissue; crush, burn, frostbite or missile injuries
What are the indications for tetanus in tetanus prone wounds?
Always give tetanus toxoid unless patient has had >3 doses and it has been <5 years since last booster
What are the indication for tetanus immune globulin?
Give only to patient with tetanus-prone wounds who have not been immunized or if immunization status unknown
