Microbiology 9th Edition by Laura Black, Jacquelyn Black

Exercise 35

Which of the following describes Type I immediate hyper sensitivity?
(a) After initial sensitization to antigen, subsequent ex posure to the sensitizing antigen results in formation of antigen-IgG antibody complexes. These immune complexes deposit in tissues where they activate complement.
(b) Specific antibodies react with host cell surface antigens interpreted as foreign by the immune system, lead ing to phagocytosis, killer cell activity, or complement mediated lysis. Typical sources of such antigens come from mismatched blood transfusions or Rh incompat ibility between infant and mother.
(c) This reaction is delayed and mediated by sensitized TH1 cells that release cytokines responsible for the hyper sensitivity reaction.
(d) Sensitization to allergen causes B cell activation result ing in production of anti-allergen IgE antibodies that at tach to mast cells and basophils. Subsequent exposure to that allergen causes cross-linking of IgE antibodies resulting in deregulation of chemicals that induce aller gic responses
(e) Both a and c.