K.C.S.E Biology Q & A - MODEL 2012PP2QN08
Using a relevant example, describe how an allergic reaction occurs in a human being.
An allergic reaction is a hypersensitive response; to an antigen by the body immune
system; The body immune system responds by overproducing antibodies; against
harmless antigens; The antigen-antibody reaction occurs on the surface of body cells;
which burst open; and release histamines; Histamines cause inflammation/itching!
swelling/pain, et.c; which damage the body; Allergic people are hypersensitive to
materials like dust/pollen grains/some foods/some drugs/some pollutants,