Immune response

Immune response is the immunological response originating from immune system activation by antigens, including immunity to pathogenic microorganisms and its products, as well as autoimmunity to self-antigens allergies, and graft ejections. In this process main cells involved are the T cells, B cells of lymphocytes, and macrophagea. These cells produce lymphokines that influence the other host cells activities. B cells mature to produce immunoglobulins or antibodies, that react with antigens. At the same time, macrophages are processing the antigens into immunogenic units which stimulate B lymphocites to differentiation into antibody secreting plasma cells, stimulating the T cells to realise lymphokines.

Complement is a group of normal serum proteins to aim immunity by becoming activated form as result of antigen-antibody interaction. The first contact with any antigen sensitize individual affected and promote the primary immune response. Next of the sensitized individuals with same antigen result in a more rapid and massive reaction, called the secondary immune response ("booster response" or the "anamnestic reaction"). It is most expressed in the level of circulating serum antibodies.

An anamnestic response in medicine is a delayed immunologic response. The term is frequently used in transfusion medicine and refers to a re-exposure incident where antibody is formed on initial exposure to an antigen in a transfused unit, but the specific memory B cell population fades over time, with antibody becoming undetectable over years. If a patient is re-exposed to the same offending antigen in a future transfusion (which might happen because the antibody screen would in fact be negative), there would still be a massive, rapid production of IgG antibody against the antigen, which will predictably lyse the transfused red cells, a delayed hemolytic transfusion reaction.

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