Biological roles of rodent anaphylactic IgG1 antibodies.

Described and mainly studied in guinea-pigs and mice (Benacerraf, Ovary, Bloch and Franklin, 1963; Fahey, Wunderlich and Mishell, 1964) (but also demonstrated in rats and hamsters, and others), IgG1 immunoglobulins are a fascinating class of antibodies. Long known for their anaphylactic properties, they have now been also studied in our laboratory for their cooperative, protective and immunoregulatory properties. Like other immunoglobulin classes of antibody, their biological activity is exerted through their Fc portion and expressed only after the immunoglobulin has been activated by fixation on corresponding antigen through their Fab portions. My purpose is to present a summary of the work done in our laboratory on the biological role of IgG1 antibodies. This presentation will be divided into 3 parts respectively concerned with their inflammatory properties in specific hypersensitivity reactions such as anaphylaxis and Arthus, their protective action (as a final result) of the antigen-bearing target in the facilitation reaction, and finally the relations (and common denominator) between the two types of properties.