Immunoglobulin Components of "gamma" Globulin in Human Serum.

Forty blood samples were obtame(1 from 36 subjects who ranged ill age from 3 days to 43 years. All subjects were examined! on tile day blood was drawn; the health of each was noted. Each serum sample was analyzed for immunoglobulins y G, y A, aIld y M by the agar gel precipitation method described by Claman and Merrill (2). In this test, serum is layered over a column of agar containing an antiserum specific for y G, y A, or y M globulin. A precipitate forms and appears to move down through the agar. The distance traveled by tile front of tile precipitin hand in a given time is proportional to the concentration of antigen in the serum. The test is standardized with purified immunoglobulins (nitrogen concentrations determined by the micro-K jeldahl method, and multiplied by 6.25 to give protein content). Electrophoresis of each serum was done 011 paper; 0.1 ml. of serum was