Physico-Chemical and Immunologic Studies on Macroglobulins1

Normal sera are resolved in the ultracentrifuge into two major peaks with sedimentation constants of the order of 4.5 and 6.5 S 2 and a minor peak of heavy materials, amounting to less than 3 per cent of the total proteins, with a sedimentation con- stant of about 20 S.In 1944, Waldenstrdm (1) reported the presence of a large amount of fast sedimenting moieties (19 to 20 S) in sera of some patients with marked hyperglobulinemia.This finding prompted him to assume that these serum components were of high molecular weight and he named them macroglobulins.He also reported that these serum components could be precipitated out on dilution of the serum with 16 volumes of distilled water.In recent years a number of workers have reported the presence of components in pathological sera with properties similar to those assigned by Waldenstrdm to macroglobulins (2-10).How- ever, in a number of cases the macroglobulins detected by the precipitation test with distilled water had sedimentation constants as low as 12 S and as high as 30 S. On the basis of electrophoretic mobilities, macroglobulins have been reported to occur either in the 8 or y-globulin regions (2, 3, 5, 6, 8-11).Vogler, Oberhinsli, and Kofler (12) found that the diffusion coefficient for some macroglobulins was 1.2 x 10-7 cm2.per sec. in contrast to the accepted value for normal y-globulins of about 3.8 X 10-7 cm2.per sec.This finding was considered 1 Supported by a grant from the Department of Na- tional Health and Welfare, Canada.We are also in- debted to Charles E. Frosst Co., F. W. Homer Co., Montreal and Eli Lilly Co., Indianapolis, for assistance.