PHYLOGENY OF IMMUNOGLOBULIN STRUCTURE AND FUNCTION

Abstract

Chicken 7.1S immunoglobulin was purified from whole chicken serum by DEAE-cellulose chromatography and Sephadex G-200 gel filtration. The macroglobulin was purified by a combination of salt precipitation and Sephadex G-200 gel filtration. Both immunoglobulin molecules yielded 75% heavy (H) chains and 25% light (L) chains when subjected to extensive reduction and alkylation followed by gel filtration in 5 M guanidine-HCl. Antigenically reactive H and L chains were obtained by partial reduction and alkylation followed by gel filtration in 5 M guanidine-HCl. The 7.1S and 16.7S immunoglobulin H chains were antigenically unrelated to each other, whereas the L chains were antigenically indistinguishable from one another. The 16.7S H chains were found to have a mass of ∼70,000, and the 7.1S H chains had a mass of 67,500. The mass of the L chains was ∼22,000.