Synthesis of Secretory IgA in the Rabbit

[摘要] Rabbit colostral IgA internally labeled with 14C has been isolated from culture fluids of short term cultures of mammary tissue obtained from three rabbits. Alpha, light, and T chains of intact or extensively reduced and alkylated IgA were separated by Sephadex G-200 chromatography in 5 M guanidine, and by polyacrylamide disc electrophoresis. The results indicate that all three chains are synthesized locally, and that 14C lysine and isoleucine are incorporated into α, light and T chains in a ratio of approximately 4:2:1. This ratio is in reasonably close agreement with the mass ratio of the chains of an IgA molecule with 4α, 4 light, and 2 T chains. The data indicate that local synthesis can account for all of the IgA found in rabbit colostrum.

[学科分类] 生物科学（综合）