Rabbit secretory IgA. I. Isolation of secretory component after selective dissociation of the immunoglobulin.

Abstract

Rabbit secretory component (SC) of colostral secretory IgA (sIgA) was isolated following dissociation from the immunoglobulin in 5 M guanidine ·HC1. Two procedures were used, one yielding native SC and the other SC with all half-cystines carboxymethylated. The results of analytic and preparative zone electrophoresis in polyacrylamide gels led to a correlation between the antigenic activities used to define component polypeptide chains of sIgA and the characteristics of their electrophoretic mobility. The native form of a fast-migrating component (F-component) different from alpha, light and SC polypeptides was also isolated by preparative gel electrophoresis. Its cellular localization was compared with that of other components of sIgA.