these could be shown to be due mainly to one of the following factors : low ha titer was due to lack of the immunoglobulin m and a classes of antibodies , low bca titer was due to the blocking effect of high immunoglobulin a content , and high bca titer was due to antibodies directed to bacterial components other than the capsular polysaccharide .
C0020861
immunoglobulin m
C0021017
classes