The transmission of anti- Brucella abortus agglutinins across the gut in young rats

Abstract

The anti- Brucella abortus titres of the sera of suckling rats fed 4 h previously with rabbit immune sera showed no correlation with the titres of the sera administered. This was due to them ultiplicity of the antibodies and their varying proportions in the immune sera, and their different rates of transm ission across the gut. The immune sera contained γ 1M - and γ 2 -complete agglutinins, but only the latter were transmitted in the rats. The gut exhibited selection between γ 2 -agglutinins from individual rabbits, but in all cases the antibodies appearing in the circulation were incomplete agglutinins. This qualitative difference in the antibodies before and after feeding was effected during transmission across the gut rather than after transmission in the circulation, and was attributed to a configurational change turning complete antibodies into the incomplete type rather than to a selective transfer of incomplete and exclusion of complete agglutinins. The incomplete antibodies appearing in the sera of fed rats partially reverted into the complete type on gel filtration and osmotic concentration, possibly due to the oxidation of disrupted disulfide bonds. It was not possible to relate the molecular size or electrophoretic mobilities of the agglutinins to their transmission.