THE IMMUNE RESPONSE OF THE MAMMARY GLAND AND REGIONAL LYMPH NODE FOLLOWING ANTIGENIC STIMULATION.

Abstract

SummaryThe changes in the antibody and cellular content of milk and mammary lymph have been studied in ewes given intramammary infusions of various antigens. Killed Brucella abortus, Salmonella typhi and Salmonella pullorum, the antigens used in the experiments, were infused into one udder half while the other served as a control.Apart from a transient increase in the neutrophil content of the milk immediately following the infusion, there was no difference in the cell content of the milk of the infused or control glands throughout the experiments on lactating sheep. There was a relatively small increase in plasmablasts and plasma cells in the efferent lymph from the mammary gland following intrammary infusion compared with that following subcutaneous injection. There was at the most only a slight increase in antibody litre in the milk following infusion into mammary glands of lactating sheep and in all experiments the litre in plasma was higher than that in milk. On the other hand there was a substantial rise in antibody titre in the secretion from involuting glands. After two infusions at 10‐day intervals the litres in the secretion from the involuting gland and in the lymph draining it were many times higher than that in plasma. These results suggest that much of the antibody in involution milk was locally synthesized. Killed Salmonella typhix “O” organisms were infused into the glands of two pregnant ewes 2‐6 weeks before parturition. This resulted in high litres in the colostrum and in the milk for at least three months of the next lactation. The antibody titre of the milk from the infused side was higher than that of the control side and plasma.