THE FORMATION OF ANTIBODIES IN THE POPLITEAL LYMPH NODE IN RABBITS.

Typhoid vaccine and sheep erythrocytes were injected subcutaneously into the feet of rabbits, and the subsequent formation of agglutinins and hemolysins in the popliteal lymph node was compared with the output of lymphocytes through the efferent lymph and with changes in the lymph node. Antibodies began to appear in the efferent lymph 2 to 4 days after the injection of the antigen and reached their highest titer after 6 days. This was preceded by a sharp rise in the output of lymphocytes through the efferent lymph, while in the lymph node there was lymphatic hyperplasia after preliminary infiltration of granulocytes and monocytes. This hyperplasia was first of a diffuse type, but was later superseded by large so called germinal centers, the latter lagging somewhat behind the rise in antibody titer. The fact that the tissue response accompanying the formation of antibodies was chiefly a lymphocytic one points to the lymphocyte as a factor in the formation of antibodies.