Summary
Following the injection of inactivated influenzal virus into the foot-pad of the rabbit antibodies to the viral protein can be found in the popliteal lymphnode, which drains the site of injection, and in lymph obtained from the efferent lymphatic vessel of that node. These antibodies are found earlier in the local lymphatic system that in the serum and in higher titer until the 4th day after the injection. Thereafter the serum-titer rises above that in the lymphatic tissues.
At the same time there is a burst of activity in the local lymphatic tissue. There is marked enlargement of the lymphnode, almost entirely of cortical tissue. This consists of diffuse lymphocytic hyperplasia which very soon becomes organized into the conventional follicular structure of lymphnodes. The absolute and relative count of lymphocytes in the lymph emerging from the popliteal lymphnode rises sharply.
Injection of serologically distinct strains of influenzal virus into the two legs of individual rabbits give results which corroborate the specificity of the antibodies produced.
On separation of lymph emerging from the popliteal lymphnode into cells and plasma and testing each for antibody-content, it is found that the titer of antibody in the lymph-cells exceeds that in the lymph-plasma, by ratios as high as 16:1. This ratio is found to be highest at the time when the rate of increase of antibody-content of the local lymphatic system is greatest.
These findings are interpreted to mean that the lymphocyte can be a primary source, or site of final synthesis, of antibodies to viral protein. This conclusion is in keeping with those of earlier studies in which a similar role was demonstrated for the lymphocyte in the formation of antibodies to bacterial and cellular antigens.
