Cytodynamics of the Distinctive Immune Response Produced in Regional Lymph Nodes by Salmonella Somatic Polysaccharide

Abstract

A study was made of the immune response of the rabbit to a single local injection of Salmonella enteritidis somatic polysaccharide. The cytodynamics of the antibody-forming cells in the draining popliteal node differed markedly from those produced in the spleen when this antigen was given systemically. The effectiveness of local stimulation was almost three orders of magnitude greater than that of systemic stimulation as determined by the number of plaque-forming cells (PFC) developed per millimicrogram of antigen. Maximal numbers of PFC in the draining lymph node were evoked by 0.01 µg of antigen, while the range in which numbers of specific PFC correlated with antigen dose was 10^-4 to 10^-6 µg; significant numbers of specific PFC were produced by as little as 10^-7 to 10^-9 µg of antigen. Antigen in amounts of 5 to 0.001 µg resulted in the appearance of considerable numbers of PFC in the contralateral popliteal node and in the spleen; numbers of spleen PFC were greater than could be produced in this organ by intravenous injection of equivalent doses of antigen. In contrast, the distribution and numbers of PFC developed after immunization with sheep erythrocytes was in accord with the expected pattern: dose response data for systemic and local administration did not differ greatly and PFC were found principally in spleen or draining lymph nodes after systemic or local injection respectively.