Differential Effector Functions of Central and Peripheral Compartments of Immune Response System: Characterization of Immune Responses in the Spleen and Mesenteric Lymph Nodes to Directly Injected Sheep Red Blood Cells

Abstract

When sheep red blood cells (SRBC) were injected intraperitoneally (i.p.), intravenously (i.v.), or into the Peyer’s patches, definite plaque-forming cell (PFC) and rosette-forming cell (RFC) responses were induced in the spleen but not in the mesenteric lymph nodes (MLN). When SRBC were injected directly into the spleen or MLN, stronger PFC and RFC responses were induced in the spleen or MLN, respectively, than when injected i.p. or i.v. PFC response induced in MLN by injecting SRBC into MLN with or without the polysaccharide of Klebsiella pneumoniae type 1 Kasuya strain (CPS-K) as an immunological adjuvant was weaker than that induced in the spleen by injecting the antigen into the spleen. Direct PFC (PFC of IgM type) and RFC responses induced in the spleen by injecting SRBC into MLN were rather stronger than those induced in the spleen by injecting the antigen into the spleen. In contrast, no significant responses were induced in MLN by injecting SRBC into the spleen, and no definite indirect PFC (PFC of IgG type) response was induced in the spleen by injecting the antigen into MLN. The levels of whole immunological memory as well as isolated B- or T-cell memory in the spleen and MLN of mice injected with SRBC directly into the spleen or MLN were determined by using an in vitro assay system. Definite amounts of either B- or T-cell memory were detected in the spleen of mice injected with SRBC directly into the spleen or MLN. Smaller amounts of memory were detected in MLN injected with SRBC directly into MLN, and by far less amounts of memory were detected in MLN of mice injected with SRBC directly into the spleen. Moreover, the amounts of whole memory detected in MLN were much less than compared with those of isolated T- and B-cell memories in MLN. Further experiments showed that in vitro expression of the memories preserved in MLN required supplement of glass non-adherent cells from normal spleen. Based on these results, we discussed the possible differential and collaborative functions of the central (spleen) and peripheral (MLN) immune response systems in antibody responses.