Influence of Mode of Immunization on the Relationship between the Development of Tissue Titers and the Release of Hemolysins in Vitro

Abstract

Summary The capacity of surviving tissues to release hemolysins in vitro has been investigated, using tissues from rats immunized by intravenous or intraperitoneal injection of sheep erythrocytes. In addition, an attempt has been made to correlate the results obtained with the development of hemolysin titers in serum and tissue. In rats immunized by the administration of a single intravenous dose of antigen, the peak in antibody titer of serum and saline extracts of most tissues occurred within 5 days. At this time, minced splenic tissue from these rats showed a rapid release of hemolysins in vitro. This in vitro phenomenon was inhibited by substitution of a nitrogen atmosphere for the oxygen-carbon dioxide mixture otherwise used. The results obtained by extension of the usual 3-hour incubation period to 12 hours suggested an actual production of antibody in vitro. Lymphoid tissue (mesenteric lymph nodes or thymus) obtained from similar animals appeared inactive under these conditions. Tissue extracts prepared from rats immunized by periodic intraperitoneal injection of antigen attained maximal hemolysin levels which were in general similar to those observed in tissues from the intravenous group. These titers were apparently maintained throughout the period of antigen injection. Surviving splenic tissue from these animals showed no evidence of antibody production in vitro, whereas lymphoid tissue exhibited a high capacity for the selective release of hemolysins. The data suggest that lymphoid tissue and spleen may vary in relative importance in the production and release of antibody in vivo, depending on the mode of immunization employed.