The Production of Memory Cells by the White Pulp of the Spleen in Rabbits

Differences exist between the primary and secondary responses with respect to histological changes as well as the rapidity of antibody production (Nisonoffand Thorbecke, 1964). Another difference concerns the type of antibody produced and the ease with which a secondary response in vitrocan be induced in contrast to the difficulties encountered in inducing a primary response in vitro (Michaelides, 1958). In the few cases where induction of a primary response in vitro appears to have succeeded, low antibody titers have been reported (Fishman, 1961; Globerson and Auerbach, 1965; Taoand Uhr, 1966). Nothing is known, however, about the biochemical nature of the change which renders a cell capable of giving a secondary response. Whether “primed” and uncommitted cells belong to the same or to a different morphological cell type also remains to be determined.