STUDIES ON THE LYMPHOCYTOSIS INDUCED BY PERTUSSIS TOXIN

Pertussis toxin (PT), from Bordetella pertussis, causes lymphocytosis and increased IL-4 and IgE secretion. The lymphocytosis is associated with impaired entry of lymphocytes into lymph nodes. The dose response of PT on IL-4 secretion was found to be similar to those for lymphocy tosis and IgE production. These findings are consistent with the possi bility that increased IL-4 production by PT may be related to its effe ct on lymphocyte circulation. The possibility that PT may selectively influence the entry into lymph nodes of subsets identified with CD45RB , CD4 or CD8 was tested by assessing the phenotype of lymph node cells . PT had no significant effect on the proportion of cells with these m arkers, either in unimmunized or in immunized mice. These findings ind icate that PT does not selectively impair entry of these lymphocyte su bsets into lymph nodes.