Abstract
Intravenous injection into mice of phase I Bordetella pertussis culture supernatants produces a marked lymphocytosis. The evolution of lymphocytosis was correlated with histopathological alterations in the lymphoid organs. The early phase, 17 hr to day 3, was associated with massive depletion of both lymphocytes from the white pulp of the spleen and of cortical thymocytes. There was a corresponding profound decrease of splenic and thymic weights. The later phase was associated with a marked decrease in lymphocytes of lymph nodes while concomitantly the spleen and thymus appeared to be repopulating. Both thymic-dependent and thymic-independent lymphocyte populations were mobilized from spleen and lymph nodes. There was a striking diminution in the number of lymphocytes contained within the walls of postcapillary venules (PCVS) of all lymph nodes between 2 and 7 days. The data suggest that initially the lymphocytosis is due predominantly to release of splenic lymphocytes and to a lesser extent of thymocytes into the circulation. Subsequently, the lymphocytosis is sustained by the depopulation of the lymph nodes. Lymph node depopulation is maintained by the failure of circulating lymphocytes to emigrate from the blood through the PCVS.
