Challenge of the mononuclear phagocytic system with colloidal carbon alters lymphocyte distribution and...

The objective of this study was to determine whether or not a particulate challenge to the mononuclear phagocytic system (MPS) would modulate lymphocyte populations. For this purpose subset distributions were measured in mice subsequent to colloidal carbon challenge of the MPS. The thymus underwent acute cortical atrophy followed by cellular replenishment to levels which exceeded those of the control group. The spleen and lymph nodes underwent acute expansion of all lymphocyte subsets. In lymph nodes this nonspecific expansion was disproportionately greater for B lymphocytes and Ts lymphocytes and subsided by day 30. Splenic lymphocyte expansion was equivalent for all subsets and included an increase in nonspecific esterase positive cells. The systemic MPS clearance rate underwent enhancement. Administration of colloidal carbon during topical application of DNFB depressed the cellular response to this immunogen. The cellular response to DNFB applied 28 days after carbon administration was normal. These observations indicate that distribution and responsiveness of lymphocyte subsets may be modulated by administration of a particulate material that constitutes a challenge to the MPS.