Induction of an increased number of dendritic cells in the peritoneal cavity of rats by intraperitoneal administration of Bacillus Calmette-Guérin.

Recently we described the presence of a small number of DC among the peritoneal cells of steady state rats. These DC had the same morphological characteristics and a similar antigen-presenting capacity as DC isolated from the spleen. This study shows that in the peritoneal cavity, which is a non-lymphoid microenvironment, the number of DC increases after i.p. administration of BCG. Next to this relatively small influx of DC, the approximately three-fold increase of the total number of cells is predominantly caused by an enormous influx of neutrophilic granulocytes, and to a lesser extent by an influx of macrophages. The phenotype and the antigen-presenting capacity of peritoneal DC has not changed, while the number of Ia-positive M phi has increased. Nevertheless, due to a suppressive effect of the peritoneal M phi, the total peritoneal cell suspension is no longer capable of presenting antigen.