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.

Animals↗

PubMed1991

Morphological and functional characteristics of rat steady state peritoneal dendritic cells.

Dendritic cells (DC) are present in lymphoid organs and also in many non-lymphoid tissues. In this study, DC in the steady state peritoneal cavity of rats were identified morphologically and functionally. Approximately 1% of the peritoneal cells are DC. On cytocentrifuge preparations these cells had the same characteristics as lymph node and spleen DC: they had an irregular outline, all were strongly MHC class II positive and had acid phosphatase activity in a spot in a juxtanuclear position. Also ultrastructurally, peritoneal DC were similar to DC isolated from lymph node and spleen. Enrichment of peritoneal DC, using overnight culture and a Nycodenz gradient, resulted in a highly purified DC fraction. Functionally, peritoneal DC appeared to be very potent antigen-presenting cells, far more potent than peritoneal macrophages, which had an inhibitory rather than an accessory function.

Acid Phosphatase↗