Distribution of peritoneal macrophage populations after intravenous injection in mice: differential effects of eliciting and activating agents.

Abstract

Murine peritoneal macrophages (pM phi) elicited in vivo by intraperitoneal (IP) inoculation of various agents were tested for their homing/distribution patterns after intravenous (IV) adoptive transfer to syngeneic C57BL/6 recipients. Resident pM phi (RpM phi) obtained from normal mice and pM phi elicited by proteose peptone (PpM phi) or thioglycollate broth (TpM phi) exhibited similar homing patterns following IV transfer. After initial arrest in the lungs, these cells rapidly disseminated to liver and spleen, with minimal or no detectable migration to peripheral lymph nodes, intestine, peritoneum, kidney, heart, or retention in the blood. The pattern of results reflected the properties of pM phi themselves, since highly enriched pM phi populations obtained by treatment of crude peritoneal exudate cells with anti-Thy 1.2 + C, or by fractionation on Percoll density gradients, gave similar results. The distribution of pM phi elicited by Brewer's thioglycollate medium (BTpM phi) was markedly different from other pM phi tested. BTpM phi homed rapidly to the lungs and many remained localized there for at least 72 hr with very little migration to the spleen. The distribution of PpM phi could be altered by activation of these cells in vivo through the IP injection of the pyran copolymer, MVE-2, prior to adoptive IV transfer. Activated PpM phi contained a population of highly differentiated, low density pM phi, separable on density gradients, which arrested in the lungs for appreciably longer periods of time than did PpM phi. These cells exhibited reduced ability for migration to the spleen. Macrophage-like (M phi-like) cell lines did not exhibit migration capability, but rather were rapidly cleared from the circulation in a manner similar to other types of tumor cells.