Inbred Strain Differences Influence the Focal Proliferation of Plasma Cells in Pristane Induced Oil Granuloma

Abstract

Plasmacytomas are inducible in a few genetically susceptible strains of mice (BALB/cAn, NZB) by the intraperitoneal injection of mineral oils (see Potter 1984 for refs). However, many other strains are resistant to plasma cell tumor formation (Potter et al. 1975, 1984; Potter and Wax 1981). Pristane (2, 6, 10, 14 tetramethy1pentadecane), a component of many mineral oils, also has a biogenic origin being produced by marine copepods from phytane. Pristane, like most of the components of mineral or paraffin oil, is not metabolized and its role as a piasmacytomagenic agent is not direct. When pristane and mineral oils are injected i. p., they induce the formation of a reactive tissue that forms on peritoneal surfaces, called oil granuloma (06) (Potter and MacCardle 1964). The 0G results from the phagocytosis of oil droplets by cells in the macrophage and myeloid series. A variety of configurations of oil droplets are seen in this tissue ranging from intracellular oil droplets to cystic structures onto which a variable number of macrophages and or neutrophils adhere. The oil laden phagocytes and the larger droplets surrounded by phagocytes adhere to mesothelial surfaces and become vascularized from underlying blood vessels and covered with mesothelium. The organized 0G is invaded by other types of inflammatory cells and lymphocytes. Plasma cells can be found scattered throughout. 0G formation begins very soon after the injection of pristane and is well developed by day 20.