Pristane Induces an Indomethacin Inhibitable Inflammatory Influx of CD4+ T Cells and IFN-γ Production in Plasmacytoma-Susceptible BALB/cAnPt Mice

In BALB/cAnPt (BALB/c) mice, the intraperitoneal injection of pristane induces the formation of chronic oil granulomatous tissue and a high incidence of plasmacytomas (PCT). DBA/2N (DBA) and (BALB/c × DBA)F1 hybrid (CDF1) mice develop oil granulomas but no PCT. Recent studies comparing pristane-injected conventionally housed BALB/c mice with specific pathogen-free BALB/c mice (SPF) demonstrated a significant reduction in both the incidence of PCT and the T cell infiltration of oil granulomatous tissue in SPF mice. In this study, FACS analysis was performed to determine the proportion of myeloid, T, and B cells present in pristane-induced peritoneal exudate (PE), and oil granulomas (OG) of BALB/c, DBA, and CDF1 mice. At all time points studied, the majority of cells recovered from the PE and OG of all three strains of mice were Mac-1+, presumably macrophages and neutrophils. Neither Ly-5(B220)+ B cells nor CD8+ T cells were significantly altered by pristane injection. BALB/c mice had a dramatic influx of CD4+ T lymphocytes (three- to fivefold) more than 50 days after the initial injection of pristane. The PCT-resistant DBA and CDF1 mice did not. This increase in CD4+ cells in BALB/c mice was no significantly affected by a second injection of pristane nor was it induced by a second injection in DBA mice. Indomethacin, which has been shown to prevent the development of PCT in BALB/c mice, prevented the infiltration of CD4+ T cells. In addition, pristane-induced levels of interferon-γ greater than controls were found in the peritoneal lavages of BALB/c mice at all time points tested but not in DBA or indomethacin-treated BALB/c mice. In contrast, pristane injection increased levels of interleukin-5 in DBA but not BALB/c mice.