Arachidonic acid (20:4) conversion to prostanoids was examined in murine peritoneal macrophages infected in vitro with Leishmania donovani. Four strains of mice differing in resistance to in vivo L. donovani infection were studied. Normal macrophages from all strains converted 20:4 to prostanoids and this was augmented by L. donovani infection. Although cells from each strain synthesized elevated levels of prostaglandin-E2 (PGE2), there were differences with respect to relative increases of this product, with infected macrophages from the C3H/HeJ strain showing the smallest increase above basal levels.
These results indicate that macrophages from mouse strains with distinct levels of in vivo resistance to L. donovani all respond to infection with augmented prostanoid synthesis. Although some heterogeneity in strain-specific PGE2 responses to in vitro infection were observed (with respect to increases in PGE2 synthesis above basal levels), it is unlikely that differential resistance of these strains to in vivo infection is strictly related to these relative differences. It seems likely that other genetically controlled factors may have a major impact on disease expression.