Leishmania mexicana lipophosphoglycan differentially regulates PKCα‐induced oxidative burst in macrophages of BALB/c and C57BL/6 mice

Summary Leishmania are protozoan parasites that infect macrophages and their survival is partially achieved through inhibition of the cellular oxidative burst by parasite lipophosphoglycan (LPG). PKCα is the predominant PKC isoenzyme required for macrophage oxidative burst, yet it is not known if different susceptibility of BALB/c and C57BL/6 mice to Leishmania mexicana could be related to PKCα. We analysed the effect of L. mexicana promastigotes and parasite LPG on expression of PKCα and on its activity in macrophages of both mouse strains. Our data show that expression of the isoenzyme was not altered either by LPG or by L. mexicana promastigotes. Yet LPG exerted opposing effects on PKCα activity of macrophages between both strains: in susceptible BALB/c cells, it inhibited PKCα activity, whereas in the more resistant strain it augmented enzymatic activity 2·8 times. In addition, LPG inhibited oxidative burst only in susceptible BALB/c macrophages and the degree of inhibition correlated with parasite survival. Promastigotes also inhibited PKCα activity and oxidative burst in macrophages of BALB/c mice, whereas in C57BL/6, they enhanced PKCα activity and oxidative burst inhibition was less severe. Our data indicate that control of PKCα-induced oxidative burst by L. mexicana LPG relates with its success to infect murine macrophages.