In contrast, infection for 24 hr prior to LPS stimulation significantly reduced the levels of MHC I, MHC II, CD11b and B7.1 in comparison with LPS-matured cells (Figures 4 and 5), suggesting that addition of LPS after infection is not sufficient to reverse the suppressing effect of L. mexicana promastigotes on the expression of these molecules. The gene discussed is CD80; the disease is infection.