CD43 deficient mice are susceptible to visceral leishmaniasis. CD43+/+ and CD43−/− mice on a C57BL/6 background were intravenously injected with 5 × 10 7 amastigotes of Leishmania (L.) infantum chagasi, and 30 days after infection the clinical signs of disease were examined. (A) Infection in CD43-deficient mice results in an impaired DTH response. The vertical axis in the histogram represents the individual values of the thickness of the skin reaction in mm 24 h and 48 h after intradermal injection of 107 freeze–thawed stationary phase promastigotes at 30 DPI. Controls with saline were done by contra-lateral injection and their values were subtracted from the reaction promoted by Leishmania antigen. (B) Liver/body relative weights are increased in infected CD43-deficient mice. The body weight was measured in grams at day 30 and the liver/body relative weights (grams of organ weight × 100 / grams of body weight) were determined in CD43+/+ and CD43−/− mice. (C) Increased parasite burden in the liver of CD43-deficient mice. The vertical axis in the histogram represents the average liver parasite load in Leishman-Donovan units of Stauber (LDU = number of amastigotes / 1000 cell nuclei × organ weight in mg) obtained at 30 DPI. Data are means ± SE and represent the results of three independent experiments performed with 5–6 mice per treatment. Differences between groups are significant *(p < 0.05).