Levamisole Restored the Compromized State of Immunity after Specific Chemotherapy in Experimental Schistosomiasis Mansoni

Abstract Mice infected for 45 days with 120 Schistosoma mansoni cercariae and treated with levamisole (25 mg/kg subcutaneously) have more efficient acquired immunity when challenged with 240 Schistosoma mansoni cercariae the same day of treatment (97.7% # 87.7% in infected challenged controls). In praziquantel-treated mice (500 mg/kg for 2 days orally), the reduction in the percent resistance (45.5%) was accompanied by a significant diminution in the size of granuloma, delayed foot pad swelling and granuloma proportionate T-helper cells number. Levamisole when given two weeks post praziquantel treatment and with the challenge infection increased the percent resistance to 79.2%. The increase in percent resistance recorded in mice receiving both praziquantel and levamisole was accompanied by restoration of granuloma size, delayed foot pad swelling and granuloma proportionate T-helper cells number to infected challenged untreated control values. Results reveal-beside efficacy of levamisole as immunoregulant in schistosome immunity - a possible role for the granuloma as a T-cell mediated response in maintenance of immunity.