[Bilharziasis and human immunodeficiency virus infection in Congo]. / Bilharziose et infection par le virus de l'immunodeficience humaine au Congo.

To assess the relationship between schistosomiasis and human immunodeficiency virus (HIV) infection, a cross-sectional study of HIV seroprevalence was carried out in 1992 in a village in the Bouenza region of the Congo where there is a high incidence of urinary schistosomiasis. No correlation was found between eggs in urine and positive serology for HIV in the 895 adults examined nor between positive schistosome serology and positive HIV serology. The incidence of frank schistosome infection (eggs in urine and positive blood tests) was significantly lower in patients with positive HIV serology (3.5%) than in patients with negative HIV serology (6.7%). Similarly the mean number of eggs in urine was significantly lower in patients with positive HIV serology (3.6 eggs per ml) than in patients with negative HIV serology (26.6 eggs per ml) (p < 0.01). These observations suggest that HIV infection limits schistosome development and decreases antibody production. Further study will be needed to confirm these findings.

Physical and immunological analysis of the two domains isolated from a variant surface glycoprotein of Trypanosoma brucei.

A specific surface glycoprotein of a variant of Trypanosoma brucei was cleaved with trypsin and the two major domains of the molecule have been purified. We have studied the chemical composition of each domain and compared the data to published results of the specific cDNA sequence. Circular dichroism measurements show that the amino-terminal domain includes preferentially alpha-helical or beta-sheet structure. The physicochemical analyses are supplemented by a prediction of secondary structure and a statistical pattern of hydrophilicity-hydrophobicity. The results are discussed in light of the internal limits that were described in the process of partial gene conversion occurring between the variant gene sequence and related members of the same gene family. Immunoblots with homologous antiserum indicate that the amino-terminal domain is implicated in antigenicity. In addition, immunoblotting with heterologous antiserum on native antigen, tryptic hydrolysates, or purified domains suggests a site of interaction supported by the two domains.