Études et publications

Remoué F, Rogerie F, Gallissot MC, Guyatt HL, Neyrinck JL, Diakkhate MM, Niang M, Butterworth AE, Auriault C, Capron A, Riveau G.

The Journal of Infectious Diseases, 2000, 181(5):1855-9 (PMID : 10823801)

The reduction of Schistosoma fecundity observed after experimental vaccination with the Schistosoma mansoni 28-kDa glutathione S-transferase (Sm28GST) antigen has been related to the inhibition of glutathione S-transferase (GST) enzymatic activity by specific antibody. The humoral immune response to the protective antigen Sm28GST and to the epitopes involved in the enzymatic site (amino acid ¿aa sequences 10-43 and 190-211) was evaluated in infected individuals before chemotherapy treatment. The capacity of the serum samples to inhibit GST enzymatic activity was assessed. Specific IgG3 response was predominant in the male population with a low intensity of infection and was associated with maximal GST inhibition. In contrast, the neutralizing activity of serum samples from women with a low intensity of infection was correlated with high specific IgA response specifically directed toward the 190-211 epitope. These results strongly support the hypothesis that GST-neutralizing IgG3 and IgA isotypes are sex dependent. The relationship of this specific acquired immune response with the level of intensity of infection is discussed.

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Southgate VR, de Clercq D, Sène M, Rollinson D, Ly A, Vercruysse J.

Annals of tropical medicine and parasitology, 2000, 94(2):157-64 (PMID : 10827870)

Snail-infection experiments were carried out with a number of different species and populations of Bulinus and isolates of Schistosoma haematobium. The parasites came from six localities in the Senegal River basin (SRB), in the Lower Valley (Mbodiene), Middle Valley (Podor, Diatar and Nguidjilone), and Upper Valley (Aroundou and Galladé). Isolates of S. haematobium from the Middle and Upper Valleys all showed some compatibility with laboratory-bred B. truncatus from Mali, but none of these isolates was compatible with laboratory-bred B. truncatus originating from Senegal. Schistosoma haematobium from Diatar (Middle Valley) was compatible with B. senegalensis, whereas S. haematobium from Mbodiene (Lower Valley), which is naturally transmitted by B. globosus, was incompatible with B. senegalensis and B. truncatus. These data demonstrate that different isolates of S. haematobium from different regions of the SRB exhibit distinct intermediate-host specificities, which in turn will have an effect on the epidemiology of the disease, including the periods of transmission. It is apparent that, in addition to B. senegalensis and B. globosus, B. truncatus, the most widespread bulinid snail in the SRB, may be playing a role in the epidemiology of urinary schistosomiasis. This conclusion has obvious implications for the future spread of urinary schistosomiasis in the SRB. Chemical and physical measurements from assorted habitats along the SRB, including pH, temperature, salinity, conductivity, and resistivity, are also reported.

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