Influence of vitamin A on the immune response of Schistosoma mansoni-infected rats.
Nutritional (vitamin A levels, weights), parasitological (adult worm burden, count of eggs in liver, stool examination) and immunological (IgE serum levels, anti-Schistosoma mansoni antibodies, lymphocyte stimulation by concanavalin A and S. mansoni antigenic extract) parameters were studied in three groups of rats, a non-infected and normally fed control group, a S. mansoni-infected but normally fed group, and a S. mansoni-infected group with experimentally induced vitamin A deficiency. The number of worms was found significantly higher in the third (53 +/- 19) than in the second group (2 +/- 2) (p less than 0.001). There were many eggs in the liver surrounded by granulomatous reactions in the third group (399 +/- 73 epg liver). All stool examinations were negative. IgE levels and anti-S. mansoni antibody titres were significantly lower (p less than 0.001) in the third than in the second group. The concanavalin A lymphocyte stimulation indexes did not differ significantly between groups 2 and 3; the S. mansoni lymphocyte stimulation index was only significantly positive in group 3 (p less than 0.001). These results indicate a decrease in the humoral immune response without alteration of cellular immune response in vitamin A-deficient rats infected with S. mansoni.
D000818:Animals; D000906:Antibodies / Q000032:analysis; D000917:Antibody Formation; D001835:Body Weight; D005260:Female; D007073:Immunoglobulin E / Q000032:analysis; D008213:Lymphocyte Activation; D051381:Rats; D011919:Rats, Inbred Strains; D012550:Schistosoma mansoni / Q000276:immunology; D012552:Schistosomiasis / Q000150:complications / Q000276:immunology* / Q000469:parasitology; D014802:Vitamin A Deficiency / Q000150:complications*
D000906:Antibodies; D007073:Immunoglobulin E