Effect of chemically modified biomphalaria alexandrina snail antigen on cellular immune response in murine schistosomiasis mansoni

ABSTRACT

This study was designed to test the effect of a chemically modified Biomphalaria alexandrine snail antigen on the cellular immune response in thymus, mesenteric lymph nodes [M.L.N.] and spleen in murine Schistosomiasis mansoni. Antigen [0.16 micro g/ml] was extracted from tissues of pretreated snails with thioxanthone derivative [4-[Beta-diethylaminoethylamino] 2-cyclohexeno thiaxant- hone] Mice were divided into preimmunized group [immunization before infection], postimmunized group [immunization post infection], infected and uninfected groups. Mice were immunized subcutaneously at two weeks intervals [3 x 0.2 ml/mouse], either before or after the challenge with 200 Egyptian Schistosoma mansoni cercariae. Mice were sacrificed at two weeks post the third immunization and were compared with two groups of mice; uninfected control and infected positive control groups. The phenotypic analysis of the cellular immune response [CD3[+] pan T-cells, CD4[+] inducer/helper T-cells, CD8[+] suppressor/cytotoxic T-cells and B-cells] in thymus, mesenteric lymph nodes and spleen were assessed by direct immunoflourescence technique. A significant increase in CD3[+], CD4[+] and CD8[+] T -splenocytes and mesenteric lymph node cells were observed post 2[nd] and 3[rd] immunizations [Preimmunized group, Vacl and Vac2], as compared with negative control, as well as post-infection as compared with infected control. B-lymphocytes showed a significant increase post 2[nd] and 3[rd] immunizations preimmunized group, [Vac1 and Vac2], both in splenocytes and M.L.N. cells as compared with uninfected group, as well as post-infection as compared with infected positive control group [P Thymocytes did not reveal considerable changes in CD3[+], CD4[+] or CD8[+] T-cells in preimmunized group, [Vacl and Vac2 and Vac3]. However, neither the T-cells [CD3[+], CD4[+] CD8[+]] and norB-cells number differed significantly between postimmunized group as compared with infected group in spleen and mesenteric lymph nodes. In contrast, CD3[+] and CD4[+] thymocytes were significantly increased in postimmunized group [P control group. It is concluded that the chemically modified Biomphalaria alexandrina snail antigen succeeded in enhancing the cellular immune responses of the host