Exposure to mercurial secretions induces specific antibody responses, which can be
useful to evaluate exposure to S. ma`nsoni infection. This paper describes work designed to measure
the anti-CTF response (IgG1, IgG4 and IgE) in individuals from a schistosomiasis endemic area of
Piida village, Uganda. The predominant anti-CTF antibodies in sera were IgG1 and IgG4. IgG4
specifically recognized antigens at approximately 30 kDa, 46 kDa and 58 kDa molecules. In
addition, IgE antibody weakly recognized some molecules of CTF at approximately 22 kDa, 58 kDa
and 80 kDa. The effects and the interactions of age, sex, prevalence and intensity of infection on
specific antibody levels were also assessed. This study demonstrated that there were different
responses in sex dependent age groups. In addition, the anti-CTF IgG1, and IgG4 responses were
significantly higher in the age groups of 10-14 and 20-24 years. There was however, no remarkable
effect of age on IgE anti-CTF. In addition, there were significant positive correlations between eggcount and the anti-CTF antibody isotypes responses. This study also investigated the relationship
between anti-CTF and antibody responses to other S. mansoni antigens, including adult (AWA), egg
(SEA) and whole cercarial homogenate. Most of these antibodies were strongly correlated with each
other. These results suggest that the anti-CTF antibody response appears a reliable indicator of
exposure to S. mansoni in endemic areas, and might also be exploited for schistosomiasis
epidemiological studies.
Key words: Schistosoma Mansoni, Schistosomiasis, immune responses, ELISA, SDS-PAGE.