Studies on the Interaction of Schistosoma Mansoni and Leishmania Major in Experimentally Infected Balb/c Mice

Schistosoma mansoni and Leishmania major are important tropical human parasites. It is crucial to know the effect of the two infecting man concurrently. Two groups of BALB/c mice were infected with each of the parasites separately; another group was co-infected with both parasites and there was a na\uefve control. Draining lymph node and spleen cells from mice infected with either of the parasites showed high proliferative responses to their specific parasite antigen. However, crossreactivity occurred between S. mansoni and L. major. Spleen and Lymph node cells from co-infected group demonstrated high and sustained proliferative responses to schistosome soluble worm antigen preparation and killed Leishmania major antigen, respectively. There was high and sustained IgG levels for both the single and coinfected groups. At 10 weeks post-infection, co-infected mice had significantly larger nodules than mice with L. major infection alone. However, co-infected animals had less severe liver pathology and less enlarged mesenteric lymph nodes than those infected with S. mansoni only. This work shows that co-infection results in two different outcomes: protection against S. mansoni and exacerbated pathogy in L. major. We suggest that cellular responses possibly protect against S. mansoni, while high IgG levels lead to exacerbated L. major response

Influence of Age of Mice on the Susceptibility to Murine Schistosomiasis Infection

Intensity of human schistosomiasis infection increases with age, a peak being attained at early puberty. Hormones could be involved in the age-related changes in susceptibility to schistosomiasis. Male BALB/c mice were infected with Schistosoma mansoni either before or after puberty and worm numbers, cellular immune responses, hormonal levels and pathology analysed. Pre-puberty infected mice had a significantly higher number of adult worms (p<0.05), more severe granulomas, higher mortality rate and higher proliferative responses as compared to postpuberty infected mice. Levels of the hormones were lower in the pre-puberty infected mice as compared to the post-puberty group early in the infection. Plasma levels of testosterone and luteinizing hormones decreased significantly (p<0.05) in infected mice when compared to controls. Susceptibility to S. mansoni in male BALB/c mice seems to be influenced by levels of testosterone and leutenizing hormone at infection. Albeit, an infection with S. mansoni seems to lower the hormonal levels

The Effect of Vaccinating S. Mansoni\u2013infected BALB/c Mice Either Before or After Treatment*

In Schistosoma mansoni endemic areas, there are people with ongoing S. mansoni infection, others have been infected and treated while others have never been infected. What would happen if these different groups of people were vaccinated against S. mansoni? BALB/c mice were divided into five groups: Infected-Treated-Vaccinated; Infected-Vaccinated-Treated; Vaccinated-Treated Control; Challenge Control and Untreated challenge Control. Vaccination (500 20krad irradiated S. mansoni cercariae), Treatment (praziquantel), Infection and Challenge (150 S. mansoni cercariae) were carried out at specified times. Proliferation assay, Enzyme linked immunosorbent assay, gross pathology, histopathology and perfusion were performed. High protection levels were obtained in mice treated after vaccination: Vaccinated-Treated control, 96.5%; Infected-Vaccinated-Treated, 68.9%; and Infected-Treated-Vaccinated, 41%. A good correlation was obtained between proliferative responses and protective levels, implying cellular involvement in protection. Although all protected animals had high IgG levels, there was no strong correlation between the two. Specificity rather than amounts of IgG, seem more important in protection. Praziquantel seemed to boost protective immunity when administered after vaccination. Granuloma development and modulation in the two test groups was similar. It seems better to vaccinate infected patients before treatment, the ideal situation being vaccinating people who have not encountered S. mansoni

The effect of vaccinating S. mansoni–infected BALB/c mice either before or after treatment

In Schistosoma mansoni endemic areas, there are people with ongoing S. mansoni infection, others have been infected and treated while others have never been infected. What would happen if these different groups of people were vaccinated against S. mansoni? BALB/c mice were divided into five groups: Infected-Treated-Vaccinated; Infected-Vaccinated-Treated; Vaccinated-Treated Control; Challenge Control and Untreated challenge Control. Vaccination (500 20krad irradiated S. mansoni cercariae), Treatment (praziquantel), Infection and Challenge (150 S. mansoni cercariae) were carried out at specified times. Proliferation assay, Enzyme linked immunosorbent assay, gross pathology, histopathology and perfusion were performed. High protection levels were obtained in mice treated after vaccination: Vaccinated-Treated control, 96.5%; Infected-Vaccinated-Treated, 68.9%; and Infected-Treated-Vaccinated, 41%. A good correlation was obtained between proliferative responses and protective levels, implying cellular involvement in protection. Although all protected animals had high IgG levels, there was no strong correlation between the two. Specificity rather than amounts of IgG, seem more important in protection. Praziquantel seemed to boost protective immunity when administered after vaccination. Granuloma development and modulation in the two test groups was similar. It seems better to vaccinate infected patients before treatment, the ideal situation being vaccinating people who have not encountered S. mansoni. African Journal of Health Sciences Vol. 12(3-4) 2005: 65-7