1Kamal SH, 2Maklad SS, 2Higazi FF, 1El-Nagaar MB and 1El-Sheikh NA.
1Pediateric and 2Microbiology Departments, Faculty of Medicine For Girls, Al- Azhar University, Cairo, Egypt.
Idiotypic/anti-idiotypic (Id/anti-Id) interactions have been reported in human schistosomiasis. The nature of their role in S. mansoni infection is a controversy. The presence of circulating anti-Id antibodies (Ab2) in active, reinfected children and adolescents with S. mansoni (n=30) and formerly treated, resistant to reinfection (n=26) schistosomal patients was examined and correlated with the intensity of infection and morbidity of the disease. Affinity purified polyclonal Id antibodies (Ab1) to soluble worm antigen (SWAP) were prepared in hamsters and used to capture anti-Id (Ab2) antibodies in patients plasma using ELISA. The results revealed that patients with Ab2 reactivity were more frequent in the former group than in the active group (P<0.001). However, both groups had significantly higher Ab2 reactivity compared with controls (p <0.05, P< 0.001) respectively. Significant negative correlations were found between Ab2 reactivity and both intensity of infection (egg count/gm stools), and morbidity of the disease (S. mansoni related symptoms and hepatomegaly) P<0.001 for both. In conclusion, the present study provides an evidence on the existence of anti - Id antibodies (Ab2) in the circulation of S. mansoni infected children and suggests a role for these Id/anti - Id interactions in the immunopathology as well as regulation of the protective immune response.