The isolation of a 22 kDa band after SDS‐PAGE of Schistosoma mansoni adult worms and its use to demonstrate that IgE responses against the antigen(s) it contains are associated with human resistance to reinfection

Abstract

In schistosomiasis endemic areas, intensities of reinfection after treatment are greater amongst young children than amongst adults, and high levels of parasite-specific IgE are associated with resistance to reinfection in an age-dependent manner. Previously we have reported that, in Western blots, a 22 kDa band was recognized by human IgE and that the incidence and intensity of S. mansoni reinfection were significantly lower amongst individuals who had IgE against this band, compared with those who did not (Dunne et al. 1992). Here we report the isolation of a 22 kDa SDS-PAGE band, its incorporation into ELISA and the demonstration that levels of human anti-22 kDa IgE had a significant negative correlation with intensities of subsequent reinfection. Rabbit anti-22 kDa band serum recognized the outer tegument, gut tegument, and the collecting ducts and flame cells of adult worms. The 22 kDa band antigen(s) was also present in "lung'- and "post-lung' schistosomula stages of S. mansoni, and in S. haematobium, S. bovis and S. japonicum adult worms. Metabolic labelling of schistosomula and worms demonstrated the in vitro synthesis and release of 22 kDa antigens.

Progressive Cross-Reactivity in IgE Responses: an Explanation for the Slow Development of Human Immunity to Schistosomiasis?

“…The evidence that antibody responses to the three TALs are boosted when worms are killed by chemotherapy (11) supports this conclusion. Previous studies have correlated TAL1 IgE with resistance to reinfection (8,9,20,28), but this association was not significant in the current study. The response to worm antigen TAL1 is likely to be a marker for protective responses rather than protective in itself, and factors such as environmental and behavioral heterogeneity may mask the association with immunity in some studies (20).…”

“…Dunne et al reported that the dominant IgE antigen in S. mansoni is tegumental-allergen-like protein-1 (TAL1). Also known as Sm22.6, it is a molecule from the outer, tegumental layer of both schistosomula and adult worms (9,25), and the IgE response to TAL1 has been associated with resistance to reinfection in studies in Kenya and Uganda (8,9,20,28). The molecule is a member of a family of 13 developmentally expressed tegumental proteins (TAL1 to TAL13) (11,12).…”

Human T- and B-Cell Responses toSchistosoma mansoniRecombinant Glyceraldehyde 3-Phosphate Dehydrogenase Correlate with Resistance to Reinfection withS. mansoniorSchistosoma haematobiumafter Chemotherapy

“…Several reports have documented an association between IgE responses to schistosome antigens and resistance to reinfection, mostly in young individuals (12,15,16,24,30,39). Other reports and ours are not consistent with this view, possibly because of the difference in the age range of the individuals examined (38).…”

Identification of a Novel Antigen ofSchistosoma mansoniShared withPlasmodium falciparumand Evaluation of Different Cross-Reactive Antibody Subclasses Induced by Human Schistosomiasis and Malaria

“…The methods used for preparation of S. mansoni soluble worm antigen (SWA) and crude P. falciparum schizont antigen have been described previously (7,25). Specific levels of IgG1, IgG3, and IgG4 against SEA, SWA, and Pfs were determined by enzyme-linked immunosorbent assays (ELISA), as described previously (25).…”