Human antibody responses to Schistosoma mansoni: does antigen directed, isotype restriction result in the production of blocking antibodies?

Abstract

After treatment young Kenyan schoolchildren are highly susceptible to reinfection with Schistosoma mansoni. Older children and adults are resistant to reinfection. There is no evidence that this age related resistance is due to a slow development of protective immunological mechanisms, rather, it appears that young children are susceptible because of the presence of blocking antibodies which decline with age, thus allowing the expression of protective responses. Correlations between antibody responses to different stages of the parasite life-cycle suggest that, in young children, antigen directed, isotype restriction of the response against cross-reactive polysaccharide egg antigens results in an ineffectual, or even blocking antibody response to the schistosomulum.

Immunoglobulin M antibodies are not specific for serodiagnosis of human toxocariasis

“…Moreover, there are many reports on the production and reactivity of IgM antibodies in human helminth infections, suggesting that they react mainly with glycosidic epitopes from polysaccharide or glycoprotein antigens and may block the effector immune response against the parasite . However, very little is known on the reactivity of IgM antibodies in human Toxocara infections.…”