Puberty and Age-related Changes in Susceptibility to Schistosome Infection

Fulford, Anthony J. C.; Webster, Michelle Lee; Ouma, John H.; Kimani, Gachuhi; Dunne, David W.

doi:10.1016/s0169-4758(97)01168-x

Cited by 122 publications

(90 citation statements)

References 29 publications

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“…Such a profile perhaps indicates that adult worm burden in the population was fluctuating with age. In a study of patients with schistosomiasis, 30 similar fluctuations have been attributed to changes in levels of certain hormones, particularly dehydroepiandrosterone, shown to affect certain immune functions and leading to a decrease in infection intensity when dehydroepiandrosterone levels are highest.…”

Section: Discussionmentioning

confidence: 86%

Worm burden and host responsiveness in Wuchereria bancrofti infection: use of antigen detection to refine earlier assessments from the South Pacific.

Steel¹,

Ottesen²,

Weller³

et al. 2001

The American Journal of Tropical Medicine and Hygiene

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Abstract. A population from the Wuchereria bancrofti-endemic island of Mauke was reevaluated retrospectively by use of the Og4C3 circulating antigen (CAg) enzyme-linked immunosorbent assay to assess active infection in relation to host responses by age and gender. Use of microfilaremia (Mf) alone misclassified ϳ 50% of infected people, although CAg and Mf levels were positively correlated. Levels of CAg peaked between those aged 31-60 years; men aged Ͼ 60 years had a significantly higher CAg prevalence (Ͼ 90%) than women. Filaria-specific immunoglobulin (Ig) G4 reached maximum levels in both genders at age 51-60 years. By analysis of variance, both age and gender significantly influenced CAg and IgG4, with men having higher levels of both in the total population. Individuals positive for CAg had significantly lower lymphocyte proliferation responses to parasite antigen than did CAg-negative people, regardless of clinical status. This study reemphasizes the importance of CAg measurements for accurately assessing filarial prevalence and clinical status and demonstrates the relationship between active infection and immune responsiveness.

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Section: Discussionmentioning

confidence: 86%

Worm burden and host responsiveness in Wuchereria bancrofti infection: use of antigen detection to refine earlier assessments from the South Pacific.

Steel¹,

Ottesen²,

Weller³

et al. 2001

The American Journal of Tropical Medicine and Hygiene

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“…Another conundrum in schistosome human immunology is the length of time and exposure required for individuals to demonstrate evidence of resistance (31). This is best illustrated in age-acquired immunity where young children demonstrate susceptibility to infection/reinfection, heavy parasite burden, and low levels of schistosome-specific IgE (32). Resistance begins to develop around the time of puberty onset when schistosome-specific IgE is apparent (33,34), but the mechanisms remain unclear and are the subject of debate (35,36).…”

Section: Discussionmentioning

confidence: 99%

CD23-Bound IgE Augments and Dominates Recall Responses through Human Naive B Cells

Griffith

Liang

Onguru

et al. 2011

The Journal of Immunology

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Human peripheral blood BCRμ+ B cells express high levels of CD23 and circulate preloaded with IgE. The Ag specificity of CD23-bound IgE presumably differs from the BCR and likely reflects the Ag-specific mix of free serum IgE. CD23-bound IgE is thought to enhance B cell Ag presentation to T cells raising the question of how a B cell might respond when presented with a broad mix of Ags and CD23-bound IgE specificities. We recently reported that an increase in CD23+ B cells is associated with the development of resistance to schistosomiasis, highlighting the potential importance of CD23-bound IgE in mediating immunity. We sought to determine the relationship between BCR and CD23-bound IgE-mediated B cell activation in the context of schistosomiasis. We found that crude schistosome Ags downregulate basal B cell activation levels in individuals hyperexposed to infectious worms. Schistosome-specific IgE from resistant, occupationally exposed Kenyans recovered responses of B cells to schistosome Ag. Furthermore, cross-linking of CD23 overrode intracellular signals mediated via the BCR, illustrating its critical and dominating role in B cell activation. These results suggest that CD23-bound IgE augments and dominates recall responses through naive B cells.

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“…Fulford et al (1998) propose that in mice and in humans that this might be related to dehydroepiandrosterone levels. Worm development and egg production were delayed in mice deficient in the 5th component of complement at 7 wk of infection (Ruppel et al 1982) but no difference was found in another laboratory at 12 wk (Cheever et al 1987).…”

Section: Worm Development Fecundity and Fecal Egg Excretionmentioning

confidence: 99%