Trichuriasis: spontaneous and stimulated Th1/Th2 cytokine production by isolated T-cells - abstract

ABSTRACT

Although trichuriasis is the most prevalent known infection in the CARICOM countries, only a small proportion of infected children acquire intense infection, i.e., Trichuris Dysentry Syndrome (TDS). Hypotheses to be investigated are that there is a specific T-Cell anergy to the parasite in such hosts or that they have general predisposition to the "TH2" T-helper-cell response, which would be in keeping with the TDS local anaphylactic response we have shown by various techniques in our other reports. We investigated 3 groups of children controls from a surgical private practice unlikely to have ever been significantly infected TDS cases. We used the ELISPOT technique with primary and secondary monoclonal antibodies to show cytokine production by cells separated from peripheral blood or colonic mucosal biopsies, expressing the final result in numbers of positive cells per 100,000 CD3+ cells (T-cells). Interferon-gamma detection was taken as indicative of the TH1 phenotype and Interleukin 4 (IL4) as indicative of TH2. Spontaneous production in short-term culture was compared with that after stimulation ionophore, staphylococcal enterotoxin B (superantigen) or T. trichiura excretory-secretory (ES) antigen. There was great variability in proportions of cytokine positive cells after culture, both spontaneously and after stimulation. There was also variability in the rank of potency of a given stimulant to "the T-cells of different children. ES antigen provoked the greatest IL4 response for one active TDS case, refuting the anergy hypothesis. The active cases had two highest productions (spontaneous) of interferon-gamma and (stimulated) of IL4. No significant difference in Th1/Th2 phenotypic profile emerged between the control and ex-TDS groups. We conclude that it is not innate character in T-helper-cell response to mitogen or antigen that accounts for predisposition to intense trichuriasis (AU)