African-European differences in the capacity of T-cell cytokine production

Regional differences in immune responsiveness have been studied by comparin g the frequency of cytokine producing T cells in healthy African children a nd adults and their age-matched European counterparts. By use of flow cytom etry for the intracellular detection of cytokines an overall expansion of C D4(+) and CD8(+) T cells producing the Type I cytokines interleukin (IL)-2 and interferon (IFN)-gamma was observed in adults when compared with childr en, giving credit to the cumulative effect of contacts with environmental a ntigens. The CD4(+) cells expressing the Type 2 cytokines IL-4 and IL-13, h owever, increased only in Africans, probably reflecting continuously presen t challenges with antigens that preferentially drive Type 2 responses. A st riking increased frequency of both Type 1 and Type 2 cytokines producing T cells was found in African adults when compared with their European counter parts. The quantitative and qualitative regional differences in immune reac tivity are likely to be of significance for all immune intervention strateg ies, especially for the design of vaccines.