Protective responses in plasmodium falciparum Malaria: interferun - gamma and interleukin - 4 production CD4 + and CD8+ T-cells from individuals resistant and those susceptible to re-infection with plasmodium falciparum
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The T-cell system is probably important in protection against development of malaria through cytotoxicity mediated by CD8+ T-cells and/or by other T-cell activities such as through the action of cytokines. Interferon-gamma (IFN-gamma) has been implicated in resistance to diseases such leishmaniasis. In malaria as well, this cytokine has been shown to have an anti-parasite effect. Although interleukin-4 (IL-4) is associated for example, with increased susceptibility to leishmaniasis among other diseases, its role in malaria remains controversial. In the present study, the ability of CD4+ and CD8+ T-cells from a group a volunteers in the production of IFN-gamma and IL-4 in response to the T-cell epitopes P326-345, P361-380 and P368-390 of the Plasmodium falciparum CSP and a malaria vaccine candidate SPf66 was investigated. The aim was to seek a possible relationship between the ability to produce these two cytokines and resistance to re-infection with Plasmodium falciparum. CD4+ andCD8+ T-cells were depleted using anti-CD4/anti-CD-coated magnetic (Dyna) beads. The number of cells producing either IFn-gamma or IL-4 was assayed using the ELISPOT technique. Data was expressed as mean number of spots for replicate cultures. The paired t test was used to compare results of stimulated and unstimulated cell cultures. IL-4 responses to all stimulating agents except SPf66 gave IFN-gamma responses that were above background responses. Baseline data concerning the week on which each volunteer became parasitaemic after radical cure was available. Using the unpaired t test and correlation analysis, only IFN-gamma responses to P368 - 390 and IL-4 responses to P361-380 showed correlation with resistance to re-infection. These findings have implications that should be considered for the selection of immunogens to be included in future P.falciparum vaccines.
- MST-Zoological Sciences