ISSN:
1365-3083
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Innate mechanisms involving natural killer cells have been implied to play an important role in immunity against Leishmania infection. Previous studies have evaluated responses to three purified amastigote antigens, P-2, P-4 and P-8, of Leishmania pifanoi. The P-4 and P-8 antigens have been demonstrated to induce protection in mouse models, as well as to induce cellular responses in American cutaneous leishmaniasis patients. Cells from Leishmania aethiopica-infected leishmaniasis patients preferentially responded to P-8 and, to a lesser extent, to the cysteine proteinase, P-2. In this study, it is shown that cells from healthy donors, including cells from truly naïve donors (cord blood), could be stimulated to proliferation and cytokine production by P-2. The main proliferating cell types in healthy adult donors were CD16/56+ and the CD8+ cells. Blocking of major histocompatibility complex (MHC) class II with α-MHC class II antibodies markedly inhibited proliferation and interferon-γ (IFN-γ) production, whereas interleukin-10 production was not affected. Experimental evidence indicates that CD4+ cells were not necessary for the proliferative and IFN-γ responses; however, an adherent cell population was required. Furthermore, CD16/56+ cells expressing MHC class II were expanded following P-2 stimulation. The responses to P-2 show a striking similarity to responses induced by the vaccine candidate Leishmania homologue of receptors for activated C-kinase (LACK) in healthy donors. The responses described here may not be desirable when aiming at inducing protective immune responses with a vaccine, and the implications of these results for the development of vaccines against leishmaniasis are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.0300-9475.2004.01388.x
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