Induction of Inhibitory Receptors on T Cells During Plasmodium vivax Malaria Impairs Cytokine Production

PAC Costa, FMS Leoratti, MM Figueiredo… - The Journal of …, 2015 - academic.oup.com
PAC Costa, FMS Leoratti, MM Figueiredo, MS Tada, DB Pereira, C Junqueira, IS Soares
The Journal of infectious diseases, 2015academic.oup.com
The function and regulation of the immune response triggered during malaria is complex
and poorly understood, and there is a particular paucity of studies conducted in humans
infected with Plasmodium vivax. While it has been proposed that T-cell-effector responses
are crucial for protection against blood-stage malaria in mice, the mechanisms behind this in
humans remain poorly understood. Experimental models of malaria have shown that the
regulatory molecules, cytotoxic T-lymphocyte attenuator-4 (CTLA-4), lymphocyte activation …
Abstract
The function and regulation of the immune response triggered during malaria is complex and poorly understood, and there is a particular paucity of studies conducted in humans infected with Plasmodium vivax. While it has been proposed that T-cell-effector responses are crucial for protection against blood-stage malaria in mice, the mechanisms behind this in humans remain poorly understood. Experimental models of malaria have shown that the regulatory molecules, cytotoxic T-lymphocyte attenuator-4 (CTLA-4), lymphocyte activation gene-3 (LAG-3), and programmed death-1 (PD-1) are involved in the functional impairment of T cells during infection. Our goal was to define the role of these molecules during P. vivax malaria. We demonstrate that infection triggers the expression of regulatory molecules on T cells. The pattern of expression differs in CD4+ and CD8+ T cells. Higher frequencies of CD4+ express more than 1 regulatory molecule compared to CD8+ T cells. Moreover, lower proportions of CD4+ T cells coexpress regulatory molecules, but are still able to proliferate. Importantly, simultaneously blockade of the CLTA-4, PD-1, and T-cell immunoglobulin and mucin–3 signaling restores the cytokine production by antigen-specific cells. These data support the hypothesis that upregulation of inhibitory receptors on T cells during P. vivax malaria impairs parasite-specific T-cell effector function.
Oxford University Press