RESUMEN
BACKGROUND: Tuberculosis (TB) continues to be the most frequent cause of illness and death from an infectious agent globally, and its interaction with HIV is having devastating effects. To investigate how HIV alters the immune response to Mycobacterium tuberculosis (Mtb), we assessed basal and Mtb-induced proliferation, cytokine production, and expression of signalling lymphocytic activation molecule (SLAM), inducible costimulator (ICOS) and programmed death-1 (PD-1) on T lymphocytes from HIV-positive individuals coinfected with TB, HIV-positive subjects, TB patients and healthy donors (HD). FINDINGS: HIV-TB patients showed increased ICOS, SLAM and PD-1 basal levels on T lymphocytes, whereas HIV-positive individuals displayed elevated levels of SLAM and PD-1, TB patients high levels of SLAM, and HD low levels of the three proteins. Mtb-stimulation enhanced ICOS expression in the four groups, but only TB and HD increased SLAM and PD-1 levels. CONCLUSIONS: These data show the immune deregulation that takes place during the immune response against TB in different study populations.
Asunto(s)
Antígenos CD/biosíntesis , Perfilación de la Expresión Génica , Infecciones por VIH/complicaciones , Proteína Coestimuladora de Linfocitos T Inducibles/biosíntesis , Receptor de Muerte Celular Programada 1/biosíntesis , Receptores de Superficie Celular/biosíntesis , Linfocitos T/inmunología , Tuberculosis Pulmonar/inmunología , Proliferación Celular , Citocinas/metabolismo , Humanos , Miembro 1 de la Familia de Moléculas Señalizadoras de la Activación Linfocitaria , Linfocitos T/químicaRESUMEN
Effective host defense against tuberculosis requires Th1 cytokine responses. We studied the regulation of interferon (IFN)- gamma production during tuberculosis by investigating the role of CD31, a receptor that attenuates T cell receptor signals. After antigen stimulation, CD3(+)CD31(+) blood lymphocytes decreased in healthy donors and in tuberculosis patients with robust Th1 responses to Mycobacterium tuberculosis and IFN- gamma was secreted only by CD31(-) T cells. In contrast, in patients with weak Th1 cytokine responses to M. tuberculosis, the level of CD3(+)CD31(+) lymphocytes was increased and IFN- gamma production was low. Furthermore, the inverse relationship between CD31 expression and IFN- gamma production was in contrast to signaling lymphocytic activation molecule (SLAM) expression, an IFN- gamma inducer in tuberculosis. Interestingly, CD31 bound to SLAM-associated protein (SAP), an IFN- gamma inhibitor in tuberculosis, and when CD31 and SAP were coexpressed in lymphocytes, their association inhibited the IFN- gamma response to M. tuberculosis. Thus, CD31, when binding to SAP, interferes with Th1 responses, suggesting that CD31 has a key regulatory role in the signaling pathway(s) leading to the IFN- gamma response to M. tuberculosis.