Expression of signaling lymphocytic activation molecule-associated protein interrupts IFN-gamma production in human tuberculosis

• Published in: The Journal of immunology (1950) Vol. 172; no. 2; pp. 1177 - 1185
• Main Authors: Pasquinelli, Virginia, Quiroga, María F, Martínez, Gustavo J, Zorrilla, Liliana Castro, Musella, Rosa M, Bracco, María M, Belmonte, Liliana, Malbrán, Alejandro, Fainboim, Leonardo, Sieling, Peter A, García, Verónica E
• Format: Journal Article
• Language: English
• Published: United States 15.01.2004
• Subjects: Adjuvants, Immunologic - metabolism; Adjuvants, Immunologic - physiology; Antibodies, Monoclonal - metabolism; Antigens, CD; Carrier Proteins - biosynthesis; Carrier Proteins - genetics; Carrier Proteins - metabolism; Carrier Proteins - physiology; Cells, Cultured; Chromosomes, Human, X - immunology; Down-Regulation - immunology; Glycoproteins - metabolism; Glycoproteins - physiology; Humans; Immunity, Cellular - genetics; Immunoglobulins - metabolism; Immunoglobulins - physiology; Interferon-gamma - antagonists & inhibitors; Interferon-gamma - biosynthesis; Interferon-gamma - pharmacology; Interleukin-12 - pharmacology; Intracellular Signaling Peptides and Proteins; Ligands; Lymphoproliferative Disorders - genetics; Lymphoproliferative Disorders - immunology; Mycobacterium tuberculosis; Mycobacterium tuberculosis - immunology; Receptors, Cell Surface; SAP protein; Severity of Illness Index; Signal Transduction - genetics; Signal Transduction - immunology; Signaling Lymphocytic Activation Molecule Associated Protein; Signaling Lymphocytic Activation Molecule Family Member 1; SLAM protein; Tuberculosis - genetics; Tuberculosis - immunology; Tuberculosis - microbiology; Up-Regulation - immunology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.172.2.1177

Production of the Th1 cytokine IFN-gamma by T cells is considered crucial for immunity against Mycobacterium tuberculosis infection. We evaluated IFN-gamma production in tuberculosis in the context of signaling molecules known to regulate Th1 cytokines. Two populations of patients who have active tuberculosis were identified, based on their T cell responses to the bacterium. High responder tuberculosis patients displayed significant M. tuberculosis-dependent T cell proliferation and IFN-gamma production, whereas low responder tuberculosis patients displayed weak or no T cell responses to M. tuberculosis. The expression of the signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) on cells from tuberculosis patients was inversely correlated with IFN-gamma production in those individuals. Moreover, patients with a nonfunctional SAP gene displayed immune responses to M. tuberculosis similar to those of high responder tuberculosis patients. In contrast to SAP, T cell expression of SLAM was directly correlated with responsiveness to M. tuberculosis Ag. Our data suggest that expression of SAP interferes with Th1 responses whereas SLAM expression contributes to Th1 cytokine responses in tuberculosis. The study further suggests that SAP and SLAM might be focal points for therapeutic modulation of T cell cytokine responses in tuberculosis.