The CD6 scavenger receptor is differentially expressed on a CD56 natural killer cell subpopulation and contributes to natural killer-derived cytokine and chemokine secretion

• Published in: Journal of innate immunity Vol. 3; no. 4; pp. 420 - 434
• Main Authors: Braun, Monika, Müller, Bernadette, ter Meer, Dominik, Raffegerst, Silke, Simm, Barbara, Wilde, Susanne, Spranger, Stefani, Ellwart, Joachim, Mosetter, Barbara, Umansky, Ludmila, Lerchl, Tina, Schendel, Dolores J, Falk, Christine S
• Format: Journal Article
• Language: English
• Published: Switzerland S. Karger AG 01.01.2011
• Subjects: Antigens, CD - metabolism; Antigens, Differentiation, T-Lymphocyte - metabolism; CD56 Antigen - metabolism; Cell Differentiation; Chemokine CXCL1 - secretion; Chemokine CXCL10 - secretion; Chemokines - secretion; Cytokines - secretion; Humans; Interferon-gamma - secretion; Killer Cells, Natural - cytology; Killer Cells, Natural - immunology; Killer Cells, Natural - metabolism; Medicin och hälsovetenskap; Receptors, Scavenger - metabolism; Tumor Necrosis Factor-alpha - secretion
• ISSN: 1662-811X; 1662-8128; 1662-8128
• DOI: 10.1159/000322720

The CD6 scavenger receptor is known to be expressed on virtually all T cells and is supposed to be involved in costimulation, synapse formation, thymic selection and leukocyte migration. Here, we demonstrate that CD6 is differentially expressed by a subpopulation of peripheral CD56(dim) natural killer (NK) cells and absent on CD56(bright) NK cells. CD56(dim)CD16(+) cells represent the major NK subset in the periphery, and most cells within this group are positive for CD6. Most killer immunoglobulin-like receptor- and immunoglobulin-like transcript-positive cells also belong to the CD6(+) subpopulation, as expected from their restricted expression on CD56(dim) NK cells. In addition, CD6(+) NK cells are similar to the newly identified CD94(low)CD56(dim) NK subpopulation and most distant from the recently defined CD27(+) NK subpopulation based on the reverse correlation of expression between CD6 and CD27, a marker associated primarily with CD56(bright) NK cells. With respect to CD6 function on NK cells, direct CD6 triggering did not result in degranulation but induced secretion of cytokines (interferon-γ and tumor necrosis factor-α) and chemokines [CXCL10 (IP-10), CXCL1 (GRO-α)]. Thus, CD6 expression on peripheral NK cells marks a novel CD56(dim) subpopulation associated with distinct patterns of cytokine and chemokine secretion.