Naïve blood monocytes suppress T-cell function. A possible mechanism for protection from autoimmunity.
In certain disease context, cells of the monocyte/macrophage lineage are known to exhibit T-cell suppressor function. However, whether naïve monocytes are also able to suppress T-cell responses has not been previously investigated. In this study, we have discovered that CD11b(+)Ly6G(-) mononuclear cells in the blood of naïve mice are potent suppressors of T-cell proliferation in vitro. The suppression of T-cell proliferation requires cell-cell contact and is partially dependent on nitric oxide production. Following the induction of experimental autoimmune encephalomyelitis in mice, the suppressor function of this blood CD11b(+)Ly6G(-) cell population is impaired. Therefore, blood CD11b(+)Ly6G(-) cells appear to be intrinsically suppressive and may have a key role in maintaining immune homoeostasis. Loss of this suppressive function may contribute to development of autoimmunity.
Malaghan Institute of Medical Research, Wellington, New Zealand.
Clare Y
CY
Slaney
Aras
A
Toker
Anne
A
La Flamme
B Thomas
BT
Bäckström
Jacquie L
JL
Harper
D000818:Animals; D000954:Antigens, Surface; D015551:Autoimmunity / Q000276:immunology*; D039481:CD11b Antigen / Q000276:immunology; D002450:Cell Communication / Q000276:immunology; D049109:Cell Proliferation; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000276:immunology / Q000473:pathology; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009000:Monocytes / Q000166:cytology / Q000276:immunology*; D009569:Nitric Oxide / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D000954:Antigens, Surface; D039481:CD11b Antigen; D009569:Nitric Oxide