Abstract
Purpose: :
NKT cells express various NK cell-associated molecules including proteins in the Ly49 receptor family. Ly49 C/I is an inhibitory receptor that when ligated inhibits cytolytic activity and cytokine production by NK and NKT cells Recently, in vivo studies in our laboratory established that Ly49 C/I invariant (i)NKT cells were required for induction of peripheral tolerance via the eye (Anterior chamber associated immune deviation, ACAID).The purpose of this study was to analyze the role of Ly49 C/I on iNKT cells in the production of immunosuppressive cytokines (IL-10) post exposure to tolerogenic APC( surrogate ACAID APC).
Methods: :
Antigen presenting cells (APC) were derived from either peritoneal exudate cells (PEC) or bone marrow cell cultures. Incubation of the APC with OVA or TGF β and OVA generated immunogenic or tolerogenic APC, respectively The resulting APC were then incubated with iNKT cells ( 24.8A hybridoma) for varying time periods with or without anti-LY49 (5E6). FACS analysis, ELISA and semi-quantitative RT-PCR were used to measure protein expression and mRNA expression of cytokines (IL-10 and IFNγ) relative to the house keeping genes.
Results: :
iNKT cells (24.8A hybridoma) showed an increase in IL-10 mRNA expression and decrease in IFNγ after one hour incubation with tolerogenic APC. iNKT cells responded to immunogenic APC with increased IFNγ mRNA and little or no IL-10 mRNA levels.
Conclusions: :
These results support the postulate that ligation of Ly49 C/I on iNKT cells or their hybridoma counterparts not only inhibits inflammatory cytokine ( IFNγ) production, but at the same time contributes to the production of immunosuppressive cytokines, such as IL-10. Thus the role of Ly49 C/I is enlarged and includes this novel role in the induction of peripheral tolerance. The research was supported in part by NIH grant : EY0111983
Keywords: cytokines/chemokines • immune tolerance/privilege • immunomodulation/immunoregulation