T cell secreted interferon-gamma mediates the repair response to arterial injury: studies on immune-deficient Rag-1 KO mice

Sackgreund: Arterial injury initiates an immune-modulated response but serum levels of interferon-~' (IFN~) after injury has not been characterized. We tested the effect of adoptive transfer of T cells from wild type mice or administration of exogenous IFN-y on the response to injury in B and T cell deficient Rag-1 KO mice. Methods: Carotid artery cuff injury was induced in Rag-1 KO and wild type mice. Serum IFN-~, levels were quantified by ELISA. T cell enriched splenocytes from wild type mice were injected i.v. (2-4 x 107 cells) into Rag-1 KO mice 48 hours prior to injury. Another group of Rag-KO mice was injected with murine IFN-~, (20, 000 units, every other day) starting on the day of injury. Neointimal area was measured 21 days after injury. Results: Basal serum IFN-y in wild type mice was 297.8_+123.4 pg/ml (n--4), and undetectable in 3 of 4 mice tested 24 hours after injury. IFN-~' levels returned to baseline levels 3 days after injury (272_+195.5 pg/ml; n=3). Rag-1 KO mice had low levels of IFN-~' (44.3+41.8 pg/ml; n=3), which was increased after adoptive T cell transfer (464.5_+404.2 pg/ml; n=4) indicating that the T cells were viable. Neointimal area in microns eq: