Unaltered levels of transplant arteriosclerosis in the absence of the B cell homing chemokine receptor CXCR5

Chemokine receptors and their ligands are crucial for lymphocyte trafficking under both homeostatic and inflammatory conditions. The chemokine receptor CXCR5 controls B cell migration and the organization of B cell follicles. The aim of this study was to investigate the impact of CXCR5 on the development of transplant arteriosclerosis. Fully MHC mismatched BALB/c (H2^d) donor aortas were transplanted into C57BL/6-CXCR5^-/- (H2^b), C57BL/6-CXCR5^+/- (H2^b) or C57BL/6-CXCR5^+/+ (H2^b) recipients. Grafts were analysed by morphometry and immunofluorescence and intra-graft cytokine mRNA production was analysed by RT-PCR. Transplant arteriosclerosis was evident in CXCR5+/+ and CXCR5+/- mice and only mildly reduced in CXCR5-/- recipients indicating that absence of CXCR5 had no substantial effect on the development of transplant arteriosclerosis. Analysis of the cellular infiltrate of aortic grafts implanted in CXCR5-/- recipients revealed no differences in the number of T-cells, macrophages and B cells as compared to controls. Intra-graft cytokine production showed no significant changes in Th1 (IL-12) and Th2 (IL-4) cytokines as well as in TGF-β and iNOS production. These data suggest that lack of CXCR5 expression by recipient T- and B-cells has little effect on the development of transplant arteriosclerosis.