CD43 Deficiency Has No Impact in Competitive In Vivo Assays of Neutrophil or Activated T Cell Recruitment Efficiency

Abstract

Using noncompetitive methodologies comparing CD43+/+ and CD43−/− mice, it has been reported that CD43−/− leukocytes exhibit reduced recruitment efficiency to sites of inflammation. More recent analyses demonstrate that CD43 on activated T cells can function as an E-selectin ligand (E-SelL) in vitro, suggesting that CD43 might promote rolling interactions during recruitment of leukocytes and account for the reported recruitment deficits in CD43−/− T cells and neutrophils in vivo. Internally controlled competitive in vivo methods using fluorescent tracking dyes were applied to compare recruitment efficiency of CD43+/+ vs CD43−/− activated T cells to inflamed skin and of peripheral blood neutrophils to inflamed peritoneum. A simple CFSE perfusion method was developed to distinguish arterial/venous vasculature and confirm appropriate extravasation through venules in a Con A-induced cutaneous inflammation model. In vivo recruitment of peripheral blood neutrophils to inflamed peritoneum was core 2 GlcNAcT-I dependent, but recruitment efficiency was not influenced by absence of CD43. There were also no significant differences in core 2 GlcNAcT-I-dependent, selectin-dependent, cutaneous recruitment of activated T cells from CD43+/+ and congenic CD43−/− mice in either B6 or P-selectin−/− recipients despite biochemical confirmation that a CD43-specific E-SelL was present on activated T cells. We conclude that recruitment of neutrophils and activated T cells in these in vivo models is not influenced by CD43 expression and that if CD43 on activated T cells performs an E-SelL function in vivo, it contributes in a limited physiological context.