Foxp3 Expression in Bovine CD8⁺ T Cells Is Associated with the Intensity of CD25 Expression

Abstract

The aim of the undertaken research was to determine whether Foxp3⁺CD25⁺CD8⁺ cells exist in cattle and whether Foxp3 expression in CD8⁺ T cells is correlated with the intensity of CD25 expression. It has been found that 0.66 and 2.36% of CD8⁺ cells on average showed high and low expression of the CD25 molecule, respectively. On average, 11.61% of CD25^highCD8⁺ cells expressed Foxp3, while the mean percentage of Foxp3⁺ cells within CD25^lowCD8⁺ cells was 3.66%. The absolute count of Foxp3⁺CD25^highCD8⁺ cells was not significantly different from the absolute count of Foxp3⁺CD25^lowCD8⁺ cells. The obtained results indicate that CD8⁺ cells with the regulatory phenotype, i.e. Foxp3⁺CD25^highCD8⁺ and Foxp3⁺CD25^lowCD8⁺ cells, occur naturally in bovine peripheral blood, although both of these subpopulations are relatively small. There is a positive correlation between the intensity of CD25 expression and the expression of the transcription Foxp3 factor in bovine CD8⁺ cells.