FIG. 5.

Phenotype of CD8β^bright CD4^dim lymphocytes. (A) The differentiation phenotype of CD8β^bright CD4^dim lymphocytes was assessed in terms of CD45RA and CD27 expression. Dot plots from PBMCs of a representative subject (subject 10) are shown comparing the distribution of all CD8 lymphocytes (i) against that of CD8β^bright CD4^dim lymphocytes (ii). The lack of expression of CD4 on the CD45RA⁺ CD27⁻ (effector) subset is clearly seen. (B) Percentages of CD8 lymphocytes found to express CD4 in antigen-naïve, antigen-experienced, memory, and effector subsets are shown for 13 subjects. Circles, outliers; stars, extreme outliers. P values were calculated by using the paired t test.