Relative fluorescence intensity of anti-CD8α and anti-CD8αβ staining. The fluorescence intensity of anti-CD8α and CD8αβ staining was assessed on CD8α⁺CD3⁺ T lymphocytes from an HIV-1 seronegative and a seropositive individual. The anti-CD8α staining showed a similar fluorescence intensity on T lymphocytes from investigated subjects. The CD8αβ expression on T lymphocytes from the HIV-1 seropositive individual was significantly reduced compared with the HIV-1 seronegative individual. The black bars in the CD8αβ-ECD histograms were set at channel 40 for use as a fluorescent reference point.