Table 1. Lymphocyte subsets based on cell surface markers as determined by four-color flow cytometry.

	Cell Marker
T cell subtype	FITC	PE	APC	PerCP
CD4+ T cells	CD3+	CD20−	CD4+	CD8−
CD8+ T cells	CD3+	CD20−	CD4−	CD8+
B cells	CD3−	CD20+
central memory CD4+ T cells	CD95+	CD28+	CD3+	CD8−
effector memory CD4+ T cells	CD95+	CD28−	CD3+	CD8−
naïve CD4+ T cells	CD95−	CD29+	CD3+	CD8−
CCR5+ memory CD4+ T cells	CD45RA−	CCR5+	CD3+	CD8−