Table 1.

T cell subsets in the peripheral blood of young and aged mice ^a

	CD4	CD8	CD4/CD8
Young (4-6-week)	12.9 ± 6.55	17.3 ± 9.23	1.33 ± 0.66
Aged (24-month)	5.5 ± 1.83	6.2 ± 0.37	0.56 ± 0.28

^a PBMC were stained with FITC-labeled anti-CD4 and PE-labeled anti-CD8 mAbs (BD Biosciences) and analyzed by FACScan. Data represent mean ± of three mice.