TABLE 1.

CD4 and coreceptor expression on different cells^a

Cell line	Expression level on target cells (103 molecules/cell)
	CD4	CXCR4	CCR5
PBL	70 ± 7	2.5 ± 1	0.6 ± 0.5
PBL + MβCD	50 ± 6	2.5 ± 1	0.8 ± 0.6
HOSCD4X4R5	11 ± 3	64 ± 11	249 ± 28
HeLa-RC	10 ± 3	10 ± 3	NDb
HeLa-JC	150 ± 18	17 ± 12	ND
HeLa-J10	196 ± 18	ND	6 ± 2
HeLa-J53	345 ± 37	ND	190 ± 30

^aThe levels of expression of CD4 and coreceptors on the different cell lines were assessed by flow cytometry. For each antibody, calibration curves between the fluorescence signal and the number of molecules were established by using cells of a known level of expression (35,54). The mean intensity and standard deviation were determined for each cell and each antibody and related to the level of expression with those calibration curves.

^bND, not determined.