TABLE 1.

Isolation of HIV-1 biological clones from three patients who did not develop X4 phenotype virus^a

Patient	Date	No. of CD4+ cells/μl	CD4+/ CD8+	Biological clone	TCID50/ml
ACH424b	9/1/88	660	0.45	9F4	3.31 × 103
				9H1	5.01 × 103
	5/21/92	110	0.17	23A1	1.66 × 104
				23G2	2.51 × 104
ACH142c	8/18/86	720	1.06	8A4	7.41 × 103
				8G9	5.01 × 103
	8/25/92	310	0.09	32A7	3.72 × 104
				32D2	2.51 × 104
	4/28/94	300	0.1	*E11	3.72 × 104
AMS198d	9/4/89	430	3.3	1C10	8.32 × 104
				1A11	5.01 × 103
	7/1/91	250	1.2	3F4	1.66 × 104
				3C7	2.51 × 104
	9/16/93	30	0.27	4A2	1.12 × 104

^aR5 HIV-1 biological clones were isolated from three patients in the Amsterdam cohort at different stages of disease. At each time point, blood was drawn and the numbers of CD4⁺ and CD8⁺ T cells per microliter were determined. Biological clones were isolated by limiting dilution of PBMC at each time point, stocks were made, and the titer was measured on PBMC. 

^bSeroconversion, 8/22/88; AIDS, 10/18/91 Candida esophagitis); deceased, 2/09/94. 

^cSeroconversion, before 1986; AIDS, 1991; deceased, 9/16/93. 

^dSeroconversion, before 11/22/84; AIDS, 12/15/93 (Kaposi's sarcoma); deceased, 4/28/94.