TABLE 3.

Superinfection of autologous CD4⁺ CD8⁻ T cells with viral supernatants obtained from three HIV-1⁺ subjects^a

Subject (day)	% p24+ cells	p24 concn		No. of TCID50s/ml
		ng/105 cells	ng/ml
1 (5)	30	1.7	55	31,623
2 (10)	5	0.8	15	464
3 (6)	18	2.3	0.1	10,000
Positive controls	52	3.6	17	3,162
Negative controls	0	0	0	0

^aAutologous CD4⁺ T cells were cultured in the presence of viral supernatants for 5 to 10 days, and the percentage of p24-positive (p24⁺) cells as well as p24 levels in cells and culture supernatants were measured each day. The highest values obtained are presented. CD4⁺ T cells were separated from the PBMCs of each subject by negative selection on immunobeads. Their own viral supernatants were used for superinfection. The percentage of p24⁺ cells was determined by flow cytometry, cell-associated p24 was assayed with lysed CD4⁺ T cells, and ELISA was used to measure p24 levels in CD4⁺ T-cell supernatants. The TCID₅₀ was measured as described in Materials and Methods. Negative controls were uninfected autologous CD4⁺ T cells, and positive controls were cells of a CD4⁺ T-cell line infected with HIV-1 (2A9 subclone) in the laboratory.