Fig. 1.

Comparison of the amino acid sequences of the 5 synthetic HIV-1 Env peptides used for in vitro stimulation to the corresponding amino acid sequences of the gp160 region of viruses isolated from the HIV-1 infected children. Amino acid differences between the Env peptides and the corresponding viral epitopes are shaded. In vitro T-helper cell reactivity to the Env peptides are expressed as SI’s, which are the ratio of counts per minute (cpm) from Env-stimulated cultures to that of unstimulated cultures. All SI’s >3 were considered as a positive response to the Env stimulus.