DIFFERENTIAL IMMUNOREGULATORY ACTIVITY OF HIV ENV-GAG PROTEIN ON CORD-BLOOD VS ADULT PERIPHERAL-BLOOD LYMPHOCYTES

We and others have shown that several peptides from HIV (e.g., TAT pro tein and env peptides) can modulate the activities of lymphocytes from adult donors. In this study the recombinant HIV fusion protein env-ga g was examined for its immunoregulatory activities on both adult perip heral blood lymphocytes (PBL) and cord blood lymphocytes (CBLs). Proli ferative response of lymphocytes was determined by H-3 thymidine incor poration. While 95% of PBL samples responded with significant prolifer ation to the HIV peptide, only 25% of the CBL samples responded. In th e same experiment, while none of PBL samples showed suppression of pro liferation with the HIV env-gag fusion protein, 45% of the CBL samples did show suppression. When lymphocytes were incubated simultaneously with env-gag protein and phytohemagglutinin (PHA), 75% of the CBL samp les showed significant decreases in their mitogen proliferative respon ses, while only 8% of adult lymphocytes samples showed similar decreas es. These observations suggest that HIV env-gag protein has immunoregu latory effects on lymphocytes and that this effect differs significant ly in CBLs versus PBLs.