-1-NAPHTHALENESULPHONYL)-2-(3-PYRIDYL)THIAZOLIDINE (YHI-1) SELECTIVELY INHIBITS HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1

-1-naphthalenesulphonyl)-2-(3-pyridyl)thiazolidine (YHI-1), a syntheti c analogue of D-cysteinolic acid isolated from sardines (Sardinops mel anostictus), was found to be a specific inhibitor of human immunodefic iency virus type 1 (HIV-1) replication in various cell cultures. YHI-1 inhibited HIV-1(IIIB) replication with a 50% effective concentration (EC50) of 3.35, 10.23 and 4.61 mu M in MT-4 cells, peripheral blood mo nonuclear cells and MAGI-CCR5 cells, respectively. However, no antivir al activity was observed with non-nucleoside reverse transcriptase inh ibitor (NNRTI)-resistant HIV-1 strains, such as nevirapine-resistant H IV-1(HE/NEV) and MKC-442-resistant HIV-1(IIIB-R), or with HIV-2(ROD) o r SIVMAC. YHI-1 failed to inhibit reverse transcriptase (RT) activity in vitro with different template-primer systems. Time-of-addition expe riments, the failure to inhibit NNRTI-resistant strains and the failur e to show in vitro activity against RT suggest that a metabolite of YH I-1 inside the cell acts like an NNRTI. Thus, YHI-1 seems to belong to a new class of HIV-1 inhibitor and is a good candidate for further de velopment.