SEROLOGIC REACTIVITY OF A SYNTHETIC PEPTIDE FROM HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 GP41 WITH SERA FROM A MEXICAN POPULATION

The reactivities of 1,172 serum samples obtained from asymptomatic hum an immunodeficiency virus type 1 (HIV-1)-positive and HIV-1-negative i ndividuals residing in Mexico to a synthetic disulfide-looped peptide from the HIV-1 gp41 (amino acids 602 to 616 [IWGCSGKLICTTAVP]) were ex amined by an enzyme-linked immunoadsorbent assay (ELISA) procedure. An tibodies to the synthetic peptide were detected in 261 of 268 serum sa mples from HN-positive individuals (sensitivity, 97.4%), The peptide a lso reacted with 12 of 904 serum samples from control HIV-negative ind ividuals (specificity, 98.7%), Western blots (immunoblots) of four of the seven serum samples that produced false-negative results in the EL ISA showed that three of them reacted weakly with gp41 and strongly wi th gp120, p55, and/or p24, Potential diagnostic difficulties raised by the reported C1q binding capacity of this peptide were also evaluated : few and weak false-positive results were found among sera from patie nts with rheumatoid arthritis (1 of 31) and neurocysticercosis (2 of 1 11), In fact, strong reactivity with the peptide spotted an undetected HIV infection underlying clinical neurocysticercosis.