INCREASED ENZYME-LINKED-IMMUNOSORBENT-ASSAY SPECIFICITY WITH SOLUBILIZED SIMIAN RETROVIRUS 2-INFECTED CELL-MEMBRANES

Simian type-D retrovirus (SRV) infection is a health problem in captiv e and wild-caught macaques; it interferes with acquired immune deficie ncy syndrome-related research. Because the enzyme-linked immunosorbent assay (ELISA) with gradient-purified SRV-2 virus yields a high percen tage of false-positive results, the assay was modified with membrane a ntigens from SRV-2-infected and uninfected A549 cells. The SRV-2 membr ane antigen contains the major proteins detected in positive sera by W estern blotting: enu proteins gp70 and gp20 and gag proteins p27, p14, p12, and p10. The original purified virus ELISA had a specificity of 74% compared with Western immunoblot. The modified ELISA using the dif ference in optical density between infected and control cell membrane antigens resulted in a specificity of 100% when the same samples were tested.