Biological and antigenic characteristics of HEL-12 virus.

The biological and antigenic properties of HEL-12 virus have been compared with gibbon ape lymphosarcoma virus (GALV) and simian sarcoma and simian sarcoma-associated viruses, SiSV and SSAV, respectively, HEL-12 virus did not transform human or marmoset fibroblasts but rescued SiSV focus-forming activity from non-productively transformed marmoset cells (HF/SiSV-NP). Like SSAV and GALV, HEL-12 virus induced syncytia with XC cells. In addition, HEL-12 cells which did not produce virus but which contained HEL-12 proviral DNA, rescued SiSV from HF/SiSV-NP cells in co-cultivation experiments. Results of neutralization and serum cytotoxicity tests utilizing SiSV rescued by HEL-12 [SiSV-(HEL-12)] indicated that HEL-12 virus envelope proteins are very closely related to those of SSAV but readily distinguished from those of GALV. Antigenic diversity of SiSV(SSAV), SiSV(GALV) and SiSV(HEL-12) envelope glycoproteins (gp70) was shown in competition radioimmunoassays (RIA) designed to detect minor antigenic differences using antiserum monospecific for SiSV(SSAV) gp70 or Friend murine leukaemia virus gp70. Antigenic differences between these gp70s were demonstrated in RIA using purified SSAV gp70 or HEL-12 gp70. These data indicate that HEL-12 virus has biological properties similar to those of SSAV and GALV, is distinguished from GALV in neutralization tests and has both distinct and SSAV-related gp70 antigenic determinants.