Human respiratory syncytial virus surface glycoproteins F, G and SH form an oligomeric complex

In order to study structural associations, RSV surface glycoproteins were evaluated using heparin agarose affinity chromatography (HAAC). When RSV-infected cell lysate was analyzed by HAAC, all three surface glycoproteins, (F, G and SH), were eluted. Similarly, when separate lysates from Vero cells infected with vaccinia recombinants expressing F (vvF), G (vvG) and SH (vvSH) proteins were subjected to HAAC, only vvF and vvG expressed proteins bound to heparin, whereas vvSH expressed protein did not bind. When lysates from vvF, vvG and vvSH-infected Vero cells were mixed prior to HAAC, only F and G bound heparin. In contrast, following co-infection of Vero cells with vvF, vvG and vvSH, all three proteins were detected subsequent to HAAC. Following HAAC of A2-infected cell lysate and lysate from vvF, vvG and vvSH co-infected Vero cells, two high molecular weight complexes of 175 Kd and 210 Kd, respectively, were identified that reacted with anti-F, anti-G and anti-SH antisera. In addition, anti-SH antiserum was able to co-precipitate RSV F, G and SH. Using HAAC and a NaCl step gradient we demonstrated that a fraction of RSV F, G and SH eluted at higher salt concentrations than either purified F or G protein. Taken together, these data suggest that RSV F, G and SH glycoproteins can form an oligomeric complex within infected cells and this complex has a higher affinity for heparin than either G or F protein alone.