Effect of pH, ions, bovine serum albumin and heterologous antisera on the stability of immunosorbed flexuous potato viruses

Electron microscopic studies on the stability of immunosorbed (trapped) vir ions of potato viruses X, S and Y-o (PVX, PVS and PVYo) revealed disintegra tion and dislodging of PVYo virions upon incubation with (1) antisera to PV X, PVS, or both diluted in saline, (2) 0.86% NaCl (saline) or 0.1 mol/l CaC l2 but not with 0.1 mol/l CaSO4 or 0.1 mol/l MgSO4. PVX virions, on the oth er hand, showed partial dislodging upon incubation with an antiserum to PVS diluted in saline, but complete disintegration and dislodging with saline. 0.1 mol/l CaCl2 caused partial dislodging while MgCl2, CaSO4 or MgSO4 (all 0.1 mol/l) had no apparent adverse effect. PVS virions were not affected b y saline, CaCl2, MgCl2, CaSO4 or MgSO4 (all 0.1 mol/l) and were only partia lly dislodged by antisera to PVX or PVYo. Disintegration and/or dislodging of the PVX and PVYo virions was prevented when(1)they were fixed with gluta raldehyde prior to incubation or (2) the virus extract contained bovine ser um albumin (BSA) or (3) heterologous antisera were diluted in 0.1 mol/l pho sphate buffer (PB) before use except the PVS antiserum which still caused d isintegration and dislodging of PVYo virions. Prior fixation of virions pre vented their disruption and dislodging by saline only in the case of PVYo b ut not PVX. On the other hand, BSA reverted the adverse effect of saline bu t not that of the PVS antiserum on PVYo virions. The results presented here suggest (1) a disruptive effect of Cl' on PVX and PVYo virions particularl y when it was associated with Na' and (2) an interaction between the immuno sorbed virions of PVX or PVYo and the antiserum to PVS.