Alleged common antigenic determinant of tobacco mosaic virus coat protein and the host protein ribulose-1,5-bisphosphate carboxylase is an artifact of indirect ELISA and western blotting.

We have reported the detection of an antigenic determinant shared by the tobacco mosaic virus coat protein and the large subunit of ribulose-1,5-bisphosphate carboxylase, a host protein (R.G. Dietzgen and M. Zaitlin Virology 155, 262-266, 1986). This conclusion was questioned by D. Zimmermann and M.H.V. Van Regenmortel (Arch. Virol. 106, 15-22, 1989). Thus we have reinvestigated this unexpected serological cross-reaction in Western immunoblotting and indirect ELISA. We found that when skimmed milk instead of bovine serum albumin was used as a blocking agent and as a diluent for antibodies and alkaline phosphatase conjugates, the alleged cross-reaction was abolished. In light of these findings, we retract our previous conclusions.