Anti-idiotypic antibodies against Puumala virus glycoprotein-specific monoclonal antibodies inhibit virus infection in cell cultures.

Rabbit anti-idiotypic antibodies (anti-ids) were generated against three bank vole and one human monoclonal antibody (MAb) specific for the two envelope glycoproteins of Puumala virus (G1 and G2). The anti-ids were purified by sequential immunoaffinity chromatography. Each anti-id inhibited the antigen binding of its respective MAb in a competitive ELISA. This inhibition, and the absence of cross-reactivity among the anti-ids for heterologous MAbs, showed that they all were specific for unique determinants on the antigen binding site of the homologous MAb. The anti-ids reacted with non-infected Vero E6 cells when examined by immunofluorescence and ELISA, indicating the presence of antibodies that mimic epitopes on the virus. Preincubation of Vero E6 cells with two of the anti-ids produced against neutralizing MAbs inhibited Puumala virus infection, suggesting that these two anti-ids blocked a cellular component involved in virus infection.