Efficient Anti-Idiotypic Immunization with Homologous, Virus Neutralizing Monoclonal Antibodies Conjugated with KLH and Combined with Quil A

Abstract

Recently, we described an enzyme immunoassay (EIA) on cell cultures for the rapid demonstration of Semliki Forest virus (SFV) neutralizing antibodies in serum (Tiel et al, 1986). In that assay, the spike proteins of SFV, either E1 or E2, can be detected in infected L cell monolayers with a horse radish peroxidase (HRPO-) labeled anti-E1 or anti-E2 specific monoclonal antibody (MA). Preincubation of the virus inoculum with SFV neutralizing serum reduces virus multiplication and thereby the appearance of the spike proteins on the surface of the infected L cells which are detected by inhibition of absorbance in the EIA. In Fig. 1, the strong neutralizing capacity of MA UM 5.1 (IgG2a) is demonstrated by this assay. The EIA is very useful for the determination of homologous anti-idiotypic activity in sera of mice. Preincubation of a critically neutralizing dose of MA, e.g. -10log dilution 5.5 of MA UM 5.1 (Fig. 1), with anti-idiotypic immune serum leads to a diminished capacity of this MA to neutralize and thereby to a rise in absorbance value in the EIA. The anti-idiotypic response was provoked in (female) BALB/c mice. The animals were injected intra/subcutaneously with a mixture of the saponin Quil A and protein A Sepharose-purified MA conjugated with keyhole limpet haemocyanin (KLH).