Detection of Sendai virus antibody in mouse and guinea pig sera by an enzyme-linked immunosorbent assay with protein A

An enzyme-linked immunosorbent assay using horseradish peroxidase (HRPO)-labeled protein A (P-ELISA) was established for detection of Sendai virus (SV) antibody in mouse and guinea pig sera. Sensitivity and specificity of P-ELISA were compared with those of ordinary ELISA using HRPO-labeled immunoglobulin G (IgG-ELISA) and the hemagglutination inhibition (HI) test. P-ELISA was 100 to 1,000 times more sensitive than the HI test for detection of the antibody in SV-naturally infected mice. P-ELISA and IgG-ELISA showed similar sensitivities for detection of the antibody in naturally infected mouse and guinea pig sera. A high specificity was demonstrated in P-ELISA with a cut-off optical density value of 0.2 (492 nm), while a non-specific reaction was observed when IgG-ELISA was used to both mouse and guinea pig sera at a low dilution (1:10-20). The antibody in rat sera was not detected by P-ELISA although it was realized by IgG-ELISA.