Application of immunoassay of encephalomyocarditis virus in cell culture with enzyme-labeled virus-specific monoclonal antibodies for rapid detection of virus, neutralizing antibodies, and interferon

Neutralization enzyme immunoassay for influenza virus

A neutralization enzyme immunoassay (N-EIA) was developed for the detection of antibody titer rises in sera of patients infected with influenza A (H3N2) virus. In this N-EIA, a selected strain of influenza A (H3N2) virus was added to monolayers of LLC-MK2 cells in microtiter plates. After 24 h, the replicated virus could be demonstrated with a virus-specific enzyme-labeled monoclonal antibody. Preincubation of the influenza virus with convalescent-phase sera of patients infected with influenza A (H3N2) virus resulted 1 day later in decreased absorbance values that could be used for calculation of neutralization titers. From use of paired serum samples from 10 patients with a history of flu-like symptoms, the results obtained with N-EIA correlated well (r = 0.83) with those of the standard hemagglutination inhibition test.

Inhibition of Semliki Forest virus multiplication in L-cells by combinations of interferon and ribavirin as measured by plaque titration and direct enzyme immunoassay

Inhibition of Semliki Forest virus (SFV) multiplication in L-cell monolayers by combinations of mouse interferon (IFN) and ribavirin was measured by plaque titration and by direct enzyme immunoassay of SFV in L-cells. When critically inhibitory quantities of IFN and ribavirin were combined, an additive inhibitory effect was observed in either assay.

Detection of a shared idiotope on two encephalomyocarditis virus neutralizing monoclonal antibodies by neutralization inhibition enzyme immunoassay

Idiotypic cross-reactivity between encephalomyocarditis virus (EMCV) neutralizing monoclonal antibodies UM 21.1 (IgG2b) and UM 21.3 (IgG2a) was detected by neutralization inhibition enzyme immunoassay using polyclonal and monoclonal anti-idiotypic antibodies. One strongly cross-reactive anti-idiotypic monoclonal antibody, designated 21.1A5 (IgG2b), might recognize a recurrent idiotope on EMCV neutralizing antibodies but it did not induce EMCV neutralizing anti-anti-idiotypic antibodies in homologous BALB/c mice.

Detection by a solid phase independent enzyme immunoassay of monoclonal anti-idiotypic antibodies against monoclonal antibodies neutralizing Semliki Forest virus and encephalomyocarditis virus

Neutralization inhibition enzyme immunoassay (NI-EIA) was evaluated for its usefulness to detect monoclonal anti-idiotypic antibodies (ab2mAbs) against idiotypic monoclonal antibodies (ab1mAbs) neutralizing either Semliki Forest virus (SFV) or encephalomyocarditis virus (EMCV). Purified ab1mAbs were coupled to keyhole limpet hemocyanin (KLH) mixed with the adjuvant Quil A and then injected intracutaneously into homologous BALB/c mice. Successful fusions were performed 5, 6 and 7 days after intracutaneous booster immunizations of these mice. Ab2mAbs in hybridoma supernatant fluids were detected by their capacity to block virus neutralization by ab1mAbs in NI-EIA. Two stable ab2mAb producing hybridomas were obtained against SFV neutralizing mAb UM 1.13, and twelve against EMCV neutralizing mAb UM 21.1.

Blocking by anti-idiotypic antibodies of monoclonal antibody mediated protection in mice against encephalomyocarditis virus induced diabetes and lethal disease

Monoclonal antibodies (MA) UM 21.1 and UM 21.2 protect mice against encephalomyocarditis virus (D-variant) induced diabetes and lethal disease. MA-mediated protection in vivo as well as neutralization in vitro could be specifically blocked by anti-idiotypic antibodies.