Monoclonal antibodies to rubella virus glycoprotein E1

AIM: To obtain monoclonal antibodies (MCAs) to glycoprotein E1 of rubella virus, to assess their immunochemical characteristics and ability to use fluorescent MCA for rapid identification of rubella virus. MATERIALS AND METHODS: Rubella virus strain C-74 (Moscow), vaccine strains "Orlov" (Saint-Petersburg), Wistar RA 27/3 (USA) as well as strain Judith (Germany) were used. Viral antigens were obtained using diploid cells L-68 and cell lines VNK-21-F and Vero E6. MCAs were produced by conventional method and their isotype was determined: Immunoblotting, immunoenzume assay (IEA), hemagglutination inhibition assay (HIA) and immunofluorescence assay (IFA) were performed. RESULTS: Five monoclonal antibodies--Kh-252.1, Kh-347.2, Kh-183.3, Kh-214.4, Kh-187.5--to antigens of rubella virus strain C-74 were obtained. Isotypes of these antibodies were determined and their reactivity with native and denaturated antigens of other strains ("Orlov", Wistar RA 27/3, Judith) was characterized. IEA showed that all MCAs interacted with rubella virus glycoprotein E1 at high titers ranging from 1/1600 to 1/200,000. Immunoblotting demonstrated that 4 MCAs (Kh-252.1, Kh-347.2, Kh-183.3, Kh-214.4) had aforementioned feature. MCAs inhibited hemagglutinating activity of Judith strain in titer from 1/16 to 1/1024 in HIA. FITC conjugate of MCA Kh-347.2 (most sensitive variant) allowed to detect rubella virus in infected Vero E6 cells after 24 hours since infection, whereas FITC conjugates of 3 MCAs (Kh-183.3, Kh-214.4, Kh-187.5)--after 72 hours since infection. CONCLUSION: Use of FITC conjugates of MCAs is a perspective tool for identification of rubella virus glycoprotein E1 in infected cell cultures and nasopharyngeal swabs.