Immunological properties of a chimeric protein containing the major capsid protein of echovirus 30 (Picornaviridae: Enterovirus: Enterovirus betacoxsackie)

Introduction. Enterovirus infection, widespread in the world and in Russia, is characterized by a variety of clinical forms, one of which is serous meningitis. The most common cause of enterovirus meningitis in children is echovirus 30 (E30). Previously, we obtained a chimeric protein consisting of the S domain of norovirus VP1 protein(SN), fused into one molecule with VP1 protein of E30 (SN-VP1E30), which in the future can be used to develop a vaccine for the prevention of enterovirus meningitis caused by the E30 virus. The aim of this work was to study the immunological properties of the SN-VP1E30 protein. Materials and methods. Balb/c mice and a guinea pig were immunized with the SN-VP1E30 protein. The production of IgG and IgM antibodies was studied by ELISA. The interaction of antibodies against SN-VP1E30 with virions of enteroviruses E30 of different genotypes was studied by electron microscopy. The reaction of neutralization of E30 by antibodies was carried out in vitro in RD cells. Results. In mice immunized with SN-VP1E30 without adjuvant, the average titers of total antibodies against E30 VP1 protein were 1 : 19,000. The use of adjuvant increased the average titer of antibodies by 3 times. The level of IgM antibodies was significantly lower and amounted to, on average, 1 : 1500. Using immunoelectron microscopy, it was shown that guinea pig antibodies against chimeric SN-VP1E30 are able to bind virions of E30 genotypes h and eC2. Mouse and guinea pig antibodies were able to neutralize E30 in RD cell line. Neutralizing antibody titers in mice varied from 20 to 40, and were 40 in guinea pigs. Conclusion. The immunogenicity of SN-VP1E30 in two animal species and the ability of antibodies to bind and neutralize enterovirus E30 allows us to propose it as an antigen in a vaccine for the prevention of diseases caused by E30.