Native Echovirus type 9 Antigen

Enteroviruses (EVs), such as the Coxsackie B-viruses (CVBs), are common human pathogens, which can cause severe diseases including meningitis, myocarditis and neonatal sepsis. EVs encode two proteases (2A(pro) and 3C(pro)), which perform the proteolytic cleavage of the CVB polyprotein and also cleave host cell proteins to facilitate viral replication. The 2A(pro) cause direct damage to the infected heart and tools to investigate 2A(pro) and 3C(pro) expression may contribute new knowledge on virus-induced pathologies. Here, we developed new antibodies to CVB-encoded 2A(pro) and 3C(pro); Two monoclonal 2A(pro) antibodies and one 3C(pro) antibody were produced. Using cells infected with selected viruses belonging to the EV A, B and C species and immunocytochemistry, we demonstrate that the 3C(pro) antibody detects all of the EV species B (EV-B) viruses tested and that the 2A(pro) antibody detects all EV-B viruses apart from Echovirus 9. We furthermore show that the new antibodies work in Western blotting, immunocyto- and immunohistochemistry, and flow cytometry to detect CVBs. Confocal microscopy demonstrated the expression kinetics of 2A(pro) and 3C(pro), and revealed a preferential cytosolic localization of the proteases in CVB3 infected cells. In summary, the new antibodies detect proteases that belong to EV species B in cells and tissue using multiple applications.

Mutations and recombination events have been identified in enteroviruses. Point mutations accumulate with a frequency of 6.3 x 10(-4) per base pair per replication cycle affecting the fitness, the circulation, and the infectivity of enteroviral strains. In the present report, the serological status of the Central and Western Greek population (Larissa and Ioannina, respectively) in the 1-10-year, 11-20-year, 21-30-year, and 31-40-year age groups against six non-polio enterovirus strains, their respective echovirus prototypes, and Sabin 1, 2, and 3 vaccine strains was evaluated, through serum-neutralization assay. In the Western Greek population, antibody levels were detected only for clinical isolates of E30 serotype in all age groups, and for environmental isolate LR61G3 (E6 serotype) only in the 31-40 age group, whereas an immunity level was observed in the Central Greek population, against all strains, except for EIS6B (E3 serotype). Amino acid substitutions were encountered across the structural region of the capsid, between the prototypes and the respective isolates. These substitutions may alter the antigenicity of each strain and may explain the variations observed in the neutralization titers of the different strains. As a consequence, these substitutions severely affect antibody binding and increase the ability of the virus to escape the immune response. It is tempting to assume that changes in the antigenic properties observed in circulating echoviruses represent a selection of viral variants that are less prone to be neutralized by human antibodies. These facts argue for the need of immunological studies to the population to avoid epidemics due to the circulation of highly evolved derivatives.