[The characterization of Francisella tularensis mutants and subspecies by using monoclonal antibodies]

Monoclonal antibodies to F.tularensis cells, subspecies holarctica, were studied for the capacity of reacting with F.tularensis, subspecies nearctica, and its mutants having lower virulence and altered capacity for inducing protective immunity to tularemia in laboratory animals. Among the antibody-producing hybridoma clones under study, clones F8/67 and C7/65 capable of distinguishing the mutants of F.tularensis, subspecies nearctica, with lower virulence than that of the initial strain were selected. Antibodies of these hybridoma clones did not interact with the antigens of the initial virulent strains of F.tularensis, subspecies nearctica, while giving pronounced reaction with the antigens of its mutants. Close F8/67 produced IgG antibodies and clone C7/65, IgM antibodies. As shown in immunoblotting, antibodies produced by these hybridoma clones bound with proteins of F.tularensis cell membranes.