The role of <i>Yersinia pestis</i> antigens in reception of the plague diagnostic bacteriophage L-413C

The role of surface antigens of Yersinia pestis in reception of the phage L-413C was experimentally evaluated. Based on the methods of the phage inactivation after its co-incubation with the soluble or bead-bounded antigens, an importance of LPS from the plague microbe in the phage reception and inability to bind a capsular antigen F1, Ail protein and two autotransporters YapF and YapM were confirmed. The native and recombinant PsaA, being solved, significantly inhibited the lytic activity of the phage in comparison with the bead-bound antigens. The knockout EV cells (ΔpsaA) are able to bind the phage particles as well as the wild strain. The use of three methods to evaluate the role of PsaA antigen in phage L-413C reception gave contradictory results. On the one hand the reactive domains of PsaA are able to interact with phage particles in solution. At the same time, these domains appear to determine nonspecific binding of PsaA protein to the underlying bacterial cell structures and polystyrene microsphere, preventing phage adhesion.