Comparative investigation of PMN leucocyte antimicrobial potential in animals of different species susceptibility to the plague agent.

The present work was aimed at a comparative study of oxygen-dependent metabolism (OM) and myeloperoxidase (MPO) activities as well as the content of bactericidal cationic proteins (BCP) in polymorphonuclear leucocytes (PMNL) from mammals and birds with different susceptibility to plague (mice, guinea pigs, rats, great and miday gerbils, rabbits, dogs, pigeons and man). The experimental finding of an association between infectious susceptibility and functioning of the major PMNL bactericidal systems (OM activity and BCP content) indicates that the magnitude of antimicrobial potential of professional phagocytes is a factor determining species susceptibility to plague. The intermediate and high levels of MPO activity detected in all the species studied except in pigeons suggest involvement of the MPO-H2O2-halide cytocidal system of PMNL in destroying Y. pestis.