PULMONARY INTRAVASCULAR MACROPHAGES IN THE PATHOGENESIS OF BOVINE PULMONARY-LESIONS CAUSED BY ACTINOMYCES-PYOGENES

Rabbit antisera raised against somatic antigens from two strains of Ac tinomyces pyogenes reacted specifically in a peroxidase anti-peroxidas e technique which was developed for the location of the bacteria in fo rmalin-fixed tissues. The technique was applied on experimental murine and spontaneous bovine lesions caused by A. pyogenes. By electron mic roscopy and immunohistochemistry it was demonstrated that pulmonary in travascular macrophages play a role in the uptake of A. pyogenes from the blood, and in the production of pyaemic pulmonary lesions.