CHOLESTEROL OXIDASE FROM RHODOCOCCUS-EQUI IS LIKELY THE MAJOR FACTOR INVOLVED IN THE COOPERATIVE LYTIC PROCESS (CAMP REACTION) WITH LISTERIA-MONOCYTOGENES

The CAMP reaction between Listeria monocytogenes and Rhodococcus equi was studied by a diffusion assay. Listeria monocytogenes displayed ide ntical cooperative haemolytic effect with supernatant cultures of R. e qui or with commercial cholesterol oxidase (COX). This result, even wi th enzymes of different sources (commercial COX is obtained from Pseud omonas spp.) suggests that this enzyme secreted by R. equi has a cruci al role in the synergistic haemolytic (CAMP) reaction with L. monocyto genes. The mechanism of the cooperative lytic process between L. monoc ytogenes and R. equi may represent a different and novel mechanism rea ction, in which the COX may not act as a conventional second-step fact or, and a reaction different to the direct interaction with the choles terol of the erythrocyte membrane may be involved.