Immunomodulatory effect of Listeria monocytogenes infection. III. Expression of Fc receptor and antibody-mediated cytotoxicity in infected mice.

The level of cells expressing Fc receptor and their ability to antibody mediated cytotoxicity was determined in this study. The adherent cells fraction isolated from blood leukocytes, splenocytes and peritoneal cells of Listeria monocytogenes infected Balb/c mice were rosetted with Ab-SRBC or SRBC. Moreover, blood leukocytes, splenocytes and peritoneal cells were incubated with Ab-51Cr SRBC and 51Cr SRBC as target cells and their cytotoxic activity was assessed by the per cent of specific 51Cr release. The results indicate that in the Listeria infected organisms the level of cells rosetting with Ab-SRBC is greatly increased particularly in peritoneal cells between the 3rd and 7th day of infection i.e. in the period of intensive production of macrophages. Only peritoneal cells exhibit the antibody dependent cytotoxicity. However, the intensity of this cytotoxicity does not correlate with the level of cells expressing Fc receptor.