Summary
Staphylococcal antigens and immune complexes (ic) prepared from antigen and hyperimmune canine serum were tested for their effects on certain functions of mononuclear (mn) and polymorphonuclear (pmn) leukocytes (cells) obtained from healthy dogs. The effect on mn cells was studied by determining the ability of antigen or ic to augment or inhibit mitogenesis induced by phytohemagglutinin (pha). The effect of antigen or ic on pmn cells was studied by measurement of H2O2 production as an indicator of respiratory burst. Neither the antigen nor the ic, when cultured with mn cells, was mitogenic. Coincubation of antigen or ic with mn cells and pha resulted in a concentration-dependent decrease in mitogenesis. The decreased mitogenesis could not be overcome by addition of excess pha, and may in part have been related to toxic effects of the antigen or ic on mn cells. When mn cells were instead preincubated with antigen or ic, then washed and stimulated with pha, there was still a concentration-dependent inhibition of mitogenesis, although toxicity to the cells was not observed. Low concentrations of staphylococcal antigen or IC stimulated slight H2O2 production by pmn cells. When pmn cells were co-incubated with ic and another stimulus (opsonized zymosan or phorbol myristate acetate), ic appeared to augment phorbol myristate acetate-, but not zymosan-induced stimulation. These results suggest that staphylococcal antigens, either alone or complexed with antibody, have the ability to stimulate pmn cells and inhibit mn cell function. Such actions may have a role in the pathogenesis of recurrent staphylococcal infection in canine patients.
