Background. Current research allows to consider pyoinflammatory processes as dynamical ones triggered by bacterial antigens with disturbance in regulation of systemic inflammatory response and with uncontrolled release of endogenous inflammatory mediators. The value of humoral and cellular immunity factors, role of cytokines in the pathogenesis of pyoiflammatory processes caused by S. aureus, has not been well studied yet.
Thus, the aim of research is estimation of immune state in experimental pyoinflammatory process, caused by S. aureus by examining indexes of cellular and humoral immunity, nonspecific resistance and activity of proinflammatory cytokines.
Materials and methods. Experimental model of pyoinflammatory process was conducted on mice, male of inbred lines C57 Blak. Septic and toxicological model of peritonitis was used in adaptation for S. aureus and under the European Convention for the protection of vertebrate animals used for experimental research or other scientific purposes. Immune cells were differentiated using monoclonal antibodies of firm Serotec, cytokines and IgG levels were detected by ELISA. Digital data were processed by methods of variation statistics.
Results and discussion. Immunological studies in experimental pyoinflammatory process revealed changes of cellular immunity in infected animals compared to intact control group. Pyoinflammatory process led to disturbances at all levels of the immune system including cellular and humoral responses and phagocytosis. Thus, in system of cellular immunity changes were characterized by lymphocytopenia with reducing in number of general T-lymphocytes (CD3+), T-lymphocytes helpers (CD4+), CD25+ and an increase of T-lymphocytes suppressors (CD8+) and CD16+, and low rates of immunoregulatory index. This low level of CD3+, almost two-fold decrease in CD4+ T-lymphocytes with increasing content of CD8+ and decreasing of CD4+/CD8+ index are associated with secondary immunodeficiency. At the same time, the secretion of CD16+ lymphocyte subpopulation increases. In addition, the activation of lymphocytes apoptosis parameters was revealed. Production of proinflammatory cytokines greatly exceeded the normal values, so the level of IL-1b was increased an average of 10.4 times, IL-6 at 17.4 times, TNF-a at 17.8 times compared to intact animals (p <0,001). Studies have shown that depression of phagocytosis, especially the reduction of lymphocytes phagocytic activity, phagocytic number and phagocytic index clearly seen in the experimental pyoinflammatory process, caused by S. aureus.
Conclusions. Based on the research disturbance in immune state with inhibition of lymphocytes general population (CD3+) and T-helpers (CD4+), B-lymphocytes (CD19+, CD22+) and non-specific resistance of the organism together with the activation of cytokines levels and increase in subpopulation of cells — activators of apoptosis (CD95+) was found.