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The degree of immune response to corpuscular antigen and macrophage reaction within 24 hours after thermal injury were examined in a comparative study. The number of antibody-producing cells, antigen engulfment and elimination by the cells of peritoneal exudate, their adhesiveness to glass, and cathepsin activity in the cells of peritoneal exudate and the spleen were determined. Mice subjected to thermal burns showed suppressed immune response and decreased functional activity of the cells of the monocytic phagocyte system within the first 24 hours, which was manifested by a decrease in the adhesiveness of these cells to glass, and their ability to engulf and destroy xenogenic erythrocytes.

Treatment of human blood mononuclear cells with homologous alpha-, beta-, and gamma-interferons enhanced to an approximately similar degree the phagocytosis of 51Cr-labeled sheep red cells. Examination of the dose-dependence of this effect with concentrated alpha-interferon showed the maximum effect to be achieved with approximately 1000 units of the preparation.

Bilateral electrolytic coagulation of the posterior and supraoptic hypothalamic nuclei of rabbits had practically no effect on the engulfment of sheep erythrocytes labeled with radioactive sodium chromate retarding chiefly the rate of the antigen catabolism and promoting its retention in the subcellular fractions of the macrophages function than injury of the anterior one. Coagulation of the supraoptic nucleus accelerated India ink clearance at all the periods of investigation, whereas injury of the posterior hypothalamus failed to influence this process.

Blastolysin consisting largely of glycopeptide fragments of cell walls from Lactobacillus bulgaricus has a significant antineoplastic activity against a number of transplanted and spontaneous animal tumours. Blastolysin exerts a pronounced adjuvant action and activates the cells of the mononuclear phagocytic system. This is shown by stimulation of phagocytosis and digestion as well as by acquired ability of macrophages to elicit a cytotoxic action on allogeneic and syngeneic target cells (labelled with radioactive chromium) with abnormal growth. Administration of blastolysin or BCG was demonstrated to lead to variations in the time course of macrophage acquired cytotoxicity. Macrophage activation induced by blastolysin has a clearly pronounced two-phasic nature. During the first short phase the cytotoxicity is seen 2 hours following blastolysin administration, rapidly disappears and emerges after 2 weeks, remaining unchanged up to the 5th week (experimental period).

Adhering splenic cells were separated into the following fractions by centrifugation in the Ficoll density gradient: A (12--16% of Ficoll in the interphase), B (16--21%), C (21--25%) and D (in the sediment). The influence of the cells in fractions B, C and D on the immune response to sheep red blood cells was studied in vivo (in sublethally irradiated mice). When injected simultaneously with lymphocytes, the splenic cells in fractions B and C significantly increased the number of antibody-producing cells in the recipient's spleen. Without lymphocytes neither the initial population of adhering splenic cells, nor its fractions induced the production of antibodies.

The overtime study of changes in the activity of cathepsin D, a lysosomal enzyme, in the splenocytes of CBA mice after their infection with virulent and avirulent Shigella strains of the same origin and with the same antigenic structure has been made. As the result of two months of observations, changes in the activity of this enzyme in the cytoplasmic and lysosomal cell fractions have been found to occur in phases. The activity of cathepsin D has been shown to depend on the virulence of Shigella strains used for inoculation. Virulent Shigella strains induce the pronounced and prolonged activation of the enzyme in the lysosomes, as well as in the cytoplasm. The latter phenomenon is probably indicative of the pathological labilization of the lysosomal membranes, induced by the virulent culture. Avirulent Shigella strains induce only the transient activity of the enzyme in the lysosomes without any essential changes in the permeability of their membranes. These data point to the possibility of differentiating virulent and avirulent Shigella strains by the determination of the enzymatic activity of splenocytes in infected animals.

A study of ingestion and elimination of cells of peritoneal exudate (CPE) of mouse labeled antigens of various physico-chemical nature with a simultaneous analysis of their influence on the function of the enzymatic systems of macrophages showed that both the corpuscular (sheep erythrocytes, typhoid vaccine) and the soluble (albumin, endotoxin of S. typhi, tetanus and staphylococcus toxoid) antigens caused a unitypical reaction of the cells of monocytic phagocytic system. Thirty minutes after the administration the principal mass of labeled antigens (albumin, typhoid vaccine, sheep erythrocytes) was phagocytized by macrophages and was revealed chiefly in their phagolysosomal fraction. The greater part of radioactive material was eliminated in the course of the first 24 hours; however, some of it could be found in the macrophages for a long time. During the process of phagocytosis the activity of lysosomal (catepsin, acid phosphatase, desoxyribonuclease, beta-glucoronidase) enzymes in the macrophages decreased and the activity of redox (succinic dehydrogenase, NAD-N2-diaphorase) enzymes became intensified. A fall of catepsin activity in the CPE of mice 30 minutes after the intraperitoneal administration of the antigens was accompanied by its activation in the cells of the spleen.

The authors studied the effect of adjuvants differing by origin and physico-chemical nature (complete Freund's adjuvant, S. typhi endoxin, cadmium sulfate, iron trichloride) on the ingestion and digestion of erythrocytes of the sheep by the cells of monocytic phagocytizing system, on the persistence of the antigen in these cells, its complexation with the RNA-macrophages and the function of their lysosomal apparatus. The adjuvants change the phagocytizing capacity of the macrophages only in their administration in vivo. Administration to the animals of Freund adjuvant and of the S. typhic endotoxin somewhat increased the ingestion of the antigens, whereas the administration of FeCl3 and CdSO4 failed to change it or even somewhat decreased it. The capacity of ingestion of the antigen in vitro in macrophages obtained from the animals treated with the adjuvants was changed in comparison with the normal. All the adjuvants tested produced a marked action on the lysosomal apparatus of the cells of the monocytic phagocytizing system: they changed the activity of catepsin, promoted the accumulation and the retention in the lysosomes of the highly immunogenic fractions of the antigen, and increased the permeability (except the CdSO4 of the lysosomal membranes in the cells of the antigen binding with the RNA of the cells of the peritoneal exudate or the splenic cells.

The prophylactic effect of immunization with P. aeruginosa polyvalent corpuscular vaccine has been shown on the model of P. aeruginosa generalized chronic infection in mice with leukopenia induced by the intraperitoneal injection of cyclophosphamids. This effect is manifested by the increased resistance of the animals to sublethal doses of P. aeruginosa strain, as well as by more intense general and specific immunological responses in the infected animals (the increase of specific antibody titers, the number of leukocytes in the blood serum and the phagocytic activity of the cells of peritoneal exudate).