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In staphylococcal infection the changes in functional ability of macrophages occur: their oxygen-depending bactericidity and adenosine-desaminase activity are depressed 5-nucleotidase ability increases. Introduction of homologous alpha-IFN in the dose of 1 x 10(3) u/mouse leads to enhancing macrophage bactericidity of the animals infected, inhibits their 5-nucleotidase activity and enhances adenosine desaminase one. Influence of alpha-IFN on the activity of adenosine metabolism enzymes in macrophages can be considered one of the most important mechanisms of its modulating effect in bacterial infections.

In mice with metastasizing tumors that received a reduced (by 30-40%) daily ration, suppression of neovascularization processes and normalization of macrophage function were recorded: activity of macrophages in the area of the metastatic growth increased, while activity of macrophages suppressing T-lymphocytes in the spleen was decreased. It has been suggested that these effects play a role in the phenomenon observed by the authors--suppression of the metastatic processes in the test mice kept on a reduced food ration.

Data on the participation of macrophages in the control of tumour growth and metastatic spreading are presented. Information about the macrophage activation and secretion of soluble cytotoxic factors is given. Certain biochemical mechanisms related to the antimetastatic activity of macrophages are presented. A conclusion is drawn on the possibility of macrophages to stimulate the tumour growth in certain cases. This possibility should be taken into account during the antimetastatic therapy with macrophage activators.

Adenosine deaminase and 5'-nucleotidase activities as well as chemiluminescence emission were measured in peritoneal macrophages of Syrian hamsters in the growth process of tumours with different grade of malignancy. The adenosine deaminase activity was established to decrease, while the 5'nucleotidase activity--to increase in macrophages after the subcutaneous injection of tumour cells with high level of malignancy as compared with these values in normal cells. This is accompanied by a decrease of the macrophage chemiluminescence during the whole experimental period. At the same time adenosine deaminase and 5'-nucleotidase activities as well as chemiluminescence emission in peritoneal macrophages of hamsters treated with low-malignancy cells do not differ from these values in the control group.

It has been established that N-acetylglucosaminyl-N-acetylmuramyl-L-alanyl-D-isoglutamine (GMDP), a new synthetic analog of muramyl dipeptide, while incubated in vitro with macrophages essentially inhibits 5'-nucleotidase (5-N) activity without any influence on the activity of adenosine deaminase in these cells. The maximal effect was recorded 24 h after co-incubation. As 0.01 = 1 microgram/ml concentration of GMDP was added, the enzyme activity gradually decreased to minimum. L-D-isomer of GMDP was shown to affect 5-N activity whereas the effect of its analog with a double peptide chain GM (DP)2 was found to be less. Inhibition of 5-N activity may be one of the mechanisms by which macrophages are activated under the influence of GMDP.

The antimetastatic action of bacterial endotoxins (BET), E. coli 0111:B4, B in particular, as well as their influence on the adenosine deaminase and 5'-nucleotidase activity were studied in peritoneal macrophages of mice bearing lung Lewis carcinoma. BET inhibition of lung metastasis growth was found to be due to such changes in macrophage adenosine metabolism, that testifies to the rise of their functional activity. The change in the level of macrophage purine metabolism can be considered as an important evidence of the effectiveness of the drugs capable to inhibit the metastasis growth.

Liposomes of different composition and N-acetylglucosaminyl-N-acetylmuramyl-L-alanyl-D-isoglutamine (GMPD) encapsulated in them are studied for their effect on the functional activity of macrophages by means of determining the 5'-nucleotidase and adenosine deaminase activity in the in vivo experiments. It is shown that both liposomes and GMDP encapsulated in them increase the activity of adenoside deaminase and decrease that of 5'-nucleotidase. This evidences for a change in the adenosine metabolism in the alveolar and peritoneal macrophages and an increase in the functional activity of cells which resulted from that rise. The manifestation of the process depends both on the lipid composition of liposomes and their charge. The observed increase in the functional activity of the alveolar macrophages under the effect of liposomes and GMDP encapsulated in them correlates with inhibition of the lung metastases development in mice.