The first line of defense

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Another category of primary cells protect the body from cancer are macrophages. These cells, open T. I. Mechnikov in 1882, together with polimorfnoyadernami white cells and monocytes blood log in faguoqitirute elements. In the reactions against tumors particularly important role belongs to the tissue macrophages, widely represented in different organs: liver, spleen, lymph nodes, bone marrow, lungs, intestines, skin, nervous tissue. Intravenous animals of small particles (diameters smaller than 5 microns) suppressed the activity of macrophages (cells, these particles are not valid). Such animals are greatly facilitated engraftment of transplanted and artificially stimulated tumor.
Predecessors of macrophages (as EC-cells) appear in the bone marrow, where they enter the bloodstream. Part of macrophages circulates in the blood. This is a relatively immature cells, monocytes; others are embedded in the fabric, becoming fixed cells. They can capture the antigen and translate in molecular form. The mobile macrophages after phagocytosis transmit information about the antigen in lymphocytes. This macrophages reinforce the antigenicity of foreign molecules, making them strong activators of T-helpers and B-lymphocytes.
The macrophages many responsibilities, but the main of them - treatment antigen. These cells have even been called antigen-presenting.
The first stage - the adhesion of the macrophage to alien molecule - adhesion (in the experiment macrophages stick to the surface facing towards him object, such as a glass vessel); the second stage capturing people molecules of cellular processes-pseudopodia and its translation in the cytoplasm (endocytosis); the third intracellular cleavage (processing) a foreign protein.
After that, the macrophage forms on its surface complex of another protein molecules its antigens tissue compatibility II class. Only this combination is recognized by T-helper and serves as a signal to launch further immunological reactions.
In 1949, in the laboratory of the French biochemist K. de Duve was discovered there in the cell cytoplasm special pellets - of lysosomes, which were clusters of enzymes, Packed in lipoprotein membranes. At physiological aging of cells enzymes of lysosomes erupt out and expose the cell to autolysis. Most rich lysosomes was macrophages. It is connected with them splitting alien agents on separate components of the molecule. The antigen processing and translating it into a liquid, colloidal state is the first condition of starting all immunological reactions. The second condition is komplektacija these molecules with antigens of tissue compatibility II class called Ia-antigens. Strong stimulants lysosomes are interferon, vitamins, lymphokines.
Tumor cells have the ability to activate macrophages. This indicates the specific membrane structures inherent to most, if not all, tumor cells. Perhaps this mixed so-called common tumor antigen protein nature, which has small molecular mass and immunological specificity, similar to the pregnancy hormone - horioniceski a gonadotropin. Macrophages often infiltrate the tumor, and being isolated from the tumor stroma, show a strong cytotoxic action. The degree of sensitivity to damage by macrophages in different tumors varies considerably.
Strong activators of macrophages products are allocated to the T-helper, among which are described vooruzhali (or reinforced) factor. Under his influence macrophages sensitively distinguish modified cell and normal similar origin (for example, hepatoma cells from healthy cells of the liver). Therefore, the destruction of tumor items not affecting normal cells. Macrophages also able to allocate ougolnitsky factor. All attempts by researchers to get a line of tumor cells resistant to macrophages, proved fruitless.