Go Lymphocytes against cancer | Immunology

Cancer lymphocytes

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Before proceeding to the description of methods for stimulating lymphocytes of cancer patients, it is necessary to dwell on the question of why lymphocytes, in particular T-killers, in normal conditions do not inhibit the growth of a developing tumor. The answer to this question is not so obvious. Helper lymphocytes receive information about tumor-associated proteins from antigen-recognizing macrophages. If the cells of the first line of local defense (EC-cells and macrophages) did not eliminate the germ of cancer, then the distant lymph nodes and circulating lymphocytes are involved in the response, otherwise the whole body. Proof of this are observations about the frequent sensitization of circulating lymphocytes of cancer patients to antigens of a malignant tumor, detected in the described reaction of suppression, adhesion of leukocytes. Moreover, in some patients with a developing tumor, blood lymphocytes in laboratory samples have a cytotoxic effect on tumor target cells, including cells of a tumor removed from the patient himself (this, however, does not mean that the same process takes place in the body) . But it is obvious that all these immunological functions are lacking, so that an equally inexorable rejection reaction is observed in relation to a tumor, which is observed during transplantation of a donor kidney or heart.


There are several explanations for such functional immunodeficiency. First, it has already been said that cancer cells, obviously, produce immunosuppressive substances, “blinding” not all immune cells, but those that are potentially dangerous for the tumor itself. The tumor debilitates the coordinated activity of the system, which threatens its existence. Secondly, tumor antigens are relatively weak; they occupy, as it were, an intermediate position between their own non-immunogenic proteins and the allo-antigens of a foreign body. Therefore, although they are recognized as “alien”, they do not fully mobilize an army of cytotoxic killing cells. Maturation of T-suppressors occurs with the growth of a tumor so early that it inhibits the creation of powerful cytotoxic immunity. Thirdly, in the blood plasma of cancer patients there are substances that block the interaction of even the few cytotoxic elements with target cells and the physiological reproduction of T-killers. The patient’s lymphocytes washed from plasma in test-tube reactions are more active than in the presence of serum regulators.

It must be admitted that at this stage these arguments are rather speculative. Numerous studies that prove the quantitative deficiency of T-lymphocytes, proportional to the stage of tumor development, rather meet the expectations of the authors, rather than register objective reality. If there was a general quantitative T-deficiency in the early stages of tumor growth, patients would not recover from the flu and tonsillitis, but would suffer from various infections. Total inhibition of protective reactions is observed only in the later stages of the tumor process, as with any other protracted diseases. The tumor does not destroy immunity, but “deceives” him; it kind of “cuts through the tunnel” for the survival of its cellular descendants, whose development is not as easy as in artificial nutrient media.

Therefore, today's ideas about the “breakdown” of cytotoxic immunity at the earliest stages of the appearance of stem cancer cells and in the course of their further development speak only about the insufficiency of our knowledge about the subtle mechanisms of formation and regulation of the killer function of lymphoid cells. Analysis of this issue became especially relevant after a pronounced antitumor effect of circulating lymphocytes, artificially “brought up” outside the body, and then returned to the host’s bloodstream was shown.

In the study of the cytotoxic effect of lymphocytes under an electron microscope, it was found that the killing is preceded by the appearance of numerous ring-shaped pores on the membrane of the attacked cells. In the cytoplasm of the attacking killers, the formation of granules containing newly formed proteins is observed. Selected from the granules of the substance had the ability to violate the integrity of the membranes of other cells. The occurrence of membrane pores disrupts the normal exchange of fluid and electrolytes between the cell and the environment, and swelling with water leads to death, "explosion" of the cell.