Immunotherapy of tumours

One of the methods, not burdened with side effects, is use of processes of natural immunity that is so called immunotherapy of tumours. Its aim is to support organism in natural process of fighting the diseased cells. However immunological treatment of tumour is usually a supportive treatment, i.e. used together with surgical treatment or chemotherapy.

Properly modified antibodies that are molecules produced by the immune system are weapon used with high effectiveness in fight with tumours. In each organism innumerable quantity of types of immunoglobulines is observed, where each has ability to bind with characteristic groups of molecules. Antibodies recognise and react on each strange substance in the organism. Bind with molecule or cell constitute signal for organism, that marked element is strange and should be removed. It stimulates activity of other cells of the immune system, i.e. phagocytes.

In case of tumours this reaction is however too weak, because neoplastic cells can become “invisible" for the immune system. Therapies using antibodies base on intensification of this response or on use of natural abilities of organism, or also on the newest discoveries of molecular Biology.

Unfortunately, administration of antibodies alone rarely gives desired effects. This method shows effectiveness only in few cases, mainly when neoplastic cells are hardly camouflaged and when tumour is in early stage of development. So then, more perfect methods should be looked for. One of them is use of immunotoxines that is antibodies bounded with toxins or radioisotope. Toxins, i.e. castor oil, can suppress important processes in cell, and radioisotopes excrete molecules of big energy, killing cells by serious destruction of DNA. Connection of toxins and radioisotopes with antibody causes, that destroying factor does not act on all cells, but only look for neoplastic cells (with proper markers on the surface) and acts on them on their direct surrounding only.

Use of so called antibodies of double specificity is the next method aimed to increase effectiveness of patient’s immune system in fight with tumour.
Antibodies of double specificity are in fact two antibodies of different type, combined together. One part binds with carcinogenic cells and the second with cells of the immune system, i.e. lymphocytes Te, having the ability of active killing of the diseased cells. It helps them “to see" cancer cells and their action is activated.

Autograft

Chemotherapy and radiations are used in many models of cancer therapy; however these methods not always bring desired results. Frequently the effective dose exceeds threshold of endurance of the organism, because beside neoplastic cells also healthy cells - especially stem cells - are killed.

To increase the drug dose, such therapies are combined with autologic graft. Before the therapy blood or bone marrow containing stem cells is collected form the patient. Then the patient undergoes therapy, which kills neoplastic cells. Earlier collected bone marrow, refined from neoplastic cells is given the patient after the end of therapy. Antibodies, used to remove these cells, are synthesised in laboratory and are able to recognise markers of each tumour. This therapy appeared to be effective, especially in case of myeloblastic leukaemia.

Vaccine against cancer

Vaccines against cancer are presently a subject of very intense researches. They prophylactically prevent the development of tumours caused by viruses. Vaccines against type B hepatitis may prevent infection and decrease risk of development of liver cancer. Vaccine against human papilloma virus (HPV) may prevent cervical cancer.

In turn, cells of surgically excised tumour can be used to abort immunological tolerance of organism in relation to the tumour. Neoplastic cells after the excision are radiated with sufficiently high dose to block their divisions, but not a killing dose. They are administered subcutaneously with factors supporting formation of local inflammatory state. Such procedure may cause, that immune system will “see" neoplastic cells, will learn how to recognise and fight them. In such way resistance formation against possible cancer cells remaining after surgical procedure or forming metastatic foci is possible.

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