The invention relates to the field of medicine and more particularly it relates to the problem of vaccination against tumor cells and vaccinotherapy of oncological diseases, and also to a method of treating diabetes mellitus. In the invention a new method of cultivating cells is proposed, which contemplates forming a capsule of a polyacrylamide gel in the tissue of an animal, including a human, into which capsule desirable cells are injected. The invention provides for maintaining the viability of cells during a long period of time.