[The tissue level of the organization of the parasite-host system].

The paper represents a review and analysis of different trends in the evolution of tissue parasitism. Data are given on different ways of departure of parasites from the host's immune response, inhibition of its immunity, antigenic mimicry, capsule formation. The paper considers in detail the mechanism of origin, structure and functions of capsules, which are induced by various groups of parasites in vertebrate and invertebrate hosts. Uniformity in the structure of capsules, which are formed in different host-parasite systems, suggests the universality of mechanisms ensuring their formation.