[The problem of tissue parasitism].

Possessing a different antigenic structure larvae of helminths have to withstand the protective reactions of their hosts in order exist in their tissues. A new phenomenon was noted in host-parasite relationships. Larvae of helminths inhibit the host's leucocyte reaction (by inhibiting chaemotaxis) and induce the formation of a capsule of specific structure by the host. The capsules represent a modified protective reaction of the connective tissue. The capsules perform two main functions. They do not pass the specific antibodies from the host's blood to a parasite. They are physiologically active; an intensive transport of nutrients passes through them to the parasite against concentration gradient, with a participation of ferments and expenditure of energy.