[The concept of the immunologic barrier of the brain].

Using the technique of a two-layer agar system, the authors cultivated cerebrospinal fluid cells from 9 patients with aseptic lymphocytic meningitis and from 6 clinically healthy subjects. On the 7th-15th day of culturing growth of colonies (cellular aggregates) was detected. Morphologic analysis of the colonies demonstrated that they consisted only of lymphoid and mixed (macrophagal-granulocytic) cells. To study the immunologic function of microglia, the cerebral tissue obtained from 11 patients with cerebral gliomas was cultivated. Antigenic stimulation resulted in activation of microglia cells and in their transformation into macrophages. The precursor cells, T- and B-lymphocytes, their subpopulations, monocytes, macrophages and cells of central nervous system microglia form an immunologic barrier of the brain ensuring the immunologic surveillance in the extra-barrier organ--the central nervous system.