ADHESION TO HUMAN NEURONS AND ASTROCYTES OF MONOCYTES - THE ROLE OF INTERACTION OF CR3 AND ICAM-1 AND MODULATION BY CYTOKINES

Monocytes but not unstimulated lymphocytes adhered to human neurons an d astrocytes in primary culture, as demonstrated by double labeling. T he expression of VCAM-1 was higher on neurons than on astrocytes, wher eas that of beta 1, alpha 1, alpha 2, alpha 4 and alpha 5 chains from the integrins and of ICAM-1 was identical on both types of cells. The expression on neurons of ICAM-1, but not of integrins, was up-regulate d by exogenous tumor necrosis factor (TNF) alpha, interleukin (IL)-1 a lpha and interferon (IFN)-gamma. The same was observed on astrocytes a ssociated with a sharp increase in the expression of VCAM-1. Adhesion between monocytes and neurons or astrocytes was 80% inhibited by mAbs directed against the CR3 determinant on monocytes or against ICAM-1 on neural cells but not by any of the other mAbs against adhesion protei ns that were tested. Finally, the level of endogenous production of IL -1 alpha and TNF alpha was greatly increased after the adhesion of mon ocytes to CNS cells.