Experimental Cell Research vol:143 issue:1 pages:237-45
An oligospecific antiserum (aNHFiv) was raised by intravenous injection of whole normal human fibroblasts (NHF) into rabbits. Monovalent Fab' fragments of this antiserum inhibited intercellular adhesion of trypsinized NHF to homotypic monolayers in a concentration-dependent fashion. The Fab' fragments lowered both the initial rate and the final extent of adhesion, indicating that the inhibition is a complex phenomenon. Specific antisera to four of the nine surface components recognized by aNHFiv were tested separately. Three of them, directed respectively against aminopeptidase M, dipeptidyl peptidase IV and a glycoprotein of 400 K, did not interfere with adhesion even in high titers or in combination with each other. The fourth monospecific antiserum was directed against fibronectin (FbN) and Fab' of this antiserum gave a concentration-dependent inhibition of adhesion. After adsorption of the Fab' of aNHFiv with CIG and cellular fibronectin, however, adhesion was still inhibited. Combination of aFbN Fab' with the adsorbed Fab' fully restored the effect of the native aNHFiv Fab'. Preincubation of the suspended cells with aFbN or adsorbed Fab' was without effect on adhesion. Pretreatment of the cell layers with aFbN Fab' gave a strong inhibition. A similar treatment with the aNHFiv fraction from which aFbN was removed had, however, no effect. This implies that to inhibit adhesion, the specificity different from aFbN has to be present in the assay medium during the assay.