ARE MATRIX-IMMOBILIZED NEOGLYCOPROTEINS, PLANT AND HUMAN LECTINS AND CARBOHYDRATE-BINDING ANTIBODIES FROM HUMAN SERUM MEDIATORS OF ADHESIONIN-VITRO FOR CARCINOMA AND LYMPHOSARCOMA CELLS

Mediation of cell adhesion by defined molecules can be studied by thei r immobilization onto a nitrocellulose matrix and incubation with cell s. In order to infer the capacity of deliberately selected protein-car bohydrate interactions to establish sugar-inhibitable cell adhesion, a panel of immobilized neoglycoproteins was employed for the murine lym phosarcoma lines RAW-117 with low (P) and high (H10) metastatic capaci ty, a human mammary carcinoma line (DU4475) and three human colon carc inoma lines (C205, SW480, SW620). Exhibiting an otherwise rather simil ar behavior relative to the line with low metastatic potential, the mu rine line RAW117-H10 bound strongly to the matrix with carboxyl group- bearing N-acetylneuraminic acid and glucuronic acid as well as rhamnos e. Whereas the analysis of carbohydrate-mediated adhesion yielded comp arable results for the three colon carcinoma lines, a markedly reduced number of adherent cells was counted for matrix-attached alpha- and b eta-galactosyl, alpha-mannosyl and alpha-glucosyl moieties in the case of the mammary carcinoma line, raising evidence for cell lineage-depe ndent alterations of this property. From the carbohydrate-binding prot eins, the plant lectin, concanavalin A and Viscum album agglutinin alm ost invariably served well as cell adhesion molecules. Appropriate cel l surface sugar receptors, probed with neoglycoproteins, and glycoconj ugates, probed with lectins, thus can contribute to adhesion in this m odel system. The immobilized human beta-galactoside-binding lectin (Mr 14kDa) caused adhesion of the murine lines and one colon carcinoma li ne (SW480). Neither C-reactive protein under conditions that induce it s activity as lectin nor serum amyloid P component nor a lactose-bindi ng immunoglobulin G fraction from human serum were reactive. However, cell adhesion to the alpha-galactoside-binding immunoglobulin G fracti on of human serum was seen with the murine line of low metastatic capa city and the mammary carcinoma line. Cells of this line adhered also t o the mannan-binding protein from human serum, supporting the view for its potential role in host defence against aberrantly glycosylated tu mor cells.