Interleukin-4 (IL-4) enhances homotypic adhesion of activated B-chronic lymphocytic leukaemia (B-CLL) cells via a selective up-regulation of CD54.
It is well established that cell-to-cell contact modifies cytokine signalling but little is known on the role of homotypic cell adhesion for proliferation and differentiation of B cells. Homotypic adhesion involves mainly the interaction between the adhesion molecules Leukocyte Function Antigen-1 (LFA-1) and its ligand CD54 (ICAM-1). A well-characterized B-chronic lymphocytic leukaemia (B-CLL) clone (I-83) was used as a source of monoclonal B cells inducible to DNA synthesis and differentiation by using 12-O-tetradecanoyl-phorbol-13-acetate (TPA) in combination with interleukin-4 (IL-4) and thioredoxin (Trx)-containing supernatant from a T-cell hybridoma (BSF-MP6). This paper shows that IL-4 alone was able to induce aggregation of B-CLL cells and to strongly enhance TPA+BSF-MP6-induced aggregation. The results from studying the expression of CD11a and CD18, the two subunits of LFA-1, and CD54 during stimulated DNA synthesis and differentiation suggest that IL-4-induced, or enhanced, aggregation was mainly mediated by a selective up-regulation of CD54. It was further demonstrated by antibody blockade to either CD11a, CD18 or CD54 that aggregation could be inhibited without affecting induced DNA synthesis or differentiation.
Carlsson
M
M
Department of Pathology, Uppsala University, University Hospital, Sweden.
Söderberg
O
O
Nilsson
K
K
D000906:Antibodies / Q000494:pharmacology; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000276:immunology; D002449:Cell Aggregation / Q000187:drug effects*; D002999:Clone Cells / Q000276:immunology; D006801:Humans; D018799:Intercellular Adhesion Molecule-1; D015847:Interleukin-4 / Q000276:immunology* / Q000494:pharmacology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000276:immunology*; D010703:Phorbol Esters / Q000494:pharmacology; D013879:Thioredoxins / Q000494:pharmacology; D015854:Up-Regulation
D000906:Antibodies; D015815:Cell Adhesion Molecules; D010703:Phorbol Esters; D018799:Intercellular Adhesion Molecule-1; D015847:Interleukin-4; D013879:Thioredoxins