CD5 and CD21 molecules are a functional unit in the cell/substrate adhesion of B-chronic lymphocytic leukemia cells.
The modulation of surface molecules on B-chronic lymphocytic leukemia (B-CLL) cells was studied in vitro by incubation with CD19, CD20, CD21, CD5 and anti-IgM antibodies. The cytoplasmic changes were evaluated by analyzing the organization of cytoskeletal F-actin and the adhesive properties of stimulated B-CLL cells. The following observations were made: (a) CD5 antigen is capped on the surface of B-CLL cells (but not on normal CD5+ B and T lymphocytes). (b) On B-CLL cells, CD5 and CD21, the receptors for the C3d fraction of complement, co-cap and co-modulate while surface IgM as well as CD19 and CD20 do not cap. (c) B-CLL cells, after capping of CD5 or CD21 surface molecules, fail to organize F-actin into podosomes. (d) The pre-incubation of B-CLL cells with either CD5 or CD21 antibodies prevents their binding to purified C3d protein used to coat coverslips. These data indicate that an intimate spatial relationship exists between CD5 and CD21 molecules on the B-CLL surface. The CD5-CD21 complex is involved in the redistribution of cytoskeletal proteins which may control the adhesive properties of these malignant B cells.
Bergui
L
L
Dipartimento di Scienze Biomediche e Oncologia Umana, Università di Torino, Italy.
Tesio
L
L
Schena
M
M
Riva
M
M
Malavasi
F
F
Schulz
T
T
Marchisio
P C
PC
Caligaris-Cappio
F
F
D000199:Actins / Q000032:analysis; D000951:Antigens, Neoplasm / Q000032:analysis*; D000954:Antigens, Surface / Q000032:analysis*; D001402:B-Lymphocytes / Q000145:classification / Q000276:immunology / Q000502:physiology*; D002448:Cell Adhesion; D003176:Complement C3 / Q000502:physiology; D015933:Complement C3d; D006801:Humans; D007152:Immunologic Capping; D007945:Leukemia, Lymphoid / Q000276:immunology* / Q000473:pathology; D016169:Lymphocyte Function-Associated Antigen-1; D010641:Phenotype
D000199:Actins; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D003176:Complement C3; D016169:Lymphocyte Function-Associated Antigen-1; D015933:Complement C3d