Cross-linking of at least three binding sites mediates signal transduction in a CR2-positive Burkitt lymphoma derived cell line (Raji).
In this study we demonstrate that Raji cells, a CR2-positive Burkitt lymphoma-derived cell line, during cell growth, need the cross-linking of multiple OKB7 binding sites or C3d determinants to mediate signal transduction. The loss of one of these affects the cellular response. Moreover, OKB7, the anti-CR2 MoAb, recognizes C3d determinants on the cell surface and inhibits signal transduction induced by anti-C3d polyclonal antibody. Since Raji cells are always CR2 positive during cell growth, we suppose that at least another protein, along with CR2, may be involved in setting up a cell surface complex able to receive and transduce the signal triggered by OKB7. In our experimental system the protein that offers a third binding site to OKB7, may be represented by a 33 kDa protein bearing C3d determinants.
Barile
G
G
Istituto Tecnologie Biomediche, CNR, Rome, Italy.
Pernozzoli
B
B
Tiracchia
V
V
Ioppolo
S
S
De Cristofaro
M
M
Mattei
E
E
Faggioni
A
A
D001665:Binding Sites; D002051:Burkitt Lymphoma / Q000378:metabolism*; D006801:Humans; D017464:Receptors, Complement 3d / Q000378:metabolism*; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
D017464:Receptors, Complement 3d