CD27 signals through PKC in human B cell lymphomas.
Tumour necrosis factor receptor (TNFR) superfamily members play critical roles in the regulation of cell proliferation and death. One member of the TNFR superfamily, CD27, is unique because it is the only covalently linked homodimer in the family. CD27 and its cellular ligand, CD70, have been implicated in the regulation of T cell and B cell interactions that lead to cellular activation and regulation of immunoglobulin expression. Due to the unique nature of CD27, we chose to screen a number of B cell lymphoma cell lines for CD27 and CD70 expression and evaluate CD27 activation by antibody cross-linking. Two cell lines, HT and SU-4, showed greater cellular proliferation when CD27 was cross-lined and this correlated with increased PKC activation. Additionally, in the HT cell line cell surface expression of IgG was increased by CD27 cross-linking. Thus we have identified cellular systems for the study of CD27 signal transduction that will allow definition of the CD27 signal cascade of some B cell lymphomas.