Pattern of differential expression of costimulatory molecules in myeloma cell line MM1.R

T cells constantly recognise and eliminate circulating tumour cells. They require two signals in order to be activated: antigen presentation via TCR, and costimulatory interaction with different surface molecules of the B7 family, which may either enhance or attenuate immune response. In several cancers these molecules are deregulated, thereby promoting immune escape and the settlement or migration of cancer cells. In multiple myeloma, the expression of B7 co-inhibitory molecules and their relationship to disease progression have been identified. The MM1.R cell line is a useful cellular model for studying the progression of this disease, and therefore an analysis of the pattern of expression in this cell line helps to cast light on the immune status of this disease. Using a real-time PCR (quantitative RT-PCR) assay, we found that the main molecules expressed were those with an inhibitory function (B7-H1, B7-H3 and B7-H4), which suggests a high level of immune inhibition by these cells.