Transcriptional profiling of the maturation of human in vivo-generated plasma cells

In vivo antigen (Ag)-induced differentiation of B lymphocytes into plasma cells (PCs) takes place in extra-follicular foci and germinal centers of the secondary lymphoid organs (SLOs). Most of these SLO PCs are short-living and only relatively few PCs, characterized by secreting high-affinity antibodies (Ab), travel through the circulation and finally home in specialized survival niches of the bone marrow (BM) and, at a lesser extent, in the SLOs, where they become long-living Ab-secreting PCs. Initially, we have employed whole genome microarray expression profiling as a discovery platform to identify genes with the potential to distinguish between human circulating Ag-induced PCs in comparison with tonsil and BM PCs distinctively regulate genes involved in cell proliferation. Now, moreover, to characterize further the B-cell transition into PC, transcriptomes from human naïve B lymphocytes were also included in the analysis, and genes showing significant changes in the comparison between B lymphocytes and every of the three PC subsets were selected as the PC signature. Gene expressions in human B-lymphocyte cells isolated from peripheral blood (3 samples) were measured. Each sample was isolated from a different donor.