B-cells and antibody-secreting plasma cells are key players in protective immunity, but also in autoimmune disease. To understand their various functions in the initiation and maintenance of autoimmune pathology, a detailed dissection of their functional diversity is mandatory. This requires a detailed phenotypic classification of the diversity of B-cells. Here, technologies of immunocytometry and ELISpot are described in detail, and their value for phenotypic characterization of cells of the B lineage, as well as for preparative cell sorting, to further characterize them functionally and on the molecular level are described.