Purification of human lamina propria plasma cells by an immunomagnetic selection method

Plasma cells (PC) are the terminal stage of B-lymphocyte differentiation and, as such, they are dedicated to large-scale secretion of antibodies (Ab). Bone marrow (BM) and lamina propria (LP) become the final reservoirs of PC generated in response to systemic and mucosal antigen stimulation, respectively. Although the majority of human PC are held in the mucosa LP, they have received less attention than PC present in other locations. A key step for many PC studies is the design of isolation protocols to purify them. A purification procedure for LPPC has not been described as yet and, therefore, we decided to develop a protocol for this purpose, comprising three main steps: (1) dissecting LP from colonic tissue; (2) releasing LP cells by a short 15-min collagenase digestion; (3) isolating LPPC by positive immuno-magnetic selection using the distinctive expression of CD54 (ICAM-I) on LPPC. By following this protocol, a viable, highly purified LPPC fraction can be obtained in less than 2 1/2 h.