Mouse pre-B cells synthesize and secrete mu heavy chains but not light chains |
| |
Authors: | D Levitt M D Cooper |
| |
Institution: | The Cellular Immunobiology Unit of the Tumor Institute Departments of Pediatrics and Microbiology and The Comprehensive Cancer Center University of Alabama in Birmingham Birmingham, Alabama 35294, USA |
| |
Abstract: | The immunoglobulins produced by the earliest recognizable B cell precursors (pre-B cells) were characterized in the mouse and human. Immunofluorescent analysis revealed no evidence of surface IgM components, and only mu heavy chains could be detected intracytoplasmically in pre-B cells. Surface IgM components could not be isolated from intact fetal liver cells that lacked sIgM+ B lymphocytes but possessed pre-B cells. Pre-B cells were shown to synthesize and secrete mu heavy chains but not light chains by immunochemical analysis. These mu chains constituted less than 0.01% of TCA precipitable protein synthesized and secreted by fetal liver cells during an 8 hr labelling period. Migration of both intracellular and secreted mu chains on SDS-PAGE suggested that they were smaller than mu chains secreted by mouse and human plasmacytomas. These data indicate that mu chain synthesis precedes light chain expression during B cell ontogeny and suggest a new role for pre-B cells in the generation and expression of a diverse immunoglobulin repertoire. |
| |
Keywords: | To whom correspondence should be addressed at: 224 Tumor Institute University Station University of Alabama in Birmingham Birmingham Alabama 35294 |
本文献已被 ScienceDirect PubMed 等数据库收录! |