Mouse pre-B cells synthesize and secrete heavy chains but not light chains
1980; Cell Press; Volume: 19; Issue: 3 Linguagem: Inglês
10.1016/s0092-8674(80)80038-9
ISSN1097-4172
AutoresDaniel Levitt, Matthew A. Cooper,
Tópico(s)Glycosylation and Glycoproteins Research
ResumoThe 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 μ heavy chains could be detected intracytoplasmically in pre-B cells. Surface IgM components could not be isolated from intact fetal liver cells that lacked slgM+ B lymphocytes but possessed pre-B cells. Pre-B cells were shown to synthesize and secrete μ heavy chains but not light chains by immunochemical analysis. These μ chains constituted less than 0.01% of TCA precipitable protein synthesized and secreted by fetal liver cells during an 8 hr labeling period. Migration of both intracellular and secreted μ chains on SDS-PAGE suggested that they were smaller than μ chains secreted by mouse and human plasmacytomas. These data indicate that μ 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.
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