A complex of glycoproteins is associated with VpreB/lambda 5 surrogate light chain on the surface of mu heavy chain-negative early precursor B cell lines.
Monoclonal antibodies (mAbs) have been made specific for the pre-B cell-specific proteins VpreB and lambda 5 which together form the surrogate light (L) chain. mAbs specific for VpreB protein identified the 16-kD molecule associated on precursor B cell lines with lambda 5 protein as the product of the VpreB gene. Surrogate L chain was detectable even in the absence of mu heavy (H) chain on the surface of early precursor cell lines such as pro-B cell lines where all immunoglobulin (Ig) loci are in the germline configuration, as well as early pre-B cell lines where Ig H chain loci are DHJH rearranged in reading frame I or III, which does not allow the expression of a DHJHC mu protein. A complex of glycoproteins (200, 130, 105, and 65-35 kD) was identified as coprecipitated with the Vpreb/lamba 5 surrogate L chain in mu H chain-negative precursor B cell lines. The 130-kD protein was most strongly labeled with iodine and most consistently detected in noncovalent association with surrogate L chain. This protein turned out to be a N-linked glycoprotein with a 100-kD protein core and isoelectric point 5.8, indicating that it is distinct from CD43 and the BP-1/6C3 antigen. The surface deposition of the surrogate L chain in association with the newly identified glycoproteins suggests that the surrogate L chain may function as a receptor even before the association with mu H chain in early precursor B cells.
Karasuyama
H
H
Basel Institute for Immunology, Switzerland.
Rolink
A
A
Melchers
F
F
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D002460:Cell Line; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D007143:Immunoglobulin Heavy Chains / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000276:immunology / Q000378:metabolism*; D054444:Immunoglobulin Light Chains, Surrogate; D007135:Immunoglobulin Variable Region / Q000378:metabolism; D007146:Immunoglobulin lambda-Chains / Q000378:metabolism; D007148:Immunoglobulin mu-Chains / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D011233:Precipitin Tests; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D054444:Immunoglobulin Light Chains, Surrogate; D007135:Immunoglobulin Variable Region; D007146:Immunoglobulin lambda-Chains; D007148:Immunoglobulin mu-Chains; D008562:Membrane Glycoproteins; D011947:Receptors, Antigen, B-Cell