Synthesis and secretion of gammaglobulin by lymph node cells: the acquisition of carbohydrate residues of immunoglobulin in relation to interchain disulfide bond formation (heavy and light chains-murine myeloma-mannose-glucosamine-galactose)

Acquisition of carbohydrates in the disulfide-linked heavy (H) and light (L) chain molecules of murine myeloma (ADJPC5), i.e., HH, HHL, and LHHL, was investigated. That some mannose and glucosamine residues are acquired by immunoglobulin precursor molecules was demonstrated by the detection of glucosamine and mannose in HH, HHL, and LHHL. In contrast, galactose was observed solely in LHHL molecules, which have an identical electrophoretic mobility to the secreted product. Furthermore, as judged from cells incubated with [(3)H]leucine, the more juvenile molecules HH and HHL were predominant in the rough microsome fraction, whereas LHHL was the principal molecular species in the smooth microsome fraction. Findings of this type were not observed in rabbit lymph node cells. Thus, galactose, as well as mannose and glucosamine, were found in the more juvenile molecule known for this species (HL). Moreover, the ratio of HL:LHHL, as judged from cells incubated with [(3)H]leucine, was about the same in rough and smooth microsomes.