The immunoglobulin μ constant region gene is expressed in mouse thymocytes

Publisher Website
Google Scholar
Abstract
It has been a matter of controversy whether the functional capacity of T cells to discriminate between antigens is mediated via immunoglobulin, an immunoglobulin-like molecule, or by the product(s) of unrelated genes. The progenitors of immuno-globulin-secreting cells, B cells, express membrane-bound immunoglobulin as the antigen-specific receptor on their surface1. For T cells, although products of immunoglobulin heavy chain variable region genes are implicated as receptor components2–4, there has been no compelling immunochemical evidence for participation of either immunoglobulin light chains or heavy chain constant regions (see refs 2–6 for the disparate views). Recently, using cloned immunoglobulin DNA sequences as hybridization probes, we have demonstrated that the immunoglobulin Cμ gene, but not the Cκ gene, is expressed as polyadenylated RNA in some B cell tumour (T lymphoma) cell lines7. Individual T lymphoma lines yielded up to three discrete μ RNA species of different sizes (1.9, 2.2 and 3.0 kilobases), each species being different in size from the major μ RNA species present in B lymphoma cells (2.4 and 2.7 kilo-bases)7,8. We show here that cells from the normal mouse thymus contain μ RNA species, indistinguishable in size from those in T lymphoma cells, but contain little if any κ RNA.