The immunoglobulin mu constant region gene is expressed in mouse thymocytes

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 immunoglobulin-secreting cells, B cells, express membrane-bound immunoglobulin as the antigen-specific receptor on their surface. For T cells, although products of immunoglobulin heavy chain variable region genes are implicated as receptor components, 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 Cmu gene, but not the Cmu gene, is expressed as polyadenylated RNA in some T cell tumour (T lymphoma) cell lines. Individual T lymphoma lines yielded up to three discrete mu RNA species of different sizes (1.9, 2.2 and 3.0 kilobases), each species being different in size from the major mu RNA species present in B lymphoma cells (2.4 and 2.7 kilobases). We show here that cells from the normal mouse thymus contain mu RNA species, indistinguishable in size from those in T lymphoma cells, but contain little if any kappa RNA.     

Turnover of lymphocytes in rat peritoneal fluid

Zusammenfassung Zellkinetische Untersuchungen an Ratten nach Injektion von H³-Thymidin ergaben eine rasche Markierung der grossen mononukleären Zellen innerhalb von 20 Min und eine langsaniere Markierung der kleinen Lymphozyten, für welche eine Turnover-Zeit von 23,4 Tagen errechnet wurde. Stündlich gelangen ca. 10⁵ kleine Lymphozyten in die Bauchhöhlenflüssigkeit.

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This research was performed under the auspices of the US Atomic Energy Commission.     

Immunoglobulin Cmu RNA in T lymphoma cells is not translated

It is widely believed that immunoglobulin genes might encode at least part of the receptor for antigen on the T lymphocyte. Evidence supporting this comes from the effects of anti-immunoglobulin idiotype antibodies on cellular immune networks and from the presence of idiotypes on immunologically active factors from T cells. Detailed molecular characterization of the receptors, however, has been seriously hampered by the lack of a suitable cellular source from which it might be isolated. The recent demonstration of Kemp et al. that thymocytes and certain cultured lines of mouse T lymphoma cells contain polyadenylated RNA molecules encoded by the immunoglobulin Cmu gene (Cmu RNA) prompted us to identify the corresponding protein molecules in those cells. As the haploid mouse genome contains a single Cmu gene, any polypeptide encoded by this gene should react with at least some of the antibodies present in rabbit anti-mouse IgM antiserum. In this letter we report that a number of T lymphoma lines, regardless of whether they contain Cmu RNA, synthesize no detectable mu polypeptides.     

Specificity of anti-RH serum inhibition by lipid extracts as determined by quantitative nitrogen assays

Zusammenfassung Eine Reihe der Lipidfraktionen von Rh-positiv und Rh-negativ (D-positiv und D-negativ) roten Zellen menschlichen Blutes wurde der Wirkung von anti-Rho Serum (anti-D) ausgesetzt. Die dabei adsorbierte Menge von Stickstoff wurde quantitativ bestimmt. In jedem Fall adsorbierten die Lipide von Rh-positiv roten Zellen mehr Antikörperstickstoff als die aus Rh-negativ roten Zellen extrahierten Lipide. Man darf wohl daraus schliessen, dass der höhere Grad der Adsorption von Antikörperstickstoff auf Lipiden von Rh positiv roten Zellen ein spezifischer Effekt ist.