Biomedical subjects

T Lindsten

Publications and source records attributed to T Lindsten.

59 records · Page 4Linked to original sources

PubMed1979

Ontogeny of B cells in CBA/N mice. Evidence for a stage of responsiveness to thymus-independent antigens during development.

This paper deals with the CBA/N mice, a strain bearing a genetic defect in their B-cell compartment. By using a previously described system we have been able to show that the immature cells of CBA/N mice are functionally indistinguishable from normal immature cells, in that both can be triggered to respond to thymus-independent (TI) antigens, provided they are supplied with helper T cells. When the maturation is completed, CBA/N B cells are unable to respond to TI antigens (like lipopolysaccharide and polyvinyl pyrrolidine) irrespective of the presence of helper T cells, whereas normal mature B cells have grown able to respond without any help. These data allow us to reject the hypothesis that CBA/N mice are arrested at an immature stage and clearly support the idea that they have deviated during development so that only thymus-dependent B cells develop.

Animals↗

PubMed1978

Interaction by cholestyramine on the uptake of hydrocortisone in the gastrointestinal tract.

An absolute reduction of the plasma cortisol levels and a delay of the peak concentrations were recorded in 10 healthy subjects, when a bile-sequestering anionic exchange resin, cholestyramine, was given prior to a single oral hydrocortisone dose, indicating that the resin interferes with the uptake of a neutral sterol in the human gastrointestinal tract. The possibility of a direct binding of drug to resin is supported by the affinity of hydrocortisone to cholestyramine in vitro, which was uninfluenced by the presence of sodium taurocholate. Cholestyramine significantly delayed the gastric emptying of a glucose solution, indicating that the resin not only decreases but also delays hydrocortisone absorption. Careful supervision is recommended when treatment with cholestyramine is given concomitant to neutral sterol drugs.

Cholestyramine Resin↗

PubMedDate not supplied

A third type of murine T-cell receptor gene.

By subtractive cDNA hybridizations, we have isolated a new species of T-cell receptor cDNA clone whose predicted amino acid sequence has homology to variable, constant, joining and diversity segments of immunoglobulins and T-cell receptors. The corresponding genomic sequence is also rearranged in several T-cell DNAs. The four potential N-linked glycosylation sites, frequency of expression and predicted molecular weight (27,800) of this molecule make it a likely candidate for the alpha-chain of the T-cell receptor. Expression data also indicate that this gene may be activated at a later stage of T-cell differentiation than the beta-chain.

Amino Acid Sequence↗

PubMedDate not supplied

Expression of genes of the T-cell antigen receptor complex in precursor thymocytes.

The antigen receptor on T lymphocytes has recently been characterized as a heterodimeric, transmembrane glycoprotein consisting of disulphide-linked alpha (acidic) and beta (basic) subunits of relative molecular mass (Mr) 40,000-45,000 each. The genes encoding these proteins have been cloned and shown to resemble immunoglobulin genes in both overall structure and the requirement for DNA rearrangement before expression. In humans, three additional proteins, termed the T3 complex, are found associated with the clonotypic receptor, and a role for T3 in receptor expression has been proposed. Despite these recent advances in characterizing the antigen receptor complex, there is as yet little understanding of T-cell maturation, particularly the stage of T-cell ontogeny at which the genes encoding the antigen receptor and its associated structures are expressed and assembled. In the adult, stem cells destined to differentiate into T cells arise in the bone marrow and migrate to the thymus, where T-cell precursors proliferate, develop a preference for recognizing antigens in the context of self MHC molecules and are released to the periphery. Recently, cells that have the properties of immature murine thymocytes have been isolated and described. We have now analysed these cells with a series of molecular probes and we describe three distinct patterns of T-cell antigen receptor gene rearrangements in developing thymocytes.

Animals↗

PubMedDate not supplied

Mapping of the class II region of the human major histocompatibility complex by pulsed-field gel electrophoresis.

The class II region of the human major histocompatibility complex (MHC) encodes a polymorphic set of cell surface glycoproteins involved in the regulation of the immune response. Each glycoprotein is a heterodimer composed of a alpha-chain of relative molecular mass (Mr) 34,000 (34 K) and a beta-chain of Mr = 28K. The products of the class II region have been characterized by the mixed lymphocyte reaction, serology, primed lymphocyte typing and DNA cloning. DR, DQ and DP, three subregions containing both alpha- and beta-chains, and two additional loci, DZ alpha and DO beta, locate this gene cluster on the short arm of chromosome 6. The precise genomic organization of these loci have been difficult to determine. Here we describe the use of pulsed-field gel electrophoresis together with restriction endonucleases having few genomic restriction sites and Southern blotting, to determine the order of the subregions and to derive a map for the human class II region. The order of these loci is similar to that of the homologous loci in the murine class II region. Our study establishes the use of pulsed-field gel electrophoresis in mapping large regions of the genome in higher eukaryotes.

Cell Line↗