Search

A technique is described allowing the quantification and the characterization of specific beta-adrenergic receptors in intact living human lymphocytes. 125I-Iodohydroxyhenzylpindolol, a potent beta-adrenergic antagonist was used to label specific binding sites on unfractionated lymphoid cells and on purified subpopulations of T (F1 and F2) and B cells. F1 and F2 were obtained by filtration through nylon wool column as previously described (Delespesse et al., 1976), they differ in their response to mitogens, and in their interactions with adherent cells and B cells. 125I-HYP binding to unfractionated lymphocytes was a saturable, stereospecific and rapid process with a dissociation constant of 2.5 10-10 M and a binding capacity of 400-600 sites/cell. Bindings on unfractionated lymphocytes, purified B cells and T cells of the F2 fraction were similar. No detectable binding was noted on T cells from the F1 fraction. Enriched T cells obtained by a rosetting technique displayed 200 receptors/cell. [ABSTRACT FROM AUTHOR]

The quantified lymphocyte response to phytohaemagglutin (PHA) was investigated in fifty-six control subjects, classed according to age and sex, iii twenty-nine insulin- dependent (IDD) and eight non-insulin-dependent diabetics. In nine cases one-way mixed lymphocyte cultures (MLC) were performed using mixed lymphocytes from I DD and paired controls. In the controls, a reduction of the response to PHA was observed with ageing; this was more marked in women than in men. The diabetics gave a greatly impaired response to PHA but only a slightly depressed response in MLC These anomalies are not influenced by age hut by the severity of the diabetes. [ABSTRACT FROM AUTHOR]

Increased DNA synthesis and immunoglobulin secretion was observed in human peripheral blood lymphocytes (PBL) cultured in vitro with soluble protein A from Staphylococcus aureus (Sp-A). Optimal Ig secretion was obtained in 6 day cultures containing 1 × 106 cells/mI and 10 μg/ml Sp-A. The presence of 5 × 10-5 M 2-mercaptoethanol in the culture medium as well as careful selection of foetal calf serum were needed for optimal results. In response to Sp-A stimulation, the three main classes of immunoglobulins were secreted by PBL. In some individuals, concentration of Sp-A optimal for lgG and IgM secretion inhibited IgA production. Immunoglobulin-con-taming cells were less abundant (0.5-5% of total cells) and smaller in Sp-A than in PWM-stimulated cultures (5-15%). The data suggest that Sp-A and PWM stimulated different subsets of circulating lymphocytes. [ABSTRACT FROM AUTHOR]

The lymphocyte transformation test (LTT) with thyroglobulin was correlated with humoral thyroglobulin antibodies (TGA) in different thyroid diseases. All patients with significant TGA had a positive LTT, while two LTT positive patients either had no TGA or revealed them a few weeks later. Lymphocyte transformation was found in all investigated cases of chronic thyroiditis and Hashimoto's disease, half of the patients with multinodular goitres and Graves' disease, and some cases (five out of sixteen) of simple goitres. [ABSTRACT FROM AUTHOR]

Alpha-N-Carbamoyl amino acid (CAA), whose conditions of formation in a prebiotic hydrosphere have been described previously (Taillades et al. 1998), could have been an important intermediate in prebiotic peptide synthesis through reaction with atmospheric NOx. Nitrosation of solid CAA (glycine or valine derivative) by a 4/1 NO/O2 gaseous mixture (1 atm) yields N-carboxyanhydride (NCA) quantitatively in less than 1 h at room temperature. The crude solid NCA undergoes quantitative oligomerization (from trimer to nonamer under the conditions we used) when treated with a (bi)carbonate aqueous buffer at pH 9. We therefore suggest that part of the prebiotic amino acid activation/polymerization process may have taken place in a dry phase ("drying-lagoon" scenario).

Increased DNA synthesis and immunoglobulin secretion was observed in human peripheral blood lymphocytes (PBL) cultured in vitro with soluble protein A from Staphylococcus aureus (Sp-A). Optimal Ig secretion was obtained in 6 day cultures containing 1 x 10(6) cells/ml and 10 microgram/ml Sp-A. The presence of 5 x 10(-5) M 2-mercaptoethanol in the culture medium as well as careful selection of foetal calf serum were needed for optimal results. In response to Sp-A stimulation, the three main classes of immunoglobulins were secreted by PBL. In some individuals, concentration of Sp-A optimal for IgG and IgM secretion inhibited IgA production. Immunoglobulin-containing cells were less abundant (0.5--5% of total cells) and smaller in Sp-A than in PWM-stimulated cultures (5--15%). The data suggest that Sp-A and PWM stimulated different subsets of circulating lymphocytes.