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Results for “beta 2-Microglobulin”

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At least 19 recordsLinked to original sources
PubMed1975

B-cell mitogenic effects on human lymphocytes of rabbit anti-human beta 2-microglobulin.

Rabbit Ig against human beta2-microglobulin was found to be mitogenic for human peripheral lymphocytes, tonsil lymphocytes, and appendix and spleen cells. Anti-beta2-m gave increased DNA synthesis, with peak responses on day 3 or 4 and showed a dose-response effect when diluted. The effect was seen in both serum-free and serum-containing culture medium. Anti-beta2-m, as well as lipopolysaccharide, induced polyclonal antibody production and intracellular immunoglobulin synthesis in blast cells, which is taken as evidence that these substances are human B-cell mitogens. Anti-beta2-m, but not lipopolysaccharide, could, in these experiments, activate peripheral blood lymphocytes, in addition to lymphoid cells from other sources. Thus, anti-beta2-m can serve as a functional marker for peripheral human B lymphocytes.

Animals↗
PubMed1975

Renal protein metabolism in obstructive uropathy.

Measurements of serum beta 2 microglobulin and creatinine concentrations were determined in 18 patients with lower urinary tract obstruction. Nine patients were azotemic on admission to the hospital. In 3 of these patients who had normal pre-treatment serum levels of beta 2 microglobulin, the correction of obstruction was followed by return of normal renal function. The remaining 6 patients with elevated serum beta 2 microglobulin concentrations on hospitalization, showed no significant improvement in renal function parameters in the post-obstructive period. These data suggest that determination of serum beta 2 microglobulin concentrations is helpful in predicting the return of renal function in azotemic patients with obstructive uropathy.

Aged↗
PubMed1975

Association of beta-2-microglobulin and HL-A in the cell membrane. A general property in human cells?

To study whether the recently reported close association of beta-2-microglobulin and HL-A determinants is restricted to lymphocyte membranes or might be a more general property, experiments were performed where normal and malignant human cells were tested for coaggregation-capping of the two determinants. The normal cells were fibroblasts and the epithelial cells were from skin. The turmor cell lines were HeLa clone S3 carcinoma cells and National Collection of Type Cultures strain 3075, which is a line of malignant human skin cells. The cells were double-stained with fluorescein-labelled conjugates to demonstrate the reaction of anti-HL-A and anti-beta-2-microglobulin with the respective cell membrane components. Aggregation and capping of the HL-A and beta-2-microglobulin determinants in the cell membrane were always observed after incubation at 37 C for 30 min. The red and green fluorescence were always superimposed when anti-beta-2-microglobulin was used in the first (aggregating) incubation step. This demonstrates that the HL-A and beta-2-microglobulin determinants are also associated in the cell membrane of cells other than lymphocytes.

Animals↗
PubMed2026

Dietary arginine drives codon-dependent MHC class I translation and improves immunity in colon tumorigenesis and respiratory viral infection.

Amino acid levels fluctuate across diverse pathological conditions. Whether such amino acid modulations directly shape pathophysiology by regulating host gene expression remains unknown. We found that extracellular arginine restriction, observed in cancer and infection, represses specific arginine tRNAs-directly suppressing translation of major histocompatibility complex I (MHC class I) and antigen presentation. Arginine regulation of MHC class I was codon-usage dependent, as synonymous codon mutations prevented MHC class I modulation. Dietary arginine restriction impaired anti-viral immunity against influenza and SARS-CoV-2 and increased colon tumorigenesis. Conversely, increasing arginine availability via dietary supplementation or myeloid-specific arginase 1 deletion enhanced MHC class I protein levels, suppressed colon tumorigenesis, and improved viral infection outcomes. These disease-modulating effects were abolished in β2-microglobulin (B2m)-deficient mice. Thus, dietary modulation of a single amino acid critically influences codon-biased translation and MHC class I-mediated immunity to respiratory viral infections and cancer, revealing an unexpected mechanism and disease hazard for arginine deficiency and highlighting potential for amino acid-based translation modulation therapy.

Animals↗
PubMed2025

NumSimEX: A method using EXX hydrogen exchange mass spectrometry to map the energetics of protein folding landscapes.

Hydrogen exchange mass spectrometry (HXMS) is a powerful tool to understand protein folding pathways and energetics. However, HXMS experiments to date have used exchange conditions termed EX1 or EX2 which limit the information that can be gained compared to the more general EXX exchange regime. If EXX behavior could be understood and analyzed, a single HXMS timecourse on an intact protein could fully map its folding landscape without requiring denaturation. To address this challenge, we developed a numerical simulation method called NumSimEX that models EXX exchange for arbitrarily complex folding pathways. NumSimEx fits protein folding dynamics to experimental HXMS data by iteratively comparing the simulated and experimental timecourses, allowing for determination of both kinetic and thermodynamic protein folding parameters. After analytically verifying NumSimEX's accuracy, we demonstrated its power on HXMS data from beta-2 microglobulin (β2M), a protein involved in dialysis-related amyloidosis. In particular, using NumSimEX, we identified three-state kinetics that near-perfectly matched experimental observation. This proof-of-principle application of NumSimEX sets the stage for harnessing HXMS to expand our understanding of proteins currently excluded from traditional protein folding methods. NumSimEX is freely available at https://github.com/JaswalLab/NumSimEX_Public.

Protein Folding↗
PubMed1975

Increased urinary excretion of albumin, light chains, and beta2-microglobulin after intravenous arginine administration in normal man.

Infusion of 60 g of arginine in six healthy men over a 40-50 min period caused a 16-fold increase in the excretion-rate of albumin from 8-6 to 142-4 mug/min. After injection of 3, 6, 9, and 12 g of arginine the mean albumin-excretion rate of another six normal subjects rose from 5-8 mug/min to 9-4, 13-2, 21-6, and 33-9 mug/min, respectively. Excretion of light chains of immunoglobulin increased from 5-5 mug/min to 18-0, 30-0, 40-5; and 52-0 mug/min, respectively, and the excretion rate of beta2-microglobulin increased from 0-092 mug/min to 2-97, 9-23, 16-39, and 25-71 mug/min. Thus a clear dose response pattern was found. The results strongly suggest that the mechanism behind the arginine-induced protein excretion is an inhibition of tubular reabsorption.

Albuminuria↗
PubMed1975

Beta2 microglobulin and lymphocytic infiltration in Sjögren's syndrome.

We measured salivary beta2 microglobulin concentrations in 49 patients evaluated for Sjögren's syndrome with a labial salivary-gland biopsy. The salivary concentration was elevated and a significant correlation (P less than 0.001) was found between the concentration and the degree of inflammation seen in the biopsy. Serum concentrations were increased in 135 patients with Sjögren's syndrome. Striking elevations were seen in patients with associated renal or lymphoproliferative complications. Three patients have an increase in serum beta2 microglobulin concentration in association with exacerbation of their disease, and six a decrease after clinically efficacious therapy. These data indicate that determination of beta2 microglobulin in saiva may provide a simple, noninvasive technic for estimation of the degree of local inflammation in autoimmune disease.

Adrenal Cortex Hormones↗
PubMed1975

Inhibition by anti-beta2-microglobulin antisera of responder cells and not of stimulator cells in the mixed lymphocyte reaction.

Specific antisera directed against beta2-microglobulin (B2m) have been shown to inhibit completely the mixed lymphocyte reaction (MLR). However, the mechanism of inhibition has been unclear. In the present study, further experiments were performed to determine the effect of anti-B2m on both the stimulator and responder cells in an MLR. The experimental design used was that of a xenogeneic MLR, using mouse and human lymphocytes. The ffect of anti-human B2m was studied in this system. Anti-human B2m inhibited the xenogeneic MLR only when human lymphocytes were used as responder cells and did not inhibit the MLR when they were used as stimulator cells...

Animals↗
PubMed1975

Studies of the linkage relationship of beta-2-microglobulin in man-mouse somatic cell hybrids.

Beta-2-microglobulin (beta2mu) production has been studied in 33 primary man-mouse hybrid clones and in 26 secondary man-mouse hybrid clones. These clones have also been examined for the presence of 15 human enzyme phenotypes. Karyotypic analyses have been carried out on clones. From these studies the following conclusions can be drawn: (1) Gene(s) determining human beta2mu production in humans are apparently syntenic with the MPI gene on chromosome 15. (2) Long-term fibroblast lines may be of limited use in mapping studies as chromosomal rearrangements frequently occur in these lines. (3) The gene(s) determining beta2mu production in humans segregate independently of chromosome 6. If the assignment of the genes determining HL-A alloantigens to chromosome 6 is correct, our results imply that beta2mu and HL-A alloantigens are determined by genes carried on different chromosomes, despite the fact that beta2mu forms an integral part of the HL-A molecule.

Animals↗
PubMed1978

Renal tubular function in normal pregnancy.

Maternal plasma and urine concentrations of beta2- microglobulin and gamma-glutamyl transpeptidase (EC:2.3.2.2) were measured serially in normal pregnancy. These parameters remained constant throughout and can therefore be used to evaluate tubular function in pregnancies complicated by renal disorders.

Adolescent↗