Biomedical subjects

J O Utgaard

Publications and source records attributed to J O Utgaard.

3 recordsLinked to original sources

PubMed1999

Oligoclonality of rat intestinal intraepithelial T lymphocytes: overlapping TCR beta-chain repertoires in the CD4 single-positive and CD4/CD8 double-positive subsets.

Previous studies in humans and mice have shown that gut intraepithelial lymphocytes (IELs) express oligoclonal TCR beta-chain repertoires. These studies have either employed unseparated IEL preparations or focused on the CD8+ subsets. Here, we have analyzed the TCR beta-chain repertoire of small intestinal IELs in PVG rats, in sorted CD4+ as well as CD8+ subpopulations, and important differences were noted. CD8alphaalpha and CD8alphabeta single-positive (SP) IELs used most Vbeta genes, but relative Vbeta usage as determined by quantitative PCR analysis differed markedly between the two subsets and among individual rats. By contrast, CD4+ IELs showed consistent skewing toward Vbeta17 and Vbeta19; these two genes accounted collectively for more than half the Vbeta repertoire in the CD4/CD8 double-positive (DP) subset and were likewise predominant in CD4 SP IELs. Complementarity-determining region 3 length displays and TCR sequencing demonstrated oligoclonal expansions in both the CD4+ and CD8+ IEL subpopulations. These studies also revealed that the CD4 SP and CD4/CD8 DP IEL subsets expressed overlapping beta-chain repertoires. In conclusion, our results show that rat TCR-alphabeta+ IELs of both the CD8+ and CD4+ subpopulations are oligoclonal. The limited Vbeta usage and overlapping TCR repertoire expressed by CD4 SP and CD4/CD8 DP cells suggest that these two IEL populations recognize restricted intestinal ligands and are developmentally and functionally related.

Animals↗

PubMed1998

Rapid secretion of prestored interleukin 8 from Weibel-Palade bodies of microvascular endothelial cells.

Interleukin (IL)-8, a C-X-C chemokine, activates integrin-mediated adhesion of neutrophils. Presentation of IL-8 on the endothelial cell surface may promote leukocyte extravasation. We found that cultured human microvascular endothelial cells from the intestine (HIMEC) and from nasal polyps (PMEC), but not human umbilical vein endothelial cells (HUVEC), contained IL-8 in intracellular granules that coexpressed von Willebrand factor (vWf ). This observation was corroborated by the immunohistochemical observation of double-positive granules (IL-8(+)vWf+) in vessels of small and large intestine, nasal mucosa, and skin, whereas umbilical cords revealed no endothelial IL-8. After treatment of HIMEC or PMEC with histamine or thrombin, a dramatic increase in supernatant IL-8 concentration was observed within 3 min, whereas no increase in IL-8 was detected in supernatants of identically treated HUVEC cultures. Histamine or thrombin treatment also caused IL-8-containing granules to rapidly disappear from HIMEC. In HUVEC, IL-8-containing granules were inducible by treatment with recombinant human IL-1beta for 24 h; additional histamine treatment doubled IL-8 secretion from HUVEC in the same rapid manner observed for mucosal EC. These data suggested that IL-8 prestored in microvascular endothelial cells may provide a rapid pathway for specific activation of neutrophil adhesion at sites of acute inflammation.

Cell Adhesion↗

PubMed1996

Analyte and label binding assay read by flow cytometry.

A new immunometric two-site sandwich assay is introduced, in which a label-scavenging binding partner is added to the sample in addition to the analyte-binding partner. The scavenger binding partner binds excess label antibody, giving a signal proportional to the amount of excess label antibody in the sample solution. A set of two calibration curves is obtained from the two binding partners simultaneously, and a combination of the two signals gives an unambiguous determination of the analyte concentration, even for high analyte concentrations where the hook effect may occur. Two-particle immunofluorometric assays developed for placental alkaline phosphatase and human chorionic gonadotropin on the basis of this principle and yielding signals measured by flow cytometry gave rapid results (2 h) and had working ranges in excess of 5 and 6 orders of magnitude for the respective analytes.

Alkaline Phosphatase↗