Search PubMed⌕ Search

Biomedical subjects

Jun Zhao

Publications and source records attributed to Jun Zhao.

114 records · Page 7Linked to original sources
PubMedDate not supplied

Self-assembling protein arrays using electronic semiconductor microchips and in vitro translation.

Protein arrays will greatly accelerate research and development in medical and biological sciences. We have used cell-free protein biosynthesis and a parallel immobilization strategy for producing protein biochips. We demonstrate a model two-protein microarray using luciferase and green fluorescent protein, both expressed in a cell-free system and specifically immobilized on CombiMatrix semiconductor oligonucleotide microarrays. This demonstration provides evidence for the appropriate folding, activity, robust presentation, and efficient flexible detection of proteins on the microscale.

Fluorescent Antibody Technique, Indirect↗
PubMedDate not supplied

In vivo determination of the optical properties of infant brain using frequency-domain near-infrared spectroscopy.

We investigate the optical properties of the brain in 23 neonates in vivo using a frequency domain near-infrared spectroscopy (NIRS). In this study, a calibration procedure is employed to determine the absorption and reduced scattering coefficients with single source-detector separation. The absorption coefficients of the infant foreheads are lower than the values reported in adults. A large intersubject variation in the reduced scattering coefficients is also demonstrated. Furthermore, physiological parameters are derived from the absorption coefficients at two wavelengths (788 and 832 nm). The mean total hemoglobin concentration (THC) is 39.7+/-9.8 microM and the mean cerebral blood oxygen saturation (StO2) is 58.7+/-11.2%. Our preliminary results show that this bedside frequent domain NIRS could provide quantitative optical measurement of the infant brain.

Absorption↗
PubMedDate not supplied

IgG isotype conversion of a novel human anti-carcinoembryonic antigen antibody to increase its biological activity.

BACKGROUND: The IgG isotype of antibodies is very important for their biological functions such as complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC). To increase the biological activity of a novel human monoclonal antibody (C2-45) against carcinoembryonic antigen (CEA), we tried to genetically convert its isotype from IgG4 to IgG1. MATERIALS AND METHODS: VH and VL genes were cloned from the parental antibody C2-45 (IgG4) and inserted into the pAc-kappa-CH3 expression vector which contained the constant region gene of human IgG1. The recombinant gene was transfected into Sf9 insect cells to produce recombinant protein. The resulting recombinant protein, designated C2-45 (cIgG1), in the culture medium was purified by affinity chromatography and characterized for its CEA binding activity and biological activity. RESULTS: The converted C2-45 (cIgG1) retained the original antigen-binding activity and showed significantly higher CDC and ADCC activities against CEA-expressing tumor cells than did the original C2-45 (IgG4). CONCLUSION: C2-45 (cIgG1) may be useful for antibody-based immunotherapy of human CEA-expressing tumors.

Animals↗
PubMedDate not supplied

Possible applications of antibodies or their genes in cancer therapy.

In this review article the possible applications of anti-tumor-associated antigen (TAA) antibodies in the therapy of cancer have been summarized. First, recombinant monoclonal antibodies (MAbs) are increasingly being used as therapeutic agents, especially in combination with anti-cancer drugs. Second, conjugation of antibody therapy with toxins or radioisotopes offers more therapeutic approaches. Third, development of cytotoxic T-lymphocyte (CTL) or natural killer (NK)-cell populations with anti-TAA antibody activity may be important for the success of cancer immunotherapy because the downregulated HLA class I molecules and the non-ubiquitous expression of NK receptor ligands in tumor tissues constitute the major tumor escape mechanism facing tumor-specific CTL- and/or NK-cell-mediated responses. Finally, in cancer gene therapy, the strategies to target viral vectors carrying therapeutic genes to tumor tissues by modifying the tropisms with MAbs or their genes against TAAs are also very promising.

Animals↗
PubMedDate not supplied

A fully human chimeric immune receptor for retargeting T-cells to CEA-expressing tumor cells.

BACKGROUND: Recombinant chimeric immune receptors (CIRs) with anti-CEA specificity can retarget grafted T-cells to CEA-expressing tumors in an HLA-independent manner. To reduce the immunogenicity of conventional CIR in humans, an attempt was made to generate a CIR encoded by all human genes. MATERIALS AND METHODS: A single-chain variable fragmented (scFv) antibody gene was prepared from variable region genes of the C2-45 human mAb clone specific for CEA. The scFv gene was connected to a gene construct comprised of the cDNAs for the human CD8a hinge region, the human CD28 transmembrane and cytoplasmic domains, and the human CD3zeta intracellular domain. The resulting human CIR gene, designated L45scFv-CIR, was inserted into the pcDNA3.1 expression vector and transfected into human primary T-cells. RESULTS: Flow cytometric analysis using allophycocyanin-labeled CEA demonstrated the expression of the L45scFv-CIR protein on the T-cells and its specific antigen binding activity. CONCLUSION: This L45scFv-CIR gene, consisting of four human genes, may be a useful tool for eradication of CEA-expressing but HLA-downregulated tumor cells.

CD28 Antigens↗