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Biomedical subjects

H Xie

Publications and source records attributed to H Xie.

At least 19 recordsLinked to original sources
PubMed2025

HLA-E and NKG2A Mediate Resistance to BCG Immunotherapy in Non-Muscle-Invasive Bladder Cancer.

Bacillus Calmette-Guérin (BCG) is the first-line therapy for high-grade non-muscle-invasive bladder cancer (NMIBC), yet many patients experience recurrence due to immune evasion. We identify HLA-E and NKG2A as mediators of adaptive resistance involving chronic activation of NK and T cells in BCG-unresponsive tumors. Prolonged IFN-γ exposure enhances HLA-E and PD-L1 expression on recurrent tumors, accompanied by the accumulation of NKG2A+ NK and CD8 T cells. HLA-Ehigh tumor cells preferentially cluster near CXCL12-rich stromal regions with dense effector cell presence, underscoring a spatially segregated tumor architecture. Although cytotoxic lymphocytes retain effector potential, their activity is restrained by HLA-E/NKG2A and PD-L1/PD-1 pathways located in their immediate neighborhood within the bladder tumor microenvironment. These data reveal a spatially organized immune escape program that limits anti-tumor immunity. Our findings support dually targeting NKG2A and PD-L1 checkpoint blockade as a rational, bladder-sparing strategy for patients with BCG-unresponsive NMIBC.

BCG-unresponsive↗
PubMed1992

Targeting of "T" lymphocytes against human hepatoma cells by a bispecific monoclonal antibody: role of different lymphocyte subsets.

In an attempt to construct bispecific monoclonal antibodies (bimAbs) able to target cytotoxic T lymphocytes against human hepatoma cells, an HGPRT-deficient mutant of the Hepama-6 hybridoma, which produces an antihuman-hepatoma mAb, was directly fused with splenocytes from Balb/C mice immunized by a polyclonal cytotoxic T-cell line. Hybrid hybridomas were selected in HAT medium, and their supernatants were directly screened for the ability to induce IL-2-cultured cytotoxic T lymphocytes to kill hepatoma cells in a 51Cr-release assay. The selected hybrid hybridoma, termed DQ-33, secretes a bimAb, which reacts with a CD3-associated determinant. When resting peripheral-blood lymphocytes were used as effector cells, virtually no cytolytic activity could be induced by DQ-33, whereas phytohemagglutinin-activated lymphocytes that had been expanded in vitro in IL-2-containing medium could be efficiently targeted against hepatoma cells. Targeting by DQ-33 bimAb was analyzed on different subsets of IL-2-cultured lymphocytes. It was evident that CD+4-8+ TCR alpha/beta+ and CD3+4-8-TCR gamma/delta+ lymphocytes were efficiently induced by bimAb to lyse human hepatoma cells, whereas no induction of cytolysis could be observed when CD3 + 4 + 8-TCR alpha/beta+ cells were used as effectors. DQ-33 bimAb was also able to induce lymphokine secretion (IL-2, GM-CSF and TNF-alpha) by all the different subsets of lymphocytes analyzed in the presence of target cells expressing the relevant antigen, independent of the expression of cytolytic activity.

Antibodies, Monoclonal↗
PubMed1991

Trichosanthin-monoclonal antibody conjugate specifically cytotoxic to human hepatoma cells in vitro.

A plant single-chain ribosome-inactivating protein derived from the root tuber of Trichosanthes kirilowii, termed trichosanthin (TCS), was modified with 2-iminothiolane. It was not like trichokirin, a ribosome-inactivating protein derived from the seeds of the same plant, in that TCS retained full activity when 1.5 sulfhydryl groups were introduced into each TCS molecule by 2-iminothiolane modification. The 2-iminothiolane-TCS was conjugated to Hepama-1, a monoclonal antibody directed against human hepatoma with a cross-linking reagent, N-succinimidyl-3-(2-pyridyl)-dithiopropionate. The hepatoma cytotoxicity of the immunotoxin, TCS-Hepama-1, was 500-fold higher than that of free TCS and only 1 log lower than that of free ricin. However, the immunotoxin was approximately 600-fold less cytotoxic to HeLa cells. The results suggested that the immunotoxin was a potent and quite specific antihepatoma agent and might have considerable potential in hepatoma therapy.

Antibodies, Monoclonal↗
PubMed1991

Characterization of a membrane-associated glycoprotein (gp 43) on human hepatocellular carcinoma by a monoclonal antibody.

A monoclonal antibody, Hepama-1, produced by immunizing mice with cells of a human hepatocellular carcinoma cell line, has been used to identify and characterize a previously unreported antigen present on the surface of human hepatocellular carcinoma cells. The antigen occurred on the membranes of human hepatoma cell lines and tumor biopsies but was not detectable in tumors of other origin or normal tissues. Binding was determined by enzyme-linked immunoabsorbent assay and immunofluorescence on cell lines and by immunoperoxidase staining of tissue sections. In immunofluorescence studies, Hepama-1 antibodies stained five out of six human hepatoma cell lines, showed only slight binding to breast tumor cell lines, but failed to stain colon tumor or normal cell lines. The antihepatoma antibody exhibited positive immunoperoxidase staining of human liver tumor sections but did not stain tumors of other origin. Hepama-1 bound specifically to a membrane glycoprotein with an approximate molecular weight of 43,000. Western blot and solid phase enzyme-linked immunoabsorbent assay analysis showed that the 43-kD antigen occurred on five of six human hepatoma cell lines and was expressed by every human hepatocellular carcinoma biopsy tested. This cell surface molecule represents a potentially useful target for immunotherapy and localization of human hepatocellular carcinomas.

Antibodies, Monoclonal↗
PubMed1991

Techniques for intra-axonal recording of electrical activity from single nerve fiber in vitro and in situ.

The method usually applied for recording the electrical activity of single nerve fiber is extracellular recording on isolated single nerve fiber. It is difficult to obtain stable and satisfactory results from direct intracellular recording of single nerve fiber, except for some special biological materials, such as Loligo giant axon. We present in this paper a technique for recording intracellular resting membrane potential and action potential from single nerve fiber both in vitro and in situ, using glass microelectrode and a special mirror-base plate for fixing the preparation. Besides, we also report a method for labelling single nerve fiber by means of injection of HRP into the axon.

Action Potentials↗
PubMed1991

Adhesive properties of strains of Fusobacterium nucleatum of the subspecies nucleatum, vincentii and polymorphum.

This study surveyed some adhesive properties of strains of Fusobacterium nucleatum representative of the 3 recently defined groups or subspecies that could relate to their colonization and virulence. With one exception, F. nucleatum strains agglutinated sheep erythrocytes, but the quantity of bacteria required and the sensitivity of the hemagglutination reactions to inhibition by 0.05 M galactose or arginine varied between strains, and did not exhibit clear-cut correlations with subspecies. Neuraminidase treatment of erythrocytes generally enhanced the hemagglutinating activity of most strains, but trypsin treatment had no effect. Strains of F. nucleatum also attached in moderate numbers to buccal epithelial cells. Treatment of the epithelial cells with neuraminidase or with trypsin increased the numbers of all Fusobacterium strains that attached. Treatment of hydroxyapatite (HA) beads with submandibular or parotid saliva also promoted the adhesion of all strains of F. nucleatum studied. Treatment of HA with human serum or albumin produced a selective effect. Adhesion of some strains was promoted by serum and albumin treatment, and that of other strains was unaffected. Adhesion of all strains of F. nucleatum was enhanced to statherin-treated HA, whereas HA treated with salivary proline-rich protein-1 did not foster F. nucleatum attachment. Three of 4 strains of the subspecies vincentii, and each of 2 polymorphum strains studied exhibited strong adhesion to HA treated with either human type I or type IV collagen. However, only 1 of 5 strains of the subspecies nucleatum bound well to collagen-treated HA.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Microwave processing method of semen Armeniacae Amarum].

This paper reports the microwave processing method of Semen Armeniacae Amarum (Prunus armeniaca var. ansu). The experimental results showed that amygdalase was completely inactivated and the contents of amygdaloside were not reduced at all. The time and temperature of the processing method have also been studied.

Amygdalin↗
PubMed1989

Nicardipine as a Ca2+ channel blocker in single barnacle muscle fibers.

A study has been made of the efficacy of nicardipine as a Ca2+ channel blocker by determining the magnitude of its effect on the stimulatory response of the ouabain-insensitive Na+ efflux in single barnacle muscle fibers to 100 mM external K+. The results show that nicardipine (at pH 6.5) is a potent inhibitor, the minimal effective concentration being approx. 10(-7) M and the IC(50) about 5.10(-6) M. Nicardipine, however, is not as potent as verapamil (at pH 6.5) on an equimolar basis. This is explained by assuming that the number of dihydropyridine receptors in the t-tubule membranes of barnacle fibers is not high or that verapamil is able to block the sarcoplasmic reticulum Ca2+ release channel in addition to the voltage-dependent Ca2+ channels.

Animals↗