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J S Lim

Publications and source records attributed to J S Lim.

At least 37 records · Page 2Linked to original sources
PubMed1999

Enhanced antigen-presenting activity and tumour necrosis factor-alpha-independent activation of dendritic cells following treatment with Mycobacterium bovis bacillus Calmette-Guérin.

Dendritic cells (DCs) are most potent among the antigen-presenting cells and are believed to be crucial for the initiation of a primary T-cell response to foreign antigens. Mycobacterial infection within macrophages is controlled by cell-mediated immunity. To elucidate the stimulation of immune response by Mycobacterium bovis bacillus Calmette-Guérin (BCG), we purified DCs from precursor cells in human peripheral blood mononuclear cells (PBMC) by culturing them with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) and characterized their surface antigen expression. The interaction of cultured DCs with BCG resulted in increased surface expression of several DC-related marker antigens. BCG also induced reduction of endocytosis, enhancement of CD83 expression as well as B7 costimulatory molecules and IL-12 production, suggesting that BCG treatment directly induces DCs to mature. BCG-treated DCs were much more potent antigen-presenting cells in allogeneic immune response than untreated DCs. Moreover, while the neutralization of tumour necrosis factor-alpha (TNF-alpha) significantly blocked the DC maturation induced by lipopolysaccharide (LPS), it could not inhibit the induction of DC maturation by the BCG treatment, indicating that TNF-alpha production plays a minor role in the BCG-induced DC maturation. However, the neutralization of TNF-alpha resulted in decreased IL-12 production by activated DCs. These results suggest that infection with BCG might evoke direct activation and maturation of DC and the general immune stimulant effect of BCG might be related with the activation of DCs.

Antigen Presentation↗
PubMed1999

Cloning of the genomic sequence encoding a processed adenylate kinase 2 pseudogene.

A chromosomal DNA sequence harboring a processed AK2B pseudogene was isolated from a human genomic library. It was a variant of the AK2B gene sequence including several point mutations, deletions, and insertions. The nucleotide sequence of the ORF of the AK2B pseudogene predicted a truncated form of the AK2B mutant suggesting that the processed pseudogene is nonfunctional. A repetitive sequence, AAAAGAGAG, found in the 5' and 3' flanking regions of the pseudogene and the poly(A) tract in the 3' end junction suggest that a mRNA of AK2B may have been converted to the processed pseudogene by retrotransposition events. Previously, it was suggested that an adenylate kinase (AK) 2 related gene on chromosome 2, confirmed by Southern analysis using somatic cell hybrid cell lines, may be a processed pseudogene. It is proposed that the processed pseudogene isolated in this study may be the AK2 related nonfunctional gene localized on human chromosomes 2.

Adenylate Kinase↗
PubMed1999

Isolation and characterization of cDNA clone for human liver 10-formyltetrahydrofolate dehydrogenase.

A cDNA clone encoding 10-formyltetrahydrofolate dehydrogenase (10-FTHFDH) was isolated from a human fetal liver cDNA library. It contained the open reading frame of 2,709 base pairs and predicted a protein comprising 902 amino acids with a calculated molecular weight of 98,700 Da. The deduced protein showed about 93.6% homology (90.5% identity, 3.1% favored substitutions) when compared with rat 10-FTHFDH. The distribution of 10-FTHFDH transcript in various human tissues was studied by Northern blot analysis using poly(A+) RNAs from different tissues. The 10-FTHFDH transcript with an approximate size of 2.7 kb was mainly expressed in human kidney, skeletal muscle, and liver and rarely expressed in other tissues.

Amino Acid Sequence↗
PubMed1999

Induction of cytotoxic T lymphocytes with peptides in vitro: identification of candidate T-cell epitopes in hepatitis B virus X antigen.

Cytotoxic T lymphocytes (CTL) have been suggested to contribute to viral clearance during hepatitis B virus (HBV) infection. To induce effective CTL against viral infection by peptide vaccination, it is essential to identify the epitope peptides recognized by CTL. Here, 15 peptide sequences that contain HLA-A2.1-restricted CTL binding consensus motif were identified on hepatitis B virus X (HBx) protein and synthesized for further characterization. In the binding assay, 8 of 15 synthetic peptides enhanced the expression of HLA-A2.1 molecules on the surface of T2 cells, a human transport-associated antigen processing-deficient cell line. This result implies that these eight peptides are able to bind to the HLA-A2.1 molecules. These peptides were further tested for their ability to activate CTL from peripheral blood mononuclear cells (PBMCs) isolated from HBV chronic carriers. Five of eight tested peptides activated PBMC-derived T cells, resulting in the lysis of the target T2 cells pulsed with the same peptide. Furthermore, the CTL responses to HBx antigen in HBV chronic carriers were shown to be polyclonal, multispecific, and mediated mainly by CD8+ T cells. In contrast, these responses were not detected in uninfected healthy blood donors. Although the five CTL epitope peptides identified in this study have not been proven to be the naturally processed epitopes in HBV-infected hepatocytes, they could be candidates for peptide-based immunotherapy against HBV infection.

Amino Acid Sequence↗
PubMed1999

Effects of exposure conditions to footshocks early in life on spontaneous locomotor activity at maturity in rats.

Both genetic and environmental factors are involved in establishing a behavior. An animal study was done to determine the characteristics of interaction between genetic (nature) and environmental (nurture) factors. Delivery of footshocks (0.8 mA x 60 times, at random) early in life was used as the environmental stimulus. As the footshock was delivered repeatedly, a rat showed helplessness behavior and the number of shocks necessary to elicit helplessness was measured to quantify the trait of an animal in coping with the aversive environmental stimulus. The nocturnal ambulatory activity at adulthood was measured as a behavioral expression of the nature-nurture interaction. Although the experience of footshocks early in life did not significantly alter average activity levels at adulthood, the activity was positively correlated with the number of shocks necessary to elicit helplessness (nature) while receiving footshocks (nurture) on postnatal day 14. Additionally, a second exposure to identical shock parameters on postnatal day 21 reversed the relationship. These results clearly showed that an interaction between nature and nurture during infancy leads to substantial behavioral alterations later in life, and suggest that the nature-dependent determination of an adult behavior can be modified in different directions by the conditions of an environmental experience early in life.

Aging↗
PubMed1998

A peptide from hog plasma that inhibits human cholesteryl ester transfer protein.

A peptide that inhibits the human cholesteryl ester transfer protein (CETP) was isolated from hog plasma by ultracentrifugation, two sequential column chromatographies and electroelution from gels. Molecular weight of the peptide was determined to be approximately 3 kDa on the SDS-PAGE. The peptide contained 28 amino acids with an identical sequence to the amino terminus of hog apolipoprotein-CIII except two amino acid residues: -Pro-Glu- at the fifth and sixth amino acids from the amino terminus in the isolated peptide, in contrast to -Leu-Leu- in hog apo-CIII. A peptide synthesized chemically according to the amino acid sequence of the peptide (designated P28) showed approximately the same degree of CETP inhibitory activity as the isolated peptide. Synthetic peptides with different number of amino acids were also tested for CETP inhibition. Among the peptides, the one with 20 amino acid residues (P20) from the amino terminus showed the highest inhibitory activity against the CETP. The peptide appeared to be associated with the hog high-density lipoproteins (HDL), as determined by immunoblot analysis using antibody against P28. The CETP-inhibitory activity of the peptide was examined in vivo using diet-induced hypercholesterolemic rabbits. When the peptide was injected into the rabbits (7-9 mg/kg body weight), approximately 75% CETP activity disappeared from the plasma in 1 h after the injection and the effect lasted up to 30 h. The inhibition of CETP in vivo led to a concomitant decrease in total plasma cholesterol level up to 30% and an increase in the level of HDL-cholesterol up to 32%. The cholesterol concentrations in the rabbit plasma gradually recovered to the initial level after 48 h.

Amino Acid Sequence↗
PubMed1998

A simple method for the removal of epithelium grown beneath the hinge after LASIK.

The purpose of this study is to demonstrate a method of how to remove epithelium grown beneath the hinge area after laser in situ keratomileusis (LASIK) without affecting the refractive part of the lenticule. In three cases, an incision was made at the base of the hinge by RK diamond knife to free the lenticule from the stroma. The lenticule was lifted from the nasal edge. The epithelium grown along the interface beneath the hinge area was removed with a Bard-Parker No. 15 knife. The lenticular flap was repositioned with interrupted sutures using 10-0 nylon. No further epithelial ingrowth was observed. The central cornea remained clear leaving a peripheral ring-shaped opacity without affecting the preoperative naked visual acuity. In conclusion, epithelial ingrowth along the interface after LASIK can be removed safely without affecting the refractive part by the incision of the hinge area with a RK diamond knife, removal of the epithelium, and suturing of the lenticule to the stromal bed.

Adult↗
PubMed1998

Crossed cerebellar diaschisis due to intracranial hematoma in basal ganglia or thalamus.

UNLABELLED: The purpose of our study was to evaluate the remote effects on the cerebellum and cerebral cortex from subcortical hematoma without cortical structural abnormality. METHODS: Our study included 23 patients with hematoma, strictly confined either to the basal ganglia (n = 12) or thalamus (n = 11) without cortical abnormality on CT or MRI. Twenty psychiatric patients without structural abnormality on MRI were selected as control subjects. Technetium-ethyl cysteinate dimer brain SPECT was performed in patients and control subjects. Regional cerebral blood flow (rCBF) was visually and semiquantitatively assessed. Asymmetry index (AI) was determined using data from regions of interest at the basal ganglia, thalamus, cerebellum, frontal, parietal and temporal cortex to support the semiquantitative analysis. The criteria for defining hypoperfusion that reflected diaschisis was based on an AI > the mean + 2 s.d. of AI in control subjects. RESULTS: In the basal ganglia hematoma, rCBF was reduced significantly in the contralateral cerebellum (10/12), ipsilateral thalamus (12/12), ipsilateral frontal (6/12), parietal (12/12) and temporal cortex (10/12). As for thalamic hematoma, significantly reduced perfusion was seen in the contralateral cerebellum (10/11), ipsilateral basal ganglia (7/11), ipsilateral frontal (5/11), parietal (11/ 11) and temporal cortex (3/11). CONCLUSION: Crossed cerebellar diaschisis (CCD) and cortical diaschisis frequently were observed in patients with subcortical hematoma without cortical structural abnormality. This suggested that CCD can develop regardless of interruption of the corticopontocerebellar tract, which is the principal pathway of CCD.

Adult↗
PubMed1997

Peptide-specific CTL induction in HBV-seropositive PBMC by stimulation with peptides in vitro: novel epitopes identified from chronic carriers.

Cytotoxic T lymphocytes (CTL) recognize and destroy virus-infected cells, and it has been established that epitope-based peptides could induce such CTL in vivo as well as in vitro. In this study attempts were made to define the epitopes that are recognized by the CTL, and thus a series of 9- to 10-mer peptides derived from the amino acid sequences of hepatitis B virus (HBV) proteins were synthesized on the basis of the previously described HLA-A2 peptide binding motif. The binding assay of the synthetic peptides using transporter-associated with antigen processing (TAP)-deficient human cell line, T2, showed that eight out of 11 peptides tested enhanced the expression of HLA-A2 molecules on the T2 cell surface. Some of these peptides triggered activation of CTL in peripheral blood mononuclear cells of HBV-seropositive chronic carriers. The activated CTL in turn recognized and killed the T2 cells pulsed with the same peptides. This study shows that novel HLA-A2-restricted epitopes exist in the natural repertoire of immunity against HBV. These findings can be useful in developing peptide-based therapeutics against viral infections.

Carrier State↗
PubMed1997

Complete sequence of the UPP gene encoding uracil phosphoribosyltransferase from Mycobacterium bovis BCG.

The nucleotide sequence of a 799 bp fragment of Mycobacterium bovis BCG containing the putative upp gene that encodes a uracil phosphoribosyltransferase (UPRTase [EC 2.4.2.9]) has been determined. The upp gene of BCG has an open reading frame (ORF) of 621 bp (207 amino acids) starting with GTG (position 112) and ending with TGA (position 733), and its molecular mass was calculated to be 21,864 Da. Comparative analyses of the deduced amino acid sequence of BCG UPRTase with the UPRTase of six bacterial genera revealed that 24% (50/211) of the residues are perfectly conserved and 32% (67/211) of the residues are well conserved.

Amino Acid Sequence↗
PubMed1997

Cloning and sequencing of the secY gene homolog from Mycobacterium bovis BCG.

The complete nucleotide sequence of a 1,513 bp fragment of Mycobacterium bovis BCG containing the secY gene homolog and partial adk gene that encodes an adenylate kinase has been determined. The secY gene of BCG has an open reading frame of 441 amino acids with homology to the SecY protein family. Comparative analyses of the deduced amino acid sequence of additional partial ORF revealed strong similarity to the known adenylate kinases.

Amino Acid Sequence↗
PubMed1997

Differential expression of ferritin heavy chain in THP-1 cells infected with Mycobacterium bovis BCG.

To identify the host genes induced or suppressed by infection of mycobacteria, the reverse transcriptase polymerase chain reaction (RT-PCR) and the differential display reverse transcriptase polymerase chain reaction (DD RT-PCR) methods were used. In this study, cDNAs complement to mRNA extracted from human peripheral monocyte derived naive THP-1 cells, THP-1 cells infected with live Mycobacterium bovis BCG, THP-1 cells treated with heat-killed BCG, and THP-1 cells incubated with IgG-coated glass-beads were compared on the sequencing gel. One (TG2-1) of the clones selected by DD RT-PCR is 446 bp long and is identical to human ferritin heavy (H) chain gene. Northern blot analysis confirmed that ferritin H chain gene has been markedly over-expressed in monocytic THP-1 cells incubated with live and dead M. bovis BCG. Differential display techniques of host genes whose expression levels were varied by infection of mycobacteria could provide information about the response of macrophages to mycobacterial infection.

Amino Acid Sequence↗
PubMed1996

A status report on helium inductively coupled plasma mass spectrometry.

The current status of helium inductively coupled plasma - mass spectrometry (He ICPMS) is examined, its potentials and limitations are reviewed, and a summary of fundamental properties of atmospheric pressure He ICP discharges is presented. Also included are results of He ICPMS studies with a new helium plasma torch (18 mm i.d.) operated at four sets of operating conditions. Under the "cold plasma" condition (600 W forward power), no secondary discharge is observed and ion kinetic energies ranging from 2.0 eV to 9.5 eV for 6 elements (mass range: 39-208) are measured. At higher power levels, the secondary discharge still is strong. In general, detection limits for certain elements are improved by 1-3 orders of magnitude compared to previous data acquired in 1993 with a 13-mm He ICP torch. Elements such as K, Fe, Cr, Mn, Ni, and Co that suffer from spectral interferences in Ar ICPMS can be detected at pg/mL-levels with an analogue detector and a prototype ICPMS instrument having no photon stops or obstacles present in the ion trajectory path.

Journal Article↗
PubMed1996

Selection of peptides that bind to the HLA-A2.1 molecule by molecular modelling.

Cytotoxic T lymphocytes recognize antigenic peptides in association with major histocompatibility complex class I proteins. Although a large set of class I binding peptides has been described, it is not yet easy to search for potentially antigenic peptides without synthesis of a panel of peptides, and subsequent binding assays. In order to predict HLA-A2.1-restricted antigenic epitopes, a computer model of the HLA-A2.1 molecule was established using X-ray crystallography data. In this model nonameric peptide sequences were aligned. In a molecular dynamics (MD) simulation with two sets of peptides known to be presented by HLA-A2.1, it was important to know the anchor amino acid residue preference and the distance between the anchor residues. We show here that the peptides bound to the HLA-A2.1 model structure possess a side chain of C-terminal anchor residue oriented into the binding groove with different distances between the two anchor residues from 15 to 21A. We also synthesized a set of nonamer peptides containing amino acid sequences of Hepatitis B virus protein that were selected on the basis of previously described HLA-A2.1 specific motifs. When results obtained from the MD simulation were compared with functional binding assays using the TAP-deficient cell line T2, it was evident that the MD simulation method improves prediction of the HLA-A2.1 binding epitope sequence. These results suggest that this approach can provide a way to predict peptide epitopes and search for antigenic regions in sequences in a variety of antigens without screening a large number of synthetic peptides.

Amino Acid Sequence↗
PubMed1996

Cloning and characterization of cDNA for human adenylate kinase 2A.

We have isolated and characterized a cDNA clone encoding human adenylate kinase 2A (AK2A) from cDNA libraries of fetal liver origin. The complete nucleotide sequence of the cloned 889 nucleotide cDNA fragment indicated that the deduced gene product of human AK2A is composed of 239 amino acids with a molecular weight of 26 kD. Comparison of these nucleotide and amino acid sequences with the corresponding sequences of bovine AK2A and rat AK2 revealed a high degree of conservation. It showed 91% and 98% homologies in DNA and amino acid sequences, respectively, with bovine AK2A throughout the full open reading frame. RNA blot analysis revealed that three species of mRNA were present with approximate sizes of 3.4, 2.1, and 1.0 kb. This gene was expressed in E. coli cells and the recombinant protein was enzymatically active.

Adenylate Kinase↗
PubMed1996

pH changes observed in the inflamed gingival crevice modulate human polymorphonuclear leukocyte activation in vitro.

Previous studies have noted a positive correlation between gingival inflammation and crevicular pH, which reportedly varies from 6.5 to 8.5. In the present study, we characterized the manner in which deviation from the "physiological" pH of blood (7.2) influences activation of chemotaxis, phagocytosis, superoxide generation, and degranulation by human polymorphonuclear leukocytes (PMNs). Purified PMNs were suspended in HEPES-buffered balanced salts solutions adjusted to pH 6.7, 7.2, 7.7, or 8.2. In a modified Boyden chamber, the chemotactic response to fMet-Leu-Phe was maximal at pH 7.2. In comparison, chemotaxis was significantly depressed at pH 7.7 and pH 8.2 (P < 0.05), but was not significantly different at pH 6.7. Activation of the respiratory burst by fMet-Leu-Phe was optimal at pH 7.2, but was significantly depressed at pH 6.7 and 8.2 (P < 0.05). pH had little effect on N-acetyl-beta-glucosaminidase release from primary granules. However, lactoferrin release from the secondary granules of fMet-Leu-Phe-activated PMNs was significantly lower at pH 7.2 than at pH 6.7 or 8.2 (P < 0.05). Moreover, phagocytosis of opsonized bacteria was significantly lower at pH 7.2 than at pH 7.7. In addition to these effects on functional activation, extracellular pH influenced the magnitude of intracellular Ca2+ mobilization. Peak fMet-Leu-Phe-induced Ca2+ levels were significantly higher at pH 8.2 than at pH 7.2 (P < 0.01). These findings suggest that the pH of the periodontal environment can selectively influence PMN activation, thereby altering the balance between bacteria and the host response.

Analysis of Variance↗
PubMed1994

The effects of protection by D-Pen2-D-Pen5-enkephalin or D-Ala2-NMePhe4-Gly-ol-enkephalin against beta-chlornaltrexamine in the spinal cord on the antinociception induced by beta-endorphin administered intracerebroventricularly in the mouse.

Chlornaltrexamine (beta-CNA, 0.5 micrograms) alone or beta-CNA plus either mu-agonist, D-Ala2-NMePhe4-Gly-ol-enkephalin (DAMGO, 500 ng) or delta-agonist, D-Pen2-D-Pen5-enkephalin (DPDPE, 10 micrograms) was injected intrathecally (i.t.) to protect mu- or delta-opioid receptors, respectively, for 24 h in male ICR mice. The antinociception was assessed by the tail-flick and hot-plate test. DPDPE or DAMGO injected i.t. increased inhibition of the tail-flick and hot-plate response in a dose-dependent manner. The dose-response curve for tail-flick and hot-plate response induced by DPDPE or DAMGO in i.t. saline-treated group significantly shifted to the right in i.t. beta-CNA alone treated group but returned to the control level in the group treated with i.t. beta-CNA coadministered with DPDPE or DAMGO, respectively. The effects of protection of mu- and delta-opioid receptor in the spinal cord on inhibition of the tail-flick and hot-plate response induced by beta-endorphin and morphine administered intracerebroventricularly (i.c.v.) were then studied. Intrathecal pretreatment with beta-CNA or beta-CNA coadministered with DAMGO attenuated inhibition of the tail-flick response induced by beta-endorphin administered i.c.v. However, i.t. treatment with beta-CNA coadministered with DPDPE did not affect inhibition of the tail-flick response induced by beta-endorphin administered i.c.v. Intrathecal pretreatment with beta-CNA or beta-CNA coadministered with either DPDPE or DAMGO did not alter inhibition of the hot-plate response induced by beta-endorphin administered i.c.v.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗