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Biomedical subjects

G Klein

Publications and source records attributed to G Klein.

At least 181 records · Page 10Linked to original sources
PubMed1997

Epstein-Barr virus (EBV) gene expression in lymphoid B cells during acute infectious mononucleosis (IM) and clonality of the directly growing cell lines.

We examined the patterns of viral gene expression in acute infectious mononucleosis (IM) patients and the clonality of the directly growing EBV-carrying cell lines. Both low- and high-density EBV-carrying B cells obtained from the patients' tonsils expressed EBNA1, EBNA2 and LMP1. Like LCLs and immunoblastic B-cell lymphomas, the in vivo EBV-carrying low-density cells used only the latency III program for viral gene expression. The in vivo EBV-carrying high-density B cells used both the latency I program, as indicated by the QUK-, and the latency III program, as indicated by the YUK-EBNA1. This suggests that the lymphoid tissues contained not only proliferating immunoblasts but also cells programmed for latent viral persistence in vivo. EBV-carrying cells that grew directly into permanent cell lines in the presence of virus-neutralizing antibody and a late viral inhibitor were polyclonal, as indicated by JH rearrangement. Two of the high-density-derived lines had identical JH and TR patterns, indicating a common parental origin. Our investigation indicates that EBV-carrying cells divide and survive in a fully competent immune system during the outbreak of acute IM.

Antigens, Viral↗
PubMed1997

[Double-blind comparative study of the effectiveness and tolerance of 900 mg dexibuprofen and 150 mg diclofenac sodium in patients with painful gonarthrosis].

In this randomized double-blind, parallel-group study the efficacy of 300 mg oral dexibuprofen three times daily and 50 mg oral diclofenac sodium three times daily was tested for equivalence in 110 patients with painful osteoarthritis of the knee. During the 15-day treatment period the functional index for knee osteoarthritis according to Lequesne was improved under dexibuprofen by a mean of 7.4 and by a mean of 7.3 under treatment with diclofenac sodium. The test for equivalence by one-sided Wilcoxon-Mann-Whitney test shows equivalent efficacy of dexibuprofen by a Mann-Whitney-statistic of 0.505 and 0.415 as its lower boundary of the 95% confidence interval. The descriptive analysis of secondary criteria such as intensity of pain, rest pain, pain at beginning, nocturnal pain, tenderness, restriction of movement, handicap, subjective estimation of disease progression, as well as global judgement of efficacy and tolerance by investigator and patient confirm equivalence of both preparations. The pooled analysis of all parameters, tolerability included, by a Mann-Whitney-statistic of 0.520 with the lower boundary of the 95% confidence interval of 0.467 shows equivalence of both drugs with a trend to superiority of dexibuprofen due to its better tolerability. 7.3% of the patients on dexibuprofen and 14.5% of the patients on diclofenac sodium dropped out because of side-effects.

Adult↗
PubMed1997

B-CLL cells with unusual properties.

In studies concerning the interaction of B-CLL cells and Epstein-Barr virus (EBV), we encountered one patient whose cells had several unusual properties. In addition to the B-cell markers, the CLL cells expressed the exclusive T-cell markers CD3 and CD8 and carried a translocation t(18,22)(q21;q11), involving the bcl-2 and Ig lambda loci. The patient represents the 4th reported CLL case with this translocation. The CLL cells could be infected and immortalized by the indigenous and by the prototype B958 virus in vitro. The T-cell markers were not detectable on the established lines. In all experiments the immortalized lines originated from the CLL cells. Their preferential emergence over virus-infected normal B cells may be coupled to the high expression of the bcl-2 gene due to the translocation. In spite of the sensitivity of CLL cells to EBV infection in vitro, no EBNA-positive cells were detected in the ex vivo population. In vitro, we could generate cytotoxic function in T-lymphocyte cultures which acted on autologous EBV-infected CLL cells. Therefore we assume that if such cells emerged in vivo they were eliminated by the T-cell response.

Aged↗
PubMed1997

A yeast artificial chromosome (YAC) contig encompassing the critical region of the X-linked lymphoproliferative disease (XLP) locus.

X-linked lymphoproliferative disease (XLP) is characterized by a marked vulnerability to Epstein-Barr virus (EBV) infection. Infection of XLP patients with EBV invariably results in fatal mononucleosis, agammaglobulinemia, or malignant lymphoma. Initially the XLP gene was assigned to a 10-cM region in Xq25 between DXS42 and DXS37. Subsequently, an interstitial, cytogenetically visible deletion in Xq25 was identified in one XLP family, 43. In this study we estimated the deletion in XLP patient 43-004 by dual-laser flow karyotyping to involve 2% of the X chromosome, or approximately 3 Mb of DNA sequence. From a human chromosome Xq25-specific yeast artificial chromosome (YAC) sublibrary, five YACs containing DNA sequences deleted in patient 43-004 have been isolated. Sequence-tagged sites (STSs) from these YACs have been used to identify interstitial deletions in unrelated XLP patients. Three more families with interstitial deletions were found. Two of the patients (63-003 and 73-032) carried an interstitial deletion of 3.0 Mb overlapping the 43-004 deletion. In one XLP patient (30-011) who exhibited the characteristic postinfectious mononucleosis phenotype of XLP with hypogammaglobulinemia and malignant lymphoma, a deletion of approximately 250 kb was detected overlapping the deletion detected in patients 43-004, 63-003, and 73-032. A YAC contig of 2.2 Mb spanning the XLP critical region, whose orientation on chromosome X was determined by double-color fluorescence in situ hybridization and which consists of 15 overlapping YAC clones, has been constructed. A detailed restriction enzyme map of the region has been constructed. YAC insert sizes were determined by counter-clamped homogenous electric field gel electrophoresis. Chimerism of YACs was determined by FISH and restriction mapping. On the basis of lambda subclones, YAC end-derived plasmids, and STSs with an average spacing of 100 kb, a long-range physical map was constructed using 5 rare-cutter restriction enzymes. The STSs and lambda subclones were used in Southern hybridization and PCR analyses. The work presented here substantially refines the critical region for XLP. The YAC contig with the overlapping interstitial deletions constitutes the basis for the construction of a transcriptional map of the critical region and facilitates the identification of the XLP gene.

Chromosomes, Artificial, Yeast↗
PubMed1997

CD28 is not required for rejection of unmanipulated syngeneic and autologous tumors.

To gain a better understanding of the requirement of CD28 co-stimulation in different types of T cell-dependent tumor rejection responses, we performed a series of syngeneic and autologous tumor rejection experiments on CD28 knockout mice. In a preimmunization-challenge model, virally-induced ALC lymphoma and methylcholanthrene-induced MC57X fibrosarcoma transplants were rejected similarly by syngeneic CD28 knockout and immunocompetent controls. ALC-specific cytotoxic T lymphocytes (CTL) and MC57X-specific tumor necrosis factor (TNF) release were induced in CD28 knockouts, although at a reduced level in the latter case. Secondly, the spontaneous regression of Moloney murine sarcoma virus (MMSV)-induced primary tumors in the autologous hosts occurred equally in CD28 knockouts and in immunocompetent control mice. A comparable virus-specific CTL response was generated in both, as revealed in cytolytic assays against RBL-5 targets. Thirdly, the spontaneous rejection of the B7-transfected EL-4 lymphoma by immunocompetent hosts was abrogated in CD28 knockout mice, since more than 82% CD28 knockouts developed tumors after inoculation with B7-transfected EL-4 cells. Our results therefore show that CD28 co-stimulatory molecules are not required for the rejection of unmanipulated syngeneic tumors in hyperimmunized hosts and the regression of MMSV-induced sarcoma in autochthonous hosts.

Animals↗
PubMed1997

Control of B cell lymphoma recognition via natural killer inhibitory receptors implies a role for human Vgamma9/Vdelta2 T cells in tumor immunity.

The Vgamma9/Vdelta2 T cell receptor (TCR) is expressed by most human gammadelta T cells. We show here that cytotoxic T lymphocytes of the Vgamma9/Vdelta2 subset, but not of the Vdelta1 subset of human gammadelta T cells, express natural killer inhibitory receptors (KIR) with specificity for different HLA class I alleles that down-regulate TCR-mediated signaling in response to HLA class I-expressing B cell lymphomas. Vgamma9/Vdelta2 T cell clones with a T helper cell phenotype lack KIR and produce lymphokines in response to most human B cell lymphomas, just as they do upon recognition of the HLA class I-deficient human Burkitt's lymphoma Daudi. Thus, human Vgamma9/Vdelta2 T cells have an innate specificity for nonpolymorphic cell surface structures expressed by many lymphoma cells and their cytotoxic activity is controlled by KIR. These results imply a general role of human Vgamma9/Vdelta2 T cells in the defense against hematopoietic tumors that is distinct from NK cells.

Cells, Cultured↗
PubMed1997

An association between the flat back and postpolio syndromes: a report of three cases.

The cases of three patients with a history of paralytic poliomyelitis in childhood who developed the flat back syndrome before or after spinal fusion for degenerative disease as adults were reviewed. The flat back syndrome, a combination of an inability to stand erect because of forward flexion of the trunk and pain in the low back and/or legs, typically occurs in the setting of decreased lumbar lordosis as a result of distraction instrumentation of the spine for scoliosis, vertebral fracture, or degenerative disease. Focus was placed on determining the factors responsible for the development and/or persistence of the flat back syndrome in these patients despite maintenance of, or partial operative restoration of, lumbar lordosis. Considering the essential role that the trunk extensor musculature plays in maintaining upright posture, it may be that a new onset of weakness (postpolio syndrome) in this musculature represents a major contributing factor to the flat back syndrome in these patients. Spine surgeons considering operative procedures in patients with a remote history of paralytic poliomyelitis should be aware of the possible increased risk of the flat back syndrome in this population of patients.

Back Pain↗
PubMed1997

Differential immunogenicity of Epstein-Barr virus (EBV) encoded growth transformation-associated antigens in a murine model system.

The strong immunosurveillance of humans against EBV transformed immunoblasts, mediated by CD8+ cytotoxic T cells, is based on the recognition of peptides derived from eight of the nine growth transformation-associated proteins, the nuclear antigens EBNA2-6 and the membrane proteins LMP1, -2A and -2B. The ninth protein, EBNA1, required for maintenance of the viral episomes, and expressed in a cell phenotype independent manner, has not been found to generate a cytotoxic lymphocyte (CTL) response in humans. We tested whether EBNA1 has a similar immunologically privileged status in a species that has not encountered the virus in nature, the mouse. Non-immunogenic murine mammary carcinoma cells were transfected with the appropriate viral gene. Rejection responses were assayed in syngeneic mice following repeated immunisation with irradiated cells. Previously, we found that LMP1 expression in S6C, a murine mammary carcinoma of ACA (H-2f) origin, induces high rejectability, whereas corresponding EBNA1 transfectants remained non-immunogenic. In order to test whether this finding could be reproduced on another MHC class 1 background, we expressed LMP1 and EBNA1 in another non-immunogenic mammary carcinoma, SBfnHd of CBA (H-2k) origin. LMP1 but not EBNA1 transfectants were immunogenic in this system. In order to investigate whether other growth transformation-associated EBV proteins were immunogenic in the mouse, we also transfected the S6C cells with EBNA4, EBNA5, LMP2A and -2B. All four proteins induced strong rejection reactions. These findings are fully consistent with corresponding findings in the human system. They also show that the immunologically privileged status of EBNA1 is not due to some peculiarity of the long-standing co-existence between EBV and the human species, nor to any specific features of the human MHC class I system. They are consistent with the suggestion that EBNA1 may not be properly processed and/or transported, due to specific features of the protein itself.

Animals↗
PubMed1997

Spontaneous development of plasmacytomas in a selected subline of BALB/cJ mice.

Sixty per cent of BALB/cAnPt mice injected intraperitoneally (i.p.) with tetramethylpentadecane (pristane) develop plasmacytomas (PCs), whereas less than 10% of BALB/cJ develop such tumours. Most other mouse strains are completely resistant. Resistance is dominant over susceptibility in F1 hybrids between BALB/cAnPt and the resistant non-BALB/c strains, suggesting that susceptibility may be due to some genetic defect. (BALB/cAnPtxBALB/cJ)F1 hybrids have a PC incidence of 36-42%. Previously, BALB/cJ has been shown to harbour at least one resistance gene (Potter et al., Genomics 1988, Vol. 2, pp. 257-262). On the assumption that BALB/cJ may contain a segregating resistance gene, we cross BALB/cJ females with pristane-pretreated BALB/cJ males that were found to be carrying PC cells intraperitoneally 5-7 months after pristane treatment. After two selective crosses, 62% of the BALB/cJ subline BALB/cM2/22 developed PC after pristane and 52% after pristane followed by Abelson virus, while unselected controls had an incidence of 11% and 0%, respectively. Moreover, six spontaneous plasmacytomas developed in untreated females of the selected colony. Five of these carried T(12; 15) (F2; D2/3) translocations. The sixth had a T(1; 10) (G; C1) translocation and an interstitial duplication of segment (C1/E3) on one chromosome 5. It may be concluded that pristane treatment is not a prerequisite for the induction of the PC associated Ig/myc translocations.

Animals↗
PubMed1997

Role of p53 mutation in polyomavirus-induced tumorigenesis.

Small DNA tumour viruses, such as simian virus 40 (SV40), papilloma viruses and adenoviruses, encode proteins that form complexes with and inactivate the p53 and retinoblastoma (RB) proteins. This convergent evolution reflects the common need of these viruses to inactivate these two important regulators of cell cycle progression and cell survival. Polyomavirus, a close relative of SV40, is different. Its large T protein complexes only with RB, not with p53. We have examined whether this is compensated by the frequent appearance of p53 mutations in polyomavirus-induced tumours. We tested the p53 status of 15 polyomavirus-induced sarcomas. Two sarcomas were p53-negative while six carried mutant p53. Another six sarcomas expressed low levels of wild-type p53. One tumour expressed high levels of wild-type p53 protein as shown by DNA sequencing and immunofluorescence staining. MDM2 amplification was not detected in any of the tumours, but Northern blotting showed that MDM2 was overexpressed in at least two tumours that expressed wild-type p53 and in one tumour that expressed both wild-type and mutant p53. Treatment with the DNA-damaging agent mitomycin C caused p53 protein accumulation followed by induction of MDM2 and WAF1/p21 mRNA in four of the tumours expressing wild-type p53, indicating that p53-mediated transcriptional activation was unaltered in these tumours. However, p53-mediated transactivation of WAF1/p21 was impaired in the wild-type p53-expressing tumours that expressed elevated levels of MDM2. These results demonstrate that p53 mutation and inactivation are frequently but not invariably involved in polyomavirus-induced tumorigenesis.

Animals↗
PubMed1997

Epstein-Barr virus-encoded LMP-1 protein upregulates the pNDCF group of nucleoskeleton-cytoskeleton-associated proteins.

In a recent study, we described a group of monoclonal antibodies that identify five high molecular mass proteins which associate with intermediate filaments in the cytoplasm and accumulate in nuclear foci as well. The proteins have been designated pNDCFs, proteins associated with nuclear dots and cytoplasmic filaments. Their expression in human B cells was upregulated by Epstein-Barr virus (EBV) infection or by exposure to anti-CD40 antibodies and IL4. Phenotypically representative (type I) Burkitt's lymphoma (BL) cell lines do not express pNDCFs or, if they do, the proteins accumulate preferentially in nuclear dots. Type III BL cell lines that have drifted to a more immunoblastic phenotype during in vitro passage and EBV-transformed lymphoblastoid cell lines (LCLs) of non-neoplastic origin express these proteins regularly at high levels. They are preferentially but not exclusively associated with vimentin filaments in the cytoplasm. Here we show that all five pNDCFs can be upregulated by expressing the EBV-encoded membrane protein LMP1 in type I BLs. Three of them could also be upregulated in the human keratinocyte cell line RHEK-1 by LMP1 transfection. This upregulation was paralleled by the LMP1-induced increase in vimentin expression in both cell types. One of the pNDCFs, detected by the MAb DM_4A6, accumulated in cap-like structures under the cell membrane that colocalized with membrane patches of LMP1, in addition to its localization in nuclear dots and in association with cytoplasmic vimentin filaments.

Animals↗
PubMed1997

A 3p21.3 region is preferentially eliminated from human chromosome 3/mouse microcell hybrids during tumor growth in SCID mice.

We have previously shown that four markers spanning the 3p24-p21.3 region, THRB, AP20R, D3S1029, and D3S32, were regularly eliminated from three human chromosome 3 (chr3)/mouse microcell hybrids (MCHs) during tumor growth in SCID mice. In an attempt to narrow down the eliminated region, we have studied 22 new SCID mouse tumors derived from 5 MCH lines carrying human chr3. They were analyzed by fluorescence in situ hybridization (FISH), Southern blotting, and polymerase chain reaction (PCR). MCHs that carried human chr1, chr8, chr13, and chr17 were examined as controls. We could identify a common eliminated region (CER) at 3p21.3, bordered distally by D3S1260 and proximally by D3S643/D3F15S2. Eight of 53 chr3-specific PCR markers, AP20R, D3S966, D3S3559, D3S1029, WI-7947, D3S2354, AFMb362wb9, and D3S32. were localized within the CER. This finding is consistent with the notion that a tumor suppressor gene may be located in this area, as suggested by frequent loss of heterozygosity (LOH) within this region observed in several types of solid tumors.

Animals↗
PubMed1997

Differential expression of nucleoskeleton- and cytoskeleton-associated proteins in Burkitt lymphoma-derived and Epstein-Barr virus-immortalized lymphoblastoid cell lines.

Mouse monoclonal antibodies raised against nuclear bodies isolated from an EBV-immortalized lymphoblastoid cell line (LCL) known to contain several viral and cellular proteins (Jiang et al., Exp. Cell Res., 197: 314-318, 1991; Szekely et al., J. Gen. Virol., 76: 2423-2432, 1995; Szekely et al., J. Virol., 70: 2562-2568, 1996). Seventy six clones gave detectable immunofluorescence staining on LCLs. Five independent monoclonal antibodies detected a group of apparently novel, high M(r) (> 200,000) proteins that shared common features of subcellular distribution. In LCLs, these proteins were preferentially associated with vimentin filaments in the cytoplasm and with distinct nuclear foci. The appearance of the latter differed from the premyelocytic leukemia-associated protein, EBV nuclear antigen #5, and retinoblastoma-protein-positive bodies that were used for immunization. They seemed to be connected to the cytoplasmic filaments through thin fibrillar nuclear structures. In mitotic cells, these complex structures rearranged into a perichromosomal basket that was associated with vimentin filaments. The target proteins, operationally designated as proteins associated with nuclear dots and cytoplasmic filaments (pNDCFs), were not present in resting human B cells or were expressed at a low level. The level increased considerably after EBV infection or mitogenic stimulation by interleukin 4 and anti-CD40 antibodies. In Burkitt lymphoma (BL) type I lines phenotypically representative of the in vivo tumors, the pNDCFs were either absent or exclusively localized to the nucleus, usually to well-defined nuclear foci. EBV-positive type I BLs often shift to a more LCL-like (type III) phenotype during prolonged in vitro propagation. Type I cells express only EBV nuclear antigen 1 and the surface markers CD10 and CD77, whereas type III express all nine growth-associated EBV-encoded proteins and a gamut of B-cell activation markers. Most of the type III BL cell lines contained increased amounts of pNDCFs bound to cytoplasmic filaments, as seen in the LCLs. We propose that the expression of vimentin-associated pNDCFs should be included in the definition of type III BL phenotype.

Burkitt Lymphoma↗