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Biomedical subjects

G Klein

Publications and source records attributed to G Klein.

At least 469 records · Page 26Linked to original sources
PubMed1989

Plasmacytoma induction in radiochimeras.

We have induced plasmacytomas (MPC) in BALB/c radiochimeras (RCh) repopulated with syngeneic hemopoietic cells carrying distinctive chromosomal markers. A group of 38 RCh that received 0.5 ml pristane, followed by Abelson virus infection 2-3 weeks later, developed 7 tumors (18.5%) of donor origin after a relatively short latency period (X = 83 +/- 8.3 days). In contrast, only 3 (2%) MPCs were observed in 149 RChs that received 0.5 ml pristane 3 times at monthly intervals. Two of them originated from host cells. Pristane-treated RChs developed a less extensive oil granuloma (OG), compared with pristane-treated intact mice. This may explain the low incidence of MPC in the former. Our findings also suggest that Abelson virus can overcome the postulated deficiency of OG. MPC induction in the pristane + Abelson-virus-treated RCh system will facilitate the further characterization of the MPC precursor cell and the localization of genetic resistance vs. susceptibility factors at the donor vs. host level.

Animals↗
PubMed1989

The accelerating role of Abelson murine leukemia virus in murine plasmacytoma development: in vitro infection of spleen cells generates donor-type tumors after transfer to pristane-treated BALB/c mice.

The role of Abelson murine leukemia virus (A-MuLV) in the accelerated development of murine plasmacytomas (PCs) (Potter et al., 1973: Science, 132, 592-594) was studied in a new experimental system. Spleen cells from pristane-treated or untreated BALB/c mice carrying Robertsonian 6;15 fusion chromosomes were infected in vitro with helper-free A-MuLV overnight and subsequently transplanted into the peritoneal cavity of pristane-treated or untreated BALB/c mice. Donor-derived PCs developed in 4 out of 76 pristane-treated recipients [latent periods: 38-82 (mean 51) days] that had received spleen cells from pristane-treated donors, and also in 2 out of 41 pristane-treated recipients that had received untreated donor-derived spleen cells (latent periods: 65 and 120 days). Three of the PCs in the former and both PCs in the latter group were tested for integration and expression of the v-abl gene, with positive results. This indicates that the spleen contains PC-precursor cells that can be activated by A-MuLV even before the impact of pristane. All 6 donor-origin PCs carried a translocation involving chromosome 15, band D2/3. Four of these corresponded to a typical 12;15 translocation, one was a variant 6;15 translocation and the 6th may represent a previously unidentified translocation between chromosome 15 and the lambda gene-carrying chromosome 16. No PCs developed among 29 pristane-untreated recipients that had received pristane-treated donor-derived spleen cells. In addition to PCs, monocytic tumors developed in 37 (26%) of all recipients. Their development was independent of pristane treatment of recipients but was particularly frequent in those who had received spleen cells from pristane-treated donors.

Abelson murine leukemia virus↗
PubMed1989

Relationship between tumorigenicity and the dosage of lymphoma- vs. normal-parent-derived chromosome 15 in somatic cell hybrids between lymphoma cells with rearranged pvt-1 gene and normal cells.

Somatic cell hybrids were generated between YACUT, a doubly drug-resistant subline of YAC-1 (a Moloney-virus-induced T-cell lymphoma of strain A/Sn origin with 2 proviral insertions near the pvt-1 locus) and normal diploid fibroblasts of CBAT6T6 origin. Three independent fusions were performed. Three uncloned hybrid cultures and 9 independently-derived clones were tested for tumorigenicity by the inoculation of graded cell numbers into syngeneic hosts. One of 3 uncloned hybrid cultures and 3 of 9 clones were weakly tumorigenic (take incidence 0%), and 1 of 3 uncloned hybrid cultures and 6 clones were highly tumorigenic (take incidence greater than 80%). One weakly tumorigenic hybrid and 3 weakly tumorigenic clones carried 3 copies of the tumor-derived chromosome 15 and 2 copies of the normal fibroblast-derived t(14;15) chromosomes. In contrast, 2 highly malignant hybrid clones lost one copy of the normal-fibroblast-derived t(14;15), but contained increased numbers (3.44-4.44) of the tumor-derived chromosome 15. Four tumorigenic segregants selected from the weakly tumorigenic fibroblast hybrids by in vivo inoculation showed the same cytogenetic change as the highly tumorigenic hybrid clones, in that the ratio of the normal:tumor-derived chromosomes 15 changed from 1.18-1.55 to 4.11-5.71. Tumorigenicity was thus associated with a modified balance between the tumor vs. the normal-parent-derived 15-chromosomes. Instead of the usual 3:2 ratio, the tumor-derived 15-chromosomes increased disproportionately, whereas the relative number of the normal-parent-derived 15-chromosome decreased, as a rule. These results suggest that amplification of the lymphoma-derived chromosome 15 favors tumorigenicity, but that this effect is counteracted by some influence emanating from the normal-parent-derived homologous chromosome.

Animals↗
PubMed1989

Relationship between clinical stage, histopathology and antibody titers against the second Epstein-Barr virus nuclear antigen (EBNA-2) in non-Hodgkin's lymphoma patients.

Non-Hodgkin lymphoma (NHL) patients with centroblastic (Cb) or centroblastic-centrocytic (Cb/Cc)-diffuse lymphomas, immunocytoma (IC) and chronic lymphocytic leukemia (CLL) in clinical stages III-IV and with active disease (highly malignant group) were compared to NHL patients with CLL, IC, and centrocytic (Cc) or centroblastic-centrocytic (Cb-Cc)-diffuse/follicular lymphomas, in clinical stages I-II and with inactive disease (low malignant group) based on the presence of antibodies to Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA-1) and 2 (EBNA-2). In the highly malignant group, anti-EBNA-1 geometric mean titers (GMT) were 13.2 (range less than 2-80) and anti-EBNA-2 60.6 (range: 20-320). The ratio between the logarithms of anti-EBNA-1 and anti-EBNA-2 antibody titers was less than 1.0 (mean: 0.32) in all the patients examined. In 6 out of 8 patients of the low malignant group, anti-EBNA-1 titers were higher (mean: 30.1; range 10-160) than anti-EBNA-2 titers (mean: 4.3; range less than 2-80) and the EBNA 1/2 ratio was greater than 1.0. In healthy EBV-seropositive individuals, anti-EBNA-1 GMT were 49 (range: 10-320) and only 5 out of 17 individuals had detectable anti-EBNA-2 titers (GMT: 3; range less than 5-20). The EBNA-1/2 ratio was in all cases greater than 1. Among patients of the highly and low malignant groups, patients with follicular-cell-derived lymphomas had elevated antibody titers against the restricted component of early antigens (EA-R), whereas all patients with IC and 2 out of 4 CLL patients had elevated antibody titers against the diffuse component of early antigens (EA-D). The results indicate that the ratio between anti-EBNA-1 and anti-EBNA-2 antibody titers may be of diagnostic importance in patients with immunodeficiencies.

Antibodies, Viral↗
PubMed1989

Studies of sublines selected for loss of HLA expression from an EBV-transformed lymphoblastoid cell line. Changes in sensitivity to cytotoxic T cells activated by allostimulation and natural killer cells activated by IFN or IL-2.

Murine tumor studies have suggested that variations in MHC class I expression may influence the behavior of tumor cells in vivo. Corresponding human tumor studies remain at the descriptive level but they show differences in MHC Ag expression between and even within tumors. Our purpose was to explore possible functional relationships between class I expression and sensitivity to different forms of cell-mediated lysis in a potentially immunogenic system: EBV-immortalized B cells. Their cytotoxic sensitivity was tested to CTL and to IFN- or IL-2-activated effector cells. The wild-type line (high class I) was sensitive to CTL with the appropriate Ag restriction, but resisted lysis by normal or IFN-activated PBL. In contrast, HLA loss variants showed a reduced sensitivity to CTL and an increased NK sensitivity. The latter could be related to the loss of class I molecules: an intermediate (haplotype loss) expressor variant was moderately NK sensitive, whereas a weak expressor line, with an additional down-regulation of the remaining haplotype, was highly sensitive. IL-2-activated PBL ("LAK") cells showed the same killing pattern as NK cells, although the levels of lysis were generally higher. These data support the hypothesis that the MHC class I Ag expression-dependent, CTL-mediated lysis is complemented by additional mechanisms, mediated by effectors that recognize cells with reduced MHC Ag expression that would otherwise escape CTL-mediated rejection.

Cell Line↗
PubMed1989

Immunophenotypic characterization of follicle-center-cell-derived non-Hodgkin's lymphomas.

The distribution of the BLA, CALLA (CD 10), AC-2 (CD 39), MHM-6 (CD 23), LB-I, and 351C5 (CD 45R) antigens in 40 non-Hodgkin's lymphomas was demonstrated by immunohistochemical staining of frozen tissue sections. Nine out of 10 centroblastic and centrocytic follicular and diffuse type of lymphomas (CB/CC F/D) and all 10 cases of CB/CC follicular lymphomas were BLA+ and CALLA+. A few cases also showed weak expression of activation antigens (AC-2, MHM-6 and LB-I) and 351C5. In contrast, 3 CC and 3 lymphoblastic (non-Burkitt) lymphomas showed a heterogeneous pattern of distribution with dominating activation antigen expression. A single case of lymphoblastic lymphoma of Burkitt-like type expressed BLA and CALLA but not activation antigens. In reactive follicular center and FCC lymphomas different cell populations appeared to express BLA and activation antigens, respectively. Assessment of staining intensity and proportion of the stained cells indicated that almost all BLA+ cells are CALLA+. CALLA+ BLA- cells were regularly present, in addition. The co-expression of BLA and CALLA in the same cell was confirmed by double immuno-enzymatic staining. By the same technique, BLA+ and CALLA+ cells were shown to be activation-antigen negative.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1989

Endocytosis and inositol hexakisphosphate levels in ras transformants of Dictyostelium discoideum amoebae.

Fluid-phase pinocytosis kinetics and lysosomal enzyme secretion parameters were measured in Dictyostelium discoideum amoebae constructed from strain AX3 by transformation with a multicopy plasmid carrying either a normal ras gene (ras-Gly12), a mutated ras gene (ras-Thr12) or by the vector carrying the geneticin resistance gene only (pDNEO2). It was found that the pinocytosis rate and extent as well as the lysosomal enzyme secretion were slightly different in the three strains. These changes, however, were related to minor modifications of the cellular volumes. The overall concentration of inositol hexakisphosphate was similar in the three strains.

Dextrans↗
PubMed1989

Reversion of tumorigenicity and decreased agarose clonability after EBV conversion of an IgH/myc translocation-carrying BL line.

The Epstein-Barr virus (EBV)-negative Burkitt lymphoma (BL) line BL-41, and 5 independently established EBV-converted sublines, derived by infection with a transforming (B95-8) or a nontransforming (P3HR1) strain of EBV, were compared for clonability in semi-solid agarose and for tumorigenicity in immuno-suppressed mice. One P3HR1 viral convertant and 3 out of 4 B95-8 virus-converted sublines had a high (greater than 40%) agarose clonability, like the BL 41 parent, and were slightly more tumorigenic than BL-41. In contrast, the fourth B95-8 converted subline, BL-41/95, was virtually non-tumorigenic and its agarose clonability was much lower (3-23%). It showed a more drastic shift towards an LCL-like phenotype than the other convertants as reflected by high HLA class-I and EBV-encoded latent membrane protein (LMP) expression. BL 41/95 still contains the 8;14 IgH/myc translocation, carried by the parental line, and maintains the same relatively high steady-state level of c-myc mRNA and protein as the highly tumorigenic convertants. We conclude that the tumorigenicity of BL41/95 has been suppressed by a gene that acts at a level beyond the expression of the activated oncogene, in the same way as the revertants isolated from ras and SV-40-transformed cultures (Klein, 1987b; Bassin and Noda, 1987).

Animals↗
PubMed1989

Interaction of trichorzianines A and B with model membranes and with the amoeba Dictyostelium.

Trichorzianines A (TA) and B (TB) are microheterogeneous mixtures of antibiotic nonadecapeptides of the peptaibol class which interact with lipidic membranes and modify their permeability properties. The TB differ from the TA by replacement of the Gln-18 by a Glu, giving rise to a C-terminal negative charge at neutral pH. The role of this charge on the trichorzianine-lipid interaction was investigated with model membranes by fluorescence spectroscopy and the results were correlated with the biological activity toward the amoeba Dictyostelium discoideum. The interaction of the acidic trichorzianine TB IIIc (Glu-18) with phospholipid bilayers and the subsequent induced permeability were weaker than that exhibited by the uncharged TA IIIc (Gln-18) and MeTB IIIc (TB IIIc monomethyl ester). The unfavourable effect of the negative charge in TB IIIc was strongly enhanced by incorporation of cholesterol in the bilayer. Similarly, TA IIIc as well as MeTB IIIc induced growth inhibition and lysis of the amoeba Dictyostelium at four times lower concentrations than TB IIIc. The results suggested that the interaction of trichorzianines with the phospholipid bilayer and the subsequent modifications of permeability were involved in the inhibitory properties and cell lysis induced by trichorzianines toward Dictyostelium.

Amino Acid Sequence↗
PubMed1989

Enhanced H-2 expression and T-cell-dependent rejection after intracerebral transplantation of the murine lymphoma YAC-1.

The relationship between MHC class I (H-2) expression and tumorigenicity was investigated after intracerebral inoculation of the murine lymphoma YAC-1 and its H-2 negative variant, A.H-2-. YAC-1 was less tumorigenic than A.H-2- in normal as well as NK-depleted syngeneic A/Sn mice. However, in T-cell-depleted syngeneic mice YAC-1 was as tumorigenic as A.H-2-. Following intracerebral growth, the H-2 expression of YAC-1 was markedly enhanced in a similar fashion as after intraperitoneal passage. The A.H-2- variant remained H-2 negative after intracranial passage. The H-2 negative variant cells were not rejected from the brain even when intermixed with wild-type YAC-1 cells prior to intracerebral inoculation, excluding an "innocent bystander" effect. In vitro, the intracerebrally passaged YAC-1 line showed enhanced sensitivity to lysis by H-2 Kk Dd (H-2a) specific CTLs but decreased sensitivity to NK cells. The A.H-2- line was unchanged. Our data suggest that the lack of H-2 molecules may facilitate the growth of antigenic tumor cells in the brain due to escape from T-cell-mediated immunosurveillance. Our data also suggest, in line with other recent findings, that intracerebrally growing tumor cells are sheltered from NK cell-mediated rejection.

Animals↗
PubMed1989

Allele-specific down-regulation of MHC class I antigens in Burkitt lymphoma lines.

We have reported that Burkitt lymphomas (BL) that arise in HLA-A11 positive individuals are resistant to lysis by HLA-A11-specific and HLA-A11-restricted CTLs(10,11). Here we show that this phenomenon can be explained by a selective loss of the HLA-A11 polypeptide. The HLA-A11 negative phenotype is due to a regulatory phenomenon, rather than a structural defect, as proven by the ability to rescue expression of HLA-A11 in in vitro Epstein-Barr virus (EBV)-converted sublines of EBV negative BLs.

Alleles↗
PubMed1989

Epstein-Barr virus (EBV) antigen-specific leukocyte migration inhibition in infectious mononucleosis. II. Kinetics of sensitization against five EBV-encoded nuclear proteins and the latent membrane protein.

The T cell-mediated immune response of infectious mononucleosis (IM) patients to five Epstein-Barr virus (EBV)-determined nuclear antigens, EBNAs, and to the membrane antigen associated with growth-transformed cells (latent membrane protein, LMP) was measured by the leukocyte migration inhibition (LMI) assay. Two different antigen sources were used: extracts from cells that only expressed EBNA-1, EBNA-2, or LMP after transfection with the corresponding EBV-DNA fragment, and synthetic peptides deduced from the corresponding genes. Patients in the acute phase of the disease failed to respond to EBNA-1, -5, -6, and LMP, but became responsive during convalescence. The majority of the patients responded to EBNA-2 and/or EBNA-3 in the acute phase (9/15 and 12/15, respectively). The response to EBNA-2 and/or EBNA-3 in the acute phase (9/15 and 12/15, respectively). The response to EBNA-3 disappeared more often in convalescence than the response to EBNA-2: 6 of 15 patients were negative to EBNA-2 and 12 of 15 to EBNA-3 during recovery. In addition to its value in the assessment of host sensitization to virus EBV antigens, these studies and the derived hypotheses also provide certain predictions about the predominant antigen expression in the EBV-infected host under normal and pathological conditions that can be subjected to direct experimental tests.

Adolescent↗
PubMed1989

Methyl phosphonate as a 31P-NMR probe for intracellular pH measurements in Dictyostelium amoebae.

Methyl phosphonate at concentrations up to 20 mM was found to be non toxic towards the growth of Dictyostelium amoebae and the starvation-induced differentiation program. In contrast, phenyl phosphonate at the same concentrations was found to inhibit growth. Methyl phosphonate possessed good 31P-NMR characteristics for use as a pH probe in Dictyostelium. The entry of methyl phosphonate into the cytoplasm required about 150 min of incubation before an equilibrium was reached with added extracellular methyl phosphonate. A semilogarithmic plot of the efflux of methyl phosphonate out of the amoebae was linear as a function of time, and the kinetic first-order constant was k = 0.016 min-1. The kinetic parameters were consistent with an uptake of methyl phosphonate by fluid-phase pinocytosis. The pH calculated from the chemical shift of the internalized methyl phosphonate signal was found to be pH 7.4 in aerobic Dictyostelium amoebae. The intracellular methyl phosphonate environment turned more acidic in response to anaerobiosis (delta pH = 0.8) or in the presence of a weak acid such as propionate. These pH determinations were in agreement with the values of cytosolic pH derived from the chemical shift of Pi. Methyl phosphonate should be a useful probe for pH measurements in 31P-NMR studies of Dictyostelium in situations where the signal of Pi cannot be attributed with certainty.

Dictyostelium↗
PubMed1989

Evaluation of a new assay for pancreatic amylase: performance characteristics and estimation of reference intervals.

We have evaluated a new assay for the specific determination of pancreatic (P) isoamylase, the principle being based on a synergistic inhibitory effect of two monoclonal antibodies directed towards salivary (S) amylase. After 3 min incubation, activities were determined with maltoheptaoside-PNP as substrate on a Hitachi 705 analyzer at 25, 30 and 37 degrees C, respectively. Coefficients of variation ranged from 0.6 to 5.4% for within-run and 2.1 to 9.9% for day-to-day precision. Linearity held up to 1200 U/L (25 degrees C) and 2300 U/L (37 degrees C). Comparison of the new method with the wheat germ inhibitor technique showed an excellent correlation, with coefficients ranging from 0.990 to 1.00. Using purified P- and S-amylase we observed no inhibiting cross-reactivity of the antibodies with the P-isoenzyme, but an incomplete blockage of S-amylase: residual activity was approximately 2% at 25 and 30 degrees C, and 2.5% at 37 degrees C. The distribution pattern of P-, S- and total amylase activity in serum of healthy subjects was only slightly skewed to the right. We found neither an influence of sex nor of age on the reference ranges. In random urine samples, distribution of activities was strongly skewed. However, if the activity was related to the urinary creatinine concentration, an approximately normal distribution was obtained, allowing, as in serum, the establishment of upper and lower reference values.

Adolescent↗