Human B cell alloantigens: expression of MB and MT determinants

Four HLA-DR-homozygous cell lines were examined in detail to compare alpha and beta subunits precipitated by chimpanzee antisera and alloantisera directed against HLA-DR, MB, or MT determinants. For the HLA-DR5-homozygous cell line Sweig, chimpanzee antisera directed against MT2 and against the HLA-DR5 specificity yielded identical patterns. Similar findings for MT and MB vs HLA-DR were obtained for the cell lines LG14 (HLA-DR3-homozygous), PBur (HLA-DR7-homozygous), and Eld (HLA-DRw6-homozygous). Therefore, on some cell lines MT and/or MB specificities appear to be detectable only on the same or electrophoretically identical alpha-beta complexes as HLA-DR determinants.     

Autolysis of Lactococci: Detection of Lytic Enzymes by Polyacrylamide Gel Electrophoresis and Characterization in Buffer Systems

Lactococcal strains were screened for bacteriolytic activity against Micrococcus luteus cells, lactococcal cells, and cell walls. Thirty strains were screened for bacteriolytic activity against cells and cell walls incorporated into agar medium. Enzymes from all strains hydrolyzed the substrates; however, the activity against Micrococcus cells was much higher than against Lactococcus cells or cell walls. Electrophoretic profiles of bacteriolytic activities of culture supernatants, sodium dodecyl sulfate-treated cell extracts, cell wall fractions, and cell extracts were analyzed in sodium dodecyl sulfate-polyacrylamide gels containing M. luteus cells or lactococcal cell walls as the substrate. The 22 strains tested contained two to five lytic bands in the culture supernatant, ranging in size between 32 and 53 kDa. The cell extracts, the sodium dodecyl sulfate-treated cell extracts, and the cell wall fractions revealed two lytic bands of 47 and 53 kDa. Effects of external factors on autolysis of some strains were determined in buffer systems. Optimal autolysis was observed in the exponential growth phase at pH 6.0 to 7.5 and at a temperature of 30(deg)C. Two of three strains tested seemed to contain a glycosidase, and all three strains contained an N-acetylmuramyl-l-alanine amidase or an endopeptidase.     

Protection against iron- and hydrogen peroxide-dependent cell injuries by a novel synthetic iron catalase mimic and its precursor, the iron-free ligand

Hydrogen peroxide is involved in many types of cell injury and exerts most of its injurious effects in conjunction with chelatable iron. We previously described a synthetic nonporphyrin iron-containing catalase mimic, TAA-1/Fe. Its ligand TAA-1 was designed for application in biological systems in which it is supposed to fulfill a dual task: it should chelate cellular labile iron and thus form the active catalase mimic, thereby decreasing levels of redox-active iron and enhancing the degradation of hydrogen peroxide. Here, we tested these novel compounds in cellular systems, i.e., in cultured hepatocytes and liver endothelial cells. Both the iron complex, i.e., the complete mimic, and the ligand, i.e., the putative precursor of this mimic, provided protection against endothelial cell injury induced by exogenous hydrogen peroxide. Furthermore, the ligand--but not (or less so) the complex--strongly protected both cell types against iron-dependent hypothermic injury and hepatocytes against iron-induced cell injury and against iron-dependent, histidine-induced injury. Together, these results demonstrate that the putative catalase mimic precursor TAA-1 is able to protect cells against iron- and/or hydrogen peroxide-dependent cell injuries and that--in line with our initial concept--it is likely to exert its protection by both iron chelation and hydrogen peroxide degradation.     

Efficacy of cellular vaccines and genetic adjuvants against bacterial kidney disease in chinook salmon (Oncorhynchus tshawytscha)

DNA adjuvants and whole bacterial cell vaccines against bacterial kidney disease (BKD) were tested in juvenile chinook salmon. Whole cell vaccines of either a nonpathogenic Arthrobacter spp. or an attenuated Renibacterium salmoninarum strain provided limited prophylactic protection against acute intraperitoneal challenge with virulent R. salmoninarum, and the addition of either synthetic oligodeoxynucleotides or purified R. salmoninarum genomic DNA as adjuvants did not increase protection. However, a combination of both whole cell vaccines significantly increased survival among fish naturally infected with R. salmoninarum, and the surviving fish treated with the combination vaccine exhibited reduced levels of bacterial antigens in the kidney. This is the first demonstration of a potential therapeutic effect of a whole cell vaccine against BKD.     

Design, synthesis, and in vitro antitumor activity of new 1,4-diarylimidazole-2-ones and their 2-thione analogues

A series of new 1,4-diarylimidazol-2(3H)-one derivatives and their 2-thione analogues has been prepared and evaluated in vitro for antitumor activity against the NCI human cancer cell panel. Compounds bearing a 3,4,5-trimethoxyphenyl ring linked to either N-1 or C-4 position of the imidazole core demonstrated an interesting profile of cytotoxicity with preferential activity against leukemic cell lines. Compound 13 exhibited a potent antitumor activity against MOLT-4 (GI(50)=20 nM) and SR (GI(50)=32 nM) cell lines.     

Inhibitory effect of ammonium chloride and chloroquine on the entry of the toxic lectin modeccin into HeLa cells

Ammonium chloride and chloroquine protected a variety of cell lines against diphtheria toxin and the toxic lectin modeccin. Experiments where the ability of antibody to neutralize the toxin was measured indicate that in the presence of ammonium chloride and chloroquine, modeccin remains at the cell surface and that the two compounds inhibit the uptake of modeccin into the cytoplasm. A cell line tolerating increased concentrations of modeccin was not protected against modeccin by ammonium chloride or chloroquine, whereas the compounds did protect these cells against diphtheria toxin.     

Design, synthesis and cytotoxic activities of novel hybrid compounds between 2-phenylbenzofuran and imidazole

A series of novel hybrid compounds between 2-phenylbenzofuran and imidazole have been prepared and evaluated in vitro against a panel of human tumor cell lines. The results suggest that substitution of the imidazolyl-3-position with a naphthylacyl or bromophenacyl group, were vital for modulating cytotoxic activity. In particular, hybrid compound 15 was found to be the most potent compound against 4 strains human tumor cell lines and more active than cisplatin (DDP), and exhibited cytotoxic activity selectively against liver carcinoma (SMMC-7721).     

Dual immunofluorescence labeling with cell-specific markers localizes BRCA1 in both basal and luminal epithelial cells in primary outgrowth from noncancerous mammary ductal and alveolar preparations

The role played by either of the two differentiated mammary epithelial cell types in human breast cancer progression is currently not defined. This work addresses the question of whether the mammary tumor suppressor gene product BRCA1 is localized in basal and/or luminal epithelial cells in noncancerous outgrowth cultured from breast organoids. Primary epithelial cell outgrowths from ductal and alveolar preparations were directly employed to facilitate small-scale analysis under conditions closely approximating intact tissue. BRCA1 immunofluorescence was detected for the most part in cell nuclei of the epithelial outgrowth when using confocal microscopy. Nuclear staining was punctate in the cells with higher labeling intensity. Only minimal nonspecific staining was observed with mouse IgG as a negative primary antibody control or with primary antibody against the cell membrane receptor ErbB2, reported to be expressed in breast cancer, but was either not detectable or weakly expressed in normal breast tissue. Dual labeling was used to distinguish which epithelial cell type(s) stains for BRCA1. Primary monoclonal antibody against vimentin was used to identify basal cells, while antibody against cytokeratin 19 was used to identify luminal cells. Monoclonal antibody against BRCA1 was used for colabeling with each of these markers. Epifluorescence microscopy revealed BRCA1 immunoreactivity in both basal and luminal interphase cells. BRCA1 immunofluorescence was diffusely located about the chromosome mass during mitosis.     

Induction of CD4(+) and CD8(+) Bordetella pertussis toxin subunit S1 specific T cells by immunization with synthetic peptides.

In this study two synthetic peptides from the Bordetella pertussis toxin subunit S1 were conjugated to human anti-idiotypic antibodies and used as an immunogen in cancer patients to induce immunity. The aims of the present report are to explain why no carrier or adjuvant effect of the conjugated pertussis peptides could be established regarding induction of responses against the anti-idiotype and to explore the type and quality of induced anti-pertussis immune responses. The lack of carrier and adjuvant effect of the peptides might be related to the fact that the anti-idiotypic antibodies by themselves include helper epitopes and that none of the patients had a detectable T cell response against any of the selected peptides before immunization, which might be a requirement for an adjuvant effect. However, three of four immunized patients mounted a humoral as well as cellular response against the pertussis peptides used. The induced T cell immunity was restricted to one of the two peptides in responding patients. Established T cell lines and MHC blocking studies indicated that the T cell epitopes of the two peptides had a different MHC restriction. The type of T cell response induced seemed to govern the humoral response. The only durable antibody response was accompanied by the presence of a CD4(+) T cell response against the same peptide. Immunization with an anti-idiotype conjugated to synthetic peptides might thus induce both a B and a T cell response against the peptides and the type of induced T cells (CD4 or CD8) governs the quality of the humoral response. Moreover, the possibility of boosting or inducing a response against the antigen from which the peptide sequences were deduced also seemed feasible.     

Combining liver- and blood-stage malaria viral-vectored vaccines: investigating mechanisms of CD8+ T cell interference

Replication-deficient adenovirus and modified vaccinia virus Ankara (MVA) vectors expressing single pre-erythrocytic or blood-stage Plasmodium falciparum Ags have entered clinical testing using a heterologous prime-boost immunization approach. In this study, we investigated the utility of the same immunization regimen when combining viral vectored vaccines expressing the 42-kDa C terminus of the blood-stage Ag merozoite surface protein 1 and the pre-erythrocytic Ag circumsporozoite protein in the Plasmodium yoelii mouse model. We find that vaccine coadministration leads to maintained Ab responses and efficacy against blood-stage infection, but reduced secondary CD8(+) T cell responses against both Ags and efficacy against liver-stage infection. CD8(+) T cell interference can be minimized by coadministering the MVA vaccines at separate sites, resulting in enhanced liver-stage efficacy in mice immunized against both Ags compared with just one. CD8(+) T cell interference (following MVA coadministration as a mixture) may be caused partly by a lack of physiologic space for high-magnitude responses against multiple Ags, but is not caused by competition for presentation of Ag on MHC class I molecules, nor is it due to restricted T cell access to APCs presenting both Ags. Instead, enhanced killing of peptide-pulsed cells is observed in mice possessing pre-existing T cells against two Ags compared with just one, suggesting that priming against multiple Ags may in part reduce the potency of multiantigen MVA vectors to stimulate secondary CD8(+) T cell responses. These data have important implications for the development of a multistage or multicomponent viral vectored malaria vaccine for use in humans.     

Inhibition spectrum studies of microthecin and other anhydrofructose derivatives using selected strains of Gram-positive and -negative bacteria, yeasts and moulds, and investigation of the cytotoxicity of microthecin to malignant blood cell lines

Aims:  To prepare 1,5-anhydro- d -fructose (AF) derivatives, test their microbial inhibition spectrum, and to further examine the most effective AF derivative against Pseudomonas aeruginosa and malignant blood cell lines.
Methods and Results:  Microthecin and nine other AF derivatives were synthesized from AF. The 10 compounds were tested in vitro against Gram-positive (GP) and Gram-negative (GN) bacteria, yeasts and moulds using a well diffusion method and in a Bioscreen growth analyser. Of the test compounds, microthecin exhibited the most significant antibacterial activity at 100–2000 ppm against both GP and GN bacteria, including Ps. aeruginosa. Further tests with three malignant blood cell lines ( Mutu, Ramos, Raji ) and one normal cell line indicated that microthecin was a cell toxin, with a cell mortality >85% at 50 ppm. The other nine AF derivatives demonstrated low or no antimicrobial activity.
Conclusions:  Microthecin was active 100–2000 ppm against GP and GN bacteria including Ps. aeruginosa , but was inactive against yeasts and moulds. Microthecin was also a cytotoxin to some mammalian cell lines.
Significance and Impact of the Study:  Microthecin might have potential for development as a novel drug against Ps. aeruginosa and to target cancer cells. It might also be developed as a food processing aid to control bacterial growth.     

Chemistry and function of vegetable polyphenols with high molecular weights

Structure and function of polypehnols with high molecular weights (tannins) were briefly reviewed to better understand the significance of polyphenol-rich foods and beverages. In a survey of bioactive ellagiannins with a macrocyclic structure and/or a gluconic acid core, some new oligomeric ellagitannins (eucarpanins and elaeagnatins) have been found in species of Myrtaceae and Elaeagnaceae, and their structures were elucidated by spectroscopic and chemical methods. Cytotoxic activity against human oral tumor cell lines and antibacterial activity against Helicobacter pylori have been evaluated for the ellagitannins obtained from both plants, and related compounds. The macrocyclic dimers, oentothein B, camelliin B and woodfordin C showed a remarkable cytotoxicity against human oral squamous cell carcinoma, but not against normal cells. These active tannins induced apoptosis of tumor cells. A potent antibacterial activity against Helicobacter pylori was exhibited by monomeric ellagitannins such as tellimagrandin I and stricitinin.     

Synthesis and biological evaluation of benzo[d]isothiazole, benzothiazole and thiazole Schiff bases

Three new series of benzo[d]isothiazole, benzothiazole and thiazole Schiff bases were synthesized and tested in vitro with the aim of identifying novel lead compounds active against emergent and re-emergent human and cattle infectious diseases (AIDS, hepatitis B and C, tuberculosis, bovine viral diarrhoea) or against drug-resistant cancers (leukaemia, carcinoma, melanoma, MDR tumors) for which no definitive cure or efficacious vaccine is available at present. In particular, these compounds were evaluated in vitro against representatives of different virus classes, such as a HIV-1 (Retrovirus), a HBV (Hepadnavirus) and the single-stranded RNA(+) viruses Yellow fever virus (YFV) and Bovine viral diarrhoea virus (BVDV), both belonging to Flaviviridae. Title compounds were also tested against representatives of Gram-positive and Gram-negative bacteria (Staphylococcus aureus, Salmonella spp.), various atypic mycobacterial strains (Mycobacterium fortuitum and Mycobacterium smegmatis), yeast (Candida albicans) and mould (Aspergillus fumigatus). None of the compounds showed antiviral or antimicrobial activity. The benzo[d]isothiazole compounds showed a marked cytotoxicity (CC(50)=4-9 microM) against the human CD4(+) lymphocytes (MT-4) that were used to support HIV-1 growth. For this reason, the most cytotoxic compounds of this series were evaluated for their antiproliferative activity against a panel of human cell lines derived from haematological and solid tumors. The results highlighted that all the benzo[d]isothiazole derivatives inhibited the growth of leukaemia cell lines, whereas only one of the above mentioned compounds (1e) showed antiproliferative activity against two solid tumor-derived cell lines.     

Membrane associated antigens of human malignant melanoma V: Serological typing of cell lines using antisera from nonhuman primates

Summary Antisera against various melanoma cell lines were raised in nonhuman primates (Cercopithecus aethiop.). After exhaustive absorption with AB Rh + red blood cells and pooled platelets from about 200 donors the sera were still reactive to various degrees in the microimmune adherence test with other melanoma lines, with embryonic fibroblasts, and with non-melanoma lines. As proven by absorption experiments, the main-specificity of the antisera was not directed against components of the fetal calf serum used for cell culture or against mycoplasma grown from commercial fetal calf serum. In addition, no cross-reactivity was observed with Bacillus Calmette-Gérin, and in blocking experiments no reactivity against extracts of common bacterial antigens or mixed molds was detected. Absorption with embryonic fibroblasts or embryonic tissue showed that the reactivity of most antisera was directed against melanoma-associated antigens expressed also on fetal tissue. It was not possible to determine whether the remaining reactivity on some cell lines was melanoma-specific or directed against fetal antigens not contained in the fetal material used for absorption. Cross-absorption of antisera with other melanoma cells revealed that various cell lines express different patterns of tumor-associated antigens with no, or only partial, overlap. The cross-absorption experiments made it possible to type the cell lines according to their surface antigens and arrange the cell lines in order according to the degree of mutual antigenic relationship.     

Role of tumor cell glycoproteins immunologically related to glycoproteins Ib and IIb/IIIa in tumor cell-platelet and tumor cell-matrix interactions

A panel of monoclonal and polyclonal antibodies raised against human platelet GpIb or the GpIIb/IIIa complex were used to detect immunologically related molecules on two cell lines derived from human solid tumors. Human cervical carcinoma (MS751) and human colon carcinoma (clone A) expressed molecules immunologically related to platelet GpIb and GpIIb/IIIa complex. These molecules were localized to their plasma membranes by immunofluorescence and immunocytochemistry. The immunologically related GpIb was evenly distributed on the tumor cell membrane with occasional areas of aggregates, whereas the immunologically related GpIIb/IIIa had a pronounced punctate distribution of aggregates in prefixed cells. When MS751 or clone A cells were pretreated with antibodies against platelet GpIb and/or the GpIIb/IIIa complex, their ability to induce platelet aggregation was significantly inhibited. In addition, when tumor cells were pretreated with antibodies against the platelet IIb/IIIa complex, adherence to fibronectin-coated plates was also significantly inhibited. These results suggest a role for these immunologically related tumor cell glycoproteins in tumor cell-host cell (i.e., platelet, endothelial cells) interactions, tumor cell interactions with components of the subendothelial matrix, and subsequent tumor metastasis.     

2,4,6-Trisubstituted pyridines: Synthesis, topoisomerase I and II inhibitory activity, cytotoxicity, and structure-activity relationship

Designed and synthesized were a series of pyridines substituted at 2, 4, and 6 positions with various 5- or 6-memberd heteroaromatics as antitumor agents. They were evaluated their topoisomerase I and II inhibitory activities along with cytotoxicities against several human cancer cell lines. Among the prepared compounds, 10-20 showed significant topoisomerase I or II inhibitory activities, and 21-26 showed considerable cytotoxicities against several human cancer cell lines. Structure-activity relationship study indicates that 4'-pyridine at 6-position of central pyridine plays a key role in biological activity.     

Plant phenolics as inhibitors of mutational and precarcinogenic events

Initiation of chemical carcinogenesis involves the intracellular formation of a highly reactive electrophile that can attack many chemical nucleophiles in the cell, including DNA, a process that seems to be a central mechanism of initiation. Competing chemical nucleophiles in the cell, such as endogenous glutathione, can act as protecting or blocking agents against the attack on DNA. There are chemical substances in our food supply that may act as anticarcinogens or antimutagens by blocking or trapping ultimate carcinogen electrophiles in a nucleophilic chemical reaction, to form innocuous products. A continuous input of these substances could serve as an additional buffer against DNA damage, supplementing the endogenous systems qualitatively and quantitatively. Certain plant phenolics can be effective inhibitors of chemical mutagens and (or) carcinogens. Tetrapyrroles and porphyrins, both plant and animal, can also act as blocking agents. Both plant phenolics and porphyrins are primarily active against aromatic carcinogens as inhibitors of mutagenesis in in vitro systems. Plant phenolics have also demonstrated inhibiting activity against aromatic chemically induced carcinogenesis.     

Mechanism of restriction of ecotropic and xenotropic murine leukemia viruses and formation of pseudotypes between the two viruses.

Ecotropic and xenotropic murine leukemia viruses (MuLV's) constitute separate interference groups; within each group there is cross-interference, but between the groups there is no detectable interference. Interference is manifest against pseudotypes in which the vesicular stomatitis virus genome is contained within the coat of one of the murine leukemia viruses. The pseudotypes display the cell specificity of the leukemia viruses: pseudotypes with an ecotropic MuLV coat infect mouse cells but not rabbit or mink cells; pseudotypes with a xenotropic MuLV coat infect rabbit or mink cells well but mouse cells very poorly. Efficient pseudotype formation also occurs between the two MuLV classes, and both the interference patterns and the cell specificity of these pseudotypes are entirely determined by their envelope. Using these pseudotypes, ecotropic MuLV infection could be established in xenogeneic cells, and the resulting progeny could be scored by using a conventional XC cell assay. Also, xenotropic MuLV infection could be established in a mouse cell, showing that no absolute intracellular barrier against xenotropic virus growth exists in murine cells. The major barriers against both xenotropic and ecotropic MuLV therefore are cell surface barriers. Xenogeneic cells probably lack receptors for ecotropic MuLV, but murine cells may either lack receptors for xenotropic MuLV or have receptors that are blocked by endogenous expression of the glycoprotein of endogenous xenotropic MuLV.     

Effect of Saquinavir on proliferation and telomerase activity of human peripheral blood mononuclear cells

The present study describes the effect of Saquinavir on proliferation, interferon-gamma production and telomerase activity of non-stimulated, or activated non-adherent mononuclear cells (NAMNC), obtained from peripheral blood of healthy donors. Fresh NAMNC, non-stimulated or activated in vitro with PHA or with a mixture of monoclonal antibodies against CD3 and against CD28 membrane antigens (in order to obtain prevalent T cell responses), were exposed to Saquinavir before or at the time of mitogenic stimulation. Control and treated cells were tested for DNA synthesis (3H-thymidine incorporation), interferon-gamma production and telomerase activity (TRAP assay). The results indicate that Saquinavir is able to increase proliferation and interferon-gamma release in PHA-stimulated NAMNC, and telomerase activity either in non-stimulated and in PHA or antibody-activated cells. These results suggest that the activity against HIV infection afforded by Saquinavir, could be corroborated by its effects on the host. These include its adjuvant activity on mitogen-induced responses of lymphocytes, and its possible antagonistic effects against lymphoid cell senescence, through telomerase activation.