Interleukin-21 enhances NK cell activation in response to antibody-coated targets

NK cells express an activating FcR (FcgammaRIIIa) that mediates Ab-dependent cellular cytotoxicity and the production of immune modulatory cytokines in response to Ab-coated targets. IL-21 has antitumor activity in murine models that depends in part on its ability to promote NK cell cytotoxicity and IFN-gamma secretion. We hypothesized that the NK cell response to FcR stimulation would be enhanced by the administration of IL-21. Human NK cells cultured with IL-21 and immobilized IgG or human breast cancer cells coated with a therapeutic mAb (trastuzumab) secreted large amounts of IFN-gamma. Increased secretion of TNF-alpha and the chemokines IL-8, MIP-1alpha, and RANTES was also observed under these conditions. NK cell IFN-gamma production was dependent on distinct signals mediated by the IL-21R and the FcR and was abrogated in STAT1-deficient NK cells. Supernatants derived from NK cells that had been stimulated with IL-21 and mAb-coated breast cancer cells were able to drive the migration of naive and activated T cells in an in vitro chemotaxis assay. IL-21 also enhanced NK cell lytic activity against Ab-coated tumor cells. Coadministration of IL-21 and Ab-coated tumor cells to immunocompetent mice led to synergistic production of IFN-gamma by NK cells. Furthermore, the administration of IL-21 augmented the effects of an anti-HER2/neu mAb in a murine tumor model, an effect that required IFN-gamma. These findings demonstrate that IL-21 significantly enhances the NK cell response to Ab-coated targets and suggest that IL-21 would be an effective adjuvant to administer in combination with therapeutic mAbs.     

A new cardiid bivalve from the Pliocene Baklan Basin (Turkey) and the origin of modern Ponto‐Caspian taxa

Abstract: We present the first record of the cardiid genus Monodacna from the Pliocene of Anatolia, Turkey. Monodacna imrei sp. nov. was found in the Pliocene Killik Formation from the western margin of the Baklan Basin, in very marginal brackish to freshwater lacustrine deposits. The new record extends the stratigraphic range of the modern Ponto‐Caspian genus back into the Pliocene and adds to earlier evidence that modern Ponto‐Caspian taxa originated in the Pliocene of south‐western Turkey.     

Description of Paratetrahymena parawassi n. sp. using Morphological and Molecular Evidence and a Phylogenetic Analysis of Paratetrahymena and Other Taxonomically Ambiguous Genera in the Order Loxocephalida (Ciliophora,Oligohymenophorea)

ABSTRACT. The marine scuticociliate Paratetrahymena parawassi n. sp. is described on the basis of morphology, especially infraciliature, and the sequence of its small subunit (SSU) rRNA gene to become the second known member of its genus. Paratetrahymena and other ciliates in the order Loxocephalida possess a mixture of morphological and morphogenetic features characteristic of the subclasses Hymenostomatia and Scuticociliatia. Accordingly, we used SSU rRNA sequences to analyze the phylogeny of Paratetrahymena and three other loxocephalid genera. Paratetrahymena and Cardiostomatella vermiformis formed a moderately well‐supported clade that diverged at a deep level from all other scuticociliates, supporting separation of loxocephalids from other scuticociliates as a suprafamilial taxon. Sathrophilus holtae was a sister taxon to Paratetrahymena and Cardiostomatella in a poorly supported, unresolved relationship; nevertheless, association of all three genera into a single clade was supported by an approximately unbiased (AU) test. Any association of these genera singly or as a group with the Hymenostomatia was rejected decisively by AU tests and by a complete absence in the loxocephalids of the unique nucleotide identities that distinguish hymenostomes. Therefore, the morphological and morphogenetic similarities of loxocephalids to hymenostomes may be plesiomorphies, and the conflicting mix of scuticociliate and hymenostome characteristics seen in loxocephalids may result from differing rates of character evolution. Dexiotrichides pangi and Urocentrum, which is currently classified as a peniculid, formed a small clade that associated with hymenostomes and peritrichs. Monophyly of the Loxocephalida with Dexiotrichides and/or Urocentrum included was not rejected by AU; however, inclusion of Urocentrum in the Peniculia was rejected by AU tests. A hypothesis is offered to explain the lack of resolution of loxocephalid ciliates and Urocentrum in phylogenetic trees, namely that their phylogenetic positions are influenced by a combination of heterogeneous data and long‐branch attraction caused by poor representation of taxa in analyses. The well‐known genus Cyclidium, a member of the order Pleuronematida, was revealed to be polyphyletic as a byproduct of our analyses of loxocephalids. In particular, Cyclidium porcatum appears to fall outside the clade containing typical members of the subclass Scuticociliatia and thus invites investigation as a possible member of the order Loxocephalida.     

A proteomic approach to the identification of new tPA receptors in pancreatic cancer cells

We have developed a strategy to identify putative tissue-type plasminogen activator (tPA)receptors present in pancreatic cancer cells by affinity capture with tPA-Sepharose followed by 2-DE and MALDI-MS PMF. Proteins pulled down from either total lysates or raft membrane fractions were characterized and compared with those from a total lysate of an endothelial cell line (HUVEC) to identify pancreas-restricted tPA receptors. A total of 31 proteins were found by this approach, including annexin A2, already described as a tPA receptor in pancreas and endothelial cells, other proteins acting as tPA receptors (i.e., enolase, cytokeratins 8 and 18) in other tissues, and additional proteins not previously identified as candidate tPA receptors. Confirmation of the results was performed for some of these proteins using immunoblotting. These studies are the basis for further functional analyses on the role of these proteins in the biological effects of tPA.     

Effect of IL-1 on the hydrolysis of the tumor antigen epitope gp100(280-288) by fibroblast-expressed enzymes

The role of proinflammatory cytokines in increasing the activity of specific proteases suggests the hypothesis that, by altering the expression of these mediators, adjuvants may modulate the effectiveness of peptides used as vaccines. The possible effect of IL-1 on fibroblast-expressed, peptidases was, thus, investigated by analyzing the degradation of a tumor antigen epitope (gp100(280-288), YLEPGPVTA) in the presence of cultured human fibroblasts. The data obtained indicate an increase of substrate hydrolysis after IL-1 treatment as compared with non-treated controls. Hydrolysis increase was accompanied by defined changes in the population of the by-products formed: specifically, the amount of peptidic by-products increased more than the amount of single amino acids, and the amount of the C-terminal by-products increased more than the amount of their N-terminal counterpart. These data appear to indicate that the positive effect of IL-1 on the activity of substrate-active enzymes is function of modified expression of a number of these enzymes by fibroblasts. From these data it can be inferred that the use of IL-1-inducing adjuvants, increasing the activity of peptidases expressed by bystander cells, may reduce the bio-availability of peptides used for immunization.     

在中国应用垂直波束雷达监测褐飞虱和其他水稻害虫迁飞的可行性

近年来,可用于昆虫迁飞研究且可自动运行的垂直波束雷达(vertical-looking radar,VLR)的发展使得对迁飞性害虫的周年长期自动监测成为可能。本文提供了我们对能否将这种雷达应用于中国的褐飞虱和其他水稻害虫的监测与预测体系以改善其综合治理的可行性研究结果。以往的研究已经表明,这些害虫一般在300—2000m高度迁飞;而我们根据褐飞虱的雷达和射有效截面的计算结果表明,目前使用的3．2cm波长的VLR对褐飞虱个体目标的最大可检测高度仅约240m;虽然建造一部8．8mm波长的VLR即可覆盖褐飞虱迁飞高度的绝大部分,但其造价和维护费用均过于昂贵。为此,一个更可行的解决方案是,以3．2cm波长的VLR作为包括大多数水稻害虫在内的个体较大的迁飞性害虫的监测工具。     

Escherichia coli MTC, a NADPH cytochrome P450 reductase competent mutagenicity tester strain for the expression of human cytochrome P450: comparison of three types of expression systems

Currently three different methods have been taken to develop new mutagenicity tester strains containing human cytochrome P450s (CYPs). Each of these use a single expression vector. In this paper we describe a fourth approach, i.e., the coexpression of a CYP and its electron-transfer flavoprotein, NADPH CYP reductase (RED), encoded by two different expression vectors. The Escherichia coli mutagenicity tester strain BMX100 has been expanded to a strain, MTC which stably expresses human RED. This new tester strain permits the biplasmid coexpression of human CYP1A2 and RED (MTC1A2). This novel strain can be used for the determination of the mutagenicity of chemicals known to be procarcinogens and metabolized by CYP1A2. The mutagenicity tester strain MTC1A2 was compared with: (i) BMX100 using the post-mitochondrial rat liver fraction (S9); (ii) BMX100 with expressing CYP1A2 alone (iii) or with expressing CYP1A2 fused to rat RED or (iv) with expressing CYP1A2, bicistronically coexpressed with rat RED. The biplasmid RED/CYP coexpression system generated a strain with the highest methoxy- and ethoxy-resorufin dealkylase activities and the highest mutagenic activities for the procarcinogens 2-aminoanthracene (2AA), aflatoxin B1 (AFB1) and 2-amino-3-methylimidazo(4,5-f)quinoline (IQ). Furthermore, the metabolism of 2AA and IQ was detected more efficiently using the MTC1A2 strain than with the BMX100 strain plus the standard rodent liver S9 metabolic system.