Monoclonal antibody identifies a new Ia-like (p29,34) polymorphic system linked to the HLA-D/DR region

The Ia antigens of the mouse are the basis for the genetic control of the immune response. The HLA-D/DR locus is considered to be the human counterpart of the Ia subregion of the murine major histocompatibility complex. The HLA-D/DR antigens are polymorphic, and eight well defined alleles have been identified using alloantisera. More recently, 'supertypic' antigens (MB and MT) have been defined which identify clusters of HLA-D/DR specificities. Little is known about the molecular basis for the cellular and serological polymorphism of the HLA-D/DR antigens, as alloantisera are usually of very low titre and heteroantisera frequently lack monospecificity. We present here the preparation and characterization of a monoclonal antibody which defines a new polymorphic system of the HLA-D/DR region. This and similar antisera should now begin to provide the reagents with which to correlate molecular structure with the functional repertoire of the human Ia-like antigens.     

喀斯特自然土壤中AM真菌对先锋植物根系的影响

【目的】研究丛枝菌根(Arbuscular mycorrhiza,AM)真菌在喀斯特自然土壤条件下对喀斯特先锋草本植物根系的影响。【方法】通过自然土接种AM真菌(N)、灭菌土接种AM真菌(M)及灭菌土壤对照(S)共3种土壤处理,种植喀斯特先锋植物狗尾草(Setaria viridis)、荩草(Arthraxon hispidus)、鬼针草(Bidens pilosa)及狼杷草(Bidens tripartita),并测定它们的根系生物量、根长、根表面积、根体积、根平均直径、根尖数及根分枝数。【结果】荩草、鬼针草及狼杷草在N处理及M处理下具有较高的菌根侵染率,狗尾草的菌根侵染率较低。与S处理相比,M处理下AM真菌明显提高了荩草、鬼针草及狼杷草的根系生物量、根长、根表面积、根体积、根尖数、根分枝数及组织密度,降低了根平均直径、比根长、比根面积及比根体积;与M处理相比,N处理明显降低了荩草、鬼针草及狼杷草的根系生物量、根长、根表面积、根体积、根尖数、根分枝数及组织密度,提高了比根长、比根面积及比根体积,但对根平均直径无明显影响。【结论】荩草、鬼针草及狼杷草具有较高菌根侵染率,能与AM真菌共生获得更加发达的根系,而自然土壤削弱了AM真菌对荩草、鬼针草及狼杷草根系生长的促进作用。     

CD3-negative natural killer cells express zeta TCR as part of a novel molecular complex

Natural killer (NK) cells are large granular lymphocytes capable of killing tumour cells in a non-MHC restricted manner. NK cells do not express cell-surface CD3, or any known target recognition structure analogous to the T cell antigen receptor (TCR) heterodimers (alpha beta or gamma delta). Consistent with their lack of expression of a CD3-TCR complex, NK cells do not require prior sensitization or antigen presentation by accessory cells to specifically recognize their tumour targets. Although NK cells do not express CD3-TCR, they do express CD2, the target of an alternative activation pathway which is functional in both T cells and NK cells. In T cells, this alternative activation pathway utilizes some component of the CD3-TCR complex as a transducer molecule that is required for mitogenesis. The fact that NK cells are activated by this alternative pathway suggested that they might express a related subunit of the CD3-TCR complex capable of transducing the CD2-mediated signal. Here we show that human NK cells express the zeta-chain of the TCR complex in association with additional structures not included in CD3-TCR.     

CEP41 is mutated in Joubert syndrome and is required for tubulin glutamylation at the cilium

Tubulin glutamylation is a post-translational modification that occurs predominantly in the ciliary axoneme and has been suggested to be important for ciliary function. However, its relationship to disorders of the primary cilium, termed ciliopathies, has not been explored. Here we mapped a new locus for Joubert syndrome (JBTS), which we have designated as JBTS15, and identified causative mutations in CEP41, which encodes a 41-kDa centrosomal protein. We show that CEP41 is localized to the basal body and primary cilia, and regulates ciliary entry of TTLL6, an evolutionarily conserved polyglutamylase enzyme. Depletion of CEP41 causes ciliopathy-related phenotypes in zebrafish and mice and results in glutamylation defects in the ciliary axoneme. Our data identify CEP41 mutations as a cause of JBTS and implicate tubulin post-translational modification in the pathogenesis of human ciliary dysfunction.     

Evidence for the T3-associated 90K heterodimer as the T-cell antigen receptor

Several surface molecules appear to be involved in antigen recognition by human T lymphocytes including the monomorphic 20/25K T3 structure present on all mature T lymphocytes and the subset-specific associative recognition elements, T4 and T8 (refs 1-8). More recently, Ti1, a clonally unique antigen recognition structure comprised of a 49,000 molecular weight (49K) alpha-chain and a 43K beta-chain, linked to T3 was identified on a major histocompatibility complex (MHC) class I specific T8+ T-cell clone, CT8III (ref. 9). To determine whether analogous receptor molecules could be found on other T-cell clones of differing specificity, we produced monoclonal antibodies against a clonal structure (Ti2) on an MHC class II specific T4+ lymphocyte, CT4II, derived from the same donor as CT8III. The Ti2 structure on CT4II is shown here to be a disulphide-linked heterodimer like Ti1 on CT8III and is composed of subunits of similar molecular weight. Monoclonal antibodies against Ti2 or Ti1 block antigen specific functions of the respective clone without showing any cross-reactivity. These findings suggest that each T lymphocyte, regardless of subset derivation or specificity, uses an analogous Ti heterodimer for antigen specific function. The latter is linked to T3 and expressed on the cell surface at an identical density (30,000-40,000 sites per cell).     

基于并行工程的产品开发过程管理的研究

并行工程采用集成化与并行化的思想来开发产品,强调在信息集成基础上的过程集成,运用工作流管理技术能够很好地达到此目的。在分析工作流管理技术的基础上,以冲压模具的开发过程为例来说明用工作流管理技术实现产品开发过程管理的     

GH220合金中碳化物相变规律

研究了合金中M_6C,M_(23)C_6及MC的晶体结构、化学组成、形态、分布及数量,它们的溶解析出规律及互相转化。     

A novel epitope of the LFA-1 antigen which can distinguish killer effector and suppressor cells in human CD8 cells

The CD4 subset of cells displays helper/inducer activity and recognizes class II antigens of the major histocompatibility complex (MHC), while the CD8 subset recognizes class I MHC antigens and exhibits cytotoxic or suppressor function. Considerable functional as well as corresponding phenotypic heterogeneity exists within the two major T cell subsets. Although the CD8+ population contains pre-cytotoxic, cytotoxic, pre-suppressor and suppressor effector T cells, these distinctions still rest largely on the use of functional assays. Attempts have been made to define the CD8+ precursor of the killer cell with new monoclonal antibodies. But more precise phenotypic distinctions between the functional subpopulations within CD8+ cells will be needed. We have now developed a monoclonal antibody, anti-S6F1 which can distinguish killer effector and suppressor effector cells in CD8 lymphocyte populations. The cell-surface structure defined by this antibody comprises two glycoproteins with relative molecular mass (Mr) 180K and 95K respectively. Also sequential immunoprecipitation studies and two dimensional gel electrophoresis indicate that anti-S6F1 recognizes a novel epitope on the LFA-1 antigen.