Modulation of cell adhesion and motility in the immune system by Myo1f

Although class I myosins are known to play a wide range of roles, the physiological function of long-tailed class I myosins in vertebrates remains elusive. We demonstrated that one of these proteins, Myo1f, is expressed predominantly in the mammalian immune system. Cells from Myo1f-deficient mice exhibited abnormally increased adhesion and reduced motility, resulting from augmented exocytosis of beta2 integrin-containing granules. Also, the cortical actin that co-localizes with Myo1f was reduced in Myo1f-deficient cells. In vivo, Myo1f-deficient mice showed increased susceptibility to infection by Listeria monocytogenes and an impaired neutrophil response. Thus, Myo1f directs immune cell motility and innate host defense against infection.     

A neuroendocrine marker in tissues of the immune system

Antibodies to chromogranin, a secretory protein marker for the diffuse neuroendocrine system, were used to analyze rat lymphoreticular tissues by means of immunochemistry and immunohistochemistry. Chromogranin-positive cells were present in spleen, lymph node, thymus, and fetal liver. When these organs were gently dispersed and separated on a Ficoll gradient, the chromogranin-immunoreactive cells became enriched in the dense red-cell pellets. The unexpected distribution of these neuroendocrine cells in all immunologically relevant structures suggests that they may link the nervous and immunological systems.     

Retraction in amoeboid cell motility powered by cytoskeletal dynamics

Cells crawl by coupling protrusion of their leading edge with retraction of their cell body. Protrusion is generated by the polymerization and bundling of filaments, but the mechanism of retraction is less clear. We have reconstituted retraction in vitro by adding Yersinia tyrosine phosphatase to the major sperm protein-based motility apparatus assembled from Ascaris sperm extracts. Retraction in vitro parallels that observed in vivo and is generated primarily by disassembly and rearrangement of the cytoskeleton. Therefore, cytoskeletal dynamics alone, unassisted by conventional motors, are able to generate both of these central components of amoeboid locomotion.     

Glycosylation and the immune system

Almost all of the key molecules involved in the innate and adaptive immune response are glycoproteins. In the cellular immune system, specific glycoforms are involved in the folding, quality control, and assembly of peptide-loaded major histocompatibility complex (MHC) antigens and the T cell receptor complex. Although some glycopeptide antigens are presented by the MHC, the generation of peptide antigens from glycoproteins may require enzymatic removal of sugars before the protein can be cleaved. Oligosaccharides attached to glycoproteins in the junction between T cells and antigen-presenting cells help to orient binding faces, provide protease protection, and restrict nonspecific lateral protein-protein interactions. In the humoral immune system, all of the immunoglobulins and most of the complement components are glycosylated. Although a major function for sugars is to contribute to the stability of the proteins to which they are attached, specific glycoforms are involved in recognition events. For example, in rheumatoid arthritis, an autoimmune disease, agalactosylated glycoforms of aggregated immunoglobulin G may induce association with the mannose-binding lectin and contribute to the pathology.     

猪蓝耳病的几种血清学诊断方法

调查云南省猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)的流行规律和混合感染情况。

采用分子生物学方法对2013—2021年间的3112份血液样品进行PRRSV核酸检测,并进一步分析其流行和混合感染情况。

检测样品中,有801份样品为PPRSV阳性,阳性率为25.74%,二重、三重和四重混合感染率分别为41.20%、12.48%和1.87%;不同生长阶段猪群的PRRSV感染程度差异较大,生长育肥猪感染最严重(33.24%);相对于育肥场和散养户,种猪场的感染程度较轻,三者的感染率分别为27.94%、28.94%和14.29%。对不同毒株类型分析发现：高致病性毒株和经典毒株仍是主要的流行毒株,分别占毒株数的58.49%和22.64%,但占比呈逐年下降趋势。于2019年和2021年在云南省内分别发现了类NADC30毒株和类NADC34毒株,分别占毒株数的15.09%和3.77%,其感染率呈逐渐上升趋势。

猪繁殖与呼吸综合征仍是影响云南省生猪产业健康发展最重要的疫病之一,表现形式以和其他疾病混合感染为主。随着新毒株的发现,云南省PRRSV基因更加多样,防控形势愈加复杂。

     

虾类免疫系统组成及免疫机理探讨

研究对虾免疫系统和免疫机理,有效提高对虾自身抗病力,被认为是解决虾病暴发的根本途径之一。本文就虾类免疫系统及免疫机理研究作一综述,以期为开展虾类免疫防病工作提供理论基础。从免疫进化角度,虾类的免疫系统仅由遗传控制的组织相容性反应和中胚层起源的效应细胞组成,不具     

虾类免疫系统组成及免疫机理探讨

研究对虾免疫系统和免疫机理,有效提高对虾自身抗病力,被认为是解决虾病暴发的根本途径之一。本文就虾类免疫系统及免疫机理研究作一综述,以期为开展虾类免疫防病工作提供理论基础。从免疫进化角度,虾类的免疫系统仅由遗传控制的组织相容性反应和中胚层起源的效应细胞组成,不具     

Two-photon imaging of lymphocyte motility and antigen response in intact lymph node

Lymphocyte motility is vital for trafficking within lymphoid organs and for initiating contact with antigen-presenting cells. Visualization of these processes has previously been limited to in vitro systems. We describe the use of two-photon laser microscopy to image the dynamic behavior of individual living lymphocytes deep within intact lymph nodes. In their native environment, T cells achieved peak velocities of more than 25 micrometers per minute, displaying a motility coefficient that is five to six times that of B cells. Antigenic challenge changed T cell trajectories from random walks to "swarms" and stable clusters. Real-time two-photon imaging reveals lymphocyte behaviors that are fundamental to the initiation of the immune response.     

硒对山羊细胞免疫功能的影响

【目的】探讨硒对山羊细胞免疫功能的影响。【方法】12只试验羊随机分为4组,分别灌服0.3,0.5和0.7 mg/kg的硒以及1 mL/kg的蒸馏水,每周1次,连续3周,检测硒对山羊外周血单个核细胞(Peripheral bloodmononuclear cell,PBMC)的活化作用。无菌分离未服硒山羊PBMC,分别加入4,8,12和16μg/mL亚硒酸钠进行体外培养,检测硒在体外对PBMC的活化作用及其分泌IL-2的影响。【结果】山羊灌服0.7 mg/kg硒2周后及灌服0.5mg/kg硒3周后,其PBMC对PHA刺激的反应性显著提高。8~16μg/mL亚硒酸钠在体外培养中可显著促进山羊PBMC的活化,且呈剂量依赖关系,4μg/mL亚硒酸钠对PBMC的活化作用较弱,与对照组间差异不显著;山羊PB-MC体外培养时,加入8~12μg/mL亚硒酸钠可显著促进山羊PBMC的IL-2分泌,4和16μg/mL亚硒酸钠虽能诱导PBMC分泌IL-2,但与对照组差异不显著。【结论】山羊灌服一定量的硒,可显著提高其免疫细胞对抗原刺激的反应性。亚硒酸钠在一定质量浓度范围内可显著促进山羊PBMC的活化,且能促进其IL-2分泌。     

苦马豆素对小鼠细胞免疫功能的影响

【目的】探索苦马豆素(SW)对小鼠免疫器官发育、外周血液中细胞数及淋巴细胞增殖功能的影响,为SW免疫研究提供新的试验依据。【方法】将80只昆白系小鼠随机分为8组,其中5个试验组按0.05,0.2,0.8,3.2和6.4 mg/kg剂量每天灌服不同质量浓度的SW生理盐水溶液,连续21 d;其他3组均为对照组(分别为生理盐水组、环磷酰胺组和空白对照组)。检测小鼠胸腺和脾脏指数,用细胞分析仪检测外周血液中白细胞、红细胞及淋巴细胞数;用MTT法检测脾脏淋巴细胞的增殖活化。【结果】在SW剂量为0.2~0.8 mg/kg,小鼠脏器(胸腺和脾脏)指数及外周血液中的细胞数均增加;SW单独作用或其协同刀豆蛋白A(ConA)和植物血凝素P(PHA-P)刺激时,小鼠脾脏淋巴细胞的增殖活性增强,SW协同脂多糖(LPS)刺激时,小鼠脾脏淋巴细胞增殖活性降低。SW剂量为6.4mg/kg时,小鼠的脏器指数和外周血液中的细胞数均减少;无论小鼠脾脏淋巴细胞受丝裂原刺激与否,小鼠脾脏淋巴细胞的增殖活性均降低。【结论】SW可以通过提高小鼠脏器指数及外周血液中细胞数提高淋巴细胞的增殖活性,增强小鼠的细胞免疫功能;SW剂量为6.4 mg/kg对小鼠细胞免疫功能有抑制作用,提示SW对小鼠细胞免疫功能的影响具有选择性和双向调节作用。     

Promiscuity and the primate immune system

The behavioral and ecological factors involved in immune system evolution remain poorly explored. We present a phylogenetic analysis of white blood cell counts in primates to test three hypotheses related to disease risk: increases in risk are expected with group size or population density, exposure to soil-borne pathogens, and mating promiscuity. White blood cell counts were significantly greater in species where females have more mating partners, indicating that the risk of sexually transmitted disease is likely to be a major factor leading to systematic differences in the primate immune system.     

The rhizosphere microbial complex in plant health: A review of interaction dynamics

Climate change, urbanization, and population increase limit food availability. To sustain human existence, there is the need to increase food and agricultural production to mitigate the impact of these factors. Scientists have been working for years on ways to increase food production. From plant breeding techniques to soil science, scientists have made tremendous progress. The rhizobiome has been proven to be important to crop production, and the impact of the rhizobiome on plant health cannot be overemphasized. Being rich in diverse complex microbial interactions, the rhizosphere has become a major force in recent plant growth promotion studies. The upsurge in next-generation sequencing applications with the various “omics” technologies is helping to unearth information relating to rhizosphere impact on plant growth. Explaining the complex interactions between and across microbial species present in the rhizosphere is important to further enhance our understanding of their mechanistic and mutualistic functions. Knowledge from this can be used in rhizosphere biome engineering for improved plant growth and yield in the face of the various biotic and abiotic challenges.     

SARS患者免疫系统的变化及发病机制研究进展

严重急性呼吸综合征(severe aute respiratory syndyome,SARS)是一种由新型冠状病毒(SARS-associated coronavirus,SARS-CoV)引起的多器官、多组织损伤的急性呼吸道传染病[1～3],免疫功能状态的变化已成为SARS基础研究中的重要课题之一.本文就SARS-CoV导致的免疫器官、免疫细胞、免疫分子的变化及可能的发病机制作一综述.     

Fluorescence imaging of cellular metabolites with RNA

Genetically encoded sensors are powerful tools for imaging intracellular metabolites and signaling molecules. However, developing sensors is challenging because they require proteins that undergo conformational changes upon binding the desired target molecule. We describe an approach for generating fluorescent sensors based on Spinach, an RNA sequence that binds and activates the fluorescence of a small-molecule fluorophore. We show that these sensors can detect a variety of different small molecules in vitro and in living cells. These RNAs constitute a versatile approach for fluorescence imaging of small molecules and have the potential to detect essentially any cellular biomolecule.     

Interactions between the microbiota and the immune system

The large numbers of microorganisms that inhabit mammalian body surfaces have a highly coevolved relationship with the immune system. Although many of these microbes carry out functions that are critical for host physiology, they nevertheless pose the threat of breach with ensuing pathologies. The mammalian immune system plays an essential role in maintaining homeostasis with resident microbial communities, thus ensuring that the mutualistic nature of the host-microbial relationship is maintained. At the same time, resident bacteria profoundly shape mammalian immunity. Here, we review advances in our understanding of the interactions between resident microbes and the immune system and the implications of these findings for human health.