Receptor-mediated cell entry of paramyxoviruses: Mechanisms, and consequences for tropism and pathogenesis Microbiology

Research in the last decade has uncovered many new paramyxoviruses, airborne agents that cause epidemic diseases in animals including humans. Most paramyxoviruses enter epithelial cells of the airway using sialic acid as a receptor and cause only mild disease. However, others cross the epithelial barrier and cause more severe disease. For some of these viruses, the host receptors have been identified, and the mechanisms of cell entry have been elucidated. The tetrameric attachment proteins of paramyxoviruses have vastly different binding affinities for their cognate receptors, which they contact through different binding surfaces. Nevertheless, all input signals are converted to the same output: conformational changes that trigger refolding of trimeric fusion proteins and membrane fusion. Experiments with selectively receptor-blinded viruses inoculated into their natural hosts have provided insights into tropism, identifying the cells and tissues that support growth and revealing the mechanisms of pathogenesis. These analyses also shed light on diabolically elegant mechanisms used by morbilliviruses, including the measles virus, to promote massive amplification within the host, followed by efficient aerosolization and rapid spread through host populations. In another paradigm of receptor-facilitated severe disease, henipaviruses, including Nipah and Hendra viruses, use different members of one protein family to cause zoonoses. Specific properties of different paramyxoviruses,...
Source: Journal of Biological Chemistry - Category: Chemistry Authors: Tags: JBC Reviews Source Type: research

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The number of disorders associated with congenital or acquired asplenia and functional hyposplenism has increased substantially over the past couple decades. Previously, screening for asplenia and hyposplenism was a barrier to identifying patients at risk. Recent methods for measuring splenic function have emerged as accurate and reliable. Identifying patients prevents overwhelming postsplenectomy infection or invasive pneumococcal disease. Approaches to protect patients with asplenia or hyposplenism include patient education of risks and signs/symptoms of infection, vaccination, and antibiotic prophylaxis. Physicians have...
Source: Immunology and Allergy Clinics of North America - Category: Allergy & Immunology Authors: Source Type: research
Evaluation of antibodies produced after immunization is central to immune deficiency diagnosis. This includes assessment of responses to routine immunizations as well as to vaccines administered specifically for diagnosis. Here, we present the basic concepts of the humoral immune response and their relevance for vaccine composition and diagnosis of immune deficiency. Current vaccines are discussed, including nonviable protein and glycoprotein vaccines, pure polysaccharide vaccines, polysaccharide –protein conjugate vaccines, and live agent vaccines. Diagnostic and therapeutic applications of vaccine antibody measurem...
Source: Immunology and Allergy Clinics of North America - Category: Allergy & Immunology Authors: Source Type: research
Authors: Naik R, Peden K Abstract Developing traditional viral vaccines for infectious diseases usually takes years, as these are usually produced either by chemical inactivation of the virus or attenuation of the pathogen, processes that can take considerable time to validate and also require the live pathogen. With the advent of nucleic-acid vaccines (DNA and mRNA), the time to vaccine design and production is considerably shortened, since once the platform has been established, all that is required is the sequence of the antigen gene, its synthesis and insertion into an appropriate expression vector; importantly...
Source: Current Topics in Microbiology and Immunology - Category: Microbiology Tags: Curr Top Microbiol Immunol Source Type: research
Publication date: Available online 9 July 2020Source: Journal of Microbiology, Immunology and InfectionAuthor(s): Pei-Hsuan Tsai, Mao-Song Tsai, Yin-Hsuan Chiang, Chung-Yu Shih, Chia-Ying Liu, Yu-Chung Chuang, Chia-Jui Yang
Source: Journal of Microbiology, Immunology and Infection - Category: Microbiology Source Type: research
Covid-19 outbreak accelerates across Africa; Venezuelan Socialist Party boss also tests positive; Brazilian President Jair Bolsonaro ‘in good health’. Follow the latest updates:South Africa warns of coronavirus ‘storm’ as outbreak accelerates across continentBolivia ’s president and Venezuela’s Socialist party leader test positive for Covid-19WHO says coronavirus pandemic still acceleratingTrudeau and Trump ’s responses see wildly different results1.54amBSTPlans for the fall semester at the University ofCalifornia, Berkeley, are in question after 47 new Covid-19 cases tied to frate...
Source: Guardian Unlimited Science - Category: Science Authors: Tags: Coronavirus outbreak World news UK news US news Australia news Science Infectious diseases Africa Microbiology Medical research Source Type: news
Publication date: Available online 8 July 2020Source: Medicina Intensiva (English Edition)Author(s): A. González-Castro, P. Escudero-Acha, Y. Peñasco, O. Leizaola, V. Martínez de Pinillos Sánchez, A. García de Lorenzo
Source: Medicina Intensiva - Category: Intensive Care Source Type: research
This study aimed to evaluate the distribution and zoonotic transmission routes of Cryptosporidium species and microsporidia to humans referred to medical laboratories of Kurdistan Province, Iran. A total of 1,383 stool samples were collected and investigated. Cryptosporidium spp. and microsporidia were detected using microscopic methods (i.e., formol-ether concentration, Ziehl-Neelsen staining, and modified trichrome staining methods). DNA was extracted from positive samples, and specific fragments of the Cryptosporidium GP60 gene and microsporidia SSU rRNA gene were amplified. Furthermore, positive samples were sequenced ...
Source: The Journal of Parasitology - Category: Parasitology Authors: Tags: J Parasitol Source Type: research
Novavax will earn $1.6 billion for its vaccine and Regeneron $450 million for its antibodies
Source: Chemical and Engineering News - Category: Chemistry Authors: Source Type: research
The human papillomavirus (HPV) vaccine plays an important role in preventing a series of diseases caused by HPV. Recent studies have shown that as a primary prevention measure, it can considerably prevent HPV infection and HPV-associated cervical cancer. However, studies on the safety, efficacy, and coverage of the HPV vaccine remain insufficient, especially in developing countries. Therefore, in this review, we outlined the recent studies of the HPV vaccine in terms of immunogenicity, safety, efficacy, latest vaccination concepts, and strategies. This review may provide a theoretical basis for use of the HPV vaccine.
Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
AbstractEscherichia coli field isolates from calves were characterized and categorized into the most significant diarrheagenic pathotypes using polymerase chain reaction (PCR) assays with different specific primers. The used PCR systems were designed to detect sequences representing the group-specific virulence genes encoding fimbriaef5 (K99), Shiga toxins (stx1 andstx2), heat-stable enterotoxins (st), heat-labile enterotoxins (lt), intimin (eae), hemolysin (hylA), and EAEC heat-stable enterotoxin (astA). In the present work, a total of 150E. coli field isolates were recovered from 150 fecal swabs collected from 100 diarrh...
Source: Tropical Animal Health and Production - Category: Veterinary Research Source Type: research
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