This case report details the identification of a novel likely pathogenic splicing variant in the TTN gene, associated with dilated cardiomyopathy (DCM), in a 42-year-old male patient presenting with early-onset heart failure and reduced ejection fraction. DCM is a nonischemic heart condition characterized by left biventricular dilation and systolic dysfunction, with approximately one-third of cases being familial and often linked to genetic mutations. The TTN gene, encoding the largest human protein essential for muscle contraction and sarcomere structure, is implicated in about 25% of DCM cases through mutations, especially truncating variants.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2020
While single-cell sequencing technologies have revealed tissue heterogeneity, resolving mixed cellular libraries into cellular clones is essential for many pooled screens and clonal lineage tracing. Fluorescent proteins are limited in number, while DNA barcodes can only be read after cell lysis. To overcome these limitations, we used influenza virus hemagglutinins to engineer a genetically encoded cell-surface protein barcoding system.
View Article and Find Full Text PDFAntibodies play a crucial role in coupling the innate and adaptive immune responses against viral pathogens through their antigen binding domains and Fc-regions. Here, we describe how to measure the activation of Fc effector functions by monoclonal antibodies targeting the influenza virus hemagglutinin with the use of a genetically engineered Jurkat cell line expressing an activating type 1 Fc-FcγR. Using this method, the contribution of specific Fc-FcγR interactions conferred by immunoglobulins can be determined using an in vitro assay.
View Article and Find Full Text PDFThe aim of candidate universal influenza vaccines is to provide broad protection against influenza A and B viruses. Studies have demonstrated that broadly reactive antibodies require Fc-Fc gamma receptor interactions for optimal protection; however, the innate effector cells responsible for mediating this protection remain largely unknown. Here, we examine the roles of alveolar macrophages, natural killer cells, and neutrophils in antibody-mediated protection.
View Article and Find Full Text PDFInfluenza viruses exhibit a remarkable ability to adapt and evade the host immune response. One way is through antigenic changes that occur on the surface glycoproteins of the virus. The generation of escape variants is a powerful method in elucidating how viruses escape immune detection and in identifying critical residues required for antibody binding.
View Article and Find Full Text PDFInfluenza virus strain-specific monoclonal antibodies (mAbs) provide protection independent of Fc gamma receptor (FcγR) engagement. In contrast, optimal in vivo protection achieved by broadly reactive mAbs requires Fc-FcγR engagement. Most strain-specific mAbs target the head domain of the viral hemagglutinin (HA), whereas broadly reactive mAbs typically recognize epitopes within the HA stalk.
View Article and Find Full Text PDFPathogenic H7N9 avian influenza viruses continue to represent a public health concern, and several candidate vaccines are currently being developed. It is vital to assess if protective antibodies are induced following vaccination and to characterize the diversity of epitopes targeted. Here we characterized the binding and functional properties of twelve H7-reactive human antibodies induced by a candidate A/Anhui/1/2013 (H7N9) vaccine.
View Article and Find Full Text PDFIn the early spring of 2013, Chinese health authorities reported several cases of H7N9 influenza virus infections in humans. Since then the virus has established itself at the human-animal interface in Eastern China and continues to cause several hundred infections annually. In order to characterize the antibody response to the H7N9 virus we generated several mouse monoclonal antibodies against the hemagglutinin of the A/Shanghai/1/13 (H7N9) virus.
View Article and Find Full Text PDFViruses are obligate parasites and thus require the machinery of the host cell to replicate. Inhibition of host factors co-opted during active infection is a strategy hosts use to suppress viral replication and a potential pan-antiviral therapy. To define the cellular proteins and processes required for a virus during infection is thus crucial to understanding the mechanisms of virally induced disease.
View Article and Find Full Text PDFThe emergence of influenza virus strains resistant to approved neuraminidase inhibitors and the time constrains after infection when these drugs can be effective constitute major drawbacks for this class of drugs. This highlights a critical need to discover new therapeutic agents that can be used for the treatment of influenza virus-infected patients. The use of broadly neutralizing anti-influenza monoclonal antibodies (MAbs) has been sought as an alternative immunotherapy against influenza infection.
View Article and Find Full Text PDFThe emergence and seasonal persistence of pathogenic H7N9 influenza viruses in China have raised concerns about the pandemic potential of this strain, which, if realized, would have a substantial effect on global health and economies. H7N9 viruses are able to bind to human sialic acid receptors and are also able to develop resistance to neuraminidase inhibitors without a loss in fitness. It is not clear whether prior exposure to circulating human influenza viruses or influenza vaccination confers immunity to H7N9 strains.
View Article and Find Full Text PDFUnlabelled: Due to continuous changes to its antigenic regions, influenza viruses can evade immune detection and cause a significant amount of morbidity and mortality around the world. Influenza vaccinations can protect against disease but must be annually reformulated to match the current circulating strains. In the development of a broad-spectrum influenza vaccine, the elucidation of conserved epitopes is paramount.
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