Biology subjects

Phelps, A.

Publications and source records attributed to Phelps, A..

4 recordsLinked to original sources

bioRxiv2023

Pathogenic IgE-fated B cell memory retains functional plasticity

Long-lived immunoglobulin (Ig) E responses against innocuous environmental and dietary antigens (Ags) are maintained by an IgG1-dominant memory B cell (MBC) compartment primed for IL-4 responsiveness. The plasticity of the MBC compartment destined for IgE class switch recombination (CSR), however, remains poorly understood. In this work, we report a critical IL-4/IL-13 dependency for the pathogenic IgE fate of type 2-polarized MBCs. Initiating a recall response in the absence of IL-4/IL-13 signaling diminished the type 2 MBC phenotype in mice and humans and, in mice, permitted the emergence of long-lived Ag-specific IgG2c+ MBCs. The divergence to a type 1-like response was dependent on IFN-{gamma} signaling and arose from both unswitched and class-switched Ag-specific B cells in vivo. This reprogrammed fate was sustained even beyond therapeutic intervention, revealing fundamental insight into the plasticity of the allergen-specific MBC response. One Sentence SummaryB cell responses to allergens can be reprogrammed away from a pathogenic fate through IL-4/IL-13 signaling blockade.

immunology↗

bioRxiv2023

A Distinct Phenotype of Polarized Memory B cell holds IgE Memory

Allergen-specific IgE antibodies mediate allergic pathology in diseases such as allergic rhinitis and food allergy. Memory B cells (MBCs) contribute to circulating IgE by regenerating IgE-producing plasma cells upon allergen encounter. We report a population of type 2 polarized MBCs defined as CD23hi, IL-4Rhi, CD32low at the transcriptional and surface protein levels. These "MBC2s" are enriched in IgG1 and IgG4-expressing cells, while constitutively expressing germline transcripts for IgE. Allergen-specific B cells from patients with allergic rhinitis and food allergy were enriched in MBC2s. MBC2s generated allergen specific-IgE during sublingual immunotherapy, thereby identifying these cells as the primary reservoir of IgE. The identification of MBC2s provides insights into the maintenance of IgE memory, which is detrimental in allergic diseases, but which could be beneficial in protection against venoms and helminths. One-Sentence SummaryIdentification of a novel memory B cell subset which holds allergen specific IgE memory.

immunology↗

bioRxiv2021

Single-dose respiratory mucosal delivery of next-generation viral-vectored COVID-19 vaccine provides robust protection against both ancestral and variant strains of SARS-CoV-2

The emerging SARS-CoV-2 variants of concern (VOC) increasingly threaten the effectiveness of current first-generation COVID-19 vaccines that are administered intramuscularly and are designed to only target the spike protein. There is thus a pressing need to develop next-generation vaccine strategies to provide more broad and long-lasting protection. By using adenoviral vectors (Ad) of human and chimpanzee origin, we developed Ad-vectored trivalent COVID-19 vaccines expressing Spike-1, Nucleocapsid and RdRp antigens and evaluated them following single-dose intramuscular or intranasal immunization in murine models. We show that respiratory mucosal immunization, particularly with chimpanzee Ad-vectored vaccine, is superior to intramuscular immunization in induction of the three-arm immunity, consisting of local and systemic antibody responses, mucosal tissue-resident memory T cells, and mucosal trained innate immunity. We further show that single-dose intranasal immunization provides robust protection against not only the ancestral strain of SARS-CoV-2, but also two emerging VOC, B.1.1.7 and B.1.351. Our findings indicate that single-dose respiratory mucosal delivery of an Ad-vectored multivalent vaccine represents an effective next-generation COVID-19 vaccine strategy against current and future VOC. This strategy has great potential to be used not only to boost first-generation vaccine-induced immunity but also to expand the breadth of protective T cell immunity at the respiratory mucosa.

immunology↗

bioRxiv2021

Evaluation of the SARS-CoV-2 inactivation efficacy associated with buffers from three kits used on high-throughput RNA extraction platforms

Rapid and demonstrable inactivation of SARS-CoV-2 is crucial to ensure operator safety during high-throughput testing of clinical samples. The inactivation efficacy of SARS-CoV-2 was evaluated using commercially available lysis buffers from three viral RNA extraction kits used on two high-throughput (96-well) RNA extraction platforms (Qiagen QiaCube HT and the ThermoFisher Kingfisher Flex) in combination with thermal treatment. Buffer volumes and sample ratios were chosen for their optimised suitability for RNA extraction rather than inactivation efficacy and tested against a representative sample type; SARS-CoV-2 spiked into viral transport medium (VTM). A lysis buffer from the MagMax Pathogen RNA/DNA kit (ThermoFisher), used on the Kingfisher Flex, which included guanidinium isothiocycnate (GITC), a detergent, and isopropanol demonstrated a minimum inactivation efficacy of 1 x 105 TCID50/ml. An alternative lysis buffer from the MagMax Viral/Pathogen Nucleic Acid kit (Thermofisher) also used on the Kingfisher Flex and the lysis buffer from QIAamp 96 Virus QIAcube HT Kit (Qiagen) used on the QiaCube HT (both of which contained GITC and a detergent) reduced titres by 1 x 104 TCID50/ml but did not completely inactivate the virus. Heat treatment alone (15 minutes, 68 {degrees}C) did not completely inactivate the virus, demonstrating a reduction of 1 x 103 TCID50/ml. When inactivation methods included both heat treatment and addition of lysis buffer, all methods were shown to completely inactivate SARS-CoV-2 inactivation against the viral titres tested. Results are discussed in the context of the operation of a high-throughput diagnostic laboratory.

microbiology↗