ORCID Profile
0000-0002-6837-8881
Current Organisations
University of Oxford
,
Stanford University School of Medicine
,
VA Palo Alto Health Care System
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Elsevier BV
Date: 02-2016
Publisher: Elsevier BV
Date: 07-2022
Publisher: Wiley
Date: 22-06-2022
DOI: 10.1111/BJH.18312
Abstract: Allogeneic haematopoietic stem cell transplant (HSCT) recipients remain at high risk of adverse outcomes from coronavirus disease 2019 (COVID‐19) and emerging variants. The optimal prophylactic vaccine strategy for this cohort is not defined. T cell‐mediated immunity is a critical component of graft‐versus‐tumour effect and in determining vaccine immunogenicity. Using validated anti‐spike (S) immunoglobulin G (IgG) and S‐specific interferon‐gamma enzyme‐linked immunospot (IFNγ‐ELIspot) assays we analysed response to a two‐dose vaccination schedule (either BNT162b2 or ChAdOx1) in 33 HSCT recipients at ≤2 years from transplant, alongside vaccine‐matched healthy controls (HCs). After two vaccines, infection‐naïve HSCT recipients had a significantly lower rate of seroconversion compared to infection‐naïve HCs (25/32 HSCT vs. 39/39 HCs no responders) and had lower S‐specific T‐cell responses. The HSCT recipients who received BNT162b2 had a higher rate of seroconversion compared to ChAdOx1 (89% vs. 74%) and significantly higher anti‐S IgG titres ( p = 0.022). S‐specific T‐cell responses were seen after one vaccine in HCs and HSCT recipients. However, two vaccines enhanced S‐specific T‐cell responses in HCs but not in the majority of HSCT recipients. These data demonstrate limited immunogenicity of two‐dose vaccination strategies in HSCT recipients, bolstering evidence of the need for additional boosters and/or alternative prophylactic measures in this group.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 29-01-2021
Abstract: Mucosal-associated invariant T (MAIT) cells are a T cell subset important for mucosal homeostasis. These cells recognize derivatives of microbiota-derived vitamin B2 precursors but can also be activated by certain cytokines in the context of viral infections. Provine et al. report that a leading adenoviral vector vaccine, ChAdOx1, activated MAIT cells in immunized mice (see the Perspective by Juno and O'Connor). This activation required interferon-α produced by plasmacytoid dendritic cells as well as monocyte-derived interleukin-18 and tumor necrosis factor. MAIT cell activation positively correlated with vaccine-mediated T cell responses in human subjects, and mice deficient in MAIT cells showed impaired CD8 + T cell immunity to target antigens after vaccination. This work suggests an additional pathway that could be exploited to enhance the efficacy of vaccines. Science , this issue p. 521 see also p. 460
Publisher: Elsevier BV
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 17-08-2021
DOI: 10.1038/S41467-021-25167-5
Abstract: The extent to which immune responses to natural infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and immunization with vaccines protect against variants of concern (VOC) is of increasing importance. Accordingly, here we analyse antibodies and T cells of a recently vaccinated, UK cohort, alongside those recovering from natural infection in early 2020. We show that neutralization of the VOC compared to a reference isolate of the original circulating lineage, B, is reduced: more profoundly against B.1.351 than for B.1.1.7, and in responses to infection or a single dose of vaccine than to a second dose of vaccine. Importantly, high magnitude T cell responses are generated after two vaccine doses, with the majority of the T cell response directed against epitopes that are conserved between the prototype isolate B and the VOC. Vaccination is required to generate high potency immune responses to protect against these and other emergent variants.
Publisher: Elsevier BV
Date: 2022
Publisher: Elsevier BV
Date: 11-2021
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United States of America
Location: United States of America
Location: United States of America
No related grants have been discovered for Ali Amini.