Immunosenescence, age-related immune dysregulation, reduces immunity upon vaccinations and infections. Cytomegalovirus (CMV) infection results in declining naïve (T) and increasing terminally differentiated (T) T cell populations, further aggravating immune aging. Both immunosenescence and CMV have been speculated to hamper the formation of protective T-cell immunity against novel or emerging pathogens. The SARS-CoV-2 pandemic presented a unique opportunity to examine the impact of age and/or CMV on the generation of de novo SARS-CoV-2-specific CD8 T cell responses in 40 younger (22-40 years) and 37 older (50-66 years) convalescent individuals. Heterotetramer combinatorial coding combined with phenotypic markers were used to study 35 SARS-CoV-2 epitope-specific CD8 T cell populations directly ex vivo. Neither age nor CMV affected SARS-CoV-2-specific CD8 T cell frequencies, despite reduced total CD8 T cells in older CMV and CMV individuals. Robust SARS-CoV-2-specific central memory CD8 T (T) responses were detected in younger and older adults regardless of CMV status. Our data demonstrate that immune aging and CMV status did not impact the SARS-CoV-2-specific CD8 T cell response. However, SARS-CoV-2-specific CD8 T cells of older CMV individuals displayed the lowest stem cell memory (T), highest T and PD1 populations, suggesting that age, not CMV, may impact long-term SARS-CoV-2 immunity.
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http://dx.doi.org/10.1002/eji.202451565 | DOI Listing |
Eur J Immunol
March 2025
Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
Immunosenescence, age-related immune dysregulation, reduces immunity upon vaccinations and infections. Cytomegalovirus (CMV) infection results in declining naïve (T) and increasing terminally differentiated (T) T cell populations, further aggravating immune aging. Both immunosenescence and CMV have been speculated to hamper the formation of protective T-cell immunity against novel or emerging pathogens.
View Article and Find Full Text PDFJ Korean Med Sci
March 2025
Emerging Infectious Diseases Research Institute, Chungnam National University Hospital, Daejeon, Korea.
Background: We evaluated severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2)-specific humoral and cellular responses for up to 6 months after the 3rd dose of ancestral coronavirus disease 2019 (COVID-19) vaccination in people living with HIV (PLWH) and healthy controls (HCs) who were not infected with COVID-19.
Methods: Anti-spike receptor-binding domain IgG (anti-RBD IgG) concentrations using chemiluminescence immunoassay and neutralizing antibodies using focus reduction neutralization test (FRNT) were assessed at 1 week after each dose of vaccination, and 3 and 6 months after the 3rd dose in 62 PLWH and 25 HCs. T-cell responses using intracellular cytokine stain were evaluated at 1 week before, and 1 week and 6 months after the 3rd dose.
Commun Biol
March 2025
Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA.
The nature of the effector and memory T cell response in the lungs following acute SARS-CoV-2 infections remains largely unknown. To define the pulmonary T-cell response to COVID-19, we compared effector and memory T-cell responses to SARS-CoV-2 and influenza A virus (IAV) in mice. Both viruses elicited potent effector T cell responses in lungs, but memory T cells showed exaggerated contraction in SARS-CoV-2-infected mice.
View Article and Find Full Text PDFJ Virol
March 2025
Department of Medicine II (Gastroenterology, Hepatology, Endocrinology and Infectious Diseases), Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
The COVID-19 pandemic has greatly enhanced our understanding of CD8+ T cell immunity and their role in natural infection and vaccine-induced protection. Rapid and early SARS-CoV-2-specific CD8+ T cell responses have been associated with efficient viral clearance and mild disease. Virus-specific CD8+ T cell responses can compensate for waning, morbidity-related, and iatrogenic reduction of humoral immunity.
View Article and Find Full Text PDFJ Med Virol
February 2025
Department of Microbiology and Immunology, Medical School of Southeast University, Nanjing, China.
The polymorphism of human leukocyte antigens in the Northeast Asian populations and the lack of broad-spectrum T-cell epitopes covering this cohort markedly limited the development of T cell-directed vaccines against SARS-CoV-2 infection, and also hampered the universal detection of SARS-CoV-2 specific T cells. In this study, 93 CD4 T-cell epitopes restricted by 12 prevalent HLA-DRB1 allotypes, which covering over 80% Chinese and Northeast Asian populations, were identified from the S, E, M, N and RdRp proteins of SARS-CoV-2 by in silico prediction, DC-peptide-PBL coculture experiment, and immunization in HLA-A2/DR1 transgenic mice. Furthermore, by using validated 215 CD8 T cell epitope peptides and 123 CD4 T-cell epitope peptides covering Northeast Asian cohort, the universal ELISpot detection systems of SARS-CoV-2 specific CD8 T cells and CD4 T cells were established, for the first time, and followed by the tests for 50 unexposed and 100 convalescent samples.
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