Unraveling the impact of SARS-CoV-2 mutations on immunity: insights from innate immune recognition to antibody and T cell responses.

Throughout the COVID-19 pandemic, the emergence of new viral variants has challenged public health efforts, often evading antibody responses generated by infections and vaccinations. This immune escape has led to waves of breakthrough infections, raising questions about the efficacy and durability of immune protection. Here we focus on the impact of SARS-CoV-2 Delta and Omicron spike mutations on ACE-2 receptor binding, protein stability, and immune response evasion.

Booster COVID-19 mRNA vaccination ameliorates impaired B-cell but not T-cell responses in older adults.

Age-associated differences in the effect of repetitive vaccination, particularly on memory T-cell and B-cell responses, remain unclear. While older adults (aged ≥65 years) exhibited enhanced IgG responses following COVID-19 mRNA booster vaccination, they produced fewer spike-specific circulating follicular helper T cells-1 than younger adults. Similarly, the cytotoxic CD8 T-cell response remained diminished with reduced PD-1 expression even after booster vaccination compared with that in younger adults, suggesting impaired memory T-cell activation in older adults.

Targets of influenza human T-cell response are mostly conserved in H5N1.

Frequent recent spillovers of subtype H5N1 clade 2.3.4.

Early antiviral CD4+ and CD8+ T cells are associated with upper airway clearance of SARS-CoV-2.

T cells are involved in protective immunity against numerous viral infections. Data regarding functional roles of human T cells in SARS-CoV-2 (SARS2) viral clearance in primary COVID-19 are limited. To address this knowledge gap, we assessed samples for associations between SARS2 upper respiratory tract viral RNA levels and early virus-specific adaptive immune responses for 95 unvaccinated clinical trial participants with acute primary COVID-19 aged 18-86 years old, approximately half of whom were considered at high risk for progression to severe COVID-19.

Patterns and cofactors of polyfunctional mycobacteria-specific T cell response restoration following 6-month antiretroviral treatment in children living with HIV.

Background: Despite immune restoration after initiation of antiretroviral treatment (ART), the risk of tuberculosis (TB) persists in children living with HIV (CLHIV). We determined patterns of immune restoration of mycobacteria-specific T cells following ART in CLHIV.

Methods: CD4 and CD8 T cell activation and memory phenotype and functional profiles before and 6 months after ART were evaluated in peripheral blood mononuclear cells (PBMCs) from CLHIV enrolled in the PUSH study (NCT02063880) in Nairobi, Kenya.