Omicron breakthrough infections after triple-dose inactivated COVID-19 vaccination: A comprehensive analysis of antibody and T-cell responses.

This study longitudinally evaluated the immune response in individuals over a year after receiving three doses of an inactivated SARS-CoV-2 vaccine, focusing on reactions to Omicron breakthrough infections. From 63 blood samples of 37 subjects, results showed that the third booster enhanced the antibody response against Alpha, Beta, and Delta VOCs but was less effective against Omicron. Although antibody titres decreased post-vaccination, SARS-CoV-2-specific T-cell responses, both CD4+ and CD8+, remained stable. Omicron breakthrough infections significantly improved neutralization against various VOCs, including Omicron. However, the boost in antibodies against WT, Alpha, Beta, and Delta variants was more pronounced. Regarding T cells, breakthrough infection predominantly boosted the CD8+ T-cell response, and the intensity of the spike protein-specific T-cell response was roughly comparable between WT and Omicron BA.5.

Neuroprotective Effect of Ganoderic Acid against Focal Ischemic Stroke Induced by Middle Cerebral Artery Occlusion in the Rats via Suppression of Oxidative Stress and Inflammation.

Stroke is recognized as a leading cause of disability and mortality worldwide, posing a significant challenge, particularly in developing countries. The current study aimed to evaluate the neuroprotective effect of Ganoderic acid (GA) against focal ischemic stroke in rats. MATERIAL AND METHODS: Swiss Wistar rats were used for the current study. The rats were subjected to middle cerebral artery occlusion (MCAO) to simulate transient focal ischemia, followed by reperfusion. Various neurological parameters, including infarct size, neurological deficit score, brain water content, Evans blue leakage, nitric oxide (NO), inducible nitric oxide synthase (iNOS), lactate dehydrogenase (LDH), antioxidant levels, inflammatory cytokines, apoptosis markers, inflammatory parameters, and matrix metalloproteinases (MMP) levels, were estimated. Additionally, mRNA expressions were evaluated in the brain tissue. RESULTS: Dose dependently treatment of GA significantly (P < 0.001) suppressed the infarct size, neurological deflects score, brain water, evans blue leakage, NO, iNOS, LDH, C-X-C chemokine receptor type 4 (CXCR-4), monocyte chemoattractant protein-1 (MCP-1), S100 calcium-binding protein B (S-100ß) and K+-Cl- cotransporter 1 (KCC1) positive cells. GA altered the level of oxidative stress parameters like Total antioxidant capacity (T-AOC), 8-hydroxy-2'-deoxyguanosine (8-OhdG), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH), malonaldehyde (MDA); cytokines viz., tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), IL-1ß, IL-6, IL-9, IL-10; inflammatory parameters such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), prostaglandin (PGE2), Nuclear factor kappa B (NF-κB); apoptosis parameters like B-cell leukemia/lymphoma 2 protein (Bcl-2), Bcl-2-associated protein x (Bax), Caspase-3; matrix metallopeptidase (MMP) parameters like MMP-2, MMP-3, and MMP-9, respectively. GA remarkably suppressed the mRNA expression of TRL-4, Syndecan-1, CSF, Aquaporin-1, OCT3, and RFX1. CONCLUSION: Ganoderic acid exhibited the protection against the cerebral ischemia reperfusion via multiple mechanism.

PD-1/PD-L1 governed cross-talk of exhausted CD8+ T and memory B cells in systemic lupus erythematosus.

BACKGROUND: Indeterminate readout of the quantitative interferon-γ release test (QFT) for Mycobacterium tuberculosis screening is a specific laboratory finding for systemic lupus erythematosus (SLE), which may be due to T-cell exhaustion and abnormal programmed death receptor 1 (PD-1)/programmed death-ligand 1 (PD-L1) signalling. METHODS: We enrolled 104 patients with SLE and 225 with other rheumatic musculoskeletal diseases (RMDs) who presented to the outpatient clinic between 2020 and 2023. Twenty healthy donors served as the controls. The QFT was performed in all participants, and those with indeterminate results were compared among the groups. Immunophenotyping and functional assays were performed using blood mononuclear cells. Interferon (IFN)-γ was detected in vitro and ex vivo in patients with SLE with indeterminate or negative QFT results, before or after rituximab therapy. RESULTS: 104 patients with SLE had a significantly higher rate of indeterminate QFT results was significantly higher (17.31%) than that of 225 patients with RMD (3.56%). Patients with SLE with indeterminate QFT had more active disease (SLEDAI-2K, mean 10.94 vs 4.02, p<0.0001), including a higher incidence of active nephritis (55.56% vs 29.07%). Indeterminate QFT in SLE is mainly caused by an insufficient IFN-γ response in CD8+T cells with exhausted immunophenotypes. The abnormal interaction between exhausted PD-1 high CD8+ T cells and activated PD-L1 low memory B cells in SLE can be reversed with a PD-1 agonist or increased PD-L1 expression. Rituximab treatment indirectly reversed this IFN-γ response. CONCLUSION: The PD-1/PD-L1 signalling pathway, which governs the crosstalk between exhausted CD8+ T cells and activated memory B cells, is a mechanistic explanation for insufficient interferon-γ response in patients with SLE.