Mass Cytometry Analysis of High-Dimensional Single-Cell Immune Profiles in ZF2001-Vaccinated Patients Infected with SARS-CoV-2.

INTRODUCTION

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared a public health emergency of international concern (PHEIC) by the WHO. ZF2001, a protein subunit vaccine targeting the RBD, was utilized to evaluate its impact on the immune system of COVID-19 patients. This study aimed to investigate peripheral cell profiles one year after three doses of ZF2001 vaccine using single cell mass spectrometry flow cytometry (CyTOF), a technique that allows detailed characterization of the immune response against SARS-COV-2 infection and further evaluation of ZF2001 mechanisms as a prophylactic against chronic disease and reducing mortality.

METHODS

This study profiled peripheral blood mononuclear cells (PBMCs) from 16 vaccinated COVID-19 patients (Omicron 5.2) and 8 hDs using CyTOF with a 41-antibody panel. PBMCs isolated via Lymphoprep density gradient underwent metal-tagged antibody staining. Data analysis included FlowJo gating, Seurat/Harmony batch correction, PhenoGraph clustering (k=45), and t-SNE visualization. Statistical assessments employed Wilcoxon tests and Spearman correlation.

RESULTS

Our findings revealed significant differences between infected and healthy individuals one year after three doses of ZF2001. Specifically, infected individuals exhibited: significant elevation of cytotoxic T cells expressing CD8 with a proliferation marker antigen-Kiel 67 (Ki67) and an adhesion molecule (CD138), expansion of B cells and reduction of monocytes expressing CD16, as well as depletion of CD4+ T cells and differentiation of T cells 1 year after the vaccine. These changes suggested that the vaccine was effectively modulating the immune response.

DISCUSSION

Our results provided a detailed single-cell profile of the immune response to SARS-CoV-2 infection in vaccinated patients, highlighting significant changes in immune cell kinetics indicative of an active innate and adaptive immune cell response.