Immunological Facets of SARS-CoV-2 Infection: Host Immune Responses and Immunopathogenesis

The recently identified Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), responsible for the worldwide outbreak of coronavirus disease 2019 (COVID-19), has posed an unparalleled challenge to public health systems globally. Acute respiratory distress syndrome (ARDS), multiorgan failure, and asymptomatic infection exemplify illness severity, with host immune responses significantly influencing clinical outcomes. This work meticulously investigates the immunological mechanisms underlying SARS-CoV-2 infection, focusing on host–virus interactions, innate and adaptive immune responses, and immune dysregulation associated with severe disease. Important topics covered include the significance of type I interferon signaling, stimulation of dendritic cells, macrophages, and T lymphocytes, and viral entry pathways mediated by spike protein interactions with ACE2 and TMPRSS2. The review focuses on the immunopathological hallmarks of COVID-19, including antibody-dependent enhancement, cytokine storm, increased neutrophil activation, and lymphopenia. Additionally, methods used by SARSCoV-2 to avoid host immune surveillance, such as interferon pathway disruption and antigen presentation disruption, are thoroughly examined. Additionally, a summary of vaccination programs, therapeutic drugs, and immunological therapies targeted at regulating immune responses and slowing the progression of disease is provided. This review highlights possible targets for therapeutic and preventive measures and offers a comprehensive explanation of the immunological foundation of COVID-19 pathogenesis by combining the available data. Such knowledge is crucial for enhancing the treatment of illnesses and directing upcoming investigations into new coronavirus infection