Characteristics and immunobiology of COVID-19

COVID-19 (coronavirus disease-2019) has been identified as a serious respiratory infection by the SARS-CoV2 virus (severe acute respiratory syndrome coronavirus 2), was first reported in Wuhan, Hubei Province, China in December 2019. World Health Organization (WHO) declared COVID 19 as a pandemic on March 11, 2020 considering the exponential spread and unmanageable mortality. It continues currently as the utmost urgent/critical ailment of global public health. Moreover, the COVID-19 pandemic has not only affected global health scenarios but also has heavily burdened the economic, financial, political, educational, and other dimensions of humanity across the world. Monitoring the COVID 19 pathology reveals a potential respiratory infection followed by severe pneumonia like clinical observations with greater chances of microvascular injuries and multiorgan failures in worse scenario. The preexisting comorbidities including type II diabetes, cardiovascular diseases, hypertension, and older age are other major aggravating factors. Rather than other flu viruses, the intricate interplay of SARS-CoV2 virus with the immune system underlies the pathological manifestations in both symptomatic and asymptomatic patients. This chapter highlights the role of heterogenous immune cell population, cytokine storm, immune cell activation, and potential signaling pathways associated with COVID 19 infection that are greatly appreciated to evolve novel translational therapeutic interventions.