The Role of the Host Immune System in SARS-CoV-2 Infection

The disease (COVID-2019) caused by (SARS-CoV-2) spread around the world. The new virus is a member of the Coronaviridae family and has been detected in various birds and mammals. The Spectrum of SARS-CoV-2 disease varies from asymptomatic infection to severe and often fatal disease. Immune responses against this SARS-CoV-2 are initiated by the innate immune system by the production of proinflammatory cytokines and chemokines. After that acquired immune responses begin, including cellular and hemoral immunity, are activated. The persistence of the antibody response to SARS-CoV-2 has not been determined precisely. There is a strong correlation between the neutralization antibody titer and the number of virus-specific T cells. The findings also show that both B and T cells participate in Immunological protection against viral infection. Understanding the behavior of SARS-CoV-2 in human host cells and its effect on the immune system can help to better understand the nature and pathogenesis of the virus. Furthermore, understanding the complexity of the function of immune system against the virus is necessary to developing new treatment protocols. However, there is a lot of controversy about the immune responses to this viral infection and its challenges, because the immune response against the SARS-CoV-2 virus is different from other coronavirus infections in many ways. According to the importance of this issue in this paper, while mentioning the structural features, virology of SARS-CoV-2 and its pathogenesis, immunological responses to this virus and the challenges are reviewed. For this purpose, review and original articles were collected from PubMed, Scopus, Google Scholar, and other reputable databases by using keywords such as COVID-19, Coronavirus, SARS-CoV-2, Pathogenesis, clinical features, Immune system, Antibody responses, B cell, T cell.