Response of Immune system towards SARS-CoV-2 Infection

Author(s): Chritiana William*

Following the 1918 influenza pandemic, the world is once again confronted with a similar dilemma. However, advances in medical science have allowed researchers to determine that the new infectious agent belongs to the coronavirus family. The structure and function of the virus, as well as its immunogenicity in different populations and potential preventive treatments, were all identified thanks to rapid genome sequencing by several organizations. Coronavirus infects the lungs, causing pneumonia and lymphopenia in those who are affected. Viral components such as spike and nucleocapsid proteins activate the host’s immune system, causing the virus to be eliminated. In the acute phase of infection, these viral antigens can be identified by B cells or presented to T cells via MHC complexes, resulting in antibody formation, enhanced cytokine secretion, and cytolytic activity. MHC genetic variability allows it to present some T cell epitopes more effectively than other MHC alleles. The relationship between MHC alleles and their downregulated expression has been linked to the severity of sickness caused by influenza and coronaviruses. Infected individuals can produce substantial protective responses after recovery by creating a memory T-cell pool against SARS-CoV and MERS-CoV, according to studies. These memory T cells were not long-lasting and caused local harm when reactivated due to cross-reactivity. According to reports so far, SARS-CoV-2, which is extremely contagious, exhibits similar symptoms in three stages and develops an extensive T-cell pool at higher viral loads. Because there are no particular treatments for this unique coronavirus, COVID-19 patients are given a variety of tiny molecular medications that are used to treat diseases including SARS, MERS, HIV, ebola, malaria, and tuberculosis, and clinical studies for several of these drugs have already begun. For the neutralization of viremia in terminally ill COVID-19 patients, a traditional immunotherapy of convalescent plasma transfusion from recovered patients has also been started. Due to the limits of plasma transfusion, researchers are now concentrating on producing virus-neutralizing antibodies as well as immuno-modulation of cytokines such as IL-6, Type I interferons (IFNs), and TNFs, which could aid in the fight against infection. The similarities between the coronaviruses that caused SARS and MERS and the novel SARS-CoV-2 in terms of pathogenicity and immunogenicity are highlighted in this review, as well as possible therapeutic options that could be used to cure COVID-19.