Adaptive Immune Responses to SARS-CoV-2 and Prophylactic Vaccines for COVID-19

June 2020 | JMHS

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Published: 09 June 2020


The world experienced the outbreaks of SARS and MERS in the past and now experiencing the pandemic of SARS-CoV-2. Initially the infection were linked to seafood market in Wuhan for that studies were designed and investigation were done to know about the intermediate host of SARS-CoV-2. However, to date, there is no evidences that defines the SARS-CoV-2 specific relationship or association with animals and birds. The number of confirmed cases and deaths are rapidly increasing day by day, but unfortunately we have no prophylactic agent till date.   It is noted that individuals have strong immune system can wins the race from SARS-CoV-2. The host immunity is divided into innate and adaptive immunity. The innate immunity relies on the activation of interferon 1 and its downstream cascade mechanism. While the adaptive immune responses are cell mediated and greatly relies on the activation of T cells. T helper cells type 1 plays a dominant role in host adaptive immunity to any viral antigen. Antigen presenting cells (APC) activates the cytokines which act as an inducers of T cells responses. However, titer of neutralizing antibodies is directly proportional to T cell Reponses, higher the titer higher will be the responses. Receptor binding domain in spike S1 protein could be considered good vaccine antigen, as it contains regions which induces the production of neutralizing antibodies to prevent attachment of SARS-CoV-2 to ACE2. However, nucleic acid- based vaccine, RNA and DNA vaccine are the advance vaccine platforms against emergency infections. R0 value of SARS-CoV-2 is 2.2 to 2.6 greater than 1 which means continued transmission can occur. As we have no vaccine and other prophylactic agents. So to reduce transmission, the reduction of R0value less than 1 is must, for which more than half of the infections must be prevented or controlled.


Host-pathogen interaction, Adaptive immunity, Prophylactic vaccines, SARS-CoV-2, COVID-19, T cells

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