Question

Describe the innate immune responses to COVID-19 infection. Be sure to include the IFN response, and the innate immune cells responding to viral infection (and the mechanism how the do it). In addition, include the “cytokine storm” induced by COVID-19

Answer 1

Upon entry of a foreign entity into the body, the innate immune response occurs almost immediately. Innate immune responses do not improve upon frequent encounter with the same infectious agent. Key players in the innate immune response include macrophages , neutrophils and soluble bactericidal proteins such as complement and lysozyme .
in the case of COVID 19 infection, the expression of pro inflammatory genes , especially chemokines was markedly elevated, suggesting that COVID 19 infection causes hypercytokinemia.

In addiction to this SARS CoV-2 triggered  expression of numerous IFN-inducible genes (ISGs). These ISGs show immunopathogenic potential, with overexpression genes involved in inflammation.

Beside this there is also increasing population of activated dendritic cells and neutrophils.

Cytokines are small proteins released by many different cells in the body , including those of the immune system where they coordinate the body's response against infection and trigger inflammation.

In case of COVID 19,when virus enters the lungs , it triggers an immune response, attracting immune cells to the region to attack the virus, resulting in localised inflammation.

But in some patients, excessive or uncontrolled levels of cytokines are released which then activate more immune cells , resulting in hyper inflammation. This is known as cytokines storm, which can seriously harm or even kill the patient.

Cytokines storm is a common complication not only for COVID 19 and flu but of other respiraratory diseases such as SARS and MERS.

Cytokine storm might explain why some people have a severe reaction to corona viruses while others only experience mild symptoms.