Question

The COVID-19 virus infects cells of the respiratory system. The virus spreads by moving from one cell to the next. While the virus moves from one cell to the next, it will outside of the cell temporarily and can be taken up by an antigen-presenting cell (APC) for processing and presentation. Explain how these antigens would be presented on the surface of these cells so that the immune system could react against it. What cells would recognise these antigens and why?

Answer 1

The antigen-presenting cells are the group of cells involved in the presenting of antigens for identification by lymphocytes like T cells. Thus, They help our immune system to develop immunity against viruses (antigen).

Examples of antigen-presenting cells (APC) are dendritic cells, macrophages, Langerhans cells and B cells.

The innate immune system is the first line of defense when a virus enters our body. The antigen-presenting receptors recognize the COVID-19 virus with the help of innate immune receptors present on APCs.

The receptors of APCs help APCs to bind to the COVID-19 viruses by identifying Pathogen-Associated Molecular Patterns (PAMPs).

This binding results in the secretion of interferons and other chemical mediators to destroy and control the replication of viruses by recruiting more immune cells at the site of infection.

The activation of adaptive immunity is the second line of defense. In this, T cells get activated, The T cells and B cells recognize these viruses.

T cells identify specific protein fragments of viruses that bind on special receptors of T cells that results in destroys of COVID-19 viruses by T cells.

The B- cells produce antibodies that can recognize specific molecules of the COVID-19 viruses and destroy these viruses.

The T cells and B cells recognize viruses to destroy the viruses.