Question

Describe the cellular and humoral responses to viral (COVID-19) infection. Be sure to address the role of CD4 and CD8 cells, and the role of B cells and antibodies.

Answer 1

The humoral response is activated by the cellular response, refers to the chemical response made by white cells, that is the antibody production that will kill the infected cells. This process occurs when a B cell (or any other antigen presenting cell) is infected by a virus. These cells are capable of taking some protein fragments form the viral copies with their MHC molecules and take them to their surface (this is the cellular response). This process is called antigen presentation, and they are basically showing to the rest of the immune system what are they being infected with. The CD4 T cells recognize this antigens and start an immune response by inducing inflammation and recruiting CD8 T cells, which are known by the name of killer cells. These killer cells produce cytotoxins to eliminate the infected cells.

The cellular immune response refers to the action of macrophages that will undergo lysis of the pathogen molecules, the lyzed fragments are the ones being presented as antigens in order to be identified by the cells that will activate th humoral response.