Anatomy and Physiology II Practice Test

What type of cells are the main components of humoral immunity?

1. T-cells, or T Lymphocytes

2. B-cells, or B Lymphocytes

3. Natural killer cells

4. Dendritic cells

The correct answer is: B-cells, or B Lymphocytes

Humoral immunity is primarily mediated by B-cells, also known as B Lymphocytes. These cells are crucial for the adaptive immune response, as they are responsible for producing antibodies that specifically target and neutralize pathogens such as bacteria and viruses. When a B-cell encounters its specific antigen, it becomes activated and differentiates into plasma cells, which secrete large quantities of antibodies into the bloodstream. These antibodies can bind to pathogens, marking them for destruction and preventing their ability to infect host cells. In contrast, T-cells primarily operate through cellular immunity rather than humoral mechanisms, as they assist in the activation of B-cells and directly kill infected cells, contributing to the cellular immune response. Natural killer cells are part of the innate immune system and play a role in recognizing and destroying infected or cancerous cells, but they do not produce antibodies. Dendritic cells are important in antigen presentation and signaling to T-cells and B-cells, thus initiating the adaptive immune response, but they do not produce antibodies themselves. Therefore, the main components of humoral immunity are indeed B-cells, which play a vital role in the body's defense against specific pathogens through antibody production.