The MHC II receptors are found on macrophages. These receptors are an essential part of the immune system and play a crucial role in presenting antigens to T-helper cells. Macrophages are a type of white blood cell that engulfs and digests cellular debris, foreign substances, microbes, and cancer cells. They act as antigen-presenting cells (APCs) by displaying antigens on their surface using MHC II receptors. This presentation helps activate T-helper cells, initiating an immune response against the specific antigen. Therefore, the correct answer to the question is:
1. Macrophage
It is important to understand the role of MHC II receptors on macrophages in the immune response to pathogens and the coordination of immune reactions in the body.
