In the immune response process, the cells in charge of the notification to Lymphocytes about the presence of a new antigen are called:
The correct answer and explanation is:
The cells responsible for notifying lymphocytes about the presence of a new antigen are called Antigen-Presenting Cells (APCs). The most important types of APCs are dendritic cells, macrophages, and B cells.
Explanation:
Antigen-presenting cells play a crucial role in the immune response by acting as messengers between the innate and adaptive immune systems. When a foreign antigen, such as a pathogen or a toxin, enters the body, APCs recognize and capture these antigens. After capturing, APCs process the antigen into smaller fragments and present these fragments on their cell surface bound to molecules called Major Histocompatibility Complex (MHC) proteins.
There are two main classes of MHC proteins: MHC class I and MHC class II. APCs typically present antigen fragments using MHC class II molecules, which are recognized by helper T lymphocytes (CD4+ T cells). This antigen presentation is essential for activating the adaptive immune response.
Dendritic cells are the most potent and specialized APCs. They reside in peripheral tissues, such as the skin and mucosa, where they encounter antigens. Upon capturing antigens, dendritic cells migrate to lymphoid organs, like lymph nodes, where they present the antigen fragments to naive T lymphocytes. This interaction activates T cells, which then proliferate and differentiate into effector cells that can target and eliminate the pathogen.
Macrophages can also function as APCs by engulfing pathogens and presenting their antigens to T cells. Additionally, B cells, which are lymphocytes themselves, can present antigen to helper T cells to enhance antibody production.
In summary, antigen-presenting cells are vital for initiating the adaptive immune response by alerting lymphocytes to the presence of new antigens and facilitating their activation. Without this crucial step, the immune system would not efficiently recognize or respond to pathogens.