What Are Professional Antigen Presenting Cells?

TL;DR

Professional antigen presenting cells, such as phagocytes and B cells, specialize in engulfing pathogens and displaying their pieces using MHC class II proteins. This process is vital for activating helper T cells and orchestrating an effective immune response.

Transcript

In the very first immunology video, where we talked about nonspecific defense mechanisms, we said if we had some type of a pathogen-- let's say it's a bacteria-- that our phagocytes can recognize either proteins on the bacteria or maybe it was some other type of pathogen-- some other marker on the pathogen. It doesn't know what type of pathogen it ... Read More

Key Insights

• 🎁 Phagocytes and B cells are professional antigen presenting cells that engulf pathogens and present pieces of them using MHC proteins.
• 🎁 MHC class II proteins are found on the surface of antigen presenting cells and are involved in presenting antigens to helper T cells.
• ❓ Antigen presentation is a crucial step in activating the immune response.

Questions & Answers

Q: What are professional antigen presenting cells?

Professional antigen presenting cells are specialized cells, such as phagocytes and B cells, that engulf pathogens, break them down, and present pieces of them using MHC proteins. They are called professional because antigen presentation is their main function.

Q: What are MHC class II proteins?

MHC class II proteins are proteins found on the surface of antigen presenting cells, like phagocytes and B cells. They bind to pieces of pathogens and present them to helper T cells for recognition and activation of the immune response.

Q: How do phagocytes and B cells break down pathogens?

Phagocytes and B cells break down pathogens by engulfing them and forming a membrane around them. They then use lysosomes to release enzymes that break the pathogens into smaller molecules, which can be presented using MHC proteins.

Q: What is the role of antigen presentation in the immune system?

Antigen presentation is important for activating the immune response. By presenting pieces of pathogens using MHC proteins, cells can stimulate the recognition and activation of helper T cells, which coordinate the immune response.

Summary & Key Takeaways

• Phagocytes recognize pathogens and engulf them, forming a membrane called a phagosome. They then break down the pathogens and present pieces of them using MHC class II proteins on their surface.

• B cells, part of the adaptive immune system, have specific membrane-bound antibodies that recognize and bind to particular pathogens. They engulf the pathogen and also present pieces of it using MHC class II proteins.

• Both phagocytes and B cells are professional antigen presenting cells, which means they specialize in engulfing, breaking down, and presenting antigens.