Antigen-presenting cells

  • Thread starter Cheman
  • Start date
  • Tags
    Cells
In summary, antigen-presenting cells, such as macrophages and dendritic cells, migrate to the lymph nodes when they encounter antigens. The exact signal that causes this migration is still being researched, but it is believed to be similar to the system that causes monocytes to move into tissues where they are needed. While dendritic cells are known to migrate to the lymph nodes, it is unclear if macrophages also do so or if they rely on pre-existing cells in the nodes. Macrophages primarily function as phagocytes for opsonized particles and are not recruited to the lymph nodes.
  • #1
Cheman
235
1
Antigen-presenting cells...

When antigen-presenting cells (eg - macrophages, dendritics, etc) encounter antigens, do they all migrate to the lymph nodes? What causes them to do this?

I know from sources I've read that dendrites do it, but do macrophages as well - or does the macrophage system rely on ones which are alread present in the nodes? Or do they just move around randomly in tissues, hoping to bump into a T / B cell? I can't seem to ifnd a detailed and clear site anywhere on the net! :confused:

Thanks in advance. :smile:
 
Biology news on Phys.org
  • #2
Cheman said:
When antigen-presenting cells (eg - macrophages, dendritics, etc) encounter antigens, do they all migrate to the lymph nodes? What causes them to do this?
Scientists are trying to find out what exactly the signal is, I think it is the same type of system that causes monocytes to move into tissues where they are needed: a signal cause them to become sticky for the site, so they have the time to enter.

I know from sources I've read that dendrites do it, but do macrophages as well - or does the macrophage system rely on ones which are alread present in the nodes? Or do they just move around randomly in tissues, hoping to bump into a T / B cell? I can't seem to ifnd a detailed and clear site anywhere on the net! :confused:

Thanks in advance. :smile:
Well, monocytes circulate in the blood until they move into tissue, where they differentiate into macrophages. A macrophage has antigen presenting abilities, but that is not its major function. Macrophages recognize particles opsonized by the immune system and they phagocytose those, I don't think they are recruited to the lymph nodes.
 
  • #3


Antigen-presenting cells (APCs) are a crucial part of the body's immune response. They play a vital role in presenting foreign antigens to T cells, which are responsible for initiating an immune response. When APCs encounter antigens, they do indeed migrate to the lymph nodes, where they can interact with T cells and initiate an immune response.

The migration of APCs to the lymph nodes is a highly coordinated process that is essential for the immune response to function effectively. APCs are specialized cells that are capable of recognizing and binding to antigens, which are foreign substances or molecules that can trigger an immune response.

When an APC encounters an antigen, it engulfs and breaks it down into smaller fragments. These fragments are then displayed on the surface of the APC, bound to a protein called the major histocompatibility complex (MHC). This MHC-antigen complex is then recognized by T cells, triggering an immune response.

The reason why APCs migrate to the lymph nodes is to increase the chances of encountering T cells. The lymph nodes are strategically located throughout the body and act as checkpoints for immune cells. T cells are constantly circulating through the body, and when they encounter an antigen-presenting cell, they can recognize the antigen and initiate an immune response.

Some APCs, such as dendritic cells, are specialized in migrating to the lymph nodes. They have long, branching processes that allow them to extend and sample their surroundings, increasing their chances of encountering antigens. Other APCs, such as macrophages, can also migrate to the lymph nodes, although they may rely on dendritic cells to present antigens to T cells.

In summary, APCs play a crucial role in the immune response by presenting antigens to T cells. When they encounter antigens, they migrate to the lymph nodes to increase their chances of interacting with T cells. This migration is a coordinated process that is essential for the immune response to function effectively.
 

1. What are antigen-presenting cells (APCs)?

Antigen-presenting cells (APCs) are specialized immune cells that play a crucial role in the body's defense against pathogens. They are responsible for identifying, capturing, and presenting foreign particles, such as bacteria or viruses, to other immune cells to initiate an immune response.

2. What are the different types of APCs?

The three main types of APCs are dendritic cells, macrophages, and B cells. Dendritic cells are found in tissues and are responsible for initiating immune responses. Macrophages are found in various tissues and are responsible for engulfing and destroying pathogens. B cells are found in the lymph nodes and are responsible for producing antibodies.

3. How do APCs present antigens to other immune cells?

APCs present antigens by first engulfing foreign particles through a process called phagocytosis. They then break down the particles and display fragments of the antigens on their cell surface, where they can be recognized by other immune cells, such as T cells and B cells.

4. What is the significance of APCs in the immune response?

APCs are essential for initiating and coordinating the body's immune response. They play a critical role in activating other immune cells and directing them to the site of infection. They also help in the development of memory cells, which provide long-term protection against future infections.

5. Can APCs cause autoimmune diseases?

While APCs are necessary for a healthy immune response, they can also contribute to autoimmune diseases. In these conditions, the immune system mistakenly attacks the body's own cells and tissues. This can happen when APCs present self-antigens, causing the immune system to target healthy cells. However, the exact causes of autoimmune diseases are still not fully understood.

Similar threads

Replies
1
Views
756
  • Biology and Medical
Replies
21
Views
3K
  • Biology and Medical
Replies
4
Views
6K
Replies
2
Views
1K
Replies
2
Views
1K
Replies
14
Views
15K
Replies
152
Views
4K
  • High Energy, Nuclear, Particle Physics
Replies
2
Views
2K
  • Cosmology
Replies
4
Views
1K
  • Math Proof Training and Practice
3
Replies
101
Views
11K
Back
Top