What is the Difference Between T Memory Cells and B Memory Cells

The main difference between T memory cells and B memory cells is that T memory cells do not produce antibodies, whereas B memory cells produce antibodies.  

T memory cells and B memory cells are two types of lymphocytes in the immune system. The most significant feature of T memory cells and B memory cells is their ability to memorize antigens. Normally, they memorize the characteristics of antigens to accelerate secondary immune responses.

Key Areas Covered

1. What are T Memory Cells
   • Definition, Characteristics, Importance
2. What are B Memory Cells
   • Definition, Characteristics, Importance
3. Similarities Between T Memory Cells and B Memory Cells
   • Outline of Common Features
4. Difference Between T Memory Cells and B Memory Cells
   • Comparison of Key Differences

Key Terms

B Memory Cells, T Memory Cells

What are T Memory Cells

T memory cells are a class of T cells that persist after having previously responded to antigenic stimulation; for example, prior infection. More importantly, memory T cells mount a more vigorous immune response than the initial immune response upon exposure to the second exposure of a particular pathogen. Mucosal tissue sites serve as the primary interface, for example, the mucosal surfaces in the gut and lung are the anatomical sites that are rich in memory T cells.

Figure 1: T Memory Cells

For instance, shortly after the HIV infection, memory T cells of the mucosal tissue sites decline rapidly and are depleted within a few weeks. During T cell depletion, only a few viruses occur in the peripheral blood and, the viruses replicate inside the mucosal tissues. However, the virus is detectable in the peripheral blood only after the drop of mucosal T memory cell levels below the low threshold and after that, the virus is exposed to the cytotoxic T cells in the peripheral blood.

What are B Memory Cells

Memory B cells are a type of B lymphocytes that forms a part of the adaptive immune system. Generally, memory B cells develop within germinal centers of the secondary lymphoid organs. They circulate in the bloodstream in a quiescent state, sometimes for decades. In general, the main function of B memory cells is to memorize the characteristics of the antigen. More importantly, this antigen activates its parent B cell during initial infection. Therefore, memory B cell later encounters the same antigen, but it triggers an accelerated and robust secondary immune response.

Figure 2: B Memory Cells

Moreover, memory B cells have B cell receptors (BCRs) on their cell membrane. These B cell receptors are identical to the ones on their parent cell, allowing B cells to recognize antigens and mount a specific antibody response. Significantly, B memory cells produce antibodies upon re-exposure to the antigen, differentiating into the antibody-producing plasma cells.

Similarities Between T Memory Cells and B Memory Cells

• T memory cells and B memory cells are two types of memory cells in the immune system.
• Their main function is to memorize the characteristics of antigens that activated their parent cells.
• Both types of memory cells help in accelerating the robust secondary immune response.
• Both types of cells produce adaptive immune responses.

Difference Between T Memory Cells and B Memory Cells

Definition

T memory cells refer to antigen-experienced cells that mediate a faster and more potent response upon repeat encounter with antigens, while B memory cells refer to a type of B lymphocyte that forms part of the adaptive immune system.

Generation

T memory cells generate from effector T cells while B memory cells generate in response to T-dependent antigens.

Occurrence

Furthermore, T memory cells occur in the mucosal tissue sites of the gut and lungs while B memory cells occur in the bloodstream.

Function

T memory cells react to the antigen-bearing pathogens in the mucosal tissue sites while B memory cells produce antibodies against the antigen.

Conclusion

In brief, T memory cells are a type of T lymphocytes that occur in the mucosal tissue sites in the gut and lungs. They develop from the effector T cells. Their function is to recognize and destroy pathogens upon re-exposure to the same antigen for the second time. Memory B cells, on the other hand, are the type of B lymphocytes that occur in the bloodstream. Upon re-exposure to the same antigen for the second time, these B lymphocytes differentiate into plasma cells and produce antibodies. However, the main function of both types of memory cells is to trigger a vigorous immune response upon the re-exposure to the same antigen. The main difference between T memory cells and B memory cells is the type of immune response they generate.

References:

1. Memory T cell. An overview | ScienceDirect Topics. (n.d.). Retrieved September 26, 2022.
2. Memory B cell. An overview | ScienceDirect Topics. (n.d.). Retrieved September 26, 2022.

Image Courtesy:

1. “A picture for the developmental differentiation model for memory T cell lineage” By Immcarle133 – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Original antigenic sin ” By png: User:DO11.10 – Own Work (CC BY-SA 3.0) via Commons Wikimedia