What is the Difference Between B Cell Receptor and T Cell Receptor?
🆚 Go to Comparative Table 🆚The main difference between B cell receptors (BCRs) and T cell receptors (TCRs) lies in the way they recognize and bind antigens. Both BCRs and TCRs are integral membrane proteins that enable the recognition of specific molecular structures, or antigens, and are present in thousands of identical copies on the cell surface. However, they differ in their structure and function:
- Structure:
- BCRs are made up of four peptides: two light chains and two heavy chains.
- TCRs are made up of either alpha/beta (αβ) or gamma/delta (γδ) chains, with each chain having a variable (V) region and a constant (C) region.
- Antigen Recognition:
- BCRs recognize and bind intact antigens directly, such as soluble molecules present in the extracellular fluid or intact pathogens.
- TCRs do not recognize and bind antigen directly; instead, they recognize short peptide fragments of pathogen protein antigens that are bound to major histocompatibility complex (MHC) molecules on the surfaces of other cells.
- Function:
- BCRs are responsible for the activation of B cells, leading to clonal expansion and specific antibody production.
- TCRs are responsible for activating T cells to trigger the B cells to develop a humoral response, removing pathogens from the body.
In summary, BCRs bind intact antigens directly, while TCRs recognize short peptide fragments of pathogen protein antigens bound to MHC molecules. This difference in antigen recognition and function leads to the distinct roles of B and T cells in the immune response.
Comparative Table: B Cell Receptor vs T Cell Receptor
B cell receptors (BCRs) and T cell receptors (TCRs) are both integral membrane proteins that play crucial roles in the immune system. However, they have some key differences in their structure and function. Here is a table comparing the two:
| Feature | B Cell Receptor (BCR) | T Cell Receptor (TCR) |
|---|---|---|
| Structure | Composed of two light chains and two heavy chains, forming a transmembrane receptor protein | Composed of either an alpha/beta (αβ) or gamma/delta (γδ) heterodimer, with each chain having a variable (V) region and a constant (C) region |
| Antigen Recognition | Binds to soluble antigens freely in the extracellular space | Recognizes antigens displayed on Major Histocompatibility Complex (MHC) Class I and Class II molecules |
| MHC Interaction | BCRs do not interact with MHC molecules | TCRs interact with MHC molecules to recognize antigens |
| Antibody Production | B cells produce antibodies after being activated | T cells do not produce antibodies |
| Activation | B cells can be activated by T cell-dependent or T cell-independent mechanisms | T cells require a stimulus from antigen-presenting cells (APCs) |
| Memory | Memory B cells have an extended lifetime and help to recognize antigens to which they were previously exposed | Memory T cells have an extended lifetime and help to recognize antigens to which they were previously exposed |
Both BCRs and TCRs share some properties, such as being integral membrane proteins, possessing unique binding sites, and being encoded by genes assembled through the recombination of DNA segments.
- T Cells vs B Cells
- T Lymphocytes vs B Lymphocytes
- B Cell vs T Cell Lymphoma
- Antibodies vs T Cells
- Memory T Cells vs Memory B Cells
- B Cell vs T Cell Leukemia
- B Cells vs Plasma Cells
- T Helper vs T Cytotoxic Cells
- Internal Receptors vs Cell Surface Receptors
- CAR-T vs TCR-T
- Positive vs Negative Selection of T Cells
- T Cell Dependent vs Independent Antigens
- Naive vs Effector T Cells
- Cell Mediated vs Antibody Mediated Immunity
- Humoral vs Cell Mediated Immunity
- Immunoglobulin vs Antibody
- Endocytosis vs Receptor Mediated Endocytosis
- G Protein Coupled Receptors vs Receptor Tyrosine Kinases
- Toll-Like Receptors vs Nod-Like Receptors