What is the difference between T cells and B cells?
T cells and B cells are both types of lymphocytes, crucial components of the adaptive immune system, but they function differently in defending the body against pathogens.
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Primary Function: B cells produce antibodies, proteins that bind to specific pathogens, marking them for destruction. T cells directly attack infected cells or regulate the immune response. [Reference: MD Anderson, Cleveland Clinic, Cancer Center, NCBI Bookshelf, Genome]
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Mechanism of Action: B cells mediate humoral immunity, targeting pathogens outside of cells. T cells mediate cell-mediated immunity, directly attacking infected or cancerous cells. [Reference: NCBI Bookshelf]
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Types: There are several types of T cells, including helper T cells (which coordinate the immune response), cytotoxic T cells (which kill infected cells), and regulatory T cells (which suppress the immune response). B cells differentiate into plasma cells, which are antibody factories. [Reference: Cancer Center, NCI]
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Antigen Recognition: B cells recognize antigens directly on the surface of pathogens. T cells recognize antigens presented by other cells, typically antigen-presenting cells (APCs) like macrophages. [Reference: Implicit in multiple sources discussing T-cell/B-cell function]
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Role in Immunity: Both B and T cells play essential roles in both the initial immune response and the development of immunological memory. B cell involvement leads to antibody production, providing protection against future encounters with the same pathogen. T cells are critical for initiating and controlling the entire immune response and directly eliminate infected cells. [Reference: CDC, multiple other sources]
Examples of Their Actions:
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Viral Infection: B cells produce antibodies that neutralize viruses, preventing them from infecting cells. Cytotoxic T cells directly kill cells already infected with the virus. Helper T cells coordinate the entire response. [Reference: Implicit in multiple sources]
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Bacterial Infection: B cells produce antibodies that bind to bacteria, making them easier for other immune cells to engulf and destroy. T cells help to eliminate bacteria residing within cells. [Reference: Implicit in multiple sources]
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Cancer: Cytotoxic T cells recognize and kill cancer cells. This is the basis of some advanced cancer treatments like CAR T-cell therapy. [Reference: NCI]
In summary, while both B cells and T cells are vital for adaptive immunity, B cells produce antibodies for extracellular pathogen neutralization, while T cells directly attack infected cells and regulate the immune response.
