T cells

Definition

T cells are a type of white blood cell that plays a central role in the immune response by identifying and destroying infected or cancerous cells. They originate from bone marrow but mature in the thymus, where they acquire the ability to recognize specific antigens presented by other cells, which is crucial for effective immune function and defense against pathogens.

5 Must Know Facts For Your Next Test

1. T cells are crucial for adaptive immunity, distinguishing them from innate immune responses which rely on other immune components.
2. There are several types of T cells, including cytotoxic T cells, helper T cells, and regulatory T cells, each with distinct functions in the immune system.
3. The activation of T cells requires two signals: recognition of the specific antigen via the T cell receptor (TCR) and a second signal provided by co-stimulatory molecules.
4. T cell therapy has become a significant focus in cancer treatment, harnessing the body's own immune system to target and destroy tumors.
5. Memory T cells are formed after an infection or vaccination, allowing for a faster and stronger response upon subsequent encounters with the same pathogen.

Review Questions

• How do T cells contribute to both cellular immunity and the overall adaptive immune response?
  • T cells play a vital role in cellular immunity by recognizing and eliminating infected or cancerous cells directly through cytotoxic mechanisms. Additionally, they assist in coordinating the overall adaptive immune response by activating other immune cells like B cells and macrophages through cytokine release. This dual functionality enables T cells to not only clear infections but also create a more robust and targeted immune response.
• Discuss the significance of antigen presentation in the activation of T cells and its implications for immunotherapy strategies.
  • Antigen presentation is essential for T cell activation because it ensures that T cells recognize specific antigens presented by antigen-presenting cells (APCs). This process involves MHC molecules displaying peptide fragments derived from pathogens. Understanding this mechanism has critical implications for immunotherapy strategies, as enhancing antigen presentation can improve T cell responses against tumors or infections. Therapies that manipulate APCs can boost the effectiveness of T cell-mediated treatments.
• Evaluate the impact of memory T cells on vaccine development and their role in providing long-term immunity.
  • Memory T cells are crucial for vaccine development as they provide long-lasting immunity against previously encountered pathogens. When a vaccine introduces an antigen into the body, it stimulates the formation of memory T cells that can rapidly respond to future infections with the same pathogen. Evaluating how effectively vaccines induce memory T cell responses is key in developing successful vaccines, especially in creating durable protection against diseases like influenza or COVID-19.

Related terms

Cytotoxic T cells: A subset of T cells that directly kill infected or cancerous cells by recognizing specific antigens presented on their surfaces.

Helper T cells: A type of T cell that assists other immune cells by releasing cytokines, which help coordinate and amplify the immune response.

Antigen-presenting cells (APCs): Cells that process and present antigens to T cells, initiating the T cell activation and response. Common examples include dendritic cells, macrophages, and B cells.