Adaptive immunity

Definition

Adaptive immunity is a specific immune response that develops over time and involves the activation of lymphocytes, specifically T cells and B cells, in response to pathogens. This type of immunity is characterized by its ability to recognize and remember specific antigens, leading to a more effective response upon subsequent exposures to the same pathogen. Adaptive immunity plays a crucial role in long-term protection against infections and forms the basis for vaccination.

5 Must Know Facts For Your Next Test

1. Adaptive immunity is divided into two main types: humoral immunity, mediated by B cells, and cell-mediated immunity, mediated by T cells.
2. The process of clonal selection allows for the proliferation of lymphocytes that specifically recognize the invading pathogen's antigens.
3. Memory cells are generated during an adaptive immune response, allowing for a faster and stronger response if the same pathogen is encountered again.
4. Vaccination works by exposing the immune system to a harmless form of a pathogen, stimulating an adaptive immune response without causing disease.
5. Adaptive immunity takes time to develop after the initial exposure to a pathogen, usually requiring days to weeks to mount a full response.

Review Questions

• How does adaptive immunity differ from innate immunity in terms of specificity and memory?
  • Adaptive immunity is characterized by its specificity for particular antigens and its ability to create memory cells that enhance future responses to the same pathogen. In contrast, innate immunity provides a general defense against pathogens without specificity or memory. While innate immunity acts quickly upon infection, adaptive immunity takes longer to activate but results in a more robust and targeted attack against specific pathogens.
• Discuss the roles of T cells and B cells in adaptive immunity and how they interact during an immune response.
  • T cells and B cells play distinct but complementary roles in adaptive immunity. T cells are responsible for cell-mediated responses, including directly killing infected cells and helping other immune cells. B cells, on the other hand, are responsible for producing antibodies that neutralize pathogens and mark them for destruction. During an immune response, helper T cells activate B cells, which then differentiate into plasma cells that secrete antibodies. This collaboration ensures a coordinated attack against pathogens.
• Evaluate the impact of vaccinations on public health concerning adaptive immunity and herd immunity.
  • Vaccinations have a significant impact on public health by leveraging adaptive immunity to protect individuals and communities from infectious diseases. By introducing harmless forms of pathogens, vaccines stimulate an adaptive immune response that leads to the production of memory cells. When enough individuals are vaccinated, herd immunity is achieved, reducing the overall transmission of disease within the community and protecting those who cannot be vaccinated due to medical reasons. This collective immunity helps control outbreaks and can lead to the eradication of certain diseases.

Related terms

T cells: A type of lymphocyte that plays a central role in cell-mediated immunity, including the killing of infected cells and the coordination of the immune response.

B cells: A type of lymphocyte responsible for producing antibodies that neutralize pathogens and mark them for destruction by other immune cells.

antigen: Any substance that can trigger an immune response, typically a foreign protein or polysaccharide found on the surface of pathogens.