Innate immune responses act quickly, slow pathogen growth, and help contain infection. They may not eliminate a pathogen, but they buy time for the adaptive response to develop. Innate immune cells also send signals that guide adaptive immune cells toward an effective response. Together, innate and adaptive immunity form two coordinated arms of host defense.
All flashcards
What does a T-cell receptor recognize?
A T-cell receptor recognizes the combined surface of an antigen fragment and an MHC molecule.
What is positive selection of thymocytes?
A thymic process that allows cells able to recognize the body's MHC to survive.
What is clonal expansion?
The repeated division of an activated lymphocyte, increasing the number of cells with the same receptor specificity.
What is a Th2 cell's principal role?
It helps B cells differentiate into antibody-secreting plasma cells.
What do regulatory T cells do?
They suppress other T-cell responses and help limit excessive immune activity.
Quiz questions
How are many intracellular proteins prepared for presentation by MHC class I?Answer: Proteasomes degrade them, and TAP transports fragments into the endoplasmic reticulum.
How are many extracellular antigens presented by MHC class II?Answer: They are taken up into vesicles, processed, and loaded onto MHC class II.
Which activity is characteristic of dendritic cells in adaptive immune responses?Answer: They capture antigen in tissues and carry it to regional draining lymph nodes.
How can a cytotoxic T cell trigger apoptosis in a target cell?Answer: It can use Fas ligand or release perforins and granzymes.
Which immune activity is associated with Th1 cells?Answer: Regulating macrophages and other T cells to support cell-mediated responses.
Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.