Lecture 9 (innate immunity lectures) Flashcards
What type of immune cells are Natural Killer (NK) cells?
NK cells are innate lymphoid cells (ILCs).
What is the progenitor cell shared by NK cells, B cells, and T cells?
NK cells, B cells, and T cells all share a progenitor called the common lymphoid progenitor.
Are NK cells part of the innate or adaptive immune system?
NK cells are part of the innate immune system, even though they share a progenitor with B and T cells.
Where are Innate Lymphoid Cells (ILCs) and Natural Killer (NK) cells derived from?
ILCs and NK cells are both derived from the common lymphoid progenitor.
Are ILCs and NK cells antigen-specific?
No, ILCs and NK cells are not antigen-specific and provide innate immunity.
How many types of ILCs are there?
There are three types of ILCs.
What can influence the differentiation of ILCs?
Cytokines can influence the differentiation of ILCs, leading to different types of ILCs that secrete different cytokines.
Where do ILCs tend to reside and what is their role?
ILCs tend to reside in tissues and play an important role in mucosal immunity and defense against specific pathogens.
What is the primary function of NK cells?
NK cells can directly kill cells and can be found in tissues or circulation.
How do ILCs and NK cells differ in their location?
ILCs primarily reside in tissues, while NK cells can be found in both tissues and circulation.
What is the significance of the cytokine environment for ILC differentiation?
Different inducing cytokines lead to the differentiation of ILCs into distinct types, each secreting different cytokines, contributing to immune responses.
Where do Innate Lymphoid Cells (ILCs) primarily act?
ILCs primarily act in tissues, particularly in the gut mucosa.
What activates Innate Lymphoid Cells (ILCs)?
ILCs are activated by cytokines produced by dendritic cells (DCs) or other cells such as epithelial cells.
What do Innate Lymphoid Cells (ILCs) secrete and what is their role?
ILCs secrete cytokines that contribute to pathogen killing.
How does new knowledge affect our understanding of the immune system?
New knowledge constantly changes our understanding of the immune system.
Are ILC2 cells solely tissue residents?
No, ILC2 cells are not solely tissue residents; in some cases, they can travel.
What type of immune cells are NK cells and what is their role?
NK cells are lymphoid cells with innate immune functions.
What do NK cells express receptors for?
NK cells express receptors for self proteins that can be induced by infections, malignant transformations (cancer), and other stresses.
What happens when NK cells are activated?
When activated, NK cells can:
- Kill altered self cells (due to infection or tumor cells)
- Produce cytokines that induce adaptive responses against the altered self cells.
What is unique about the receptors on NK cells?
NK cell receptors are germline encoded, meaning they don’t change.
What types of receptors do NK cells have?
NK cells have activating receptors and inhibitory receptors.
What happens in a normal context when an NK cell receives signals?
- NK cell receives both activating and inhibitory signals.
- The inhibitory signal prevents activation of the NK cell, keeping it from killing target cells.
How does an NK cell respond in a disease context?
- Altered self-cell does not trigger the inhibitory receptor.
- NK cell only receives the activating signal.
- The NK cell kills the target cell using granules that trigger apoptosis (cell death).
What role do costimulatory molecules play in NK cell function?
- The exact details of costimulatory molecules are unclear, but they help balance signaling in NK cells.
- This balance determines whether the NK cell will kill a target cell or not.
How does an NK cell induce apoptosis in target cells in a disease context?
- NK cells can trigger apoptosis in target cells that express specific receptors (DR4/DR5).
- These receptors bind to TRAIL on the NK cells, activating apoptosis in the target cells.
What do NK cell receptors recognize?
NK cell receptors recognize MHC class I molecules or MHC class I-like molecules.
(MHC I molecules are expressed on all nucleated cells).
How does an NK cell respond to signals?
The NK cell has to interpret a variety of signals from its activating and inhibitory receptors.
