BHS 316 Quiz 4
The protein molecules that display (i.e., present) lipids instead of the classical peptides are called:
CD1 proteins
The portion of the invariant chain that occupies the class II MHC groove in an endosome is called:
CLIP
The types of proteins that can be presented on a class I MHC molecule include (check all that apply):
Cellular enzymes in your own cells Proteins encoded by parasites that have infected your own cells Proteins encoded by viruses that have infected your own cells All the proteins made inside of your own cells Cellular structural proteins in your own cells
To be activated, a naïve helper T cell requires formation of the TCR-antigen-MHC complex and:
Co-stimulation by the APC displaying the antigen
HLA-DM has which functions (check all that apply):
Competes with other peptides for binging to class II MHC molecules Releases CLIP
The idea that an exogenous antigen could be displayed by a class I MHC molecule is called:
Cross presentation
What kinds of cells inspect the peptides presented on class I MHC molecules?
Cytotoxic T cells
Proteins displayed on class I MHC molecules are:
Endogenous proteins
The proteasome-TAP-class I MHC pathway displays:
Endogenous proteins
T cells can only recognize antigens that have been "presented" by an APC. Class II MHC molecules are specifically useful for antigen presentation because they: (check all that apply)
Ensure that activation of the adaptive immune system occurs when both an APC and T cell agree that a potentially dangerous invasion has occurred Are able to describe pathogens in the extracellular environment (i.e., blood, tissues) Ensure that smaller epitopes are available for "viewing" as opposed to large, folded proteins
T cells can only recognize antigens that have been "presented" by an APC. Class I MHC molecules are specifically useful for antigen presentation because they: (check all that apply)
Ensure that smaller epitopes are available for "viewing" as opposed to large, folded proteins Prevent cytotoxic T cells from killing cells that are surrounded by pathogenic debris outside the cell. Allow cytotoxic T cells to "see" proteins that are made inside an infected cell that would otherwise not be visible to the immune system. Ensure that activation of the adaptive immune system occurs when both an APC and T cell agree that a potentially dangerous invasion has occurred. Allow cytotoxic T cells to focus on cells that have been infected
The invariant chain-CLIP-HLA-DM-class II MHC pathway displays:
Exogenous proteins
A class I MHC molecule is made up of (check all that apply):
HLA protein B2-microglobulin
NKT cells (check all that apply):
Have some properties of traditional T cells and some properties of NK cells Have limited diversity of TCRs Recognize lipid antigens
On mature T cells, CD4 and CD8 co-receptors (check all that apply):
Help to stabilize the TCR-antigen-MHC interaction Strengthen the signal sent by TCRs Clip onto the MHC molecule after the ab receptor has bound to its cognate antigen
The location at which an APC and a T cell contact one another and adhesion molecules strengthen the connection is called the:
Immunological synapse
When a TCR-peptide-MHC complex forms, the upregulation of CD 40L on the surface of the helper T cell (check all that apply):
Improves the lifespan of the APC Causes the T cell to be more able to activate B cells Causes the APC to produce more CD40 proteins on its surface
The peptide that occupies the class II MHC groove to serve as a chaperone, thereby preventing endogenous proteins in the endoplasmic reticulum from binding is the:
Invariant chain or CLIP
The proteins responsible for immediate rejection of an organ transplantation are:
MHC molecules
Which statement about TCRs is false: Each individual T cell's receptor consist of either ab receptor or a gd receptor but not both types of receptors. Usually the TCRs on any specific mature T cells are identical to each other. Most mature T cells circulating in the body have gd receptors on their surface. Traditional T cells recognize both the peptide that is their cognate antigen and the MHC molecule on which the cognate antigen is presented
Most mature T cells circulating in the body have gd receptors on their surface.
Proteins that have many different variants across the human population are called:
Polymorphic
As dendritic cells leave the battle site and migrate to the lymph node, they:
Produce chemokines to recruit more immature dendritic cells (monocytes)
The component of human cells that destroy proteins is called the:
Proteasome
The primary role of a dendritic cell is to:
Serve as sentinels, collect information on invaders, and report that information by traveling to lymph nodes
Peptides fragments in the cytoplasm of human cells are taken to the endoplasmic reticulum by:
TAP transporters
The cellular component that screens for peptide fragments that have approximately the correct number of amino acids and the right kind of amino acids on their ends for presentation on a class I MHC molecule is:
TAP transporters
In traditional T cells, the TCR signaling requires that:
TCRs cluster near each other on the surface of a T cell
Dendritic cells can become activated by (check all that apply):
TNF secreted by macrophages and neutrophils Compounds secreted by cells being killed by a pathogen Pattern-recognition receptors that are on the surface of dendritic cells that recognize a pathogen directly
One way in the which the adaptive immune system differs from the innate immune system is that:
The adaptive immune system makes cells on demand in response to a specific invader, whereas the innate immune system stockpiles cells that can act individually against a variety of invaders
What feature of peptides determines which peptides can be presented by a specific class II MHC molecule?
The type of amino acids in the middle of the peptide
What feature of peptides determines which peptides can be presented by a specific class I MHC molecule?
The type of amino acids on the ends of the peptide
Activated B cells have what advantage over other APCs? (check all that apply)
They are able to concentrate antigen to make presentation more efficient They can process antigen and display in on a class II MHC molecule much more quickly than other cells
The "typical" job of proteasomes in an uninfected human cell is:
To recycle defective proteins
Each person expresses up to how many different class I MHC molecules:
6
Clonal selection can best be described as:
Activated helper T cells producing factors that upregulate their growth to focus proliferation on T cells that have recognized nvaders
Which of the following are antigen presenting cells? (check all that apply)
Activated macrophages Activated B cells Activated dendritic cells
What kinds of cells express class I MHC molecules?
Almost all human cells
Antigens that are presented by class I MHC molecules [ Select ] amino acids long, and antigens that are presented by class II MHC molecules [ Select ] amino acids long.
Answer 1: 8-9 Answer 2: 13-25
Put the following events in the activation of a helper T cell in order from beginning to end:
Answer 1: A T cell binds to the cognate antigen being presented by a class II MHC molecule Answer 2: The T cell's CD4 co-receptors clip into the class II MHC molecule of the APC, stabilizing the interaction between the T cell and APC. Answer 3: The expression of adhesion molecules on the surface of the T cell is upregulated. Answer 4: The expression of CD40L on the surface of the T cell are upregulated, increasing the ability to bind to the APC's CD40 proteins, which results in production of co-stimulatory molecules like B7 on the surface of the APC. Answer 5: The T cell and APC separate. Answer 6: The Th cells proliferate
When a Th cell becomes activated, it produces more IL-2, for which the same Th cell also has receptors. This is an example of [ Select ] that results in [ Select ].
Answer 1: A positive feedback loop Answer 2: Proliferation of daughter Th cells
Dendritic cells are [ Select ] and plasmocytoid dendritic cells are [ Select ].
Answer 1: Cells that present antigens Answer 2: Cells that produce IFNa and IFNb in response to viral attack
Put the following events in the dendritic cell life cycle in order from beginning to end:
Answer 1: Dendritic cells in tissue express low levels of MHC molecules and some B7 protein Answer 2: Dendritic cells are activated by TNF, chemical signals from dying cells, or recognition of pathogens directly by PRRs such as Toll-like receptors Answer 3: Dendritic cells increase phagocytosis to sample pathogens Answer 4: Dendritic cells quit phagocytosis and increase expression of class I and class II MHC molecules while traveling to the lymph node
Class I MHC molecules present Endogenous proteinsto [ Select ] and are displayed on [ Select ] cells, but class II MHC molecules present Exogenous proteins to [ Select ] and are displayed on [ Select ] cells.
Answer 1: Endogenous proteins Answer 2: Cytotoxic T cells Answer 3: Nearly all types of human cells Answer 4: Exogenous proteins Answer 5: Helper T cells Answer 6: Only on immune system cells
Class I MHC molecules specialize in showcasing what is happening [ Select ] a cell, and class II MHC molecules specialize in showcasing what is happening [ Select ] of a cell.
Answer 1: Inside Answer 2: Outside
[ Select ] can only recognize their cognate antigens if they are presented, but [ Select ] cells can recognize their cognate antigens if they are not presented (i.e., soluble).
Answer 1: T cells Answer 2: B cells
An individual class I MHC molecule can bind to [ Select ] type(s) of peptides; an individual antibody can bind to [ Select ] type(s) of peptides.
Answer 1: a variety of Answer 2: exactly one
Macrophages and dendritic cells both present antigen most efficiently when they have been activated by other signals suggesting an invader is dangerous. They differ in that activated macrophages [ Select ] , and activated dendritic cells [ Select ].
Answer 1: can kill cells directly and do not travel Answer 2: cannot kill cells directly and can travel
The purpose of activated macrophages presenting antigens is to [ Select ] , and the purpose of activated dendritic cells presenting antigens is to [ Select ].
Answer 1: continually stimulate experienced T cells so that they stay activated Answer 2: activate virgin T cells so they can contribute to the battle against invaders
Because helper T cells [ Select ], they need to inspect cells that [ Select ]. Therefore, helper T cells inspect antigens that are presented on [ Select ] , and helper T cells use [ Select ] as the co-receptor.
Answer 1: help activate other immune cells Answer 2: present antigens of invaders Answer 3: class II MHC molecules Answer 4: CD4
Because CTLs [ Select ] , they need to inspect cells that [ Select ]. Therefore, CTLs inspect antigens that are presented on [ Select ], and CTLs use [ Select ] as the co-receptor.
Answer 1: kill our own cells directly Answer 2: are infected Answer 3: class I MHC molecules Answer 4: CD8
Cells that can display both class I and class II MHC molecules and can provide co-stimulatory signals are called:
Antigen presenting cells
Non-traditional T cells (check all that apply):
Are most abundant in areas that are in contact with the external environment. Do not express CD4 or CD8 co-receptors
To become activated, which kind of cells need to bind to their cognate antigens and receive a co-stimulatory signal? (check all that apply)
B cells T cells
CTLs require which of the following to be activated initially (check all that apply):
Binding to its cognate antigen presented on a class I MHC molecule Co-stimulation by the APC that is presenting the antigen
TCRs from traditional T cells and BCRs are the same in which of the following ways (check all that apply):
Both have extracellular and intracellular components that allow recognition of an antigen and transmission of a signal inside the cell. The variation in receptors between different T cells are the result of a mix-and-match strategy that uses the RAG proteins.
The two-step activation process for a helper T cell includes formation of the TRC-antigen-MHC complex and co-stimulation by the APC that presents the antigen. This ensures that:
Both the T cell and the APC agree that there is an invasion