Old exam questions - Immunology Flashcards
(220 cards)
What are two immunological events that happen in the thymus?
- Maturation of T-cells
2. Education of T-cells - negative/positive selection
Primary lymphoid organ in cattle, what happens here
Ileocecal peyer’s patches, B cell maturation
What is a PAMP and why is it important to phagocytes?
- Pathogen-associated molecular patterns
2. PRRs on phagocytes recognize PAMPs on pathogen/foreign antigen, inducing phagocytosis
How does a dendritic cell play a role in INNATE immunity?
- Uses PRRs to recognize and phagocytize antigens
- Increases the release of cytokines, specifically chemokines (neutrophils and macrophages), to the site of invasion
One factor that makes the SECONDARY ADAPTIVE immune response “faster” than the primary
Memory cells
What is one characteristic of the antibody generated during the secondary adaptive immune response that is different from the primary response?
Increased specificity and binding affinity
What is the role of the constant region of the antibody - how does it interact and with what cells does it interact?
The constant region determines the isotope or class of antibody (which determines where it will be located and with what cells it will interact with), BUT it does not alter the antigen specificity. The Fc part of the constant region interacts with Fc receptor on effector molecules (neutrophils, NK cells) once bound to antigen.
What is the paratope of an antibody and what structures is it comprised of?
- The paratope is the antigen binding site on the antibody (binds epitope of antigen)
- It is composed of the variable regions of both the light and heavy chains
List three different characteristics that make a good antigen (increase immunogenicity)
- Size: larger molecule is better
- Increased complexity (protein>CHO>lipid)
- Foreignness of Ag: more unlike self
If an animal lacked DNA-pk, what difference would you see in B and T cell activity?
DNA-pk is responsible for creating B and T cell diversity. Without DNA-pk, expect decreased diversity, and thus, activity. Patient would be severly immunocompromised with no functional lymphocytes.
Where in the immune system does somatic hypermutation occur and what is its function?
- Secondary lymphoid organs
2. Functions in affinity maturation (increase in binding affinity)
What would happen to an animal if there was no education of T-cells in thymus?
Education of T-cells consists of positive and negative selection, where positive selection ensures T-cells are able to recognize MHC and negative selection ensures T-cells do not recognize self as foreign. Therefore, absense of education would result in auto-immunity.
ENDOGENOUS antigens are presented on which cells in the body?
All nucleated cells in the context of MHC I
EXOGENOUS antigens are presented on which cells in the body?
Only on professional APCs in the context of MHC II
Where in the cell is antigen processed if it will be presented on MHC II?
Phagolysosomes
What are two differences between a dendritic cell in the TISSUES and one that has be ACTIVATED and is in SECONDARY lymphoid organ?
- Tissues - innate, increases cytokine release
2. Secondary lymphoid organ - adaptive, interacts with B and T cell to induce immune response
In addition to the BCR, what is another part of the BCR complex and what’s its function?
- CD79
2. Generates signal following antigen binding to BCR
Why is it important that there is a second signal to activate a T-lymphocyte?
The lack of a second signal leads to tolerance, and thus auto-immunity. The second signal is considered the danger signal.
Cytotoxic T-cells have a co-receptor molecule in addition to TCR complex. What is the co-receptor and what does it recognize?
- CD8
2. MHC I
Primary lymphoid organ for T-cells in birds, what happens here
Thymus - maturation of T cells
Secondary lymphoid organ for B-cells in cattle
Lymph node
List two different ways antigens are recognized by phagocytes
- PRRs on phagocyte recognize PAMPs on pathogens
- Fc receptors on phagocytes recognize Fc region of the antibody bound to antigen
- Opsonization
What are two molecules that play a primary role in the innate immune response?
Macrophages, neutrophils, NK cells, complement
What is the main function of the variable region of the antibody?
This is the paratope, it bind the epitope of the antigen