Cumulative Final deck from Study Guides and Case Studies Flashcards
What are the two major groups of the immune system
Innate immune cells (hours to days)
Adaptive immune cells (days to weeks)
What are the cells in the innate immune system
Neutrophils, mast cells, eosinophils, basophils, macrophages, natural killer cells
What are the immune cells in the adaptive immune system
T cells, B cells
What are the mediators of humoral vs cell-mediated immunity
Humoral: mediated by the blood/B lymphocytes
Cell-mediated: T-lymphocytes (destroy microbes)
What system is the first line of defense for the human body against invaders?
innate
What cells in the immune system are responsible for producing antibodies?
Plasma cells ( B cells)
What is the function of natural killer (NK) cells in the innate immune system?
Kill cells that are infected with viruses or other intracellular pathogens
- Perforin forms pores in membrane, granzymes enter and trigger apoptosis
What are the primary lymphoid organs?
Thymus ( t cells) and Bone marrow ( B cells)
What are the secondary lymphoid organs and what is their main function?
Spleen, Lymph nodes
Where do B cells complete their maturation
Spleen
What is required in T-cell dependent activation of B cells
Co-stimulatory signal required by T helper cell. CD40 on B cells and CD40L on T helper cells. Checks and balance system.
Where do T cells mature before migrating to secondary lymphoid organs?
Thymus
What has PAMPS
Microbial invaders have PAMPS on them and Macrophages have receptors that detect PAMPS
Which cells produce antibodies
Plasma cells
Where do plasma cells mature from
B cells
What are the 2 proteins that make up the B cell’s surface receptor
Two heavy chains and 2 light chains
What are the 2 signals a B cell must recieve for activation
Co-stimulatory signal, BCR engaged signal
Describe the antibody classes, IgM, IgA, IgG, IgE
IgM: First antibody produced, great at activating complement
IgA: Protects mucosal surfaces such as the digestive tract
IgG: Passes from mother to fetus through placenta, long lasting
igE: Involved in allergic reactions and defense against parasites
Which antibody is most abundant in the human body and protects mucosal surfaces
IgA
During class switching, which part of the antibody changes?
Fc (the constant region)
What role does class switching play on the immune response
Change in antibody class allows the immune response to be more specific to the type of infection
Explain the importance of somatic hypermutation
- Somatic hypermutation allows rearranged genes of BCr to increase affinity to cognate antigen
- introduces random mutations into the variable (Fab) region of the B cell receptor.
This process increases the affinity of the antibodies produced, allowing for stronger binding to the antigen.
B cells that produce higher-affinity antibodies are selected to survive and differentiate into plasma cells or memory B cells
True/False - The process of opsonization involves antibodies binding to a pathogen and directly killing it
False- Opsonization involves antibodies binding to a pathogen, but the antibodies do not directly kill the pathogen. Instead, they “tag” the pathogen for destruction by immune cells such as phagocytes, making the pathogen easier for these cells to engulf and destroy.
What are the 2 types of cells that B cells can differentiate into
plasma cells (secrete antibodies) and memory b cells ( long-term immunity)
What region on the antibody determines the class
the Fc region
Which region of the antibody bind to specific antigens
the Fab regions
Which antibody is The most abundant antibody in blood; provides long-term immunity and can cross the placenta.
IgG
Which antibody is Found primarily in secretions. Such as tears, saliva, and mucus, and plays a role in mucosal immunity.
IgA
Which antibody is Involved in allergic reactions and defense against parasites.
IgE
Which antibody does the complement system produce
IgM
Describe the antibodies created in a primary and secondary immune response
The primary immune response occurs where a B cell encounters an antigen for the first time. This response is complement and typically involves the production of the IgM class of antibodies.
The secondary immune response occurs upon subsequent exposure to the same antigen. It is faster, stronger, and mainly involves the production of Ag specific antibodies.
What is the germinal center for B cells after activation
the spleen (undergo further processes to improve the immune response)
Which mutation occurs in the germinal centers, and where does this mutation occur?
Somatic hypermutation, where the Fab region of the B cell receptor gets mutations ( increases affinity of antibodies produced, allows for stronger binding of the antigen)
Which B cells are selected to survive and differentiate into plasma cells or memory b cells after somatic hypermutation
B cells that produce higher- affinity antibodies
Name 3 APC’s
Dendritic cells, macrophages, B cells
Which MHC do T cells recognize
T cells do not recognize MHC I; they recognize antigens only when they are presented by MHC II.
Where do you find MHC1 vs MHC2
MHCI: presents antigens to II
MHC class II presents antigens B & T cells.
Where does the source of the antigen come from for MHC class1 vs class 2?
MHC class 1: Antigens come from intracellular infected cells (i.e. viruses)
MHC class 2: Antigens come from extraceular sources (i.e. bacteria)
MHC class 1 presents to which T cells
CD8 (cytotoxic)
MHC class 2 presents to which cells?
T cell or B cell
Which cells are the key APCs
Dendritic cells ( capture antigens and migrate to the nearest lymph node to present antigens to T cells)
Which MHC class does a dendritic cell express
Dendritic cells express both MHC class I and MHC class II molecules, allowing them to present antigens to both naive T cells and helper T cells.
A “helper T cell(CD4)” is a differentiated T cell that specifically interacts with MHC Class II molecules to activate other immune cells
A Cytotoxic T cell responds to MHC 1 (CD8)
Which signals are required for full activation of T cells
two signals are required: the first signal comes from TCR with the antigen-MHC complex, and the second signal comes from the co-stimulatory molecules (like CD28 that interacts with the B7 on the surface of APCs)
What does a T cell become if it only recieves the first signal from a TCR without co-stimulation?
Anergic- becomes unresponsive and can’t make an immune response
The majority of T cells have what kind of receptors?
Alpha Beta
Can B cells or T cells undergo somatic hypermutation?
Only B cells
Which protein on T cells is critical to receive co-stimulatory signals during activation?
CD 28
What are the 3 things that are required for T cell proliferation
MHC II & Ag bind to TCR
CD40 bind to CD40L
B7 bind to CD28
What do cytotoxic T cells release and why
Perforin and granzyme B → induce apoptosis of infected cell
A t- cell that recognizes its self-antigen will undergo:
apoptosis or anergy
What is the primary function of a T cell receptor (TCR)?
To recognize antigens presented by MHC molecules
Which protein is involved in co-stimulation during T cell activation?
CD28
What is the role of the CD4 molecule on helper T cells?
To bind to MHC Class II molecules and assist in stabilizing the TCR-MHC interaction
What is the primary role of the CD3 complex in T cell activation?
It transmits the activation signal from the T cell receptor to the cell’s nucleus
What is the primary role of the CD40 and CD40 Ligand interaction in T cell signaling?
It helps in the activation and survival of antigen-presenting cells like dendritic cells
What is the primary purpose of IL-2 and IL-2 receptor expression in T cell activation?
To stimulate the proliferation and survival of activated T cells
True/False - Traditional T cells express γδ T cell receptors.
FALSE: Traditional T cells express αβ T cell receptors. γδ T cells are a distinct, less common subset of T cells.
True/False - Naive T cells can be activated without receiving any co-stimulatory signals.
False: Naive T cells require both TCR binding to the antigen-MHC complex and co-stimulatory signals to be fully activated. Without co-stimulatory signals, they become anergic.