Immunology Exam 2 Flashcards
Lymphocyte that is part of humoral immunity
B lymphocyte
Lymphocyte that is part of cell mediated immunity
T lymphocyte
These cells can recognize antigens without specific antigen receptors
Natural killer cells
Three common types of processes for B and T lymphocyte maturation
- Proliferation
- Expression
- Selection
Where antigen-independent lymphopoiesis occurs
Bone marrow
Site of maturation for B lymphocytes
Bone marrow
This CD marker signals to regulate B cell development and activation
CD19
This CD marker is thought to be involved in B cell activation
CD20
Important B cell CD Markers:
Receptor for complement breakdown component
CD21
Important B cell CD Markers:
Found on activated T and B cells; receptor for interleukin-2 (IL-2); it is a growth factor made by T cells
CD25
Important antigen that is found on all nucleated cells
MCH I
Important antigen that interacts with Th cells; is present on all stages of B lymphocytes except plasma cells
MHC II
CD marker that is found on all hematopoietic cells and is involved in activation
CD45R
Basic unit construction of an antibody contains what type and how many chains?
2 Heavy chains and 2 Light chains
Maturation sequence of a B lymphocyte
- Lymphoid stem cell
- Pro-B cell
- Pre-B cell
- Immature B cell
- Mature B cell
Also known as Pro-B Cell
Progenitor B Cell
This maturation stage of a B lymphocyte is committed to the formation of mu; the IgM heavy chain
Pro-B cell
AKA
Progenitor B Cell
During this stage of maturation of B lymphocytes the bone marrow stroll cell stimulates the lymphoid stem cell to become a B cell. This is the first recognizable cell in the B-cell line.
Pro-B cell
The formation of the mu heavy chains signal the beginning of this stage of maturation for B lymphocytes
Pre-B cell
Also known as Pre-B Cell
Preliminary B-Cell
During this stage of maturation for B lymphocytes, the cell is committed to the formation of light chains
Preliminary B-Cell
AKA
Pre-B Cell
What forms the Pre-B receptor to stimulate proliferation and further maturation?
mu heavy chains and surrogate light chains
B cell maturation:
This stage sees the completion of IgM molecule on the cells surface.
Immature B cell
B cell maturation:
In this stage of maturation, mu is no longer in the cytoplasm.
Immature B cell
B cell maturation:
In the immature B cell stage, what is the cell committed to the formation of?
IgD
about what percentage of B cells are eliminated due to self-reacting?
About 90%
If the B cells are not eliminated via apoptosis due to self-reacting, where do they go to continue maturation?
Spleen
Definition:
Cell self-destruction
Apoptosis
The B cell receptor is the co-expression of ____ and ____
IgD and IgM
TRUE OR FALSE:
IgM and IgD have the same antigen specificity
TRUE
The BCR is seen during which stage of B cell maturation?
Mature B cell
Where are plasma cells found?
Bone marrow and secondary follicles
Function of plasma cells
Production of antibodies
What is required in order for B cells to form memory cells?
Protein antigen
Produces antibodies
Plasma cell
Expression of IgM and IgD
Mature B cell
Starts forming mu chain
Pro-B cell
Antigen-dependent lymphopoiesis
Activated B cell
Expression of IgM only
Immature B cell
1st recognizable B cell
Pro-B cell
Has a long life span; found in secondary follicles
Memory B cells
Formation of IgD
Immature B cell
Starts forming lights chains
Pre-B cell
This cell produces cytokines
T helper lymphocyte
This cell kills altered cells
T cytotoxic lymphocyte
Percentage of peripheral blood lymphocytes that are B cells
10-15%
Where T cells mature
Thymus
Lymphocyte precursor for T cells
Thymocytes
Percentage of peripheral blood lymphocytes that are T cells
60-80%
What drives T cell maturation?
Chemokines
T cell marker involved in T cell acitvation
CD2
Complex of proteins that delivers the signal to T cell interior upon TCR-AGN recognition, alpha and beta chains
CD3
CD marker known as T-cell maker
CD5
This marker on T cells creates rosettes when mixed with sheep RBCs and is used to detect and identify T cells.
CD2
TRUE or FALSE:
Thymocytes lack both CD4 and CD8
TRUE
Name of the first cell in T cell maturation
Double-Negative T cells (thymocytes)
In this stage of T cell maturation, both CD4 and CD8 are expressed
Double-Positive T cells
What is completed during the Double-Positive T cells maturation phase?
CD3:TCR complex
What happens if T cells show a weak recognition of MHC 1 and peptide?
A mature CD8+ T cell forms
What happens if T cells show a weak recognition of MCH II and peptide?
A mature CD4+ T cell forms
What happens if there is no recognition by the T cell of MHC and peptide?
Apoptosis
The negative selection process for T cells determines tolerance to _____
Self
Estimated amount of T cells that are CD4
~2/3
Estimated amount of T cells that are CD8
~1/3
What activates T cells?
Antigens
Type of memory cells produced by CD4 T cells
T helper memory cells
Type of memory cells produced by CD8 T cells
T cytotoxic memory cells
Estimated percentage of CD4 cells that become T regs
5-10%
What CD markers do T regulatory cells possess?
CD4 and CD25
Purpose of T regulatory cells
Maintain self-tolerance and exert active immune suppression
Location of T cells in the lymph nodes
Paracortex
Location of T cells in the spleen
Central PALS
Location of B cells in the lymph nodes
Cortex
Location of B cells in the spleen
Marginal PALS
These cells are found mainly in the spleen and peripheral blood
Natural Killer cells
Percentage of peripheral blood lymphocytes that are natural killer cells
10-15%
TRUE or FALSE:
Natural Killer cells contain either T or B cell markers
FALSE - they generally do not have T or B cell markers
What are natural killer cells believed to be derived from?
Double Negative Thymocytes with gamma and delta chains
This cell is considered a transitional cell bridging the natural and acquired immune responses.
Natural Killer cell
This CD marker is the receptor for the Fc portion of IgG on Natural Killer cells
CD16
This CD marker is the main Natural Killer marker
CD56
This cytokine activates NK cells in to lymphokine-activated killer cells (LAK)
Interleukin-2 (IL2)
This cell kills diseased/infected and cancerous cells
Natural Killer cells
TRUE or FALSE:
Natural killer cells kill cells with reduced MCH I expression
TRUE
The ability for natural killer cells to lyse cells with reduced MHC I expression is known as
Antibody-Independent Cytotoxicity
What CD marker is used on natural killer cells for antibody-coated cells to bind to?
CD16
CD16 on natural killer cells is a receptor for which antibody class?
IgG
What other cell types can perform Antibody-dependent cytotoxicity like natural killer cells? (3)
Monocytes
Macrophages
Neutrophils
Antibody-independent cytotoxicity
Natural Killer cells
Step with CD4 and CD8
Double Positive Stage
Step with either CD4 or CD8
Mature stage
Produce cytokines when activated
T helper cell
Step with neither CD4 nor CD8
Double Negative Stage
Has CD4 and CD25 markers
T Regulatory cell
Kills diseased/infected cells when activated
Cytotoxic T cell
How often does the spleen filter our blood?
4-5 times a day
These are the backbone of T cell activation
Antigen Presenting Cells
Viral antigens that present to both CD8 and CD4 cells are known to be __________
“Cross-presenting”
All nucleated cells have what MHC class?
MHC I
These lymphocytes act against changed self-antigens (viruses, intracellular microbes, tumors)
Cytotoxic T lymphocytes AKA CTLs AKA Tc lymphocytes
TRUE or FALSE:
The initial binding of Tc cells with APCs is non-specific
TRUE
What complex and marker bind with the MHC 1?
TCR-CD3 and CD8
What toxins are released from CTLs?
Perforin and Granzymes
Purpose of perforin
Destroys cell wall
Purpose of granzymes
Apoptosis
How are activated T helper lymphs important in humoral immunity?
They help B cells produce antibodies
How are activated T helper lymphs important in cell-mediated immunity?
They help T cytotoxic cells activate
T-dependent antigens are made of ______
Protein
T-independent antigens are ____-______
Non-Protein (typically carbohydrates)
TRUE or FALSE
Non-protein antigens produce a weaker response due to no production of memory cells
TRUE
These molecules stabilize binding and allows time for the TCR to “scan” the peptide antigen
Adhesion molecules
What are the Th cell subsets?
Th1
Th2
T-Reg
This Th cell subset occurs in response to intracellular microbes (cell-mediated immunity)
Th1
This Th cell subset occurs in response to helminths and allergens (humoral immunity)
Th2
This Th cell subset exerts active immune suppression to reduce immune response to avoid chronic inflammation
T-Reg
What are the different types of T-Reg cells?
tTreg and pTreg
This T-Reg cell is thymus derived
tTreg
This T-Reg cell is peripheral derived
pTreg
T cell that deals with cell-mediated immunity
T helper 1
T cell that deals with humoral immunity
T helper 2
T cell that deals with suppressing the immune system in order to avoid overactive immune response
T reg
Cells that T regs inhibit
Th1, Th2, and APCs
This T cell enhances the activity of Tc cell, NK cells, and antigen presentation
T helper 1
This T cell enhances the activity of antibody formation, allergic response, anti-parasitic response, and antigen presentation
T helper 2
This subset of T helper cells is driven by IL-9 and is a major player in the development of allergic pathologies, especially asthma
T helper 9
This interleukin stimulates cell proliferation and is proven to prevent apoptosis
IL-9
This T helper subset is a pro-inflammatory cell
T helper 17
This T helper subset is influenced by IL-21 and IL-6 and participates in the development of antigen-specific B-cell immunity. Located in the follicular areas of lymphoid tissue
T follicular helper cell
This interleukin causes proliferation and differentiation of B cells
Interleukin-2
B cells proliferate in to:
Plasma cells and memory cells
What type of Th subset develops in response to intracellular microbes?
T helper 1
What type of Th subset develops for helminths and allergens?
T helper 2
What type of antigen is referred to as T-dependent antigen?
Protein
What type of antigen is referred to as T-independent antigen?
Carbohydrate
What is the main antibody produced during the primary immune response?
IgM
What is the secondary immune response is also known as?
Anamnestic
What is the primary antibody produced in the anamnestic immune response?
IgG
Immunogen stimulates cells expressing specific BCR or TCR
Monoclonal activators
Also known as Superantigens. Typically derived from bacteria. Bind without being processed; outside of the peptide-bind groove.
Oligoclonal activators
Superantigens can activate up to ____% of Th cells
20%
Capable of inducing cell division in high percentages of T or B cells regardless of their antigen specificities
Mitogens
What are mitogens?
Polyclonal activators
This lymphocyte activator is typically plant proteins
Polyclonal activator
Polyclonal activator of B cells
Lipopolysaccharide
