Infection/Bacteria/Virus/Immune Response/Tropical Disease Flashcards
(202 cards)
What cells does the common myeloid progenitor cell give rise to?
Erythrocytes, Megakeryocytes (turn to platelets), Mast Cells, and Myeloblasts
What cell gives rise to a majority of our innate immune cells?
The Myeloblast Cell
Gives rise to basophils, neutrophils, eosinophils, and monocytes (which can give rise to macrophages and dendritic cells)
What are the different Antibodies?
Immunoglobulin: G, A, M, E, D
What immunoglobulin is largest, and what is it’s function?
M- form is a pentamer
First made in immune response
Complement activation
What is the difference between MHC Class 1 and 2?
Class 1 presents to Cytotoxic T Lymphocytes (CD8) which initiates perforin and granzyme release from T cell, resulting in apoptosis of Antigen Presenting Cell.
Class 1 is found on all nucleated cells, 2 is only on dendritic cells, macrophages, B cells (APC related cells)
Class 2 presents to Helper T Cells (CD4), and the T cell will activate the APC.
What are the steps in Extravacation?
- Rolling adhesion (E and P selectins on endothelial cell (expressed after histamine exposure) form weak bond with glycoprotein on leukocyte)
- Tight Binding (Integrins on leukocyte bind ICAMs 1 and 2 on endothelium with strength)
- Diapedesis (Leukocyte/Endothelium expresses PECAM (CD31), which binds leukocyte tightly and allows for diapedesis, leukocyte releases enzymes to break down basement membrane)
- Migration (leukocyte follows chemotaxis to site of infection)
Where is the primary residence of IgA?
Found in gut, respiratory tract, tears, saliva, urogenital tract.
Which Ig is most prevalent in the blood?
IgG mainly, and some IgM
What do antibodies do?
Opsonization- Bing pathogen and “draw attention” to it
Complement activation- bind pathogen, end of an Ig can bind first enzyme in complement cascade, initiating complement and lysis
Neutralization- bind pathogen, signal for macrophage ingestion (neutralization of target)
What receptors are found on B and T cells?
B Cell Receptor
T Cell Receptor
What response would an extracellular microbe cause in humeral immune response?
B lymphocyte will become activated after encountering microbe (and T cell activates it), release antibody that will either:
- Clump the bacteria together, causing macrophage to ingest the bacteria to kill it
- Initiate Complement (Classic Ab:Ag pathway)
What response would an extracellular microbe cause in Cell Mediated Immunity?
Dendritic/macrophages may take up the pathogen, and present to Helper T Cells
CD4 cell will activate Antigen Presenting Cell causing phagocytosis of microbe.
What response would an intracellular microbe cause in Cell Mediated Immunity?
Our CD8 cytotoxic T cells will kill the infected APC after presentation by injecting perforin and Granzymes into it, causing apoptosis.
Where does an adaptive immune response happen?
In the secondary lymph nodes
When does a T cell loose its naïve status?
Once encountering a pathogen
What is the difference between Humeral Immunity and Cell-Mediated Immunity?
Humeral involved antibodies and complement
Cell-mediated involves cytokines and T cell activation
What do the two classes of MHC bind to?
MHC1 on APC- Binds CD8 Cytotoxic T cells causing apoptosis of the antigen presenting cell it is on.
MHC2 on APC- Bind CD4 T Helper Cell causing activation of the cell that is presenting the antigen. Either presenting APC (macrophage, dendritic cell), or presenting B Cell is activated.
Give a summary of the adaptive immune response.
B and T Helper cells in lymph node interact with pathogen (APC presents to T cell)
B and T Helper cells migrate to each other (parafollicular cortex)
B and Th Cell bind, and clonal expansion begins,
B cell proliferate into plasma cell (or memory cells), and will begin to make Antibodies specific to pathogen.
Th cell will clonally expand and secrete large amounts of cytokines, helping to mount an immune response
Do B cells require antigen presentation?
No, they are regarded as APCs themselves.
Where are B and T cells found in the spleen?
Both found within “White Pulp”
T Cells- Paracortical area
B Cells- Lymphoid follicles
How many types of Helper T cells are there and their basic role?
Th1- Macrophage activation
Th2- Humoral Activation
Th17- Autoimmune disease pathogenesis
Treg- Modulates immune response
What are the types of complement pathways (give brief description of initiation)?
Lectin- Serum Lectin binds mannose on pathogen
Classical- Antigen/ Antibody complexes
Alternative- C3b binding to pathogens or apoptotic tissue
What are the goals of the Complement Pathway?
Kill Pathogen
Opsonize Pathogen
Recruit inflammatory cells
How does a macrophage initiate phagocytosis?
Pattern Recognition Receptors (PRRs), typically Toll-Like Receptors, recognize/bind DAMPs and PAMPs on pathogen or dying host cell, invagination of microbe begins, and is fused with lysosome.