End of Chapter 17 Microbiology
Which two CDs are most significant?
CD4 and CD8
What sort of CD do you find on T helper cells? Therefore, what is another name for T helper cells?
CD4, AKA CD4+
What sort of CD fo you find on T cytotoxic cells? Therefore, what is another name for T cytotoxic cells?
CD8, AKA CD8+ cells
What can a T cytotoxic (Tc) cell differentiate into?
CTL
How are natural killer cells different from CTLs?
CTLs recognize specific antigens on MHC sites in order to respond to an infection NK cells do not require an MHC I antigen to be activated
Which molecules located on the surface of T cells aid in their classification?
Clusters of differentiation
Which of these three APCs are the principal APCs to induce immune response by T cells?
Dendritic cells
The cytokines produced by TH17 cells stimulate what and where are they mostly situated?
IL17, important for inflammatory response, help stimulate neutrophils, and targets extracellular pathogens (bacteria, fungi)
The cytokines produced by TH2 cells are mostly involved in which processes?
IL4, important in allergic reactions, help stimulate mast cells, basophils, and eosinophils
The recognition of antigens by a T cell requires that they be first processed by what types of cells?
Antigen presenting cell (APC) and MHC antigen-complex on cell surface. B cells, dendritic cells, and activated macrophages are important for T cell activation.
What are endogenous antigens and how are they made?
Antigens that are synthesized within our cells (viruses, viral proteins, cancerous surface proteins)
What are the three main types of APCs
B cells, T helper, and dendritic cells
What are natural killer cells?
Big leukocytes that destroy any weird looking cells (viral infection, cancerous, and damaged cells) Work by secreting perforins and granzymes, inducing apoptosis They are non-specific They don't need to be activated, no MHC I antigen
What is the second signal for activation?
APC and T helper cells secrete a co-stimulatory molecule that finally activate a T helper cell
Why is the immune system of older individuals relatively weak?
APCs do not present the MHC antigen-complexes on their surface as efficiently as younger individuals. Therefore, their T cells can't be activated.
How is a T helper cell activated?
Activated by the MHC II antigen-complex that's being presented on the APC (B cell, macrophages, or dendritic cells)
What is the primary function of Treg cells?
Control autoimmunity, differentiate self from nonself, keep us from attacking our cells, suppress T cells against self
T cytotoxic cells are not capable of attacking; they need to first differentiate into which type of cell?
Cytotoxic T lymphocytes or CTL
The cytokines produced by TH1 cells are mostly involved in which process?
Gamma interferons, important in activating macrophages and attacking intracellular bacteria and protozoa
What are clusters of differentiation (CD)?
Glycoprotein found on surface of T cells They are important for attachment (bc they are receptors) They are different on different types of T cells
Once pores have been made in the target cell, which enzymes can enter through the pore?
Granzymes
How do Treg cells help protect good intestinal flora?
Protect intestinal bacteria required for digestion
How are Treg cells helpful during pregnancy?
Keep our immune system from attacking the fetus
The CTL recognizes endogenous antigens on the target cell's surface that are in combination with what type of MHC molecule?
MHC I complex bound to endogenous antigen
When the CTL attacks the target cell, what does it release?
Perforins
What is perforin and what does it do to the target cell?
Pore forming protein that punches holes on the target cell membrane
What is apoptosis
Programmed cell death
WHat do CTLs recognize and kill?
Responsible for recognizing our cells and kill self cells altered by infection (viral infection, cancerous)
What type of cells contain MHC class I molecules on their cell surface?
Self-cell surface
Treg cells are a subset of which T cells; what differentiates them from CD4+T helper cells?
Subset of CD4+ cells Carry additional CD15 molecule
What is the first signal for activation?
T cell receptor will bind to antigen on the MHC II antigen-complex
What are the three main categories of T cells?
T helper cells T cytotoxic cells (can differentiate into cytotoxic T lymphocyte or CTL) T regulatory cells (AKA T suppressor cells)
T helper cells produce cytokines and differentiate into which 3 cell types
TH1, TH2, and TH17
What are granzymes and what do they do?
They are Proteases (destroy protein) go into cell's cytoplasm and destroy the proteins and induce apoptosis in the infected cell
Which cells do natural killer cells target for destruction?
Tumors and virally infected cells
