Chapter 8.3 Flashcards
What does humoral immunity ultimately result in?
- it ultimately results in the production of antibodies
- >it takes as long as a week for these antibodies to become fully effective after initial infection
What are the three outcomes that can occur when an antibody binds to an antigen
1)antibodies may attract leukocytes to phagocytize those antigens immediately
2) antibodies may cause pathogen to clump together or agglutinate
- >these pathogens form large complexes that can be phagocytized
3)Antibodies can block the ability of pathogens to invade tissues
What is the difference between an antigen binding to the antibody of a B cell vs a mast cell
Mast cell
- > degranulation occurs
- > exocytosis of granule contents
- > allowing the release of histamine and causing an inflammatory allergic reaction
B cell
->results in the proliferation and formation of plasma and memory cells
What holds the heavy and light chains together in an antibody?
-it is disulfide linkages and noncovalent intractions that hold the heavy and light chains together
What is the significance of the constant domain or region
- it is here that cells such as natural killer cells, macrophages, monocytes and eosinophils have receptors for
- > they bind here and then initiate that cascade
Describe the significance of having antibodies come in different type of isotopes
- different antibodies are used during different times during the adaptive immune response
- > or they can be used for different types of pathogens or for different locations in the body
What is the process where cells change the type of isotype antibody depending on the specific cytokine present?
-it is referred to as isotype switching
What is meant by the primary response in relation to B cells
- it means the first exposure to a new antigen for the B cells
- > B cells will proliferate and produce two types of cells
- > plasma cells and memory cells
- > it takes approximately seven to ten days
What is meant by the secondary response in relation to B cells
- it means the second exposure to an antigen that was already encountered before
- > the memory B cells immediately recognize it and the response is more rapid
What is meant by positive and negative selection of T cells?
Positive
- > refers to maturing cells that respond to the presentation of antigen on MHC
- > those that don’t undergo apoptosis
Negative
- > refers to the apoptosis of T cells that are self reactive
- > self reactive means that these cells target the proteins produced by the organism itself
What peptide hormone ensures the maturation of T cells
-thymosin, a peptide hormone ensures the maturation of T cells
What is the role of helper T cells? What are they also referred to as?
- helper T cells are also called CD4+ T-cells
- > they coordinate an immune response by secreting chemicals known as lymphokines
- > these chemicals are capable of recruiting other immune cells such as plasma cells, cytotoxic T cells or macrophages
Which cells are helper T cells most effective against? Remember the relationship among MHC cells and the T cell
- helper T cells interact with MHC-2 molecules, which presents exogenous antigens
- > therefore, helper T cells are most effective against bacteria, fungi and parasites
What is the role of cytotoxic T cells? Why(discuss this in relationship to MHC class molecules)? What is cytotoxic cells referred to as?
- they are referred to as CD8+ T cells
- > they are capable of directly killing virally infected cells by injecting toxic chemicals that promote apoptosis
- they respond to antigens presented by MHC-1(endogenous antigens)
- > therefore, they are most effective against viral infections
What is the role of suppressor T cells
- they are referred to as CD4
- they express a protein Foxp3
- > these cells help tone down the immune response once the infection has been adequately contained
- they also turn off self reactive lymphocytes
- > this is referred to as self-tolerance
How does B cell proliferation work?
- proliferation happens upon exposure to an antigen
- > only those B cells that bind tightly to the antigen with high affinity survive(these ones will produce the correct antibodies)
- > they then begin dividing into plasma and memory cells, resulting in clonal selection
How does helper T cells help with the removal of bacterial infections?
- they come in two cell types
- > Th1 and Th2
Th1
->activate macrophages and increases their ability to kill bacteria
Th2
->help activate B-cells and are more common with parasitic infections
What is the role of interferons in a viral infection
- the virally infected cell begins to produce interferons
- > reducing the permeability of nearby cells
- > also reduces the rate of transcription and translation in virus cells
What are self antigens? What is their purpose?
- they are proteins and carbohydrates present on the surface of every cell in the body
- they indicate to the cell that it is not threatening and that it should not be attacked
Contrast active immunity from passive immunity
Active immunity
- > the immune system is stimulated to produce antibodies against a specific pathogen
- > the exposure of the pathogen may be natural or artificial
Passive immunity
- > results from the transfer of antibodies to an individual
- > immunity is transient(lasts for a short while) because only the antibodies and not the plasma cells that produce them are given to the individual
Give examples of passive immunity
- mother feeding her infant with breast milk
- transfer of antibodies across the placenta during pregnancy
What is meant by the term hypermutation
- hypermutation is the reason it takes so long to initiate the antibody response
- > it is the process of trying to find the best match for the antigen
- > only th B cells that can bind the antigen with high affinity survive
- > the B cells that bind with high affinity undergo clonal selection
