Chapter 43: The immune system Flashcards
Lysozyme
A protein that acts as an antimicrobial agent
Phagocytosis
Cell eats another cell, usually virus or some kind of antigen
Hemocyte
Travel in Hemolymph to carry out phagocytosis
Antigen
Something which causes a reaction for the body
Antigen receptor
A part of the body which detects the antigen
Epitope
The part of T or B cell which recognizes the antigen
Antibodies
Physically block antigens from moving by filling up all of their epitopes
Immunoglobulins
A protein that helps the body fight infection
Neutralization
Antibody binding to a cell to prevent it from binding to a host cell
Opsonization
The binding of antibodies to a cell signals to macrophages that they should eat the cell
Immune rejection
Immune system rejects cells from another organism, thus causing the immune system to destroy it
Antigenic variation
A virus changing its epitomes which our immune system is looking for
What are the two types of immunity and how do they differ?
Innate: Things which do not change, always looking for the same things
Adaptive: Can change according to what the body is fighting off
What is an antimicrobial peptide?
A protein released by the body which interferes with pathogen reproduction, such as Interferon
What are the similarities and differences in the innate responses of invertebrates and vertebrates? What additional defenses are unique to vertebrates?
Similarities: Outside barriers and a lined digestive system
Differences: Hemocytes (invert.), Interferons and Natural killer cells (Vert.)
What is a barrier defense?
A barrier which physically stops microbes from entering our body
What are the major types of phagocytic cells and how do they differ from one another?
Neutrophils: Most common, found in blood
Macrophages: Really large, found in lymph nodes
Eosinophils: Releases enzymes, found in mucus
Dendritic cells: Stimulate adaptive immunity, found in skin
What are the two classes of antimicrobial peptides that are unique to vertebrates?
Defensins and Cathelicdins
What is the role of mast cells in the inflammatory response?
Release histamines which causes blood vessels to dilate
What is the relationship between natural killer cells and class 1 MHC protein?
NK cells are checking body cells for Class 1 MHC proteins, if it does not have it then it is either not a body cell or a malfunctional body cell (such as cancer), in either scenario it will try to kill it
What does immunological memory mean?
Your immune system remembers pathogens through memory cells, so it knows what to do if it encounters the same pathogen once again
What are cytokines?
A protein which draws in lymphocytes to the site of release and makes them do their job
What is a B cell and how is its receptor constructed?
It is a lymphocyte that matured in the bone marrow, it has two epitopes
What is a T cell and how is its receptor constructed?
A lymphocyte which matured in the Thymus, only one epitope
How do B cells and T cells differ with respect to antigen binding?
B-cells look mostly at what is in your blood (humoral immune response) and T-cells look at other cells to see if they are body (cell-mediated immune response)
What is the role of MHC molecules in an infected cell?
It stops being there, causing it to alert NK and T-cells to the fact that it is infected
What is the difference between Class I and Class II MHC molecules?
Class 1: Found in all body cells (except blood)
Class 2: Found only in antigen presenting cells, acts as a signal to helper T-cells to show that this is an antigen presenting cell
What are four important properties of the adaptive immune system
Receptor diversity
Lack of reactivity to host cells
Cell proliferation
Immunological memory
How is it possible for each person to produce more than 1 million different B cells and 10 million different T cells when there are only ~20,000 protein-coding genes in the human genome?
It is because of gene reconfiguration, the process where two random genes in a cell are picked as the primary genes, and anything between those are deleted, leading to a ton of possibilities
What is meant by the term self-tolerance?
Won’t try to kill its own cells
What is clonal selection?
T or B-cells encounter a pathogen that it can react to, then rapidly divides into effector cells and memory cells
How do effector cells and memory cells differ?
Memory cells: Don’t act right away, there to make sure if the antigen appears again the body knows how to react, long life
Effector cells: Do the deed right there, then die shortly after
How does the secondary immune response differ from the primary immune response?
Much faster and more intense
What are the two branches of adaptive immunity?
Humoral immune response: Looks at the blood to check for pathogens
Cell-mediated immune response: Checks the body cells for infections
What is the role of the helper T cells in the humoral and cell-mediated immune responses?
It calls B and T cells to action
Which cells are primarily involved in the humoral immune response?
B-cells
Distinguish between active and passive immunity
Active: Your own immune system working to keep you safe
Passive: Immediate but for short term protection, given by somebody else
How does immunization (vaccination) protect against an infectious disease?
It gives your body a not disease causing version of the pathogen, that your body then fights off with the proper B or T cells, which then causes it to acquire memory cells for that pathogen, if the real thing ever comes around
What is the relationship between MHC molecules and the rejection of tissue grafts and transplanted organs?
Tissue grafts and transplanted organs might have different MHC molecules than what your body is looking for, so if it finds those different MHC proteins your cells will attack it
What is an autoimmune disease?
A disease which causes your body to attack its own cells
What is an immunodeficiency disease?
A disease where your immune system becomes weakened
How does HIV affect the immune system? Why is HIV difficult to eradicate?
It interferes with Helper T-cells, this means that neither of the immune responses can function properly
