Lecture 1 Flashcards
Compare Innate and Adaptive immune responses in terms of speed, specificity, and memory
Innate Immunity:
works rapidly
has some (very little) specificity for common antigens but cannot distinguish between microbes
no memory
Adaptive Immunity:
works slowly
is highly specific
has memory (T and B cells)
what are immunogens?
antigens which can stimulate an immune response
“antigenic determinant” is another term for what?
“antigenetic determinant” is another word for an epitope (portion of an antigen)
True or False:
Each Ag has one specific epitope that can be captured and presented by antigen-presenting cells. explain
False
An Ag may have a number of different epitopes, which could all theoretically stimulate their own immune response (usually these epitopes are identifiable as coming from the same source, however)
Compare what Cell Mediated Immunity (CMI) and Humoral adaptive Immunity are controlled by.
CMI: is controlled by responses of T lymphocytes, which are Ag-stimulated, which often function in concert with Ag-presenting cells and phagocytes to kill microbes
Humoral immunity: (antigen-dependent) is controlled by the Development/maturation of B lymphocytes (effector B cells make antibodies)
What type of antigens is the CMI used to target? why is this important?
CMI attacks intracellular antigens (could be a cancer cell which isn’t a pathogen)
This eliminates reservoirs of infection (perhaps a cell filled with viruses) and kills cells that develop cancer
What exactly does an immune complex consist of?
an Antigen bound to an Antibody
give a general explanation as to how humoral immunity targets antigens
a specific and Mature B cell binds it’s cell surface receptors to an antigen.
Then effector B cells create antibodies for that antigen
Name 2 ways in which antibodies combat antigens
Neutralize the infectivity of the antigen by binding to it (sort of handcuffs it from freely conducting it’s infective processes)
Targets (opsonizes) extracellular microbes, and their toxins, for elimination via various mechanisms
Compare early innate and adaptive immune responses to pathogens
Early innate responses happen quickly and are much less specific, compared to adaptive responses (ex. phagocytes, unguided Natural killer cells, and blood complement pathways)
Adaptive immune response occurs over days to weeks and generates very specific receptors to battle the antigen (their efficiency is improved based on their memory of the antigen)
State the origin and properties (3) of Phagocytes
Originate in the bone marrow (arise from precursors that can also become mononuclear phagocytes)
properties:
destruction of microbes via phagocytosis and digestion
recruit cells to the site of infection (by secreting cytokines)
recognize activation of the immune system from microbes
State the properties of Mast cells, Basophils, and Eosinophils (treat them like one group for this flashcard)
they play a role in innate AND adaptive immune responses
The protect against helminths (multicellular pathogens) and allergic diseases
They all have cytoplasmic granules that are filled with various inflammatory and antimicrobial mediators (allows for their quick release rather than synthesizing them)
State the properties of Antigen-presenting cells (APC’s (there is a specific cell type to mention here)
B cells or resident tissue macrophages can function as APC’s but that is not their main function
Dendritic cells are a diverse group of professional APC’s that stimulate T cells to induce adaptive immune responses
What is the most abundant population of circulating WBC? describe it in terms of it’s appearance and what type of specific immune system response it is involved in.
Neutrophils and they have 3 to 5 connected lobules in their nucleus
12 to 15 micrometers in diameter
Involved in the earliest phases of inflammatory reactions
True or False:
All immunogens are antigens, however not all antigens are immunogens. Explain.
True
Some antigens do not cause an immune response and would therefore not be considered an immunogen
True or False:
All immunogens are antigens, however not all antigens are immunogens. Explain.
True
Some antigens do not cause an immune response and would therefore not be considered an immunogen
Name the origin of myeloid dendritic cells (mDC’s). Also name the 3 types of dendritic cells
mDC’s originate from monocytes
mDC’s
Plasmacytoid DC’s (pDC’s)
Langerhan’s cells (found in the epidermis of the skin)
Explain what immunopathology is
it is basically the “collateral damage” that can occur when there is an immune response to an antigen that damages the surrounding tissues (tissue remodeling occurs after this happens)
State what T cell receptors can recognize
T cell receptors can only recognize linear AA’s
Define Hapten
Hapten: a very small antigen that can bind to antibody, however it cannot initiate an immune response
Define antimicrobial peptides
antimicrobial peptides: small peptides which target pathogenic microorganisms (like viruses or parasites)
Define Complement
Complement: a system of plasma proteins that enhances (complements) the ability of Abs and phagcytic cells to clear pathogens from an organism
Define Acute phase proteins
Acute Phase Proteins: (APP’s) a large group of blood proteins whose plasma concentrations change in response to tissue injury, acute infections, burns, or inflammation
Define Cytokines (include the type(s) of immunity they are involved in)
Cytokines: cell signalling molecules (proteins) that aid in cell to cell communication in immune responses
Involved in both innate and adaptive immunity (respective types of cytokines for each system, however)
Define Chemokines
Chemokines: a subfamily of cytokines that are secreted by immune cells to induce chemotaxis in nearby cells
Define Phagocytes
Phagocytes: immune cells that can ingest and digest microbes or damaged tissues
Generally explain the cooperation that occurs between Innate and Adaptive immunity. (3 ways this cooperation occurs)
The innate immune system is an inflammatory and “decision-making stage” that evaluates if the invader is intracellular or extracellular
The innate immune system then gives instructions to the adaptive immune system via cytokines, chemokines, and cell to cell contacts
Explain the steps in the functional responses of phagocytes
Recruitment of cells to the sites of infection
Recognition of and activation by microbes
Ingestion of microbes via phagocytosis and their destruction
True or False:
activated phagocytes secrete cytokines that mediate immune responses. Explain.
True
This occurs differently, depending on the needs of the current immune response that is happening
For Neutrophils, state what stimulates their production, where they can be found, and how long they typically survive (answer for activated and nonactivated neutrophils)
the production of neutrophils is stimulated by the granulocyte colony-stimulating factor (G-CSF), which is a cytokine.
will circulate the blood for hours or a few days
after entering the tissues, neutrophils will die after 1-2 days
True or False:
Mo (resident tissue macrophages) plays a role in the adaptive immune system only. Explain.
False
Mo’s play central roles in both the innate and adaptive immunity systems
State what the purpose of M-CSF (monocyte/macrophage colony-stimulating factor) is. Describe the process that this sets in motion
it induces the rise of Mo’s (resident tissue macrophages) in the bone marrow.
Then, Mature monocytes enter the blood circulation and migrate into the tissues where they finish maturing into macrophages
Briefly describe the function of resident macrophages (Mo’s)
Mo’s fulfill tissue-specific and niche-specific functions
ex. homeostatic functions, central roles in immune surveillance, response to infection, and resolution of inflammation.
Dendritic cells are cells of ____ immunity.
innate
What are Dendritic cells potent stimulators of?
T cells, which induces adaptive immune system activity
State where mast cells are found, and give an explanation for this distribution.
mast cells are commonly found at sites in the body that are exposed to the external environment because they can sense invading pathogens there
They are also near blood vessels so that they can release mediators to attract whatever effector cell(s) is/are needed (T cells, or eosinophils, or etc)
Name the 2 major types of lymphocytes that are involved in adaptive immunity
B cells and T cells (both are lymphocytes)
In terms of what they are controlled by and their eventual outcomes, describe and compare Cellular immunity with Humoral immunity
Cell Mediated Immunity (CMI): is controlled by responses of T lymphocytes that are Ag-stimulated, which often function in concert with Ag-presenting cells and phagocytes to kill microbes
Humoral immunity (antibody dependent) involves the development/maturation of B cells that occurs mainly in the bone marrow (B for bone) This type of immunity creates soluble immunoglobulins
What interaction is critical to the development of specific immunity?
interactions between T and B cells
What is the principle defense mechanism for extracellular microbes and their toxins? why?
Antibodies, because they can bind to extracellular microbes and their toxins
(this assists in their elimination and can even slow/inhibit their infectious processes)
In Cell mediated immunity (CMI), name the 2 effector cells that are activated to destroy a microbe and how these cells accomplish this task.
T helper cells activate tissue resident macrophages to kill phagocytized microbes
Cytotoxic T cells directly destroy infected cells
What did Paul Ehrlich and Elie Metchnikoff discover respectively?
Paul Ehrlich discovered humoral immunity
Elie Metchnikoff (the dude) discovered the cellular theory of immunity
Explain the clonal selection hypothesis
prior to exposure to an antigen, a large number of different lymphocytes are created (the large number increases the chance of the immune system recognizing diverse microbes)
Basically, the immune system deems which specific lymphocyte will be most effective to combat an antigen, and then clones it
these clones make other clones and antibodies (memory and effector lymphocytes are made)
Describe the average lifespan of expanded lymphocyte clones and memory lymphocytes that are specific for the same antigen
Expanded lymphocyte clones die in a contraction phase that restores homeostasis
Memory cells persist for years, in case the antigen is encountered again
Describe the “contraction of immune response”
As we know, each time you are exposed to an antigen, your body makes more antibodies for it.
The contraction of immune response basically describes the half life of antibodies. After your body makes antibodies, and you go without exposure to the antigen, your antibody levels for it will gradually decrease over time.
Compare active and passive immunity. Which of the 2 generates immunologic memory?
Active immunity is created by a host response to a microbe or microbial antigens
Passive immunity is created by adoptive transfer of antibodies or T lymphocytes specific for a microbe
ONLY active immune responses generate immunologic memory
Briefly describe the function of B lymphocytes
B cells recognize soluble antigens and develop into antibody-secreting cells
Briefly describe the function of T helper lymphocytes
T helper cells recognize antigens on the surfaces of Ag-presenting cells and secrete cytokines in order to stimulate different mechanisms of immunity and inflammation
Briefly describe the function of Cytotoxic T lymphocytes
Cytotoxic T cells recognize antigens on infected cells (they TSA screen cells to determine if they need destroyed) and kill these cells
Helper T cells aid cytotoxic T cells
Briefly describe the function of Regulatory T cells
Regulatory T cells suppress and prevent immune responses to self antigens
(if these fail, autoimmune diseases occur)
