Introduction to Immunology (Lecture 1) Flashcards
Routes of infection for pathogens
whole bunch of pathogens enter via ____ surface - can inhale, eat, or via the reproductive tract
other pathogens can enter via ____ surfaces - embrasures in skin, insect type, burrowing through outer layers of the skin
different type of immune mechanisms are active at different sites [so the route the entry is ultimately important in targeting these pathogens]
mucosal
external
Stages of an Infection
different portals of entry: droplet, inhalation, eat, get bit by things, biological vectors
once a pathogen enters (or before) > ____: pathogen attaches to internal surface/external, or directly to a cell (i.e. a virus has to attach directly to a cell)
following colonization > ____ (multiply and bypass elements of immune system) > invade and disseminate (spreading at a local site, or getting inside a cell like viruses do and spread via infected cells) > pathogen may encounter element of immune system
Outcome Pathogen \_\_\_\_ by host Pathogen completes \_\_\_\_ Pathogen leaves \_\_\_\_ Pathogen enters \_\_\_\_ Pathogen destroys the \_\_\_\_
colonization proliferate eliminated life cycle host latent state host
Stages of an infection
stages of disease > signs/symptoms experienced by patients
____ is associated with incubation period - no ____ or ____ of infection occur here
____ > earliest signs/symptoms of an infectious process [highest level of ____]
as pathogen multiplies and spreads…
____ > exhibit all of classical characteristics of what infection is supposed to be; patien will be the sickest but will not be as ____s > number of viral particles may have peaked and immune system hopefully kicked in
decline > as immune system becomes more and more active > signs and symptoms of disease diminish > host fully recovers (____)
— during decline period: instead, ____ of host may be declining > lead to chronic infection/death
colonization signs symptoms prodromal contagious
clinical
contagious
convalescent
physiolology
Factors Affecting the Outcome of an Infection
____
virulence, infectivity, distribution, vector requirement
____
genetic, immune response, age
____
hygiene, social and nutritional contexts, climate, availability of health care, vector habitat
agent
host
environment
Are all microbes harmful?
NO
The human microbiome: - the “normal flora” - microbial cells outnumber human cells by \_\_\_\_ to 1 - \_\_\_\_ in composition between and within individuals - many are \_\_\_\_; others potentially \_\_\_\_
10
variability
beneficial
pathogenic
The Human Immune System
Two components:
____ immune system
____ immune system
____ is a component of the immune system > physical barrier that protects from infection
innate - mechanisms you are ____ wtih (skin, etc.)
adaptive - more complicated, not things you are necessarily born with; develop from your experience of your ____
innate adaptive skin born exposure
The Human Immune System
Distinct types of immune responses have evolved to eliminate or prevent infections by different classes of pathogens.
innate immune = ____ response
adaptive immune = ____ response
rapid
slow
The Human Immune System
The principal mechanisms of innate and adaptive immunity
all of the mechanisms of immunity (innate/adaptive) are all relevant in the ____ region
H+N
Cells of the Immune System
cells of immune system are complex; most are derived from common cell in ____: hematopoietic SC
**HSC > can differentiate into all differetn cells that are involved in ____ and ____ immunity (any of the cells that are active in immune cell)
stem cell therapy > looking to purify the ____, and transplant/regenerate
bone marrow
innate
adaptive
HSC
Molecules of the immune system
The normal (and aberrant) activity of the immune system involves a variety of molecules that are involved in:
- recognition of potential ____
- regulation of cell growth, differentiation and activation - communication between different cell types
- ____ cells to where there are needed
- elimination of ____
- ____ of immune responses
- ____ pathology
pathogens directing pathogens down-regulation immune-mediated
Properties of Innate Immunity
- ____
- Relatively non-specific
- ____ recognition
- Invariant [no matter how often it is ____]
- ____ line of defense
- Necessary for proper function of adaptive
immunity
primitive
pattern
triggered
first
Properties of Innate Immunity
Mechanisms of Innate Immunity
- Mechanical ____ (skin, cilia)
- ____ Barriers (low pH of the gut, normal microbial flora)
- ____ Barriers (complement, interferon, lysozyme, defensins)
- ____ Barriers (neutrophils, NK cells, eosinophils, mast cells)
- ____ Barriers
barrier physiologic humoral cellular inflammatory
Adaptive Immunity
humoral - activity of ____ molecules > produced ultimately from B cells (you need cells for humoral as well)
cell-mediated immunity - ____ Cells> a cell is responsible for the inactivation/elimination of a potential pathogen
B/T cells (lymphocytes) have receptors on cell surfaces that render them specific in the context of what they’ll react against; B/T can distinguish bacterial cells, virus v. bacterial, fungus v. bacteria, etc.; in CONTRAST to the innate immune system (which is relatively ____)
antibody
T
non-specific
Adaptive Immunity
Different types of cells are involved in reactions against different types of pathogens. IMPORTANT, KNOW THIS: HumoraI responses are very important in dealing with \_\_\_\_ pathogens but not very potent in dealing with \_\_\_\_ pathogens.
Why not? How do you think living inside a cell is a good idea if the pathogen is trying to avoid antibody detection? Answer: the antibodies can't get inside the cells and can't interact with pathogens, so living inside a cell is a very sophisticated approach to avoid \_\_\_\_ by elements of humoral immunity.
On the flip side cell-mediated immunity responses are extremely important in eliminating intracellular types of pathogens. Cytotoxic T cells (someimtes called killer T cells) are very important in elimination of \_\_\_\_ infections. Helper T cells involved in variety of immune responses are also important in elimination of intracellular bacterial infections. This is where human immune system has become very sophisticated compared to a sponge. Evolution has led to development of different types of immune reactions that target distinct classes of microbial pathogens.
extracellular
intracellular
detection
viral
Lymphocyte Differentiation
Primary (or Central) Lymphoid Organs – generative tissues in which lymphocytes first express ____ and become phenotypically and functionally ____.
Secondary (or Peripheral) Lymphoid Organs – tissues where lymphocyte responses to foreign ____ are initiated and develop.
two types of lymphoid organs > primary (central) > these are responsible for the generation of lymphocytes, tissue in which lumphocyte will express receptor that will allow it to interact with antigen > will be MATURE T/B cells
–____ + ____
secondary (peripheral) > these represent where lymphocyte interacts for whatever it is specific for, and then differentiates B cells into ____, in case of T cell into helper/cytotoxic T cell > enter ciruclation and be led to area where infectious agent is located
antigen receptor
“mature”
“entities”
thymus
bone marrow
plasma cells
Lymphocyte Differentiation
HSC > bone marrow; some will differentiate into common ____; within bone marrow, some will dvelop into B cell differentiation pathway > and can eventually be activated and differentiated into plasma
differentiates into precursor that will be T - cell pathway > travel to ____ via BS > developing into cells that are helper/killer T cells
lymphoid progenitor cell
thymus
Lymphocyte Recirculation
cells recirculate through lymphatics and circulatory systems > in one of the ____ lymphoid tissues they’ll experience what they were created for
most of immune rxns for something like a dog bite occurs in the ____ nodes
secondary
axillary
Lymphocyte Recirculation
Many innate immune cells including neutrophils, basophils, eosinophils and monocytes circulate through the blood stream.
Molecules derived from pathogens are carried through the lymphatic system in either a ____ form or within ____ cells and delivered to local peripheral lymphoid tissues where they can be recognized by lymphocytes.
Unstimulated lymphocytes are not sequestered in a particular peripheral lymphoid organ; they continuously ____ through the lymphatics and peripheral lymphoid tissues “looking” for a pathogenic molecule to react against.
Once stimulated in a peripheral lymphoid tissue lymphocytes differentiate into either ____ or ____ cells that have the capacity to enter the blood stream and home to sites of infection.
soluble
dendritic
recirculate
effector
memory
Lymphocyte Recirculation
The injury stimulates an ____ immune response in the form of an inflammatory reaction that leads to the accumulation of innate immune cells and molecules at the site that serve as an initial barrier to infection.
Pathogen-associated molecules are delivered to ____ lymphoid tissues where they can stimulate specific lymphocytes that once activated can home to the site of infection and assist in elimination of the pathogen if necessary.
Collectively, these events ____ the elements of the immune system necessary to prevent or eliminate an infection at the portal of entry or site of infection.
innate
local peripheral
mobilize
Properties of Adaptive Immune Responses
rabbit has never been exposed to pathogen A
first thing to achieve > get baseline antibody (assuming it to be 0, because it is adaptive)
first find a characteristic curve leading up to day 28; not instantaneous; takes ____ days for the appearance of antibody in the serum; by day 10 the level of antibody has ____ itself (inducible)
4 weeks > can measure a ____ level of antibody in the rabbit
second exposure you see an ____ in the amount of antibody in the serum of the rabbit; dramatic difference between the two responses; eventually falls off, but not anywhere near the level it falls off after ____ (come back years later and you will still have high levels) (memory: ____ immune response remembers it has been exposed to a pathogen respond, and the second response is much more efficient)
primary exposure for B is identical to A; prior exposure to A doesn’t induce any form of memory for pathogen B (specificity)
3
maximized
low
increase
primary
adaptive
Properties of Adaptive Immunity
- Evolutionarily ____
- Extremely ____
- Defined epitope target
- Variable (“custom-made”) [____ upon repeated infection]
- Helps but not essential for innate immunity
- Second line of defense
recent
specific
improves
Immune Responses
In many situations, innate and acquired mechanisms of immunity work in ____!
synergy
Stages of an Infection
First types of immune reactions initiated: immediate types of ____ immune responses >
____period: induction of ____ innate immune responses (4-96 hr), associated with not feeling well and the recognition of micro-dissociated molecular patterns
enter the illness phase: ____ immune response is kick in; there is a ____ period during which the period is induced to react against the pathogen; as number of pathogenic cells begin to decrease, you go through decline and then follow through the ____ period
innate
prodromal early adaptive lag convalescent
Immunotherapy
“Treatment (or prevention) of disease by inducing, enhancing, or suppressing an immune response. Immunotherapies designed to elicit or enhance an immune responses are classified as ____ immunotherapies, while those that reduce or suppress are classified as ____ immunotherapies.”
Activation Immunotherapy:
- ____
- ____ Immunotherapy
- Immune ____ Therapy
- Immune ____
Suppression Immunotherapy:
- ____ Drugs
- Induction of ____ Tolerance
- ____ Immunotherapy
activation
suppression
vaccination
cancer
enhancement
recovery
immunosuppressive
immunologic
allergen
Concept of Vaccination
vaccine initiates a primary response to whatever it is you’re being vaccinated against
shot for vaccine; seeking an ____ response; after a week the levels fall off to a low level (____ throughout your blood); secondary response: active toxin and antibodies are produced in response to the toxin
secondary/tertiary response is more ____ against battling the infection
antibody
detectable
effective
Immunity
natural forms of adaptive > results via ____ or exposure to infection; or via passage of ____ from mother to a developing fetus; certain types of Ab in maternal blood stream can cross the placental barrier and get into the fetal circulation and provide immunity for a new born baby for the first ____ months after birth
artificial immunity > induce an immune response; or give someone a ____ population of antibody/T cells > one form is active immunization
certain things we cannot vaccinate against venomous bites > these toxins very rapidly affect the nervous system; cannot wait long, so you inject a preformed population of Ab molecules (aka a snake, a large animals inject with toxin) > anti-venom; very actively the ____ transfered Ab can act against the transmitted toxin
infection
antibody
six
preformed
passively
What do B and T cells actually “see”?
adaptive immune response > molecule is called an ____; on surface, inside, or secreted by pathogens
antigen
Antigens
Any substance that can interact with an immune recognition molecule (____ or the ____ antigen receptor)*.
*Immunogens – an antigen that ____ an immune response.
Although many antigens can function as immunogens, some do not. These tend to be ____ molecular weight compounds that must be linked to ____ macromolecules in order to induce an immune response.
antibody T cell induces small larger
What do B and T cells Actually “See”?
immune receptors recognize the ____ (a substructural component of it) (also called an ____)
epitope
antigenic determinant
Antigens
An antigen can be thought of as being composed of a group of ____ each of which can individually interact with an immune recognition molecule.
each antigen interacts with different types of antibodies
each diffferent epitope determines the amount of antigenic determinant specifity
REWATCH
epitopes
What Do B and T Cells Actually “See”?
Lymphocytes exhibit extremely specific cell surface receptors that interact with unique ____ components of organic molecules.
“substructural”
What goes into making an antigen immunogenic?
1. Chemical Nature
• Organic vs. Inorganic
• ____>Carbohydrates>Nucleic Acids, Lipids
2. Molecular ____
3. Structural ____
molecules can be divided into organic vs. inorganic
inorganic: ____ molecules
organic: are antigenic; there is a hierarchy to how ____ an antigen is based upon the type
proteins are the most potent form of organic molecules; followed by carbs, nucleic acids and lipids
difference between the four categories is molecular size; the ____ it is, the more potent of an antigen it becomes
most important: ____ of a molecule; the more complex, the more ____ the molecule is
proteins
size
complexity
antigenic
potent
larger
structural complexity
potent
What goes into making an antigen immunogenic?
Molecules with highly complex structures have a more ____ array of epitopes each of which has the capacity to induce a specific response
proteins and nucleic acids are both large molecules; but the difference between the two: but the protein is more ____, it has a large number of ____
diverse
complex
substructural determinants
Antigens
conformation dependent epitopes: the antibody will bind to its epitope when the protein is in its ____ form (will not bind upon ____ of the protein)
linear epitope: can bind to ____ protein, cannot bind to protein when it’s in its ____ conformation
which is most important in immediating immunity: ____ mediated epitope
____ can have antibodies that recognize linear or conformational epitopes
**receptor on surface of Tcells only recognizes ____ epitopes; Tcell surface antigen receptors are not capable of recognizing protein in its native state
native
denaturation
denatured
native
conformation
B cells
linear
What goes into making an antigen immunogenic?
1. Chemical Nature • Organic vs. Inorganic
• Proteins>Complex Carbohydrates>Nucleic Acids, Lipids
2. Molecular Size
3. Structural Complexity
4. ____
5. ____
6. Mode of ____
7. ____ Constitution of Challenged Subject
albumin; all mammals have it, if you inject with another humans albumin you won’t have an immune response; albumin with a bat you will react, a chimpanzee you won’t necessarily have an immune response (closer ____ you will probably not have an immune response)
7: vaccinated against hepB, some people will have a vigorous response, some a weak; why? ____ regulation of immune responses
the two properties that are most important are the ____ and ____
charge
foreignness
administration
genetic
evolutionarily
genetic
molecular size
structural complexity
Antigens
Virtually any molecule, including those derived from ____ entities, can function as an antigen and/or immunogen.
What are the consequences of the responses induced by different types of antigens?
- Protective
- ____
- Pathogenic
most don’t respond to allergens, but if you do you get an ____ reaction
protective against a ____ stimulus
harmless against the epitopes that aren’t important in the ____ of the molecule
____ if against an allergenic or our own tissues
non-pathogenic
harmless
allergic
microbial
bioactivity
pathogenic
Properties of Adaptive Immune Responses
- ____
- ____
- ____
- non-reactivity to ____
- ____
inducibility memory specificity self diversity
