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
