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
