47-Overview of Immunology Flashcards
What is immunology?
The study of the response of an organism to microbes and allergens
Why is immunology important for clinical biology?
T cells are involved in most major pathological disorders
When was the initial description of immunity
5000 BCE in China
What did Thucydides do?
In 430 BCE first used the word immunity to describe individuals that survived the plague did not get sick again “immunological memory”
When was the 1st purposeful injection?
1000 in China “variolation”. Blew smallpox pus into noses. Variolation 2% death rate. small pox 35% death rate
What did Edward Jenner do?
Observed that milk maids didn’t get smallpox because they were exposed to cowpox. Infected the gardener’s son with cow pox and then small pox “vaccination”
What did Robert Koch do?
In 1876 proved the germ theory with the causative agent for anthrax
What did Louis Pasteur do?
1880’s developed live attenuated vaccines for chicken cholera, anthrax, and rabies
When was the germ theory developed?
1840
What did Elie Metchnikoff do?
In 1883 discovered phagocytic white blood cell ingesting pathogens “macrophages”
What did Emil von Behring do?
In 1890 identified serum of animals immune to diphtheria had antibodies
What did Shibasaburo Kitasato do?
In 1890 identified serum of animals immune to diphtheria had antibodies
What did Emile Roux do?
Worked with Behring and Kitasato to develop first anti-serum treatment for diphtheria
What is a pathogen?
Organism with ability to cause host damage
How does the immune system differentiate between pathogen and non pathogen?
It can’t. it just responds to microbes
Pathogenicity of microbe is defined by what?
The microbe and the immune response
Infection and disease are….?
Related, but distinct. You can get infected without getting a disease
What are the different types of pathogens?
Virus, Bacteria, Parasite, Worm
The immune system can respond to what external substances?
Allergens
What are the 3 main lines of defense against a pathogen?
Barriers, Innate response, Adaptive response
What are examples of barriers?
physical, chemical, microbiome
What are the types of innate response?
phagocytosis, granulocytes, inflammation, proteins
What are the types of adaptive response?
T cells, B cells/antibodies
How does a barrier fail?
wounds, defective membrane, chronic disease, malnutrition, insect bites, pathogenicity
What happens when a barrier fails?
Innate response starts
How long does it take for the innate response to start?
Minutes to hours
What is the response initiator for innate response?
broad classes of molecules
How long does it take for the adaptive response to start?
days to weeks
what is the response initiator for adaptive response?
specific antigen
What is the timing of an immune response?
Barrier is breaches, rapid activation of innate response then adaptive immune response is activated to clear pathogen. Adaptive immune cells develop into memory cells
What is required for the immune response?
both the innate and adaptive immunity
innate immune response is activated by what?
pattern recognition receptors
pattern recognition receptors are activated by what?
conserved features of pathogens (cell wall, nucleic acids, bacterial flagellin) essential for viability
examples of pattern recognition receptors:
TLR, NLR, RIG-I
What is inflammation?
hallmark of the activation of the innate immune response
how is inflammation activated?
release of inflammatory mediators
what are the five signs of inflammation?
redness (rubor) heat (calor) swelling (tumor) pain (dolor) loss of function
what are the 4 functions of inflammation?
recruit immune cells
enhance immune cell function
limit spread of infection
promote tissue repair
What are the steps of phagocytosis?
chemotaxis (movement to site of infection)
ingestion of pathogen into phagosome
formation of phagolysosome by fusing to lysosome
digestion of pathogen
release of debris that is highly inflammatory
where does t cell activation occur?
secondary lymphoid tissues
1-lymph nodes: antigens from tissues via lymph system
2-spleen: antigens from bloodstream via circulatory
3-Mucosa associated lymphoid tissues: antigens from mucosal surfaces
What is the role of the secondary lymphoid organs
localize antigen specific T and B cells with their antigen
How is the adaptive immune response activated?
antigen receptors on the surface of B and T cells
What does the T cell receptor associate with?
MHC molecules bound to specific antigen
What does the B cell receptor associate with?
free antigens
What is the hallmark of adaptive immune response?
Clonal Expansion
What is Clonal expansion?
recognition of antigen by BCR or TCR results in proliferation of the cell to increase numbers and fight infection
Explain how memory t and plasma cells respond to reinfection
1st encounter: expansion of specific T cells followed by contraction. remaining T cells differentiate into memory T cells. memory B cells and plasma cells also form
2nd encounter: Protective immunity, rapid expansion of t cells and enhanced antibody production before disease
infection years later: Immunological memory, expansion of t and b cells and increased antibody production before full blown disease occurs
