Core Principles Flashcards
What are the two major roles of the immune system?
- Host defense against microbial invaders (bacteria, virus, fungi)
- Defense against harmful assaults leading to trauma (tissue damage, environmental irritants, ionizing radiation)
When facing invasion by infection, what does the immune system recognize and differentiate between?
When there needs to be wound healing or regulation of body homeostasis, what does the immune system recognize?
- Self and non-self
2. Danger signals which are self substances released from the tissue to signal damage or aberrant metabolism
What is by far the most important role of the immune system?
Defense against microbes
What is the first line of defense against immune threats?
What is the time frame?
What 2 actions does it usually involve?
When did this defense arise evolutionarily?
The innate immune system - immediate response
It usually involves:
- inflammation to sterilize the body and block the assault by “walling off” the injury
- Activates downstream host defenses including adaptive immunity
Innate immune system appeared early in evolution (amoeba)
What is the second line of defense in the immune system?
What is the time frame?
What is different between this systems sensing mechanisms from those of the first line of defense?
When did it develop evolutionarily?
- Adaptive immune system
- If microorganisms break through innate immune system, adaptive will respond but will be delayed
- The sensing mechanisms are more focused and specific
- Arose in jawed vertebrates (present in frogs and fish)
What system allows us to develop memory?
What is the benefit of memory?
The adaptive immune system allows for the development of memory and it allows us to respond more rapidly and effectively to a subsequent attack by the same invader
What genetic factor is the hallmark of the mammalian immune system?
How does it arise?
Polymorphism - variability of genes encoding immune components in different populations
It arises from selective pressures exerted by fast evolving pathogens in distinct geographical regions
What is the major consequence of of polymorphism in genes encoding immune response?
High variable pattern in how different species and different individuals within the same species respond to pathogens
What would be a negative feature of having too powerful of an immunity against foreign invaders?
There is a greater chance for “friendly fire” against “self” which can damage the host.
What percent of people in the world die of infectious disease?
1/4 or 25.9%
What were the three big infectious diseases of the past that caused global pandemics?
Smallpox, tuberculosis, plague
Even if the human immune system is healthy, what can cause it to fail?
The subversion of the microbe (adapting and mutating to enhance survival and dodge detection)
What are the top 6 infectious disease killers of 2002?
Which are caused by a single agent?
- Lower respiratory
- HIV/AIDS- single agent
- Diarrheal
- TB- single agent
- Malaria- single agent
- Measles, pertussis, tetanus
What were the three most life threatening diseases of the us in 2008?
Heart disease
Neoplasm
Lower respiratory
(influenza -8, sepsis-10)
What two major initiatives drastically reduced the prevalence of infectious disease related deaths?
- Improved sanitation
2. Vaccination programs
How many cancers are caused by the failure of the body to eradicate a virus, bacteria or parasite?
What are the three most common pathogenic causes?
1/6
Helicobacter pylori- gastric
Hepatitis B and C- liver
HPV- mainly cervical but can affect other areas (female or male)
Healthy inflammation plays a role in what three things?
- Wound healing
- Tissue regeneration
- Regulation of metabolic pathways (after pathogen induced or external trauma)
What is an immune privileged site?
Tissue that does not regenerate like the eye, brain, testes or maternal-fetal interface
So it is extra important for the immune system to work in these areas
What are the six main ways our immune system can fail?
- Immunodeficiency
- Acute inflammation and sepsis
- Chronic inflammation
- Autoinflammatory Disease
- Hypersensitivity
- Autoimmune disease
What is an immunodeficiency?
What age groups experience this and why?
What non-age related factors can cause it?
When one or more components of the immune system is absent or reduced.
Newborns/children- immaturity of the system
Elderly- immunosenescence
Diet, stress, radiation, cancer, genetics
What is the major example of pathogen acquired immunodeficiency?
What is the major example of inherited immunodeficiency?
HIV
SCID- bubble boy disease
What causes sepsis?
What can it lead to?
When an infectious organism escapes the infected tissue and spreads through blood circulation and lymphatics to overwhelm the host.
It can lead to organ dysfunction.
10th leading cause of death in the world
What causes inflammation to be chronic?
Why is chronic inflammation harmful to the host?
What two actions does it do simultaneously?
- Persistence of the pathogen in the host
- It leads to a shift in cell type at the site of inflammation and produces harmful mediators
- It destroys tissue and regenerates/scars
What are the 5 non-immunological disorders listed that may be caused by chronic inflammation?
- Atherosclerosis- immune inflammation leads to the initiation, progression and thrombotic complications
- Obesity and type 2 diabetes- excess adipose triggers inflammation
- Cancer- proliferation, survival and migration of neoplasms
- Depression- stress and alcohol activate the innate immune system
- Acute inflammation promotes muscle growth , but chronic inflammation promotes muscle loss
What is autoinflammatory disease?
What normally causes it?
How does it differ from autoimmune disease?
Autoinflammatory disease is where the innate immune system turns against self for unknown reasons (without an intruder).
It is caused by a strong genetic component and can be neonatal.
It differs from autoimmune disease because autoimmune disease is when the adaptive immune system attacks self.
What is autoimmune disease?
What are the most common in the US?
What is the cause?
Does it affect more men or women?
When the adaptive immune pathways recognize and damage self instead of “non-self”.
Hypo and hyperthyroidism, rheumatoid arthritis, vitiligo, type 1 diabetes, mult. Sclerosis, lupus, myasthenia gravis
Strong genetic influence- affects more women than men
What is hypersensitivity?
Inappropriate response to foreign or self-derived antigens that can lead to self-damage independent of the antigen
What is type 1 hypersensitivity mediated by?
What are examples of reactions?
Ig-E mediated
Respond to allergens like hay fever, asthma, food allergies
What is type 2 hypersensitivity mediated by?
What does it react to?
Antibody mediated
Responds to blood transfusions
What is type 3 hypersensitivity mediated by?
What does it respond to?
Immune complex mediated
Responds to serum sickness, SLE
What is type 4 hypersensitivity mediated by?
what can it also be called?
What does it respond to?
Cell mediated
Delayed type hypersensitivity because it takes time to develop
Graft-rejection, dermatitis, most auto-immune disorders
Which hypersensitivity is associated with autoimmune disorders?
Type 4 although there can be aspects of other types
What are the three listed examples of immunomodulatory drugs?
- Anti-inflammatory
- Immunosuppressant
- Monoclonal antibodies
What are examples of anti-inflammatories?
Aspirin, ibuprofen, Tylenol, acetaminophen, roids
When would you use an immunosuppressant drug?
Transplants and grafts (anything where there would be implication of autoimmune, auto inflammatory, or hypersensitivity)
What are the 6 current challenges listed for immunology?
- Vaccine development
- Vaccine implementation
- Treatment and prevention of rare diseases
- Transplantations (organ and marrow) and stopping rejection of grafts
- Personalized medicine to the patients specific polymorphic immune system
- Monoclonal antibody reagents for diagnosis
How many Nobel prizes have been in immunology?
What was Dr. Beutler’s prize for?
21
Activation of innate immunity regarding the dendritic cell
What bacteria caused the bubonic plague? How was it nearly eradicated?
Yersinia Pestis- essentially eradicated by improved sanitation
What type of pathogen caused smallpox?
variola virus
What observation led to Edward Jenner’s discoveries?
Milkmaids who had been infected by cowpox were not susceptible (“immune”) to smallpox outbreaks
How did Jenner test his hypothesis about acquired immunity?
He inoculated a 12 year old boy with scrapings from a cowpox lesion and the boy developed one “cowpox” at the site of the lesion.
Next, he inoculated the boy with scrapings from a smallpox lesion and found the boy did not develop the disease = acquired immunity.
What was a negative consequence of Jenner’s study?
Physicians started inoculating patients with mildly virulent smallpox with the hopes that the people would become resistant to more severe cases of the smallpox later.
Obviously, some of these patients got very severe cases.
What are the names of the smallpox and cowpox viruses?
smallpox- variola
cowpox- vaccinia
Why is cowpox able to serve as an attenuated virus of smallpox?
The have similar antigens thus making them able to elicit an adaptive response from the immune system