Week 6 Flashcards
What is immunity?
The ability of an organism to resist infection
What are the 2 pronged defense systems the human body employs?
Innate immunity and adaptive immunity
What is innate immunity
The non inducible and pre existing ability of the body to recognize and destroy a broad range of pathogens or their products
What does innate immunity depend on?
Depending on the virulence of the pathogen, the infectious dose, and the immune competence of the individual, innate mechanisms alone may be insufficient to eliminate the pathogen
What is adaptive immunity?
The acquired ability to recognize and destroy a specific pathogen or its products
How long does it take for an innate response to develop?
Several hours
What does innate immunity NOT require?
Previous exposure to the pathogen
How are Eukaryotes functionally similar to innate immunity?
functionally similar pathogen recognition mechanisms that lead to rapid and effective host defences
example: Fruit flys and humans use immune cells that show structural and evolutionary homology
What does Innate immunity consist of?
a) A variety of physical and chemical barriers to infection
b) Largely dependent on the activity of phagocytes
What are phagocytes
Cells that ingest, kill and digest microbial pathogens
Examples of phagocytes?
Neutrophils
Macrophages
Dendritic cells
Eosinophils
What are some cells of the innate immune system?
Mast cells, basophils, NK cells
What do mast cells/basophils do?
trigger inflammation when activated
What do NK cells do?
identify and destroy infected host cells
What are antigens?
A particular strain of pathogen or type of foreign material
How long does an adaptive response take to develop?
Several days
What increases the strength of the adaptive response?
Increase in the number of antigen-reactive lymphocytes (highly specific)
What is immune memory?
The ability of the lymphocytes to quickly respond after subsequent exposure to a previously encountered pathogen
What does adaptive Immunity consist of?
Antigen presenting cells, B lymphocytes, T lymphocytes
What do T lymphocytes/B lymphocytes do?
T lymphocytes (T cells): play a key role in initiating the adaptive
response
The B lymphocyte (B cell), also presents antigen to T cells.
What do differentiated B cells do?
Specialize in the production of antigen specific proteins called antibodies which bind the pathogen and mark it for destruction
What are epitopes
Presented antigen peptides that bind specific receptors on the surface, triggering the expression of genes that cause the lymphocytes to proliferate and differentiate
Examples of Innate (nonspecific) defences?
First line defenses
Phagocytosis
Inflammation
Complement system
Examples of Adaptive (specific) defenses?
Humoral immunity
cell mediated immunity
Antigen processing and presentation
What is normal microbiota?
Critically important for resisting pathogen infection, especially on the skin and in the mucosal tissues of the GI, resp, and reproductive tracts
How do Abx disrupt the normal microbiota composition?
nonspecifically kill harmless and even
beneficial microbes in the body, to trigger the onset of disease by opportunistic pathogens.
In what ways do resistance factors inhibit infection?
nonspecific ways
what ways can a pathogen cause disease in a host?
- General condition of the host
- Route of infection
- Susceptibility of the host
- Endothermic to Ectothermic
What is anthrax?
a disease caused by germ that lives in soil found in many specifies of animals can range from fatal blood poisoning in cattle to mild pustules of human cutaneous anthrax
What does anthrax do?
Anthrax causes a localized infection when acquired through the skin but a
lethal, systemic infection when acquired through the mucous membranes of the
lungs.
What is tissue specificity?
Most pathogens must adhere to and colonize the site of exposure to
initiate infection.
* But the organisms cannot colonize the host if the site is not compatible
with the pathogen’s nutritional and metabolic needs.
What is host specificity?
a) Pathogens that interact exclusively with members of a few closely related host species
b) Many other pathogens exhibit tissue specificity to such a degree that
they infect only a single species.
Aids & Tissue/cell infected? Pathogen?
T helper lymphocytes, HIV
Botulism & tissue/cell infected? Pathogen?
Motor end plate, Clostridium Botulinum
Cholera & tissue/cell infected? Pathogen?
Small intestine epithelium, vibrio cholerae
Dental Caries & tissue/cell infected? Pathogen?
Oral epithelium, strep, s sobrinus, s mitis
Diphtheria & tissue/cell infected? Pathogen?
Throat epithelium, Corynebacterium diphtheria
Gonorrhea & tissue/cell infected? Pathogen?
Mucosal epithelium, Neisseria gonorrhoeae
Influenza & tissue/cell infected? Pathogen?
Respiratory epithelium, influenza A and B
Malaria & tissue/cell infected? Pathogen?
Blood (erythromycin) plasmodium spp.
Pyelonephritis & tissue/cell infected? Pathogen?
Kidney medulla, proteus spp.
Soon abortion & tissue/cell infected? Pathogen?
Placenta, brucella abortus
Tetanus & tissue/cell infected? Pathogen?
Inhibitory interneuron, clostridium tetani
