ANBI 470.3 Lecture Notes - Lecture 10: Antigen, Fibrinogen, Lysozyme
20 Jun 2018
School
Department
Course
Professor
Biotechnology and Animal Health
Overview of immune defenses:
Innate immunity
-First line of defense
-Acts within hours/days of infection
-Broad protection
-Systems that are designed to protect against all microorganisms and not designed for a specific
pathogen
Adaptive/ Acquired immunity
-Acts days/weeks following infection
-Specific to a pathogen (antibodies, cytotoxic T cells)
-Provides memory
These two function inter-dependently; innate immunity is always working and presenting the pathogens
to the adaptive immunity
Innate Immunity
Anatomical/ physical barriers
-Skin: keratinized physical barrier
-Epithelial cells/ tight junctions
opathogens cant get through tight junctions, like in the intestines
-Mucus membranes
oSaliva and tears wash it away
oMucus secretion in lungs, intestine, reproductive system (entrapment and physical
barrier to epithelium)
oCilia that lines the trachea, physically expel pathogens entrapped in mucus
Physiological barriers
-Body temperature: pathogens are designed to function at different temperature, body
temperature increases with infection to change to a less desirable temperature for pathogens
-Skin and stomach pH
oSebum from sebaceous gland
Lactic and fatty acids- skin pH between 3 & 5
Acne causing bacteria metabolize sebum
-Anti-microbial peptides
oSaliva, tears, mucus secretions
oPunch holes in the plasma membrane of bacteria and this causes bacteria to die or
inhibit replication
oKill bacteria on membrane surface
-Interferons
oSecreted by virally infected cells and induce non-viral state in neighboring cells
omore relevant with viral infections, have been used in cancer treatments, they are a
category of protein hormones that are produced by the immune cells in your body when
you are infected by a virus your cells sense this and start producing interferons which
binds to receptors on the surrounding cells and put them into a non viral state (this
shuts down protein and RNA synthesis so that viruses cannot use them to replicate)
making surrounding cells less likely to be infected
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Document Summary
Systems that are designed to protect against all microorganisms and not designed for a specific pathogen. Specific to a pathogen (antibodies, cytotoxic t cells) These two function inter-dependently; innate immunity is always working and presenting the pathogens to the adaptive immunity. Epithelial cells/ tight junctions: pathogens cant get through tight junctions, like in the intestines. Mucus membranes: saliva and tears wash it away, mucus secretion in lungs, intestine, reproductive system (entrapment and physical barrier to epithelium, cilia that lines the trachea, physically expel pathogens entrapped in mucus. Body temperature: pathogens are designed to function at different temperature, body temperature increases with infection to change to a less desirable temperature for pathogens. Skin and stomach ph: sebum from sebaceous gland. Lactic and fatty acids- skin ph between 3 & 5. Anti-microbial peptides: saliva, tears, mucus secretions, punch holes in the plasma membrane of bacteria and this causes bacteria to die or inhibit replication, kill bacteria on membrane surface.
