LEC 12/13 SPECIFIC AND NONSPECIFIC Flashcards
• Ways in which the body protects itself from
pathogens—referred to as three lines of
defense:
• The first two lines of defense are NONSPECIFIC
• The third line of defense, the immune
response, is VERY SPECIFIC
host defense mechanism
In the third line of defense, special proteins called ANTIBODIES are produced response to foreign substances called ____
antigens
are general and serve to protect the body against many harmful substances ex: innate or inborn resistance
nonspecific host defense mechanism
• In addition to the skin as a physical barrier, there are other factors
-pH and temperature of skin
-perspiration (flush out from sweatpores)
-cilia (mucociliary movement expels pathogens upwards)
-mucosal barrier/enzymes: lactoferrin
cellular and chemical factors
when indigenous microbiota prevent colonization of “new arrivals” as a result of
competition for sites and nutrients and production of lethal substances.
microbial antagonism
overgrowth of pathogens/opportunistic pathohens
superinfection
• Levels of this glycoprotein increase in response to systemic bacterial
infections; it binds to iron depriving pathogens of this viral nutrient
transferrin
• Stimulated by pyrogenic (fever-producing) substances (e.g.,
pathogens and interleukin 1 [IL-1])
• Augments host’s defenses by stimulating leukocytes, reducing
available free plasma iron
fever
• These are small antiviral proteins produced by virus-infected cells;
they prevent viruses from multiplying.
• There are three types (alpha, beta, and gamma), produced by three
different types of cells.
• These three types are induced by different stimuli (e.g., viruses,
tumors, bacteria, and foreign cells).
• Interferons are not virus-specific, but they are species-specific.
interferons
• These are small antiviral proteins produced by virus-infected cells;
they prevent viruses from multiplying.
• There are three types (alpha, beta, and gamma), produced by three
different types of cells.
• These three types are induced by different stimuli (e.g., viruses,
tumors, bacteria, and foreign cells).
• Interferons are not virus-specific, but they are species-specific.
interferons
- is a group of about 30 different proteins
found in normal blood plasma —
“complementary” to the immune system.
• Complement components interact with each
other in a stepwise manner known as the
complement cascade.
• The complement system assists in the
destruction of many different pathogens.
• Opsonization is a process by which
phagocytosis is facilitated by the deposition
of opsonins (e.g., antibodies or certain
complement fragments) onto objects (e.g.,
pathogens)
the complement system
• Plasma proteins that increase rapidly in response to infection, inflammation,
or tissue injury;
acute phase proteins
• These are chemical mediators released from many different types of cells in
the body; they enable cells to communicate with each other—within the
immune system and between the immune system and other systems of the
body.
• Some cytokines (called chemokines) are chemoattractants; they recruit
phagocytes to site
cytokines
The body responds to any local injury, irritation, microbial invasion, or bacterial toxin
by a complex series of events referred to as inflammation; the three major events in
acute inflammation are
• An increase in the diameter of capillaries, (vasodilation) which increases blood
flow to the site
• Increased permeability of the capillaries, allowing the escape of plasma and
plasma proteins
• Exit of leukocytes from the capillaries and their accumulation at the site of injury
inflammation
primary purposes of the inflammatory response are to???
• Localize an infection
• Prevent the spread of microbial invaders
• Neutralize any toxins being produced at the
site
• Aid in the repair of damaged tissue
The four major signs and symptom
