3 Microbiology: Innate and Adaptive Immunity Flashcards
What is innate immunity?
Refers to the basic resistance to disease that an individual is born with.
What is adaptive immunity?
the response of ANTIGEN-SPECIFIC LYMPHOCYTES to antigen, including the development of IMMUNOLOGICAL MEMORY
Most micro organisms that encounter a healthy individual (or animal) are cleared in about how much time and by what kind of response?
usually cleared within a few days by INNATE defense mechanisms
When invading microorganisms elude the innate host defense mechanisms and persist in host, what response is enlisted?
ADAPTIVE immune response
What are the INNATE defense mechanisms?
epithelial barriers (i.e. skin)
Phagocytes
NKC (Natural Killer Cells)
What are the ADAPTIVE defense mechanisms?
B Lymphocytes —> Antibodies
T Lymphocytes —> Effector T cells
What provides the first line of defense against invading pathogens?
INNATE defense mechanisms
until an adaptive immune response develops
What are three important factors about INNATE IMMUNITY? (true all the time)
Present in ALL individuals at ALL times
does not increase exposure to a given pathogen
does not discriminate between pathogens
What are the components of INNATE IMMUNITY?
anatomic barriers (epithelial)
physiological barriers
inflammation
phagocytosis
What are the body’s first line of defense against infection?
The skin and mucous membranes
results in both MECHANICAL and CHEMICAL FACTORS
What is the skin composed of and describe them.
dermis (thick layer)
epidermis (thin layer) consists of several layers of tightly packed epithelial cells that prevent the penetration of most pathogens.
What are two ways for pathogenic organisms to get past the skin?
breaks in the skin (even small ones)
penetration by biting arthropods (introduce pathogens as they feed if they are harboring pathogenic organisms)
What are SEBACEOUS GLANDS?
they are associated with the hair follicles and produce an oily secretion called SEBUM
What is SEBUM?
consists of LACTIC and FATTY ACIDS
maintains the pH of skin between 3 AND 5
what is the pH that is inhibitory to the growth of most organisms?
between 3 and 5 (acidic)
What do mucous membranes line?
gastrointestinal, respiratory, and genitourinary tracts
What layers does the mucous membrane consist of?
epithelial layer and an underlying connective tissue layer
mucous membranes provide what kind of protection compared to the skin?
LESS protection
What are GOBLET cells?
cells in the epithelial layer of a mucous membrane that secrete a viscous fluid, mucus
What does mucus do?
prevents the tracts from drying out
entraps foreign microorganisms that enter the respiratory and gastrointestinal tracts (?genitourinary tract {female}?)
what covers the LOWER RESPIRATORY tract and why?
covered with CILIA (hairlike processes)
by moving synchronously, the cilia propel inhaled DUST and MICROORGANISMS that have become trapped in mucous, upward toward the throat to be swallowed (or coughed?)
What is another mechanical factor that prevents microbial colonization in the GENITOURINARY tract?
cleansing the URETHRA by the flow of URINE
What are NORMAL FLORA and what do they do?
they are nonpathogenic organisms that tend to colonize the epithelial cells of mucosal surfaces.
they generally outcompete pathogens for ATTACHMENT SITES on the epithelial cell surface and for necessary NUTRIENTS.
they may also secrete BACTERIOCINS that INHIBIT OR KILL INCOMING PATHOGENS. yay :)
What are the physiologic barriers that contribute to innate immunity?
temperature
pH
oxygen tension
various soluble factors (eg, complement proteins)
How does TEMPERATURE contribute to innate immunity?
many species are not susceptible to certain diseases due to the fact that their body temperature inhibits pathogen growth.
What causes a FEVER and what is its purpose?
The most frequent cause is infection from bacteria (and their toxins especially ENDOTOXIN) or viruses.
it inhibits the growth of some pathogens.
How does low pH (acidity) help protect the body from infections, and where does it come from?
Comes from gastric juices created by the stomach.
the pH ranges from 1.2-3 and it destroys many viruses, bacteria and most bacterial toxins.
What is mixed in gastric juice?
hydrochloric acid
enzymes
mucus
What is one reason newborns are susceptible to some diseases that do not affect adults?
Their stomach contents are less acidic than that of adults
How can enteric pathogens enter the body?
They are protected by FOOD PARTICLES and MILK and can enter the intestines via the GI tract
How does OXYGEN TENSION protect the body?
Inhibits the growth of obligate anaerobes, especially in the lungs, where oxygen tension is very high
How does IRON-BINDING PROTEINS help protect the body?
proteins in the blood such as TRANSFERRINS, inhibit bacterial growth by reducing the amount of available iron.
How does too much iron affect the body?
It suppresses chemotaxis and phagocytosis.
It is needed by bacterial for the synthesis of CHYOCHROMES and certain ENZYMES therefore increases the risk of infection
What is the purpose of LYSOZYME and where are they found?
It cleaves the PEPTIDOGLYCAN LAYER of bacterial cell wall, rendering the bacterial cell susceptible to OSMOTIC LYSIS.
It is a HYDROLYTIC ENZYME found in MUCOUS SECRETIONS, TEARS, NASAL SECRETIONS, BLOOD, etc.
What does INTERFERONS do to cells?
It compromises a group of proteins produced by VIRUS-INFECTED CELLS.
They bind to neighboring cells and induce a generalized ANTIVIRAL STATE.
What is the COMPLEMENT SYSTEM?
is a group of blood proteins that circulate in an INACTIVE PROENZYME state.
These proteins can be activated by a variety of mechanisms that convert the INACTIVE PROENZYMES INTO ACTIVE ENZYMES.
Damage to membrane of pathogenic organism (LYSIS) or Facilitates PHAGOCYTOSIS (through chemotaxis)
The activated complement components participate in what?
In a controlled enzymatic cascade that results in damage to the membranes of pathogenic organisms, either destroying the pathogens or facilitating their clearance via phagocytosis.
What is the process INFLAMMATORY RESPONSE?
Tissue damage caused by a wound or by invasion by a pathogenic microorganism induces the sequence of events that concentrates the cells of the immune system and their products at the site of the injury or infection.