Nonspecific Immunity Flashcards
What is a first line offense?
any barrier that blocks the invasion, limits access to the internal tissues of the body, not considered a true immune response because it does not involve recognition of foreign substances
What is a second line of defense?
internalized system of protective cells and fluids, acts rapidly at both the local and systemic levels once the 1st line of defense has been circumvented
What is a third line of defense?
Specific, recognizes, acquired as each foreign substance is encountered by lymphocytes
What is an example of a 1st line defense
physical barriers, chemical barriers, and genetic components
What is an example of a 2nd line defense?
Phagocytosis, inflammation, fever, antimicrobial proteins
What is an example of a 3rd line defense?
B and T cells and their effects
What do mucous membranes do?
mucous coat impedes entry and attachment of bacteria
How do mucous coats work in other parts of the body?
blinking and tear production flush the eye’s surface
constant flow of saliva carries microbes to the stomach
vomiting and defecation evacuate noxious substances from the body
Nonspecific chemical defenses
Sebaceous secretions exert an antimicrobial effect
Specialized glands of the eyelids lubricate the conjunctiva with an antimicrobial secretion
What is a lysozyme
an enzyme found in tears and saliva that hydrolyzes the peptidoglycan in the cell wall of bacteria
What leads to a loss of immunity or absence of normal immunity?
patients with severe burns are very susceptible to all kinds of infections
blockages in salivary glands, tear ducts, intestine, and urinary tract are at greater risk
Because the first line of defense is not enough, what else is required?
inflammation, phagocytosis, and specific immune responses
How does a healthy immune system work?
surveillance of the body
recognition of foreign material
destruction of entities deemed to be foreign
What are many autoimmune disorders the result of?
the immune system mistakenly attacking the body’s own tissues and organs
WBC do what as part of the 2nd and 3rd lines of defense?
Recognize between self and non-self (is central to the functioning of the immune system)
What are PAMPs?
Pathogen-associated molecular patterns: very generic, if it came in connect with a pathogen it doesn’t know its TB, but knows it has LPS (or something that doesn’t belong) like double stranded RNA
What is a pathogen-recognition receptor?
will bind and say it is foreign
What is serum used for?
essentially the same as plasma, except that it is the clear fluid from clotted blood; used in immune testing and therapy
How do neutrophils work?
React early in the inflammatory response to bacteria and other foreign materials and to damaged tissue
Phagocytosis
How do monocytes and macrophages work?
Monocytes are transformed into macrophages after they migrate out of the bloodstream and into the tissues
Process foreign substances and prepare them for reactions with B and T lymphocytes
What are the events of phagocytosis?
Chemotaxis, Ingestion, Phagolysosome formation, Destruction, Excretion
What is rubor?
redness caused by increased circulation and vasodilation in the injured tissue
What is calor?
warmth caused by the heat given off by the increased flow of blood
What is tumor?
swelling caused by fluid escaping into the tissues
What is dolor?
pain caused by the stimulation of nerve endings
Factors the elicit inflammation
trauma from infection
tissue injury or necrosis due to physical or chemical agents
specific immune reactions
What does pyogenic mean and examples
Things that are good at forming pus
streptococci, staphylococci, gonococci, and meningococci
What is a pyrogen?
substances that reset the hypothalamic thermostat to a higher setting
What are exogenous pyrogens?
products of infectious agents such as viruses, bacteria, protozoans, fungi, endotoxin, blood, blood products, vaccines, or injectable solutions
The majority of fevers are endogenous, meaning?
liberated by monocytes, neutrophils, and macrophages during phagocytosis such as interleukin-1 and tumor necrosis factor
What do interferons do?
all three IFNs can inhibit the expression of cancer genes and have tumor suppressor effects
What do IFN alpha and beta do?
stimulate phagocytes
What do IFN gamma do?
is the immune regulator of macrophages and T and B cells
Overall Stages in the Complement Cascade
initiation, Amplification and cascade, Polymerization, Membrane attack
Initiation:
C1 components bind to an initiator bound to a foreign cell
Amplification and cascade
C1 leads to C5 being cleaved and bound to the membrane
Polymerization
C5 product becomes the site for the assembly of the membrane attack complex
Membrane attack
C5 – C9 form the membrane attack complex that punctures pores in the cell membrane, leading to lysis
Classical pathway
initiated either by the foreign cell membrane of a parasite or a surface antibody
Alternative pathway
activated when components of the complement pathway recognize and bind to pathogen membranes
quicker response than the classical pathway
Lectin pathway
mannose binding proteins (lectins) must bind to mannose residues on the surface of pathogens in order for the pathway to proceed
Antimicrobial Proteins:
Iron-Binding Proteins
Humans and bacteria require iron for their enzymes
becomes a rate-limiting factor in bacterial growth
iron-binding proteins keep available iron bound so tightly that it cannot be used by bacteria
Siderophores
proteins produced by bacteria capable of scavenging iron from iron-binding proteins
bind iron more tightly than human proteins
Iron-binding Proteins
Hemoglobin: found in red blood cells
Transferrin: found in blood and tissue fluids
Lactoferrin: found in milk and saliva
Ferritin: found in every cell type
