Chapter 31: Innate Host Resistance

Most pathogens need to overcome what?

-surface barriers ---> skin, mucus, epithelium

-resistance by host ---> needs to overcome the immune system

If a pathogen can cross innate AND adaptive immunity, then the pathogen can:

kill you

Nonspecific resistance is known as:

innate immunity

Specific immune response is known as:

adaptive immunity

The immune system is composed of widely distributed:

-cells

-tissues

-organs

What is the main job of the immune system?

the recognize foreign substances/microbes and act to neutralize or destroy them.

Immunity=

the ability to resist a particular disease or infection

Infection=

cells are present and replicating

Disease=

cells are present, replicating, AND causing damage

The immune system is able to attack things don't don't "look" like itself. If the immune system attacks itself, this is known as:

an autoimmune disorder

Nonspecific immune response is the first line of defense, T or F?

true

Nonspecific immune response is acquired, T or F?

false; it is acquired

Nonspecific immune response is used in resistance to a certain microbe, T or F?

false; resistance to ANY microbe

Nonspecific immune response lack memory, T or F?

true

Nonspecific immune response is quick to respond, T or F?

true

Specific immune response is acquired, T or F?

true

Specific immune response is resistance to a certain foreign agent, T or F?

true

Specific immune response lacks memory, T or F?

false; has memory

Specific immune response is quick to respond, T or F?

False; does take time to respond

What type of cells are included in innate immunity?

-epithelial barriers

-phagocytes

-dendritic cells

-plasma proteins

-NK cells

What type of cells are included in adaptive immunity?

Naïve B cells ---> becomes plasma cells ---> make antibodies

Naïve T cells ---> Effector T cells (CD4, CD8)

What are the physical barriers of the immune system? What is this a part of?

-part of the first line of defense

-skin, mucous membranes, respiratory system (mucociliary escalator)

What does the skin do in terms of immunity?

Doesn't allow things to enter

What does the mucous membranes do in terms of immunity?

-found in nose and throat

-is open to the environment

-these areas that have mucous will have epithelium; these have lysozymes/antibodies (IgA) so it can bind to the pathogen and kill it

What does the respiratory system do in terms of immunity?

-uses mucociliary to either push mucous out or swallow so pathogen cannot survive in stomach environment

-in terms of mucociliary escalator, there is cilia on membrane that have mucous on top of it and it moves things up and out

What is the most ancient primary defense mechanism in terms of innate resistance?

antimicrobial peptides and proteins

Antimicrobial peptides and proteins are amphipathic, T or F?

true

What does amphipathic mean?

having both hydrophilic and hydrophobic regions/capabilities

What are some examples of antimicrobial peptides/proteins

lysozymes, lactoferrins, and granzymes

Where are lysozymes found?

found in secretions such as tears and mucus

What does lactoferrin do? Why?

sequesters iron; we need iron for development

What do granzymes do?

causes holes in the membrane of pathogens

What are the two major types of antimicrobial peptide?

-cationic antimicrobial peptides (CAMPs)

-bacteriocins

Who makes CAMPs?

us (humans)

Who makes bacteriocins?

bacteria (flora)

Cationic peptides are produced by bacterial cells, T or F?

false; they are produced by host cells

How many classes are there in cationic peptides?

three

The first class of cationic peptides include:

cathelicidin

Cathelicidins are released into the lymph as activated always so it can immediately act on any foreign bodies, T or F?

false; they are released into the lymph as inactive protein and will only activate when needed

Cathelicidins are released as:

inactive proteins

Cathelicidins are ___ spectrum. What does this mean?

broad; means that they are not specific and can attack most pathogens (gram-positive, gram-negative, etc)

What do cathelicidins do to the pathogen?

creates holes in the membrane, causing the pathogen top leak and die.

The second class of cationic peptides include:

alpha and beta defensins

How are alpha and beta defensins released?

Released as precursor proteins

Alpha and beta defensins are not broad spectrum, T or F?

false; while more specific than 1st class and not made by everyone, they are still considered broad spectrum

Where are alpha and beta defensins found?

found in neutrophils, intestinal Paneth cells, intestinal and respiratory epithelial cells

The third class of cationic peptides include:

histatin

Where are histatins found?

found in human saliva

Are histatins are small peptides, T or F?

false, they are large peptides

What do histatins do?

they have anti-fungal activity; they are supposed to get rid of fungal infections

Why do histatins have anti-fungal activity?

b/c it's target is the mitochondria

What is the main difference between 1st and 2nd class cationic peptides?

amino sequence

Who produces bacteriocins?

normal microbiota

Bacteriocins are lethal to who?>

related species

Which type of bacteria produces bacteriocins?

gram-positive and gram-negative cells

What is the specific type of bacteriocins gram-negative bacteria make?

colicins

Colicins are known to kill:

E. coli (gram negative rods)

What is the specific type of bacteriocins gram-positive bacteria make?

Lantibiotics

What are some bacteria that produce lantibiotics?

-streptococcus

-bacillus

-staphylococcus

-lactococcus spp

Lantibiotics are known to kill:

gram-positive bacteria

What is the name of the system that helps the immune system respond?

the complement system

The complement system is composed of how many serums proteins?

over 30

How many different pathways are there in the complement system? What are they?

three

-Alternative pathway

-Lectin pathway

-Classical pathway

What are the three potential outcomes of the pathways?

-stimulating inflammatory response

-cell lysis

-opsonization

What is stimulating inflammatory response doing?

calling for backup; inflammation is good for you b/c its how the body fights off pathogens, but if its chronic inflammation, that is bad.

If a response of a pathway is cell lysis, what does this mean? How does it do this?

means that cell lyses which equals cell death; many proteins produce MAC, which is Membrane Attack Complex, and what this does is creates holes in the cell membrane, causing the cell to leak and die.

What is opsonization?

complement proteins "flag" the microorganism for phagocytosis; flagging the pathogen makes it easier and more accessible to identify via phagocytic cells

What do phagocytic cells do?

they eat pathogens

What are leukocytes?

they are the white blood cells (WBC) of the immune system

Leukocytes are only a part of innate immunity, T or F?

false; they are found in innate and adaptive immunity

All lymphocytes are leukocytes, T or F?

true

All leukocytes are lymphocytes, T o rF?

false; all lymphocytes are leukocytes, but not all leukocytes are lymphocytes.

Leukocytes are part of which kind if immunity?

both specific (adaptive) and non-specific (innate) immuntity

All leukocytes come from the same pluripotent stem cells, T or F?

true; they come from the same stem cells and will then differentiate

What are the 5 major leukocytes? Do they all do the same role in defending host or different?

-mast cells

-granulocytes

-monocytes and macrophages

-dendritic cells

-lymphocytes

each cell has a specialized role in defending host

What do mast cells cause?

allergies

Which leukocytes contain granules?

granulocytes

How many types of granulocytes are there? What are they?

3

-basophils

-eosinophils

-neutrophils

B.E.N.=

basophils, eosinophils, and neutrophils

Basophils stain what color? What dye is used?

stain bluish-black; basic dyes

What do basophils release?

vasoactive mediators

Basophils plays a role in:

development of allergies and hypersensitivities (think of sneezing and coughing ---> releasing and pushing out pathogens)

What shape is basophils nucleus?

saddle; indented

Basophils are found mainly in blood circulation, T or F?

false; found mostly in tissues

What color to eosinophils stain? What dye is used?

stain red; acidic dyes

Eosinophils defend against what types of pathogens?

protozoan and helminth parasites

What do eosinophils release?

cationic proteins and reactive oxygen metabolites

Eosinophils play a role in? Which type?

allergic reactions; type I hypersensitivity

What is the shape of a eosinophils nucleus?

indented

Eosinophils circulate in the blood stream in high number, T or F?

false; they circulate in low numbers

Neutrophils stain at:

a neutral pH

Neutrophils are highly phagocytic, T or F?

true

Neutrophils are considered the last line of defense which is why they are phagocytic, T or F?

False; they are the first line of defense

Neutrophils circulate in high numbers in the blood and never reach tissues, T or F?

false; why they do circulate in high number in the blood, they do migrate tp sites of tissue damage

How do neutrophils kill ingested microbes?

with lytic enzymes and ROS contained in granules

When neutrophils eat pathogens, they are able to do so until there are no more left, T or F? Eating pathogens causing what?

false; eating a pathogen causes death to the pathogen and themselves; this is what causes pus to form.

Place the granulocytes order of lightest stained to darkest stained:

neutrophils --> eosinophils --> basophils

Place the granulocytes in order of least found in circulation and most found in circulation:

basophils --> eosinophils --> neutrophils

Monocytes and macrophages are high phagocytic cells, T or F?

true

What are monocytes?

mononuclear phagocytic leukocytes