Unit 4 Packets and Practice

What are some of the sites normally colonized by human microbiota?

Skin, Nose, Eye, Urethra, Vagina, Ear, Stomach, Oropharynx, Large intestine, and small intestine

What does the human body use to move microbes out of the respiratory tract?

Mucociliary escalator

What makes the stomach a hostile environment for microbes?

Acidic nature

How does the human body prevent bacteria from colonizing the small intestine?

(Jejunum/Ileum)

Bile from the gall bladder and pancreas increase the pH making it alkaline

How does the vagina discourage the growth of many microbes?

Acidic secretions

What are some of the benefits of a microbiome?

• Digesting food

• Synthesizing compounds - Like vitamin B 12

• Training and enhancing function of the immune system

• Interfering with colonization by pathogens by

  • competing for attachment sites

  • competing for food sources

  • synthesizing antimicrobial compounds

Describe what microbial dysbiosis is.

Dysbiosis occurs when the balance of members of the gut microbiome is altered

An organism that is part of normal microbiota but can cause infection of an immunocompromised host is called a/an _____.

Opportunistic pathogen

What are three examples of tight junctions in the human body that help keep microbes in

their place?

a. Epithelial barriers

b. Blood-brain barrier

c. Materno-fetal (placental) barrier

True/False: Bacteria can cause changes in host gene expression.

True

Compare / contrast probiotics and prebiotics

a. Probiotics – actual, living microbes

b. Prebiotics – food for microbes

c. Both can support a healthy microbiome

Phage therapy was originally used to help fight infections using bacteriophage. What are

bacteriophage again? And how would they help fight infections?

Bacteriophage are bacterial viruses and they kill bacterial cells by lysing them

Which area of the human body is NOT likely to be a site of colonization with microbiota

bacteria?

a. skin

b. mouth

c. brain

d. intestine

e. nose

brain

A bacterial species that can survive in the stomach is likely able to tolerate ________

conditions.

a. alkaline

b. basic

c. dry

d. acidic

e. neutral

acidic

Which of the following would be able to cross the blood-brain barrier under normal

circumstances?

a. bacterial cells

b. glucose molecules

c. toxin proteins

d. protozoa

e. fungi

glucose molecules

The improvement in hygiene practices over the past century has been associated with

_____.

a. increased cases of intestinal infections

b. increased cases of allergies

c. decreased life span

d. an increase in antibiotic-resistant organisms

e. increased microbiota

increased cases of allergies

Which of the following is true regarding bacteria and host hormones?

a. There are no interactions between bacteria and the host endocrine system.

b. More than 50 different types of bacteria respond to host neuroendocrine

hormones.

c. Bacteria secrete hormones that affect the confidence levels of the host.

d. It is well understood that the bacterial response to host hormones causes host cell

death.

b. More than 50 different types of bacteria respond to host neuroendocrine hormones

Why would an individual be given a fecal transplant?

a. The person has a stomach virus.

b. The person has a severe gastrointestinal bacterial illness that is not

responding to antibiotics.

c. The person is constipated.

d. The person needs a new colon.

e. The person has nausea and vomiting

The person has a severe gastrointestinal bacterial illness that is not

responding to antibiotics

What is a possible advantage to phage therapy over antibiotics?

a. Phage therapy kills a wider range of organisms.

b. Bacteria do not become resistant to phages.

c. There are more side effects to phage therapy.

d. Phages evolve while antibiotics do not.

e. There are a limited number of phages available.

phages evolve while antibiotics do not

What are the three responsibilities of a healthy, functioning immune system?

a. Surveillance of the body

b. Work together to differentiate between self and non-self

c. As well as destroy the non-self substances

The first line of defense includes…

a. Physical barriers – skin, mucosal membranes, skin secretions

b. Chemical barriers – nonspecific: lysozyme, free radicals, Salt concentration, pH

c. Human microbiota – train immune system, prevent pathogens from establishing

The second line of defense includes…

a. Phagocytic leukocytes

b. Inflammation

c. Fever

The third line of defense includes…

Specific host defenses – Lymphocytes: B cells, T cells, antibodies and memory cells

What do natural killer cells secrete and how to do they work to destroy invaders?

Perforins; poke holes in cell membranes

skin - briefly describe the components that help with protection

i. Protective layer of keratinocytes

ii. Oily substance that covers skin – sebum

iii. Acidic pH inhibits bacterial growth

iv. Microbiota – prevent colonization of pathogens

v. SALT - Skin-associated lymphoid tissue (SALT) recognizes microbes that

may slip past the physical barrier

vi. Langerhans cells (specialized dendritic cells) can phagocytize microbes

mucosal membranes - briefly describe the components that help with protection

i. Mucus coats surface and traps microbes

ii. Lysozyme – attacks peptidoglycan

iii. Lactoperoxidase – superoxide radical

iv. Mucosa-associated lymphoid tissue (MALT)

v. Gut-associated lymphoid tissue (GALT): Peyer’s patch, Tonsils, Adenoids

lungs - briefly describe the components that help with protection

. Respiratory mucociliary elevator: expel invaders with cilia movement

ii. Alveolar macrophages: Ingest and kill most bacteria, then send out messages

to the immune system

what causes redness

increased blood flow to area – vasodilation

what causes heat

increased blood flow

edema

swelling from fluid escaping into the tissues

what causes pain

stimulation of nerve endings

what causes loss of function

generally caused by the other symptoms of inflammation and/or other immune responses

what are the first leukocutes on the scene after an invasion

• macrophages

• cytokines

what are the role of cytokines

regulate immune response

How do chemokines (an example of a cytokine) work?

Form a concentration gradient for cells to follow

Examples of microbial MAMPs include:

Peptidoglycan, lipopolysaccharides, teichoic acid, flagellin, dsRNA

What are on the surface of host cells that are used to detect MAMPs?

PRRs – pattern recognition receptors

What are the benefits of a fever?

a. Inhibits growth of microbes

b. Activate immune system

Any foreign substance that stimulates a specific immune system response is called a(n):

Antigen

The blood cells that function in allergic reactions and inflammation, contain peroxidase and

lysozyme, and particularly target parasitic worms and fungi are

eosinophils

The least numerous of all white blood cells that release histamine during inflammation and

allergic reactions are

basophils

The white blood cells that comprise 20% to 30% of the circulating WBCs and are the cells that function in the body's specific immune system

Lymphocytes

The most numerous WBCs that have multilobed nuclei and are very phagocytic are

Neutrophils

The white blood cells that comprise 3-7% of circulating WBCs, are phagocytic, and can migrate out into body tissues to differentiate into macrophages

Monocytes

Substances that cause a fever are called:

Pyrogens

Microbes have markers called _____ that host cells recognize

with ____

MAMPs, PRRs

The movement of leukocytes out of blood vessels is called…

Extravasation

What cell component do defensins destroy?

Cytoplasmic membranes

Hematopoiesis is the

a. production of only red blood cells.

b. loss of blood due to hemorrhaging.

c. migration of white blood cells from the blood out to the tissues.

d. production of white blood cells, red blood cells, and platelets.

e. plugging of broken vessels to stop bleeding.

d. production of white blood cells, red blood cells, and platelets.

After loading wood into a fireplace, you realize you have gotten a splinter in your finger.

Within a short period of time, your finger is painful, red, and swollen, and is warm to the

touch. This is an example of ______.

a. nonspecific resistance

b. specific resistance

c. acquired immunity

d. adaptive immunity

e. reactive immunity

a. nonspecific resistance

Components of the first line of defense include all of the following, except:

a. the tough cell sheet of the upper epidermis of the skin.

b. the flushing action of tears and blinking.

c. nasal hairs.

d. phagocytic white blood cells.

e. the flushing action of urine.

d. phagocytic white blood cells.

when monocytes migrate from the blood out to the tissues, they are transformed by

inflammatory mediators to develop into ______.

a. macrophages

b. primary phagocytes

c. neutrophils

d. killer T cells

e. cytotoxic T cells

a. macrophages

The five classic signs and symptoms of inflammation include all of the following except ______.

a. Pain

b. Redness

c. Warmth

d. Loss of function

e. Chills

f. Swelling

e. Chills

Draw out the relationship between the following words. Also provide a short description of what they do.

a. Stem cells, Eosinophil, Basophil, Erythrocytes, Monocytes, Neutrophils, Dendritic cells,

Macrophages, Granulocytes, Agranulocytes

neutrophils

function/role: phagocytosis and release of granules to induce inflammation

agranulocyte or granulocyte: granulocyte

part of innate, adaptive, or both: innate

eosinophils

function/role: release granules to kill parasites

agranulocyte or granulocyte: granulocytes

part of innate, adaptive, or both: innate

basophils

function/role: release granules to induce inflamamation

agranulocyte or granulocyte: granulocyte

part of innate, adaptive, or both: innate

mast cells

function/role: stay in tissues; granules rich in histamine and heparin

agranulocyte or granulocyte: granulocyte

part of innate, adaptive, or both: innate

monocytes

function/role: circulate in the blood; differentiate into macrophages and dendritic cells

agranulocyte or granulocyte: agranulocyte

part of innate, adaptive, or oth: innate

macrophages

function/role: phagocytosis, inflammation, antigen presentation

agranulocyte or granulocyte: agranulocyte

part of innate, adaptive, or both: adaptive

dendritic cells

function/role: phagocytosis, inflammation, antigen presentation

agranulocyte or granulocyte: agranulocyte

part of innate, adaptive, or both: both

lymphocytes

function/role: differentiate into B and T cells

agranulocyte or granulocyte: agranulocyte

part of innate, adaptive, or both: adaptive

B cells

humoral or cell-mediated: humoral

function/role: differentiate into plasma and memory cells

plasma cells

humoral or cell-mediated: humoral

function/role: secrete antibodies

T cells

humoral or cell-mediated: cell-mediated

function/role: differentiate into helper T and cytotoxic T cells

T helper cells

humoral or cell-mediated: cell-mediated

function/role: antigen presented on MHC II binding to the TCR, CD4 - activate B cells

Cytotoxic T cells

humoral or cell-mediated: cell-mediated

function/role: antigen presented on MHC I binding to the TCR, CD8 - kill infected or abnormal cells

IgG

• Most abundant and lasts the longest

• Can be transmitted across the

placenta

• Can carry out opsonization

• Mounts a large secondary response

IgA

• Moves across mucous membranes

• Found in mucous, saliva, tears, and

breast milk

• Helps prevent pathogens from

getting past physical barriers

IgD

B-cell receptor

IgE

• Protects against parasitic worms

• Responsible for allergic reactions

IgM

Responsible for the early stages of immunity

agglutination

antibodies cause invader cells to clump together, makes it easier for phagocytes to find

opsonization

antibodies attach to invader cells and make it easier for phagocytes to ‘pick up’

neutralization

Toxins

• Some antibodies are ‘anti-toxins’ and neutralizes bacterial exotoxins

• Bind to toxin to prevent it from working

Viruses

• Antibodies bind to viral spikes to prevent it from infecting a host cell

Enzymes

• This can also happen with bacterial enzymes

• Antibodies block active site where substrates bind

What are the two main ways the third line of defense is different from the other host defense mechanisms?

specific, memory

B-cells divide to make what kinds of B cells?

• plasma cells

• regulatory B cells

• Memory B cells

T-cells divide to make what kinds of T cells?

• helper T cells

• cytotoxic T cells

• regulatory T cells

• memory T cells

Describe the relationship between an antigen and an epitope:

Epitopes are the specific binding spot on an antigen. Some antigens can have

more than one epitope.

Describe the three kinds of vaccines:

a. Killed cells / inactivated viruses

b. Attenuated cells and viruses

c. Inactivated microbial products – like toxins or proteins

Describe the structure of antibodies

Two heavy chains, two light chains. Looks like a Y. The bottom part is the

constant region, the upper part that splits in two is the variable region where

antigens bind

How is the secondary antibody response different from the primary?

a. Memory cells activated in secondary; immature B cells are activated in primary

b. More IgG produced, faster

c. Primary – IgM first, IgG second; Secondary – IgG first, IgM second

What type of cells have MHC I molecules? MHC II molecules?

a. MHC I – all nucleated cells

b. MHC II – only on APCs – macrophages, dendritic cells, B cells

List the two components TC cells secrete and their function in attacking target cells:

a. Perforins – poke holes in membrane

b. Granzymes – trigger apoptosis

Where do B and T cells mature, respectively?

a. B cells: – bone marrow

b. T cells: – thymus

Programmed cell death is called…

Apoptosis

What kinds of cells are antigen presenting cells?

Macrophages, dendritic cells, some B cells

A ___________ response is when B cells respond to a foreign body.

humoral

____ _______ response is when T cells respond to a foreign body

cell mediated

The immunoglobulin class that has a dimer form found in mucus, saliva, colostrum, and

other body secretions is

IgA

The immunoglobulin class that is the only one capable of crossing the placenta

IgG

The immunoglobulin class that has an Fc region that binds to receptors on basophils and

mast cells is

IgE

The most abundant class of antibodies in serum is

IgG

Which process involves antibodies covering surface receptors on a virus or toxin

molecule, thereby disrupting their activity?

Neutralization

Which process involves antibodies cross-linking cells or particles into large aggregates?

Agglutination

Which process involves antibodies coating microorganisms in order to facilitate

phagocytosis

Opsonization

CD4 receptors bind to MHC class ____ and CD8 receptors bind to MCH class ___

II; I

True/False – T-cell receptors can be secreted.

False

Malarial parasites spend part of their lifecycle inside red blood cells. Hypothesize why

these parasites are resistant to Tc killing during this time.

a. Red blood cells do not display MHC I.

b. Red blood cells do not display MHC II.

c. Red blood cells are too small to interact with cytotoxic T cells.

d. Malarial parasites do not contain proteins that can serve as antigens.

a. Red blood cells do not display MHC I.