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Life Processes B > Week 16 > Flashcards

Week 16 Flashcards

1
Q

What is an effective immune response?

A

An effective immune response is essential for the survival of all animals. Vertebrate immune systems consist of two types of response: adaptive and innate.

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2
Q

What is an innate response?

A

The first investigation assesses the anti-microbial properties of lysozyme, an enzyme which is part of the innate immune response and is found in saliva and chicken egg albumen.

The microbes used in this investigation are two bacterial species and it will be necessary to use good microbiology practice, which is explained on the next page.

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3
Q

What is an adaptive response?

A

The second experiment investigates agglutination of red blood cells caused by the interaction between specific antibodies and antigens.

The ABO blood group system in humans can be used to demonstrate this interaction and, as you will learn in the practical, this immune response can have serious consequences for blood donation (you can read about bloodgroups in the Campbell textbook on p.334 and pp.1121-1122).

In preparation for the practical you will need to understand good microbiology practice, how to use a compound microscope and spectrophotometer, and understand how to make a dilution series.

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4
Q

What are the two types of responses?

A

Innate

Adaptive

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5
Q

In experiment 2 how do we create the different concentrations?

A

To create the different concentrations, a serial dilution is set up by diluting a specified volume several times with a liquid, known as the diluent.

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6
Q

The first dilution in a 10-fold-dilution series has been made with 1 ml of an undiluted sample added to 9 ml of diluent. What is the next step?

A

Add stopper and mix 1st dilution.

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7
Q

After mixing the first dilution what is the next step in this dilution series?

A

In a dilution series, the next step is to mix the correct volume of the 1st dilution with the correct volume of diluent.

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8
Q

In a linear dilution series, after mixing the 1st dilution what is the next step?

A

In a linear dilution series, the next step is to mix the correct volume of undiluted sample with the correct volume of diluent.

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9
Q

What may a problem in logarithmic dilution series?

A

errors in one dilution will affect that concentration and all preceding dilutions.

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10
Q

Why is a Spectrophotometer used?

A

In experiment 1, this will be used to assess lysis (breaking open) of bacterial cells by various substances, including lysozyme.
A mixture containing the bacterial cells will be added to a cuvette and placed in the spectrophotometer.
Absorbance will decrease as cells are lysed and you will need to take readings at set time intervals.
It is important to set the absorbance to zero before each assay using a reference solution.

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11
Q

Why are adjustable pipettes used?

A

Make sure you are confident using the pipettes to measure small volumes.
Use the correct size pipette for the volume you are pipetting and check the tip is fitted properly.
Also, ensure you push the plunger to the first stop when filling the pipette and push to the second stop when ejecting the fluid.

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12
Q

Why is a compound microscope used?

A

In this practical you will use the compound microscope to view blood cells on microscope slides.
Remember to set up the eye pieces, light source, and condensor diaphragm at the beginning, and start with the lowest magnification objective.
If the objective is changed, adjust the fine focus and condensor diaphragm to ensure a clear view.
You will also be preparing temporary microscope mounts of the blood samples being assessed in experiment 2.

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13
Q

What is the purpose of the following?

Purified lysozyme -

PBS buffer-

Chicken egg albumen -

Escherichia coli suspension -

Micrococcus lysodeikticus suspension -

Blood samples

Blood serum sample

A

Purified lysozyme - A solution of lysozyme, an enzyme that digests peptidoglycan in bacterial cell walls, hence causing cell lysis.

PBS buffer- Phosphate buffered saline. This is an isotonic solution, which buffers changes in pH and thus maintains a constant pH. It is used in this experiment to resuspend bacterial cells.

Chicken egg albumen - This is egg white, which is largely composed of the protein albumen. It contains large quantities of lysozyme, which destroys bacteria that might infect the developing embryo.

Escherichia coli suspension - E. coli, a common enteric bacterium (found in the gut), suspended in PBS buffer. E. coli is a Gram negative bacterium and has a cell wall composed of a thin layer of peptidoglycan covered by LPS (lipopolysaccharide).

Micrococcus lysodeikticus suspension - M. lysodeikticus, a common environmental bacterium, suspended in PBS buffer. M. lysodeikticus is a Gram positive bacterium and has a thick cell wall made of layers of peptidoglycan.

Blood samples - two samples of red blood cells are used in experiment 2, each of a different blood group.

Blood serum sample - the red blood cells have been removed from the blood by clotting, leaving the serum, which contains antibodies.

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14
Q

Acceptance of cells with self antigens is known as immunological _____.

A

Blank 1: tolerance

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15
Q

Autoimmune diseases occur in what percent of the population?

A

About 8%

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16
Q

Autoimmune disease is due to the failure of ______.

A

immunological tolerance

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17
Q

For a pathogen to successfully infect a host, it must ______.

A

evade specific defenses

reproduce

evade nonspecific defenses

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18
Q

Which requires yearly vaccinations due to the changing nature of its surface antigens?

A

Influenza

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19
Q

Immunological tolerance is lack of response to ______.

A

self cells

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20
Q

The gradual accumulation of mutations in the NA and/or HA proteins of the influenza virus is known as antigen ______. In contrast, the sudden appearance of a new subtype of influenza virus in which the NA and/or HA proteins are completely different is referred to as antigen _____.
.

A

Blank 1: drift

Blank 2: shift

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21
Q

Choose the correct statements about autoimmune diseases.

A

More than 2/3 of those afflicted are female.

More than 80 known or suspected autoimmune diseases exist

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22
Q

The H5N1 virus

A

causes bird flu.

is an example of antigen shift.

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23
Q

The failure of immunological tolerance causes _____

diseases.

A

Autoimmune

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24
Q

The malaria-causing organism that evades the host’s immune system by changing expressed surface proteins throughout its life cycle belongs to the genus ____

A

Blank 1: Plasmodium

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25
Q

To establish a productive infection, a pathogen must evade the ____ and ____
immune systems of the host.

A

Blank 1: specific, adaptive, or acquired

Blank 2: nonspecific or innate

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26
Q

Because of the tendency of the virus to change its surface antigens, yearly vaccinations are needed for

A

Blank 1: influenza or flu

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27
Q

Select all that apply-

What happens when an influenza virus experiences antigenic shift?

The NA antigen may change.
The population is more resistant to infection.
Only the HA antigen changes.
A sudden new subtype appears.

A

A sudden new subtype appears.

The NA antigen may change.

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28
Q

Salmonella typhimurium evades host defenses by alternating between the expression of two ____
proteins.

A

flagellar

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29
Q

Select all that apply

Regarding H1N1,

A

it is very infectious.

it can reach pandemic levels, as, for example, in 2009.

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30
Q

What age group is the most frequent victim of malaria?

A

African children under the age of 5

31
Q

Neisseria bacteria evade the host’s immune system by secreting ______, enzymes that degrade Ig_____ antibodies.

A

proteases

A

32
Q

HIV mounts a direct attack on TH cells by binding to the ____ protein on the cell surface.

A

CD4

33
Q

Mycobacterium has evolved to be able to ______

within macrophages.

A

Blank 1: reproduce, multiply, divide, replicate, or survive

34
Q

Select all that apply

Which of the following statements about early HIV infection are true?

TH count drops steadily.
Cytotoxic T cells eliminate infected cells.
The level of HIV in the serum increases dramatically.
Antibodies can control the infection.

A

Cytotoxic T cells eliminate infected cells.

Antibodies can control the infection.

35
Q

Two common causes of death in AIDS patients are a lung infection caused by _____ jiroveci and a rare cancer known as ______
‘s sarcoma.

A

Pneumocystis

Kaposi

36
Q

For the year 2013, the World Health Organization estimates that the greatest number of people living with AIDS are in

A

Blank 1: Africa

37
Q

How do Neisseria bacteria evade the host’s immune system?

A

Secretion of proteins that degrade the host’s IgA

38
Q

Select all that apply

Which of the following describe an HIV infection?
HIV gains entry to host cells via phagocytosis.

The progression of the infection can be tracked by TH cell count.

Cells that express CD4 are targeted.

TH cells are the only cells that are infected.

A

The progression of the infection can be tracked by TH cell count.

Cells that express CD4 are targeted.

39
Q

HIV infections are characterized by which of the following?

A

In the advanced stages of the infection, HIV kills TH cells more rapidly than they can divide.

The HIV genome can be found in a latent form inside of some TH cells.

40
Q

Select all that apply

Which of the following can cause death in patients with an advanced HIV infection?

A

Kaposi’s sarcoma

Pneumocystis jiroveci

41
Q

Select all that apply

AIDS-causing HIV is transmitted through ______.

A

semen

internal body fluids

blood

42
Q

What is the fatality rate of AIDS, if left untreated?

A

Close to 100%

43
Q

What is an allergy?

A

1 in 6 suffer from an allergy
Inappropriate immune response to self or harmless antigens
e.g. pollen, food, dust mites
Normally we develop tolerance to self or harmless antigens.
• removal of T and B cells that recognise self or harmless antigens
• many aspects of the development of tolerance are not understood – complex
regulatory systems are involved

44
Q

How is an allergy tackled?

A

Development of allergic response
1. Antigen recognition leads to production of IgE antibodies.
2. IgE binds to mast cells via the Fc region.
3. When two adjacent IgE molecules bind antigen, the mast cell is triggered to
release histamine.
4. Histamine triggers capillary permeability, bronchoconstriction leading to
typical symptoms runny nose, sneezing, wheezing…

45
Q

Relate these to their functions?

Natural killer cells
T helper cells
Cytotoxic T cells
B cells

A

Natural killer cells- Lysis of virally infected cells and
tumour cells
T helper cells -Release cytokines and growth
factors that regulate other
immune cells
Cytotoxic T cells- Lysis of virally infected cells and
tumour cells
B cells -Secretion of antibodies

46
Q

Innate versus adaptive

immunity

A

Innate immune system-

  • Rapid (minutes to hours)
  • Evolutionary old
  • Relatively non-specific
  • No specific memory
  • Mostly driven by myeloid cells

Adaptive immune response

  • Slower (days)
  • Found only in vertebrates
  • Highly specific
  • Highly specific memory
  • Driven by lymphoid cells
47
Q

Living organisms interact both with their _____ ______ and _____- external and internal environment. Species include _____, _____, _____which are not all beneficial to us.

A

own species
others
bacteria, fungi, parasites

48
Q

There are two types of immune response in animals:

What are these?

A

Innate immunity and adaptive/acquired immunity

49
Q
  1. Innate immunity
A

These responses are:

  • Rapid
  • Non-specific- always follow the same pattern, not pathogen specific
  • Do not improve on repeated contact with the invading organism

Innate immune system- is something that you will have in your bloodstream but also in your tissue- includes white blood cells.

Innate immunity

Innate immunity is found in all animals.
Invertebrates, e.g. insects (>50% of all known species), are extremely successful organisms occupying a vast range of habitats.
Most invertebrates are believed to have only innate immunity and it’s the vertebrates that you find these adaptive immune systems.
They have a wide range of parasites - therefore innate immunity by itself must be an effective way to combat these invaders.

50
Q
  1. Adaptive / acquired immunity
A
  • specific
  • slow – can take several days to take an effect
  • acquired responses not encoded in the germline (not genetic)
  • result from genetic rearrangements of genes involved in recognition
  • a specific receptor for each invading organism is selected from a randomly-created repertoire of receptors- when there is a match that can be replicated.

Adaptive system includes things like B/T cells. Things that are much more adaptive.

51
Q

The major steps of immunity:

A

Barriers –Skin( includes external and internal skin), mucosa
Alarms –Macrophages, tissue response
First responders–Neutrophils- plentiful white blood cell.
Messengers–Dendritic cells, macrophages
Adaptive response-
Surveillance and coordination - T cells
Ongoing defensive measures - B cells and antibody

52
Q

Essential components of an immune system include:

A

Recognition
Cell surface receptors to discriminate between self and non-self ( considered as alarming)- they have to recognise something.

Disposal
Make the environment inhospitable, destroy or inactivate the invader.

53
Q

Defence against invaders:

A

Many kinds of parasites want to invade metazoa (multicellular organisms).

  • Viruses
  • Bacteria
  • Protozoa
  • Fungi
  • Worms
54
Q

Defence starts at the ____ – _______ barrier (that could be the ______ or skin _____/_____)

A 
surface
impermeable
cell wall
cuticles
mucus
55
Q

First line of defence-

A
  • cell wall
  • cuticle
  • skin
  • mucus

Can’t be completely impermeable as it needs to interact with the environment – take up food, gases, etc…

56
Q

Innate Immunity: Step 1: Preventing invasion

A

Defences against invasion of biotic (living- bacteria) and non biotic (non-living- dust/dirt) “things”

  • Skin
  • Mucous membranes
  • Cilia in airways + lung
  • Coughing, sneezing
  • Tears
  • Acid on skin and in stomach
  • Anti-bacterial enzymes

Layers make it hard for invaders to go any further.

Hair-like projections called cilia line the primary bronchus to remove microbes and debris from the interior of the lungs.

57
Q

What are Anti-bacterial enzymes?

A

Humoral responses (body fluids)- can have that in tears, saliva, mucus etc.

Anti-microbial peptides (AMP’s) such as defensins and lysozyme.
Lysozyme is found in many body fluids, e.g. tears, saliva, mucus.
Lysozyme breaks down peptidoglycan and is therefore very effective against gram-positive bacteria - destroying their cell wall.
Lysozyme = lyses bacteria
Discovered in 1921 by Alexander Fleming, who sneezed onto a petri dish and noticed bacteria wouldn’t grow in the contaminated place. NOT TRUE. He actually discovered by accidentally contaminating a petri dish that penicillin was actually very effective against a bacteria.

58
Q

Step 2: First response to invasion

A

This is a non-biotic disturbance but of course there can be other bacteria and pathogens that can enter the body.

Innate immunity in vertebrates

Cell-mediated responses
• phagocytic cells e.g. macrophages, neutrophils- they engulf and destroy those invaders.
• secretory cells- deal with viruses- they interact with the cell directly via enzymes and destroy it.
e.g. Natural killer cells which induce apoptosis or lysis of other cells by releasing perforin and
granzyme

Cell-mediated
Phagocytes were first recognised by Metchnikoff (1845-1916). He found that if he stuck a rose thorn into a transparent starfish embryo, the thorn was surrounded by motile cells within a few hours.
Diagram shows phagocytes (neutrophils and macrophages) migrating from the capillaries to the site of a tissue wound in a mammal.

59
Q

Summarise the innate immune response in 3 steps.

A

1) Histamines and cytokine released. Capillaries dilate.
2) Antimicrobial peptides enter tissue. Neutrophils are recruited.
3) Neutrophils digest pathogens and cell debris. Tissue heals.

60
Q

Innate immunity: First response

A

Pathogens are recognised by characteristic compounds on their surfaces e.g. lipopolysaccharide (LPS) of bacterial cell wall
= pathogen-associated molecular patterns (PAMPs) – nonspecific- so the immune system at this point can’t know exactly which pathogen it is.

PAMPs are not found on any “self” components- so they are very clear indicators that they are invaders.
PAMP’s interact with PRRs = pattern-recognition receptors.

The PAMP-PRR interaction triggers the various effector mechanisms that lead to elimination of the pathogen.

61
Q

What are elements of the alarm system?

A
  • Macrophages
  • Neutrophils

Receptors will recognise the PAMPs. They interact with them causing it to be engulfed. Call in more help.

62
Q

Macrophages are the alarm- how?

A

• Trigger alarm proteins: cytokines and chemokines- then you have vasodilation of the blood vessel- so more blood can come to the problem sight. Have inflammation occurring.

63
Q

What does the bacteria trigger?

A

1) Bacteria trigger macrophages to release cytokines and chemokines.
2) Vasodilation and increased vascular permeability cause redness, heat and swelling.
3) Inflammatory cells migrate into tissue, releasing inflammatory mediators that cause pain

64
Q

What occurs in the inflammatory response?

A
  • Signalling molecule released in response to injury or infection
  • E.g. histamine stored in mast cells triggers vasodilation and increase permeability of blood vessels nearby
  • Activated macrophages & neutrophils release cytokines which encourage blood to flow to infected area
  • Results in swelling

a) Inflammation can be either local or systemic (throughout the body)
b) Fever is a systemic inflammatory response triggered by substances released by macrophages in response to certain pathogens
c) Septic shock is a life-threatening condition caused by an overwhelming inflammatory response

65
Q

_____ Blood Cells are part of the First Response Team

A

White

66
Q

What are the white blood cells involved in the first response?

A

Neutrophils are most common and they kill bacteria, fungi and foreign debris.
Monocytes- clean up damaged cells.
Eosinophils- kill parasites, cancer cells and involved in allergic responses.
Lymphocytes- help fight viruses and make antibodies.
Basophils- involved in allergic response.

67
Q

Innate immunity in vertebrates includes:

A

Interferons
Act directly on viruses by inhibiting viral replication in host cells, but also indirectly by

  • activating antiviral defences of tissue cells
  • activating various effector cells of the immune system such as Natural Killer cells (NK cells)- excretes substances that destroy or inhibit the virus

Phagocytosis stimulation – alarm bell

68
Q

What are Dendritic cells?

A

Bridge between innate and adaptive immune system

69
Q

What are the other Phagocytic cells that help?

A
  • Dendritic: Tissues e.g. skin – Stimulate adaptive immunity
  • Eosinophils: Mucosal surfaces – Defence against multicellular invaders
  • Natural killer (NK) cells: – 5-10% – Spleen, lymph nodes, bone marrow – break down cell membranes
70
Q

The ______ system is a network of ____ , _____ and _____ that work together to move a watery fluid called _____ back into your ______ system. Moves things around the body. Responders need to be moved around the body.

A 
lymphatic
tissues,
vessels
organs
lymph
circulatory
71
Q

The lymphatic system is key to innate immunity in vertebrates- what does it help with?

A
  • Distributes lymph across body
  • Drains excess interstitial fluid.
  • Transports dietary lipids.
  • Carries out immune responses.
  • Some macrophages reside in lymph nodes
  • Dendritic cells migrate to lymph nodes after interacting with pathogens - stimulate adaptive immunity
72
Q

Summarise innate immunity-

A
  • Found in all animals.
  • Both humoral and cellular components.
  • Capable of dealing with many invading organisms quickly and effectively.
  • Relies on recognition of pathogen-associated molecular patterns (PAMPs) and discrimination of self/non-self.
  • Encoded in the genome – not capable of adapting to deal with new pathogens.

Innate immunity is not a second class immune system!

73
Q

A mature animal’s immune system normally does not respond to that animal’s ____ tissue. This acceptance of self cells is known as _______ _______. The immune system of a foetus undergoes the process of ______ to lose the ability to respond to ________ as its development proceeds.

Autoimmune diseases are produced by the failure of ______ ______.
Autoreactive _ cells become activated, and autoreactive B cells produce __________, causing ________ and ____ damage. More than 80 known or suspected autoimmune diseases exist, affecting 8% of the population. For reasons that are not understood, ___ of the people with autoimmune diseases are women.

A 
own
immunological tolerance
tolerance
self-molecules
immunological tolerance
T
autoantibodies
inflammation
organ
78%

Life Processes B (10 decks)

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