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immunology Flashcards

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1
Q

which cell - these components help stop bleeding by forming blood clots?

A

platelets

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2
Q

which cell - these cells are part of the innate immune system. They capture and destroy of foreign material through phagocytosis

A

neutrophils

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3
Q

which cells - these cells can be subdivided into two main groups: T and B cells

A

lymphocytes

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4
Q

which cells - these phagocytic cells can stimulate lymphocyte activation

A

Monocytes/Macrophage/Dendritic cells

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5
Q

which cells - these granulated cells have receptors for IgE

A

Basophils/Mast

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6
Q

which cells - these heavily granulated bi-lobed cells are phagocytic

A

Eosinophils

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7
Q

what cell type is a basophil?

A

myeloid

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8
Q

what is a large granulocyte involved in allergy response?

A

a basophil

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9
Q

what cell type is a natural killer cell?

A

lymphoid

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10
Q

what is an agranulocyte which targets and kills tumor cells?

A

a natural killer cell

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11
Q

what cell type is a an eosinophil?

A

myeloid

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12
Q

what is a granulocyte, red in colour in a blood smear, especially important in defence against parasites?

A

eosinophil

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13
Q

what cell type is a T lymphocyte?

A

lymphoid

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14
Q

what is an agranulocyte that can differentiate into three types: helper, cytotoxic, and regulatory?

A

T lymphocyte

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15
Q

what cell type is a macrophage?

A

myeloid

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16
Q

what is a differentiated monocyte with super phagocytic abilities?

A

macrophage

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17
Q

what cell type is a monocyte?

A

myeloid

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18
Q

what is an agranulocyte that travels through the blood to body tissues, where it differentiates into a macrophage when stimulated?

A

monocyte

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19
Q

what cell type is a neutrophil?

A

myeloid

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20
Q

what is a granulocyte with excellent phagocytic abilities against invading bacteria?

A

neutrophil

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21
Q

what cell type is a mast cell?

A

myeloid

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22
Q

what is a granulocyte which is key to the inflammatory response?

A

mast cell

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23
Q

what cell type is a plasma cell?

A

lymphoid

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24
Q

what is an activated agranulocyte that is actively producing antibodies?

A

plasma cell

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25
Q

what are the lymphoid cells?

A

natural killer cell (NK), T-lymphocyte, B-lymphocyte, plasma cell

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26
Q

what are the myeloid cells?

A

basophil, neutrophil, eosinophil, macrophage/dendritic cells, mast cells

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27
Q

what is haematopoiesis?

A

Leukocytes (white blood cells) develop from a pluripotent haematopoietic stem cell (HSC) during a highly regulated process called haematopoiesis (making new blood cells/blood components)

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28
Q

what is the primary site of origin for all the cells of the immune system?

A

the bone marrow

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29
Q

what are the primary lymphoid organs?

A

bone marrow and thymus - where lymphocytes mature

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30
Q

what are the secondary lymphoid organs?

A

lymph nodes, spleen, MALT and GALT - where mature lymphocytes interact with antigens collected from around the body

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31
Q

which lymphocyte matures in the bone marrow?

A

B lymphocyte

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32
Q

Blood leukocytes are made up of granulocytes and agranulocytes – which cell type is NOT an example of a granulocyte?

Neutrophil

Lymphocyte

Basophil

Eosinophil

A

lymphocyte

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33
Q

in response to chemical signals, which two pathways will the pluripotent haematopoietic stem cell (HSC) commit to?

A

either the myeloid or lymphoid pathway (they turn into either common lymphoid progenitor or common myeloid progenitor)

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34
Q

true or false - pluripotent haematopoietic stem cells (HSC) are the only cell type of this pathway able to self renew?

A

true - this maintains haematopoietic homeostasis

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35
Q

what’s the name for the chemical signals that promote bone marrow stem cell differentiation to produce precursors, immature, and mature leucocytes?

A

chemokines

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36
Q

what is apoptosis?

A

programmed cell death - for old or sick cells, regulated by chemokines (chemical signals)

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37
Q

what happens during apoptosis?

A
  • decrease in cell volume, condensation of chromatin and degradation of DNA.
  • The cell then breaks apart by blebbing “bubbles of cell” called apoptotic bodies.
  • The apoptotic bodies keep the cell contents contained and can be phagocytized by macrophages.
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38
Q

why apoptosis not necrosis?

A

necrosis causes cell lysis with the contents of the cell being released. The released cellular material is harder for macrophages to phagocytize and may induce an inflammatory response.

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39
Q

why are using blood smears/blood counts useful?

A

can help establish the state of the immune system - high (increased) or low (decreased) cell numbers can indicate a problem (haematopoietic homeostasis out of whack). For example, increased neutrophil counts can indicate inflammation, infection, or stress.

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40
Q

true or false - each animal species will have blood count reference ranges specific to that species and may vary with age?

A

true

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41
Q

what is negative selection for B lymphocytes?

A

In specialized areas of bone marrow, B lymphocytes are tested to detect any cell that might react to self and they are removed before they do any damage

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42
Q

where does B lymphocyte development occur in birds?

A

in the bursa of Fabricius (only found in birds, present in cloaca - hematopoiesis happens here too)

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43
Q

where does B lymphocyte development occur in cattle and sheep?

A

occurs first in the ileal Peyer’s patches (small clusters of lymphatic tissue found in the small intestine)

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44
Q

where does B lymphocyte development occur in rabbits?

A

in the appendix

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45
Q

where is the site of T lymphocyte development and selection (cell death)?

A

the thymus

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46
Q

part one of thymic selection - what happens during negative selection for T lymphocytes?

A

where any T lymphocytes that react with self-molecules are removed - undergone in the thymus

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47
Q

part two of thymic selection - what happens during positive selection for t lymphocytes?

A

they are checked to make sure they respond to a very important cell receptor, Major Histocompatibility Complex (MHC). If they do respond correctly, they are kept

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48
Q

what’s in the cortex (outer portion) of the thymus?

A

it’s densely packed with immature T lymphocytes (thymocytes)

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49
Q

what happens in the medulla (inner portion) of the thymus?

A

thymic selection - it’s the is the site of interaction between immature cells and antigen presenting cells

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50
Q

The lymph nodes are the site where immune responses are mounted to antigens present in the lymph fluid. These organs are packed with what cells?

A

B and T lymphocytes, macrophages and dendritic cells

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51
Q

There are three key regions in lymph nodes - in which are B lymphocytes, macrophages and dendritic cells arranged in follicles where antigens are captured?

A

the cortex (outer portion)

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52
Q

there are three key regions in lymph nodes - If antigen is captured, the cells move to the paracortex where T lymphocytes are presented with antigens and may initiate an immune response to that specific antigen. where does this happen?

A

the paracortex (between the cortex and medulla)

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53
Q

there are three key regions in lymph nodes - where do activated T and B lymphocyte respond by proliferating and releasing chemical signals and antibodies?

A

the medulla (central portion)

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54
Q

Why is it so important for the B and T lymphocytes to be tested by negative selection in the primary lymphoid organs?

A

may cause an inappropriate immune response when they encounter self-antigens in body/secondary lymphoid organs - may cause death or chronic illness (think allergies)

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55
Q

The spleen plays a major role in mounting immune responses to antigens present in the bloodstream. It filters blood, trapping antigens (systemic infections) and circulating lymphocytes. Antigens are trapped by dendritic cells which in turn activate which two cells to respond?

A

T and B lymphocytes

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56
Q

There are two key sections to the spleen - which contains mostly macrophages, red blood cells and a few lymphocytes. Any old red blood cells trapped here will be destroyed?

A

the red pulp

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57
Q

there are two key sections to the spleen - which surrounds the splenic arteries (PALS – T lymphocytes). B lymphocytes exist in the follicles and the marginal zone contains lymphocytes and macrophages?

A

the white pulp

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58
Q

what does MALT stand for?

A

mucosa associated lymphoid tissue

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59
Q

Mucous membranes are major sites of entry for many pathogens. Therefore, immune surveillance is important. There are three types of MALT - what are they?

A

BALT – Bronchial Associated (Respiratory)
GALT – Gut Associated
CALT – Cutaneous Associated (Skin)

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60
Q

define immunity?

A

immunity is the state of being insusceptible or resistant to a noxious agent or process, such as a pathogen. Immunity may occur naturally by an inherited trait, or be produced by prior exposure or by vaccination.

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61
Q

what is innate immunity?

A

non specific natural resistance

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62
Q

what does innate immunity do?

A

provides the organism with a performed, standardised response to threats. This system is considered non-specific and without memory as it will respond the same way, every time, to any threat, regardless of whether it has seen it before

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63
Q

innate (non specific) immunity includes what four barriers?

A

anatomical, physiological, phagocytic and inflammatory barriers

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64
Q

Skin: the structure retards entry of microbes, acidic environment (pH3-5) on the surface inhibits growth of unwanted organisms
Mucous membranes of the respiratory, intestinal and reproductive organs: competition with normal flora for attachment sites and nutrients, mucus entraps microorganisms, cilia propel microorganisms out of body.
which innate immune system barrier are these?

A

anatomical barrier

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65
Q

Temperature: body temperature, particularly fever, inhibits growth of some pathogens.
Low pH of the stomach acid: acid in stomach kills most ingested organisms.
Tears and sweat: wash away organisms before they can colonize.
Chemical mediators: enzymes such as lysozyme damage bacterial cell walls; chemical signals such as interferon makes cells resistant to viral infection.
which innate immune system barrier are these?

A

physiological barriers

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66
Q

Neutrophils, blood monocytes, tissue macrophages and dendritic cells internalize (phagocytose) and kill microorganisms and infected or abnormal cells.
which innate immune system barrier are these?

A

phagocytic barriers

67
Q

Tissue damage and infection induce leakage of vascular fluid containing serum proteins (e.g. complement proteins) with antibacterial activity.
The ________ process helps to contain and destroy the pathogen, and assist with repair of damaged tissues. Mast cells release chemical signals (chemokines) which cause vasodilation and increased vascular permeability to allow for the recruitment of phagocytic cells.
which innate immune system barrier are these?

A

inflammatory barriers

68
Q

The innate immune response is often broken down into two categories: the first line and second line of defence. what is the first?

A

anatomical and physiological barriers

69
Q

The innate immune response is often broken down into two categories: the first line and second line of defense. what is the second?

A

phagocytic and inflammatory barriers

70
Q

acidic stomach pH, the dead layer of skin, sweating, ciliated cells of the respiratory tract, peristalsis of the gut, normal microbial flora in the gut - first or second line of defence?

A

first line of defence (anatomical and physiological barriers)

71
Q

neutrophil engulfing a pathogen, mast cells recruiting cells, vasodilation at a wound site, serum proteins lysing bacterial cell walls, macrophage engulfing damaged cells - first or second line of defence?

A

second line of defence (phagocytic and inflammatory barriers)

72
Q

What are the structural features of the epidermis that make it an effective physical barrier against pathogens?

A

the epidermis is the outermost layer of skin, composed of tightly packed layers of epithelial cells with a lop layer of dead, flat, keratinised cells that provide a relatively impermeable layer. also slightly acidic, and colder than internal temps

73
Q

what is a professional phagocytic cell?

A

cells that engulf foreign or damaged cells, and cellular debris. They have special cell receptors on their surface that can react to the presence of pathogens and sick or dying self-cells.

74
Q

which myeloid cells are professional phagocytes? (hint - the second line of defence, and there’s four)

A

macrophage, dendritic cell, monocyte, neutrophil

75
Q

what is the process of phagocytosis>

A

Phagocytosis is a process wherein a phagocytic cell binds to the item it wants to engulf on the cell surface, and draws the item inward while engulfing around it (invagination). The surrounded particle becomes completely enclosed within a bubble-like structure (the phagosome) within the cytoplasm. The phagosomes contain enzymes that will break down the engulfed item allowing it to be destroyed by lysis and digested (phagolysosome)

76
Q

what are PAMPs?

A

Pathogen-associated molecular patterns, which alert the innate immune system to the presence of infection - eg lipopolysaccharide and peptidoglycan, molecules found only in prokaryotic cells.

77
Q

what are PRRS?

A

pattern recognition receptors - the receptors on the macrophage and dendritic cells that recognise the PAMPs and DAMPs

78
Q

what are DAMPs?

A

damage associated molecular patterns -endogenous danger molecules that are released from damaged or dying cells and activate the innate immune system by interacting with pattern recognition receptors (PRRs) on macrophage and dendritic cells.

79
Q

what do DAMPs (damage associated molecular patterns) do?

A

DAMPs promote activation of innate immune cells and recruitment and activation of antigen-presenting cells engaged in host defence and tissue repair.

80
Q

cat with swelling under chin from a cat fight, scab on lesion - how did the anatomical barrier of the innate immune system help?

A

skin structure where dead skin cell layers make the skin stronger and thicker, limiting the depth of the wound

81
Q

cat with swelling under chin from a cat fight, scab on lesion - how did the physiological barrier of the innate immune system help?

A

cooler skin temperature and normal skin flora would limit pathogen replication

82
Q

cat with swelling under chin from a cat fight, scab on lesion - how did the phagocytic barrier of the innate immune system help?

A

neutrophils, macrophages and dendritic cells in the skin phagocytosing any pathogens that may have entered

83
Q

cat with swelling under chin from a cat fight, scab on lesion - how did the inflammatory barrier of the innate immune system help?

A

the swelling bringing in mast cells, macrophages, platelets, neutrophils to the site of the wound to repair it and contain infection (this causes heat in the wound)

84
Q

What is the role of the lymph node in the immune response?

A

the lymph nodes filter the lymph fluid and allow the resident immune cells within that lymph node to assess if there are any pathogens present. if present, the T and B cells will become activated to help fight off the infection

85
Q

the mechanism by which neutrophils, macrophage and dendritic cells are able to detect pathogens present in the bite wound from cells damaged by the action of the bite?

A

these guys are professional phagocytic cells, which have pattern recognition receptors (PRR’s) - can pick up on PAMPs from pathogens and DAMPs from damaged cells

86
Q

why are neutrophils present in abscess fluid?

A

they’re professional phagocytic cells, will be trying to track down and phagocytose as much of the pathogen as possible to try and limit infection

87
Q

there are two “arms” of the adaptive immune system, the first being cell-mediated immunity - what’s this brought about by?

A

cell-mediated immunity is brought about by T-lymphocyte (T cell) activation

88
Q

there are two “arms” of the adaptive immune system, the second being antibody-mediated (or humoral) immunity) - what’s this carried out by?

A

antibody-mediated (or humoral) immunity is carried out by B-lymphocytes (B cells) and the proteins they produce called antibodies

89
Q

neutrophil - professional antigen-presenting cell, professional phagocytic cell, both or neither?

A

neutrophils are professional phagocytic cells

90
Q

macrophage - professional antigen-presenting cell, professional phagocytic cell, both or neither?

A

both - they’re professional antigen-presenting and phagocytic cells

91
Q

B lymphocyte - professional antigen-presenting cell, professional phagocytic cell, both or neither?

A

only professional antigen presenting cell - it is phagocytotic, but not a professional “eater”

92
Q

T lymphocyte - professional antigen-presenting cell, professional phagocytic cell, both or neither?

A

neither

93
Q

dendritic cell - professional antigen-presenting cell, professional phagocytic cell, both or neither?

A

both -

94
Q

how do professional antigen presenting cells (APCs) work?

A

These phagocytic cells present antigens on their surface via special receptors (major histocompatibility complexes - MHC) that are specifically designed to activate the adaptive immune system

95
Q

what does MHC stand for?

A

major histocompatibility complexes - MHC

96
Q

which cells are considered professional antigen presenting cells (APCs)?

A
  • dendritic cells
  • macrophages
  • B lymphocytes
97
Q

what is an antigen?

A

a molecule that can generate an immune response

98
Q

what is an immunogen?

A

an antigen that generates a very strong immune response

99
Q

true or false - antigens are present on all cells

A

true - Antigens are present on all cells, including an animal’s own cells (self-antigens) and most biological molecules. Antigens are like name tags that identify a cell or molecule as belonging to a specific group.

100
Q

if a substance is capable of inducing a detectable immune response, that substance is considered to be…

A

‘antigenic’ or ‘immunogenic’.

101
Q

lipids and nucleic acids are only antigenic when combined with proteins or polysaccharides, not on their own - true or false?

A

true

102
Q

what makes an antigen antigenic?

A
  • size (bigger the better)
  • complexity (more complex the better)
  • degradability (less degradable the better)
  • foreignness (more foreign/unique the better)
103
Q

does genetic composition of the animal and method of antigen administration effect immunogenicity?

A

yes

104
Q

what are adjuvants?

A

An adjuvant is a substance that, when administered with an antigen, enhances the immune response to that antigen.

105
Q

is purified horse DNA injected under the skin antigenic or non-antigenic?

A

non antigenic - it’s a nucleic acid

106
Q

is transplanted kidney tissue or parent’s red blood cells antigenic or non-antigenic?

A

antigenic - it’s foreign

107
Q

the animal has to distinguish between ‘self’ and ‘non-self’ antigens. The ability to make this distinction is achieved using….

A

the major histocompatibility complex (MHC)

108
Q

what is MHC class I?

A

endogenous antigens

109
Q

where are MHC class I (endogenous antigen detectors) found?

A

MHC Class I molecules are found on all nucleated cells

110
Q

where do MHC class I (endogenous antigen detectors) bind?

A

Endogenous (from inside the cell) proteins. These proteins may come from normal cell function, cancers, or intracellular pathogens such as viruses.

111
Q

true or false - all cells (healthy and sick/infected) MUST display a cellular protein in its’ MHC I molecule at all times. Failure to do so results is cell death!

A

true

112
Q

Once the endogenous proteins are broken down into small pieces, they will be loaded into the MHC I molecules and transported to the surface of the cell. For there, interaction with the loaded MHC I is used for…

A
  • Cell cycle regulation
  • Responding to intracellular microorganism infection
  • Management of cancerous cell transformation.
113
Q

true or false - no two individuals except identical twins have the same MHC and during transplant of an organ or stem cells, MHC molecules themselves act as antigens, provoke immune response and cause transplant rejection?

A

true

114
Q

what’s MHC class II?

A

exogenous antigens

115
Q

where are MHC class II found?

A

Only found on professional antigen presenting cells (macrophages, dendritic cells and B lymphocytes).

116
Q

what do MHC class II bind?

A

Exogenous (from outside the cell) material (protein, carbohydrates, lipids etc.). When the phagocytic APCs phagocytose foreign material from bacteria or parasites, it will be broken down in the phagosome and presented in the MHCII molecules on the surface of the cell.

117
Q

The main function of the MHCII presentation of antigens is to induce an immune response by upregulating (activating) a specific group of lymphocytes… the?

A

the T helper lymphocytes

118
Q

MHC genes, inherited from parents, will dictate the ability of an animal to…

A

respond to pathogens

119
Q

Heterozygous animals will have a wider range of MHC recognition that homozygous animals. but there is an optimal number of different MHC loci - too much diversity may increase the risk of ___(a)____, while too few increases the risk of _____(b)_____?

A

a) autoimmunity
b) infections

120
Q

which lymphocytes do MHC I activate?

A

cytotoxic T cells

121
Q

What is the role of a cytotoxic T lymphocyte?

A

intracellular proteins and pathogens get presented on the surface of the MHC I receptor of all nucleated cells, if the CTL considered the protein presented to be a pathogen or abnormal (eg cancer protein) it will release perforin and granzyme which will cause the cell to undergo apoptosis

122
Q

what do cytotoxic T lymphocytes (CTL) release to kill cells?

A

they release perforin and granzyme which will cause the cell to undergo apoptosis

123
Q

Cytotoxic T lymphocytes (CTLs) have which two surface receptors?

A
  • a T cell receptor (TCR) which binds directly with the MHC molecule containing the antigen
  • a co-receptor called CD8 on their surface, which is why they are often referred to as CD8 positive cells.
124
Q

what does the CD 8 receptor on cytotoxic T cells do?

A

This CD8 co-receptor works with the MHC Class I and TCRs receptor, locking them together in order to activate the powerful CTLs

125
Q

the CD8 co-receptor works with the MHC Class I and TCRs receptor, locking them together in order to activate the powerful CTLs. this allows what chemical to be released?

A

The locking of the cells will cause the release of a chemical (cytokine) Interleukin-2 (IL-2) which activates the CTL and allows it to clone itself

126
Q

when the cloned CTL finds a cell with the specific antigen it’s looking for presented on it’s MHC I receptor, it attaches and releases perforin and granzyme as well as…

A

IFN-gamma - will also be released to activate any nearby macrophage and CTLs. IFN-gamma is also a potent anti-viral, inhibiting viral replication

127
Q

what is IFN gamma?

A

interferon gamma (IFN-gamma)

128
Q

can cytotoxic T lymphocytes suppresses inflammation responses by the release of chemicals (chemokines) such as interferon gamma (IFN-gamma)?

A

yes

129
Q

When activated, 90% of the cloned CTLs will be sent on their quest to seek and destroy any cells displaying the “foreign antigen” in the MHC Class I receptor. They will continue to work until they exhaust themselves or told to return to the castle as the enemy has been destroyed, where they will undergo apoptosis - what do the remaining ten percent do?

A

10% of the activated CTLs will go quiescent (resting state). This allows these cells to be long-lived and quickly reactivated if the same “foreign antigen” is encountered again. In this way, the immune system is able to develop a “memory” of what it has seen in the past and respond faster in the future.

130
Q

Unlike the CTLs which have the co-receptor CD8 on their surface, Th (T helper) lymphocytes have a….

A

CD4 co-receptor - which is where their name “CD4-positive cells” originates.

131
Q

what does the CD4 co-receptor do?

A

help to activate the T helper cell by locking the MHC Class II with bound antigen and T cell receptor in place.

132
Q

what do Th lymphocytes do?

A

As their name implies, Th lymphocytes regulate the behaviour of other cells including B lymphocytes, macrophages and CTLs. All Th lymphocytes start as a Th0 lymphocyte, a mature but naive cell able to adjust its’ behavior depending on the type of antigen presented in the MHC II when it is activated.

133
Q

what does APC mean?

A

antigen presenting cell

134
Q

what does TCR mean?

A

T cell receptor

135
Q

all Th (T helper) lymphocytes start as a Th0 will then shift phenotype to either a….

A

Th1, Th2 or Treg (regulatory) lymphocyte to produce the optimal immune response for the specific antigen presented in the MHC II when it is activated

136
Q

true or false - CTLs (cytotoxic T lymphocytes) will only respond to an antigen in MHCI receptors?

A

true - this is why T helper 1s (Th1) cells are important

137
Q

which cells are T helper 1 lymphocytes able to activate by the MHCII pathway?

A
  • cytotoxic T cells (CTLs)
  • macrophages
138
Q

how are Th1 cells are able to activate CTLs and macrophage by the MHCII pathway? (hint - two types of cytokines)

A
  • Th1 cells produce IFN-G (interferon gamma, a potent cytokine) which makes macrophages eat more and sends memory cytotoxic T cells hunting
  • they also produce pro-inflammatory cytokines, which bring more macrophages to the site of the infection to be activated
139
Q

what are cytokines?

A

any of a number of substances, such as interferon, interleukin, and growth factors, which are secreted by certain cells of the immune system and have an effect on other cells.

140
Q

if the Th0 cell switches to the Th2 phenotype, the activated Th2 lymphocyte will…..?

A

bind with the MHC Class II receptor on B lymphocytes to activate them and make them produce powerful antibodies

141
Q

The principle role of the MHC Class II activation pathway to activate B lymphocytes (via Th2 cells) so that they will produce powerful antibodies - this process also has what affect on macrophages?

A

This process is also anti-inflammatory and suppresses macrophage activity

142
Q

what is the role of regulatory T cells (Treg)?

A

Regulatory T cells (Treg) are T cells that are involved in controlling the intensity of the immune response (they release cytokines that stop it being too strong and damaging the animal)

143
Q

why are T helper lymphocytes are only able to interact with antigen presenting cells (APCs)?

A

APCs are the only cells that express MHC Class II on their surface

144
Q

How do T helper lymphocytes become activated?

A

an antigen presenting cell (macrophage or dendritic cell) MUST phagocytose a pathogen, return to the secondary lymphoid tissue and express the “foreign” exogenous antigen on its MHCII

145
Q

when the mature naïve Th0 recognises and bind to the MHCII with the foreign antigen; the CD4 co-receptor will lock the cells together. The locking of the cells will cause the release of a chemical (cytokine)….?

A

Interleukin-2 (IL-2) which activates the Th0 forcing it to become either a Th1, Th2 or Treg depending on the antigen and allows it to clone itself

146
Q

MHCII antigen presentation to T helper 0 cells will result in what two things?

A

A) Th0 transition to Th1 cells which will release IFN-gamma to activate CTL and macrophages and/or
B) Th0 transition to Th2 cells which will activate B lymphocytes
*or our bestie Treg :)

147
Q

do Th lymphocytes have a memory?

A

yes - same as CTLs, when activated 90% of cloned Th lymphocytes go and work till exhaustion or apoptosis after job is done, 10% go into resting state so they live longer and can be quickly activated if the same foreign antigen is found

148
Q

Why do you think it might be important for there to be two different pathways for a T helper cell (T helper 1 vs T helper 2)?

A

so if an antigen is presented on a MHCII receptor it can still be dealt with by a CTL thanks to Th1, and Th2 so B cells can still be activated to produce antigens

149
Q

are natural killer (NK) cells a B or T lymphocyte?

A

T lymphocyte

150
Q

battle of the co-receptors: does CD16A, CD4 or CD8 belong to a natural killer (NK) cell?

A

natural killer cells express a CD16A co-receptor

151
Q

battle of the co-receptors: does CD16A, CD4 or CD8 belong to a cytotoxic T lymphocyte (CTL)?

A

cytotoxic T lymphocytes express a CD8 co-receptor

152
Q

battle of the co-receptors: does CD16A, CD4 or CD8 belong to a T helper lymphocyte?

A

T helper lymphocytes express a CD4 co-receptor

153
Q

unlike the cytotoxic and helper T lymphocytes which MUST interact with either MHC I or II (called MHC restricted) to become activated, NK cells react to…?

A

NK cells react in the absence of the MHC I receptor (MHC inhibited)

154
Q

true or false - NK cells are part of the innate AND adaptive immune response?

A

true - this is because they don’t need to be activated

155
Q

all nucleated cells in the body MUST regularly present self-antigen in an MHC I receptor for CTL (cytotoxic T lymphocyte) assessment - true or false?

A

true

156
Q

some viruses (particularly herpesviruses) and tumours down regulate MHC I expression meaning that the CTL cannot be activated to kill it. which cell is able to work around this loophole?

A

natural killer (NK) cells - they recognise cells with the absence/reduction of normal MHCI expression, eg tumour or virally infected cells, and kill them

157
Q

How are Natural Killer lymphocytes activated to kill cells?

A

an NK cell will recognise any cells that are not presenting MHCI or that have been labelled with an antibody (via their CD16A co-receptor)

158
Q

Which one of the following cells is considered an antigen presenting cell able to phagocytose the bacteria and present the bacteria antigen on an MHC receptor to initiate the adaptive immune response?
a) T helper lymphocyte
b) natural killer cell
c) macrophage
d) neutrophil
e) mast cell

A

c) macrophage

159
Q

what is a BCR?

A

B cell receptor - the BCR consists of antibody molecules (immunoglobulin) bound to the cell membrane in such a way that they are able to bind antigen to the B lymphocyte surface

160
Q

which two antibodies do B lymphocytes develop early in their maturation within the bone marrow?

A

IgM first, then IgD if it passes clonal testing

161
Q

when B lymphocytes will undergo testing, called clonal selection, which antibody is tested for auto-reactivity?

A

the IgM antibody is tested for auto-reactivity

162
Q

Within the bone marrow, an immature B lymphocyte will express an antigen-specific IgM antibody on it’s surface. The cell undergoes antigen testing to ensure it does not react to cell-bound or soluble self-antigen. If it does react with self, what happens to the B cell with strong, weak or no reactivity?

A

strong reactivity - apoptosis or anergy (long term inactivation)
weak reactivity - corrected by genetic receptor editing
no reactivity - matures and gains IgD antibody too

163
Q

Full activation of the B lymphocyte is achieved when cytokine signals are provided by a T helper lymphocyte when the TCR binds with the antigen loaded MHCII on the B lymphocyte. The T helper lymphocyte releases…

A

IL-2 (interleukin 2) to complete activation of the B lymphocyte and induce it to clone

164
Q
A

veterinary science 2.1 (22 decks)

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