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Microbiology > Chapter 15/16- Immunity > Flashcards

Chapter 15/16- Immunity Flashcards

1
Q

In order for a pathogen to successfully cause disease in humans, the pathogen must come to the surface of our body, they successfully attach to the surface of our body because they overcome our body’s first line of defense against infection. These pathogens then invade our epithelial surface and penetrate into deeper tissues. The next thing these pathogens must be able to do in order to successfully cause disease in humans is to _____ our second line of defense against infection.

A

evade

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2
Q

Most immunologists describe three lines of defenses that humans have against infection:

___ line of defense- nonspecific surface barriers (____)
___ line of defense- nonspecific immune response (___)
___ line of defense- specific immune response (____)

A

1st line of defense- nonspecific surface barriers (innate)
2nd line of defense- nonspecific immune response (innate)
3rd line of defense- specific immune response (adaptive/acquired)

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3
Q

Innate immunity

A
  • Present and functional at birth
  • Nonspecific
  • No memory
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4
Q

Adaptive immunity

A
  • Present and nonfunctional at birth
  • Specific
  • Memory
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5
Q

The environmental factors that can influence the growth of microorganisms are the nutrients, temperature, pH, and oxygen supply. In addition to these environmental factors, since our normal microbiota only live on the surface of our body, our body surface can present _____ to the growth of microorganisms.

These barriers are known as our ___ ___ of ____ against microorganisms or (to be more specific) against infection. These barriers are also known as our ____ _____ defense, they are nonspecific because basically they act against almost all microorganisms.

A

The environmental factors that can influence the growth of microorganisms are the nutrients, temperature, pH, and oxygen supply. In addition to these environmental factors, since our normal microbiota only live on the surface of our body, our body surface can present barriers to the growth of microorganisms.

These barriers are known as our first line of defense against microorganisms or (to be more specific) against infection. These barriers are also known as our nonspecific surface defense, they are nonspecific because basically they act against almost all microorganisms.

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6
Q

4 barriers:

A

structural, mechanical, chemical, and genetic barriers.

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7
Q

Structural barrier-
Microorganisms that form our normal microbiota only live on the surface of our body (it can be either external or internal surface), this body surface is made up of _____ ____. There are two main types of epithelial surfaces: the ____ and the ____ ____

A

Structural barrier-
Microorganisms that form our normal microbiota only live on the surface of our body (it can be either external or internal surface), this body surface is made up of epithelial cells. There are two main types of epithelial surfaces: the skin and the mucous membrane.

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8
Q

Structural barrier-
Because the epithelial cells of the epithelium are constantly growing and being sloughed off the surface and replaced by new ones from below the microorganisms that attach to the epithelium also tend to be soughed off ____

  • Also have _____ ____ between epithelial cells
A

Because the epithelial cells of the epithelium are constantly growing and being sloughed off the surface and replaced by new ones from below the microorganisms that attach to the epithelium also tend to be soughed off rapidly.

  • Also have tight junctions between epithelial cells
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9
Q

Mechanical barrier involves _____- _____ _____ the _____

A

Mechanical barrier involves movement- physically removing the microbe

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10
Q

(1) The first kind of mechanical barrier is due to the ______ ______ of the epithelial cells lining the surfaces of ____ and ____. These epithelial cells can produce mucus that entraps microorganisms. Cilia on epithelial cells constantly move this mucus toward the mouth, where the mucus along with the trapped microorganisms is _____ and eliminated

A

(1) The first kind of mechanical barrier is due to the mucociliary movement of the epithelial cells lining the surfaces of nose and throat. These epithelial cells can produce mucus that entraps microorganisms. Cilia on epithelial cells constantly move this mucus toward the mouth, where the mucus along with the trapped microorganisms is swallowed and eliminated

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11
Q

The second kind of mechanical barrier is due to

A

fluid movement- flushes microbes from the surface

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12
Q

(2) The second kind of mechanical barrier is due to the movement of our body fluids (such as blood, urine, tears, semen…..etc). For example, in the ____, the rapid flow of urine washes away most microorganisms that happened to establish residence on the lining of urethra. Another example would be our ___ washing microorganisms off the conjunctiva

A

(2) The second kind of mechanical barrier is due to the movement of our body fluids (such as blood, urine, tears, semen…..etc). For example, in the urethra, the rapid flow of urine washes away most microorganisms that happened to establish residence on the lining of urethra. Another example would be our tears washing microorganisms off the conjunctiva

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13
Q

Biochemical barrier (or chemical barrier)-
Biochemical barriers are..

A

chemicals produced by cells on the surface of the human body against microorganisms

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14
Q

Examples of biochemical barriers

A
  • Keratin
  • Perspiration
  • Lysozymes
  • Sebum
  • Acids (HCl)
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15
Q

Keratin

A

Keeps skin dry, waterproofs the skin

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16
Q

Perspiration

A
  • Secreted by eccrine (sweat) glands
  • Salt inhibits growth of pathogens
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17
Q

Lysozymes

A
  • Made by saliva and tears, antibacterial
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18
Q

Genetic barrier-
Some hosts are..

A

genetically immune to the diseases of other hosts

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19
Q

Genetic barrier, Species Specific Exs

A
  • HIV (humand) vs FIV (felines
  • Ebola virus
  • Heartworms
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20
Q

For genetic barriers, perhaps the microbe doesn’t have the appropriate ____ to attack the host cells (_______). This is often referred to as ____ ______

A

For genetic barriers, perhaps the microbe doesn’t have the appropriate receptors to attack the host cells (glycoproteins). This is often referred to as species specificity

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21
Q

Our body’s second line of defense against microbial invasion or infection has to do with our body’s natural, nonspecific immune responses. These immune responses include four components:

A

inflammation, phagocytosis, interferon, and complement

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22
Q

Inflammation is a

A

nonspecific response to tissue damage

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23
Q

Inflammation can be identified by four classic symptoms: _______________. A fifth symptom, the loss of ____, is often added to these classic symptoms but can be attributed to the swelling and pain.

A

Inflammation can be identified by four classic symptoms: redness, heat, swelling, and pain. A fifth symptom, the loss of function, is often added to these classic symptoms but can be attributed to the swelling and pain.

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24
Q

Goals of inflammation:

A
  • Remove the agent causing inflammation
  • Keep damage localized
  • Allow it to heal
  • Alert adaptive immunity
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25
3 sequential stages of inflammation (and local or systemic):
Vascular Changes (local) Edema/Swelling (local) Fever Development (systemic)
26
During the "vascular changes" stage of inflammation, chemicals like ______ and ______ are released, triggering ________
During the "vascular changes" stage of inflammation, chemicals like **Prostaglandin and Histamine** are released, triggering **vasodilation**
27
Vasodilation during Vascular Changes increases the ___ ____ into the injured area, hence speeding up the influx of immune components to the injured area to repair the damaged tissue. This increase in blood flow is also responsible for the _____ and ____ symptoms of inflammation.
Vasodilation during Vascular Changes increases the **blood flow** into the injured area, hence speeding up the influx of immune components to the injured area to repair the damaged tissue. This increase in blood flow is also responsible for the **redness and heat** symptoms of inflammation.
28
Edema- The formation of edema is due to the influx of ____ from blood vessels into damaged tissues. Accumulation of this fluid in the tissues gives rise to local _____ and _____
Edema- The formation of edema is due to the influx of **fluid** from blood vessels into damaged tissues. Accumulation of this fluid in the tissues gives rise to local **swelling and hardness.**
29
Edema- some of the same chemicals (prostaglandin and histamine) from vascular changes lead to _______ ______
increased permeability
30
Edema- The swelling not only _____ ____, but also applies..
The swelling not only **dilutes toxins** but also applies **pressure to nearby nerves**
31
Pain can be attributed to which stage of inflammation
Edema/Swelling
32
Fever Development- Fever is initiated when a circulating substance called _____ , _____ the ______ ______ to a _____ ______
Fever is initiated when a circulating substance called **pyrogen, resets** the **hypothalamic thermostat to a higher setting**.
33
Pyrogens can be any _____ substance coming from outside the body (_____ pyrogen) or originating internally (______ pyrogen).
Pyrogens can be any **chemical** substance coming from outside the body (**exogenous pyrogen**) or originating internally (**endogenous pyrogen**).
34
Example of exogenous pyrogen
Bacterial toxins
35
Example of endogenous pyrogen
Any chemical released by phagocytes
36
Phagocytosis is a process of engulfment and destruction of the foreign matter including microorganisms. The cells that perform phagocytosis are known as _____
phagocytes
37
5 sequential stages of phagocytosis:
1. Chemotaxis 2. Ingestion 3. Fusion 4. Killing 5. Elimination
38
Chemotaxis
**recognition** of invader due to signal molecules on the microbe surface
39
Ingestion- membrane extensions surround microbe forming a ____
membrane extensions surround microbe forming a **phagosome**
40
Fusion-______ fuses with phagosome creating a _______
**lysosome** fuses with phagosome creating a **phagolysosome**
41
Killing- _____ ______ in ______ ______ the microbe
digestive enzymes in lysosome destroy the microbe
42
Elimination
debris discharged out of the cell
43
Interferon- _____ released by certain WBCs and tissue cells to _______ inhibit the spread of ___ infections.
**protein** released by certain WBCs and tissue cells to **nonspecifically** inhibit the spread of viral infections.
44
What does interferon do?
Inhibits the reproduction/synthesis of the viruses
45
Interferons are released by a cell once infected to
**protect neighboring cells**
46
Complement is a complex of ____ molecules that work together to destroy bacteria and certain viruses.
protein
47
Actions of complement / 3 different groups of protein:
- C3a/ C5a - C3b - C5 - C9
48
C3a/ C5a
chemotaxis
49
C3b
opsonization
50
C5-C9
Membrane Attack Complex (MAC)- actually kills the microbe by punching holes in it, causing lysis
51
Opsonization means
enhancing phagocytosis
52
* There are several ways a pathogenic microorganism can evade immune attack: (1) Some pathogens can avoid direct contact with phagocytes by producing a slippery mucoid _____, so the phagocyte is unable to directly contact the surface of the pathogen. Therefore the phagocyte is unable to destroy the pathogen surrounded by a capsule. Remember the very first step involved in phagocytosis is for the phagocyte to make a direct contact with the cell surface of pathogen. (2) Besides the formation of capsules, some pathogenic microorganisms can avoid phagocytosis by producing ______ ______ _____. Just like capsules, these surface proteins interfere with the _____ _____ between phagocyte and pathogens. So again, the phagocyte cannot destroy these pathogens with surface proteins.
* There are several ways a pathogenic microorganism can evade immune attack: (1) Some pathogens can avoid direct contact with phagocytes by producing a slippery mucoid **capsule**, so the phagocyte is unable to directly contact the surface of the pathogen. Therefore the phagocyte is unable to destroy the pathogen surrounded by a capsule. Remember the very first step involved in phagocytosis is for the phagocyte to make a direct contact with the cell surface of pathogen. (2) Besides the formation of capsules, some pathogenic microorganisms can avoid phagocytosis by producing **specialized surface proteins**. Just like capsules, these surface proteins interfere with the **direct contact** between phagocyte and pathogens. So again, the phagocyte cannot destroy these pathogens with surface proteins.
53
Third Line of Defense If the pathogens survive our first and second line of defenses, the pathogens are going to be challenged by our third line of defense against infection, which is our acquired/adaptive immune response. Unlike the innate/nonspecific first and second lines of defense the adaptive immune response is pathogen_______ The specificity is due to the presence of unique _______ present on the surface of each pathogen. Unless the antigens change, the individual will have _____ against that antigen usually preventing reinfection from the same pathogen. Unfortunately, the adaptive (though present at birth) is not fully functional at birth and takes time to develop.
Third Line of Defense If the pathogens survive our first and second line of defenses, the pathogens are going to be challenged by our third line of defense against infection, which is our acquired/adaptive immune response. Unlike the innate/nonspecific first and second lines of defense the adaptive immune response is pathogen **SPECIFIC**. The specificity is due to the presence of unique **ANTIGENS** present on the surface of each pathogen. Unless the antigens change, the individual will have **MEMORY** against that antigen usually preventing reinfection from the same pathogen. Unfortunately, the adaptive (though present at birth) is not fully functional at birth and takes time to develop.
54
Adaptive Immunity- The cells utilized in the attack of the pathogen are
lymphocytes
55
2 types of lymphocytes and what they're responsible for
T Lymphocytes (T cells)- responsible for **cell-mediated immunity** which is a response against **intracellular** pathogens B Lymphocytes (B cells)- responsible for **humoral immunity** which is a response against **extracellular** pathogens
56
In both types of immunity (humoral/cell-mediated), the attack of the pathogen occurs as a result of the ______ of an ______. The antigen is a molecule that triggers an immune response. The antigen is usually a surface protein however it could also be a carbohydrate or a lipid. There are **3 basic categories of antigens:**
As a result of the **recognition of an antigen** - Exogenous antigens - Endogenous antigens - Autoantigens
57
Exogenous antigens
found outside a body's cells (including toxins and other components of microbial cell walls, membranes, flagella, pili)
58
Endogenous antigens
produced by microbes that reproduce inside a body's cells
59
Autoantigens
self made antigens
60
On the antigens are variable regions called ______. The epitopes have variable shapes, sizes, and complexity. It is the epitope that the immune system recognizes when mounting an attack against the pathogen. Epitopes are only recognized by adaptive immunity cells when carried on _____
Epitopes MHCs
61
Epitope definition
3-dimensional regions that recognize antigens
62
Epitopes are recognized by the lymphocytes when displayed as
Major Histocompatibility Complex (MHC) proteins
63
Function of MHCs
Holds and positions epitopes for presentation to immune cells
64
Cells that presents the epitope to the lymphocyte is called an
Antigen Presenting Cell (APC)
65
MHC 1
- Present on all nucleated cells - Fixed cells (stationary, not moving around)
66
MHC 2
- Wandering cells with a nucleus - Only present on APCs
67
MHC 2s include
macrophages, dendritic cells, and B cells
68
Autoantigens are displayed as
self MHC's
69
Endogenous and exogenous antigens are processed into ____ proteins to display _____ ______ Depending on the cell, these can be either ____ __ if a nucleated fixed cell, or ____ _ and ____ __ if an _____ ____ ____
are processed into **MHC** proteins to display **foreign epitopes** Depending on the cell, these can be either **MHC 1** if a nucleated fixed cell, or **MHC 1 and MHC 2** if an **antigen presenting cell**
70
The antigens of the pathogen will be ______ and ultimately _______ as an MHC containing the epitopes that can activate the immune response.
The antigens of the pathogen will be **processed and ultimately displayed** as an MHC containing the epitopes that can activate the immune response.
71
When T cells mature they are produced with a protein ___ ____ _______ that is unique and complementary to specific epitopes. Every possible epitope the human body can encounter will have a _______ TCR on a T cell. For example, there is a T cell that will have a TCR that will recognize the epitope displayed on stingray venom even though the individual may not come in contact with a stingray. Similarly, B cells have on the surface a ___ _____ ______ that too is unique for the various epitopes. In both instances, once recognition of the epitope has occurred, ____ ______ occur to produce larger numbers of lymphocytes to effectively remove the pathogen.
When T cells mature they are produced with a protein **T CELL RECEPTOR (TCR)** that is unique and complementary to specific epitopes. Every possible epitope the human body can encounter will have a **matching** TCR on a T cell. For example, there is a T cell that will have a TCR that will recognize the epitope displayed on stingray venom even though the individual may not come in contact with a stingray. Similarly, B cells have on the surface a **B CELL RECEPTOR (BCR)** that too is unique for the various epitopes. In both instances, once recognition of the epitope has occurred, **cell divisions/multiplication** occur to produce larger numbers of lymphocytes to effectively remove the pathogen.
72
Recognition of the epitopes generally requires the assistance of _______ ______ ______. These can be either ______, ______ ___, or ___ ______. The job of an antigen presenting cell is to take components of the pathogen and display it on the surface as a MHC for the appropriate lymphocytes with the complementary TCR/BCR to recognize. Once recognition occurs then proliferation can occur resulting in the mass production of T and B cells to effectively attempt to remove the pathogen.
Recognition of the epitopes generally requires the assistance of **ANTIGEN PRESENTING CELLS (APC)**. These can be either **macrophages, dendritic cells, or B cells**. The job of an antigen presenting cell is to take components of the pathogen and display it on the surface as a MHC for the appropriate lymphocytes with the complementary TCR/BCR to recognize. Once recognition occurs then proliferation can occur resulting in the mass production of T and B cells to effectively attempt to remove the pathogen.
73
The interaction between leukocytes and dendritic cells and between different leukocytes requires ________ Costimulation is a result of the surface molecules on each of the cells as well as the release of important chemical molecules. These chemical molecules are referred to as _______
The interaction between leukocytes and dendritic cells and between different leukocytes requires **COSTIMULATION**. Costimulation is a result of the surface molecules on each of the cells as well as the release of important chemical molecules. These chemical molecules are referred to as **CYTOKINES**
74
Example of a cytokine and what it does
Interleukins (ILs): signal among leukocytes
75
Remember that T cells are responsible for cell-mediated immunity, which is the..
attack of infected cells
76
Components of T cell Activation
Cytotoxic T Helper T Memory T Regulatory T
77
Cytotoxic T
kills other cells with perforins
78
Helper T (T cell activation)
- helps multiply cytotoxic T cells - Type 1 (Th1)
79
Memory T
remembers same epitope in future
80
Regulatory T
inhibits autoantigen attack
81
Important points- T Cell Activation: - Infected cells are displaying _____ _ ______ antigens - APC displays both _____ __ and ____ __ - Interleukin ____ produced by APC causes Th to become ___ - Interleukin ___ produced by both Th1 and T8- activates ___
- Infected cells are displaying **MHC 1 endogenous** antigens - APC displays both **MHC 1 and MHC 2** - Interleukin **12** produced by **APC** causes Th to become **Th1** - Interleukin **2** produced by both Th1 and T8- activates **T8**
82
Remember that B cells are responsible for humoral immunity, which is the
production of **antibodies** to attack extracellular epitopes (exogenous antigens)
83
Types of lymphocytes used in B cell activation
B lymphocytes Plasma cells Helper T Memory B
84
B lymphocytes
- initially recognize exogenous antigens, act as APC - becomes plasma cells
85
Plasma cells
produce antibodies
86
Helper T (B cell activation)
- helps multiply B cells - Type 2 (Th2)
87
Memory B
remembers the same epitope in the future
88
Key points of B cell Activation: - _____ (both dendritic and B cell) displays _____ - Interleukin ___ causes Th to become ___ - Interleukin __ from Th also activates ______ to become _____ ____ - _______ made by plasma cells attack _______ antigens
- **APC's** (both dendritic and B cell) displays **MHC 2** - **Interleukin 4** causes Th to become **Th2** - Interleukin **4** from Th also activates **B cell** to become **plasma cells** - Antibodies made by plasma cells attack **exogenous** antigens
89
Exogenous means
in the blood
90
Types of antibodies: The antibodies that are produced by plasma cells come in a variety of different forms. The basic structure is a Y shaped molecule composed of __ _____ _____ and ___ _____ ____. Each chain has a ______ region on it that creates an _______ ______ _____ that is ______ for each specific ______. The stem of the Y shaped antibody has some variation that is the premise for the difference between the types of antibody produced.
The antibodies that are produced by plasma cells come in a variety of different forms.The basic structure is a Y shaped molecule composed of **2 heavy chains and 2 light chains**. Each chain has a **variable** region on it that creates an **ANTIGEN BINDING SITE** that is **unique** for each specific **epitope**.
91
Types of antibodies: What is the premise for the difference between the types of antibody produced?
The **stem** of the Y shaped antibody
92
5 types of antibodies
IgG IgA IgM IgE IgD
93
IgM
1st antibody produced; acute
94
IgG
most common and longest lasting; chronic
95
IgA
associated with body secretions; mucous membranes
96
IgE
involved in response to parasitic infections & allergies
97
A child has been infected with pinworms
IgG
98
Got the rabies vaccine a year ago
IgG
99
Just got coughed on from a person with the flu
IgM
100
4 functions/mechanisms of attack for antibodies
Phagocytosis Lysis Agglutination Neutralization

Microbiology (17 decks)

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