Unit 8 Objectives

Question 1

Describe the difference between the innate and adaptive immune response. Given a specific scenario, determine which defense mechanism is at work.

Answer 1

• Innate Immune Response: A nonspecific, immediate defense mechanism that includes physical barriers, phagocytic cells, inflammation, and antimicrobial proteins.
• Adaptive Immune Response: A specific, slower defense that targets particular pathogens via lymphocytes (B and T cells) and memory formation for future protection.

Example Scenario: If macrophages engulf bacteria at the site of a cut, it’s the innate immune response;

if antibodies are produced against a virus after vaccination, it’s the adaptive immune response.

Question 2

Describe the role of the adaptive immune response in recognizing self vs. non-self.

Answer 2

The adaptive immune response distinguishes self from non-self through specialized receptors on T and B cells, which are trained to recognize foreign antigens while tolerating self-antigens, a process crucial for preventing autoimmunity

Question 3

Describe the role of the adaptive immune response in specificity and memory.

Answer 3

The adaptive immune response provides specificity through antigen-specific receptors on T and B cells, and it develops memory by creating long-lived cells that enable a faster, more robust response to subsequent exposures to the same pathogen

Question 4

What comes to mind?

MHC I
MHC II
Antigens
Antibodies
Fab
Fc
BCR
TCR
CD4
CD8
Clonal selection
Clonal expansion
ADCC
Tc action

Answer 4

MHC I: what is happening inside
MHC II: what is happening on the outside of the cell
Antigens: immune response
Antibodies: Ig’s
Fab: binds to antigen
Fc: stem
BCR: made before encountering any antigen
TCR: MHC I and MHC II
CD4: found on T-helper cells
CD8: found on cytotoxic T cells
Clonal selection: when you make contact with the antigen or epitope
Clonal expansion: when you divide and differentiate after being selected or activated
ADCC: antibody dependent cell cytotoxicity, apoptosis
Tc action: effector cytotoxic T cells, apoptosis virus

Question 5

MHC-I on B cells would be used to present _____

Answer 5

Endogenous antigens, peptides originating from within the cell

viral peptides or cancer peptides

Question 6

T or F
Dendritic cells can be presenting more than one epitope at an given moment

Answer 6

True;

endogenous on MHC I and exogenous of MHC II

Question 7

Dendritic cells present epitope to ____ cells

Answer 7

T- helper cells;

B cells relay their information to T helper cells because B cells can recognize foreign agents using their BCR’s and engulf them and process them into specific epitopes to present to T helper cells

Question 8

B cells have which MHC?

Answer 8

MHC I: since they’re on all cells, nucleated cells, except RBC’s

and MHC II: because they have a role as an antigen presenting cell

Question 9

B cells detect epitope with their ______

Answer 9

BCR

Question 10

T or F

B cells can recognize their epitope before they ever encounter it

Answer 10

True;

B cells are randomly made through rearrangements of the genes that are involved in making parts of the BCR in hopes that one of the combinations will meet its “soulmate”

Question 11

T helper cells have which 3 things on cell surface?

Answer 11

MHC I: because they are a nucleated cell and gives immune system an idea if any of our cells have problems

CD4: glycoproteins on a specific immune cell that helps coordinate the immune response by acting as a co-receptor on the T helper cell, immune cell marker

TCR: because this is how they recognize processed antigens or epitopes presented by MHC II on an antigen presenting cell

Question 12

What is used by Th to present their normal epitopes?

Answer 12

MHC I: because MHC I are on all nucleated cell and it tells the immune system is that particular cell is functioning properly or not

Question 13

What is used by Th to detect MHC II presenting epitope?

Answer 13

TCR: binds to the processed antigen or epitope presented to it by the antigen presenting cell via the antigen presenting cells MHC II

CD4: glycoproteins that acts and a co receptor, it will lock the TCR processed antigen MHC II into place
its like a second key for a safe deposit box

Question 14

TLR can detect the same epitope as BCR

Answer 14

False;

the TLR only recognize general PAMP’s not specific to epitopes that the BCR does

Question 15

Dendritic cells infected with a replicating virus present antigen on _____

Answer 15

MHC I: used to tell other immune cells its health status

Question 16

If you looked on the cell surface of cells of the innate (eg. macrophages) vs. that of the adaptive (eg. B or T cells), then how could yo u tell the difference between the two?

Answer 16

In an innate immune response specifically like macrophages they will have Toll like receptors (TLR’s)

Adaptive immune response (B cells or T cells) will have BC’s or TCR’s depending upon which cell you’re looking at

Question 17

What immunity are B cells apart of and what do they do?

Answer 17

Humoral immunity;

produce antibodies (plasma cells), which are a hallmark of humoral immunity

Question 18

What immunity are helper T cells apart of and what do they do?

Answer 18

Cellular immunity;

assist other immune cells (both humoral and cellular) by releasing cytokines but are part of the cellular immune response

Question 19

What immunity are cytotoxic T cells apart of and what do they do?

Answer 19

Cellular immunity;

they directly attack and kill infected or abnormal cells, a key aspect of cellular immunity

Question 20

How are the following important in the immune response?
a. Lymph nodes

Answer 20

a. Lymph nodes: Lymph nodes filter lymphatic fluid, trap pathogens, and serve as sites where immune cells, such as T and B lymphocytes, are activated

Question 21

How are the following important in the immune response?
b. Spleen

Answer 21

b. Spleen: Filters blood to remove pathogens, damaged red blood cells, and activates immune cells like lymphocytes

Question 22

How are the following important in the immune response?
c. Tonsils

Answer 22

c. Tonsils: Serve as the first line of immune defense by detecting and responding to pathogens entering through the mouth and nose

Question 23

How are the following important in the immune response?
d. MALT

Answer 23

d. MALT (Mucosa-Associated Lymphoid Tissue): Protects mucosal surfaces by trapping pathogens and initiating localized immune responses

Question 24

How are the following important in the immune response?
e. B lymphocytes

Answer 24

e. B lymphocytes: Produce antibodies to neutralize pathogens and provide long-term immunity through memory cells

Question 25

How are the following important in the immune response?
f. T lymphocytes

Answer 25

f. T lymphocytes: Mediate cellular immunity by killing infected cells and regulating the activity of other immune cells

Question 26

Describe the difference(s) between the following pairs of terms:
a. Antigen vs. antibody

Answer 26

Antigen vs. antibody

An antigen is a substance that triggers an immune response

an antibody is a protein produced by B lymphocytes that specifically binds to and neutralizes antigens

Question 27

Describe the difference(s) between the following pairs of terms:
b. Antigen vs. epitope (antigenic determinant)

Answer 27

Antigen vs. epitope (antigenic determinant)

An antigen is a large molecule that can induce an immune response

an epitope is a specific region or part of the antigen that is recognized by immune cells or antibodies

Question 28

Describe the difference(s) between the following pairs of terms:
c. Exogenous antigens vs. endogenous antigens (in this pair list examples)

Answer 28

Exogenous antigens vs. endogenous antigens

Exogenous antigens come from outside the body (e.g., bacteria, viruses)

endogenous antigens originate within the body, typically from infected or abnormal cells (e.g., virus-infected cells, tumor proteins)

Question 29

What is an autoantigen?

Answer 29

A molecule or structure within the body that is normally recognized as “self” by the immune system but becomes targeted by it in autoimmune diseases

This occurs when the immune system mistakenly identifies the body’s own tissues as foreign, leading to immune responses that damage healthy cells and organs

Question 30

Where are B cells found in the body?

B cells function in which type of immunity (humoral or cell-mediated)?

Describe what a BCR is and its role in the immune response. Be specific.

What is the likelihood that the body has a B cell for every possible epitope?

Answer 30

B cells are primarily found in the bone marrow, blood, and lymphoid tissues such as the spleen and lymph nodes.

B cells function in humoral immunity, where they produce antibodies to neutralize pathogens.

A BCR (B Cell Receptor) is a membrane-bound immunoglobulin that specifically recognizes and binds to an antigen’s epitope, triggering B cell activation and antibody production.

The likelihood that the body has a B cell for every possible epitope is very high due to the vast diversity of BCRs generated by genetic recombination, though not every possible epitope will be represented at all times.

Question 31

An antibody is composed of what type of macromolecule?

Answer 31

An antibody is composed of proteins, specifically immunoglobulins

Question 32

What are the five classes of antibodies and their roles in the immune response?

Answer 32

1. IgG:
   The most abundant antibody in blood and extracellular fluid; involved in neutralizing toxins, opsonizing pathogens, and activating the complement system.
2. IgA:
   Found primarily in mucosal areas (e.g., respiratory and gastrointestinal tracts); it plays a key role in mucosal immunity by preventing pathogens from entering through epithelial surfaces.
3. IgM:
   The first antibody produced in response to an infection; it is efficient at activating the complement system and is mainly found in the blood.
4. IgE:
   Associated with allergic reactions and the defense against parasitic infections; it binds to mast cells and basophils, triggering the release of histamine during allergic responses.
5. IgD:
   Primarily found on the surface of immature B cells; it plays a role in initiating B cell activation in response to antigen binding.

Question 33

When an antibody binds to an epitope, describe the seven things that can happen as a result of this antibody-antigen binding

Answer 33

1. Neutralization: The antibody binds to and blocks the harmful effects of toxins or pathogens.
2. Opsonization: The antibody marks the pathogen for easier recognition and phagocytosis by immune cells like macrophages.
3. Agglutination: The antibody causes the clumping of antigens, facilitating their removal from the body.
4. Precipitation: Soluble antigens are cross-linked into insoluble complexes, which can be cleared by phagocytes.
5. Complement Activation: The antibody triggers the complement cascade, leading to the destruction of pathogens by lysis.
6. Antibody-dependent Cellular Cytotoxicity (ADCC): The antibody binds to infected cells or cancer cells, signaling immune cells like NK cells to destroy these targets.
7. Inflammation: The binding of antibodies can trigger the release of pro-inflammatory cytokines, which recruit additional immune cells to the site of infection.

Question 34

Define antiserum and gamma globulin

Answer 34

Antiserum: A blood serum containing antibodies against specific antigens, often used in passive immunity treatments.

Gamma Globulin: A fraction of blood plasma rich in immunoglobulins (antibodies) used for immune protection, often administered as a treatment for immune deficiencies or infections.

Question 35

Where are T cells found in the body?

T cells function in which type of immunity (humoral or cell-mediated)?

Answer 35

Location: T cells are primarily found in the thymus (where they mature), lymphoid tissues such as the spleen and lymph nodes, and in the bloodstream;

T cells function in cell-mediated immunity, where they directly target and destroy infected cells or coordinate the immune response through other cells like B cells.

Question 36

Compare & contrast TCR and BCR

Answer 36

TCR (T Cell Receptor): Found on T cells, the TCR recognizes processed antigen fragments (peptides) presented by MHC molecules on the surface of antigen-presenting cells

BCR (B Cell Receptor): Found on B cells, the BCR is a membrane-bound form of antibody that recognizes free antigens (e.g., pathogens or toxins) directly and initiates B cell activation.

Question 37

What are the two general types of T cells?

Answer 37

Helper T cells (Th cells): These cells assist in the immune response by secreting cytokines that activate other immune cells, including B cells and cytotoxic T cells.

Cytotoxic T cells (Tc cells): These cells directly kill infected or cancerous cells by recognizing specific antigens presented by MHC I molecules on infected cells.

Question 38

What are cytokines & list examples?

Answer 38

Cytokines are small signaling molecules that are secreted by various cells in the immune system to regulate immune responses, inflammation, and hematopoiesis (blood cell formation).

Examples of Cytokines
Interleukins (IL): Ex. IL-1, IL-2, and IL-6, which help activate immune cells, promote inflammation, and support immune cell proliferation

Interferons (IFN): Ex. IFN-α and IFN-β, which are antiviral cytokines that enhance immune cell activity and inhibit viral replication

Tumor Necrosis Factor (TNF): Ex. TNF-α, which promotes inflammation and apoptosis (cell death) in infected or cancerous cells

Chemokines: Ex. IL-8 and MCP-1, which guide the migration of immune cells to sites of infection or inflammation

Growth factors: Ex. GM-CSF (Granulocyte-macrophage colony-stimulating factor), which stimulates the production of white blood cells

Question 39

What role(s) does/do cytokines play in immunity?

Answer 39

Regulating immune responses: Cytokines help control the activation, differentiation, and proliferation of immune cells like T cells, B cells, macrophages, and neutrophils.

Promoting inflammation: They are key mediators of inflammation, which is important for defense against infection but can also contribute to autoimmune diseases when overactive.

Facilitating communication between cells: Cytokines enable immune cells to communicate with each other, coordinating the body’s immune response to pathogens.

Supporting immune cell movement: Chemokines guide immune cells to the site of infection or injury.

Enhancing pathogen clearance: They activate cells involved in the destruction of pathogens, such as cytotoxic T cells and phagocytes.

Question 40

MHCs are what type of molecules?

Answer 40

MHC molecules are glycoproteins that play a crucial role in the immune system by presenting antigens to immune cells

Question 41

What role(s) does/do MHC molecules play in immunity?

Answer 41

MHC molecules present processed antigenic peptides on the surface of cells, allowing immune cells, particularly T cells, to recognize and respond to pathogens, infected cells, or abnormal cells.

MHC molecules are essential for distinguishing between “self” and “non-self,” and they help initiate immune responses against foreign invaders

Question 42

What is/are the difference(s) between MHCI and MHCII?

Answer 42

MHC I: Found on the surface of all nucleated cells (ec RBC), presents antigens derived from endogenous sources (e.g., intracellular pathogens like viruses or cancerous cells).

These antigens are presented to CD8+ cytotoxic T cells, which can kill infected or abnormal cells

MHC II: Found on specialized antigen-presenting cells (APCs) such as macrophages, dendritic cells, and B cells, presents antigens derived from exogenous sources (e.g., pathogens engulfed and processed by phagocytosis).

These antigens are presented to CD4+ helper T cells, which help coordinate the immune response

Question 43

What types of cells have MHCI? What types of cells have MHCII?

Answer 43

Types of Cells with MHC I
All nucleated cells have MHC I molecules. This includes cells such as epithelial cells, muscle cells, and most other somatic cells.
Types of Cells with MHC II
Only antigen-presenting cells (APCs) have MHC II molecules, including macrophages, dendritic cells, and B cells.

Question 44

What type of epitopes is presented by MHCI? What type of epitopes is presented by MHCII?

Answer 44

Type of Epitopes Presented by MHC I
endogenous epitopes, which are typically peptides derived from proteins inside the cell (such as viral proteins or tumor proteins).

Type of Epitopes Presented by MHC II
exogenous epitopes, which are peptides derived from extracellular sources (such as pathogens or toxins that have been engulfed and processed by APCs).

Question 45

What is the difference between a receptor and MHC?

Answer 45

A receptor is a protein on the surface of a cell that binds to specific molecules (e.g., antigens, hormones) to trigger a response within the cell.

For example, TCR binds to the antigen-MHC complex.

An MHC molecule is a specialized receptor that specifically presents processed antigen peptides to T cells.

The MHC itself does not directly initiate an immune response but plays a vital role in the recognition of antigens by T cells.

Question 46

Describe how exogenous antigens are processed include in your answer (a) the type of cells that process & present these antigens, and (b) the role of dendritic cells.

Answer 46

Processing of Exogenous Antigens:
Exogenous antigens come from outside the body, such as pathogens (bacteria, viruses).

(a) Cells that process & present exogenous antigens:
- Antigen-presenting cells (APCs) like dendritic cells, macrophages, and B cells process and present these antigens.

How it’s processed:
- The antigen is engulfed by the cell and broken down inside lysosomes.

• The MHC II molecules inside the cell bind to the broken-down antigen pieces and display them on the surface.
• CD4+ helper T cells recognize and respond to these antigens, leading to activation of other immune cells.

(b) Role of dendritic cells:
- Dendritic cells are the most effective APCs, capturing antigens, processing them, and presenting them to T cells to trigger an immune response, especially in lymph nodes.

Question 47

Describe how endogenous antigens are processed include in your answer (a) the type of cells that process & present these antigens, and (b) the role of dendritic cells.

Answer 47

Processing of Endogenous Antigens:
Endogenous antigens are from inside the body, like those produced by infected or cancerous cells.

(a) Cells that process & present endogenous antigens:
- All nucleated cells (including infected or cancer cells) process these antigens using MHC I molecules.

How it’s processed:
- The infected or abnormal cell breaks down its own proteins into small pieces (peptides) using a proteasome.

• These peptides are then loaded onto MHC I molecules inside the endoplasmic reticulum.
• The MHC I-antigen complex is displayed on the cell surface to be recognized by CD8+ cytotoxic T cells, which can destroy the infected or abnormal cell.

(b) Role of dendritic cells in endogenous antigen presentation:
- Dendritic cells can also present endogenous antigens via cross-presentation.

They can capture infected cells, process their antigens, and present them on MHC I to activate CD8+ T cells.

Question 48

Describe T-independent humoral immune response include the following in your description:
a. the role of dendritic cells, MHC, B cells, BCR, Th2 cells, TCR, cytokines, plasma cells, memory cells
b. clonal selection
c. clonal expansion
d. results of Ab-Ag binding

Answer 48

T-Independent Humoral Immune Response:

a. Role of Cells and Molecules:
- B Cells & BCR: In T-independent responses, B cells use their BCR to directly recognize and bind to the antigen, activating them.

• Plasma Cells & Memory Cells: Activated B cells become plasma cells, which produce antibodies, and some become memory cells for long-term immunity.
• Clonal Selection & Expansion: The B cell that recognizes the antigen is selected and then rapidly divides (clonal expansion) to produce more plasma cells and memory cells.
• Results of Ab-Ag Binding: Antibodies can neutralize, agglutinate, and mark antigens for destruction (phagocytosis). These responses happen without T cell help.

Question 49

12) Describe T-dependent humoral immune response include the following in your description:
a. the role of dendritic cells, MHC, B cells, BCR, Th2 cells, TCR, cytokines, plasma cells, memory cells
b. clonal selection
c. clonal expansion
d. results of Ab-Ag binding

Answer 49

T-Dependent Humoral Immune Response:

a. Role of Cells and Molecules:
- Dendritic Cells & MHC: Dendritic cells present the antigen on MHC II molecules to Th2 cells.

• Th2 Cells: Th2 cells release cytokines, which activate B cells.
• B Cells & BCR: B cells recognize the antigen using their BCR, present it to Th2 cells via MHC II, and receive help from Th2 cytokines.
• Plasma Cells & Memory Cells: B cells differentiate into plasma cells (which make antibodies) and memory cells (which provide future immunity).
• Clonal Selection & Expansion: The best-matching B cell is selected, then undergoes clonal expansion to produce more plasma cells and memory cells.

b. Results of Ab-Ag Binding: Antibodies neutralize pathogens, enhance phagocytosis, agglutinate them, and activate the complement system.

This response is stronger and longer-lasting due to the production of different antibody types (like IgG) and memory cells.

Question 50

Key differences between T-independent cells and T-dependent cells

Answer 50

• T-Independent: B cells act alone to make IgM antibodies, with no memory cells formed.
• T-Dependent: B cells need help from Th2 cells, leading to a broader antibody response (like IgG) and memory cells for future immunity.

Question 51

Describe cell-mediated immune response include the following in your description:
a. how Th1 and Tc cells are activated
b. role of dendritic cells, MHC-I, CD 8, cytokines, “second signals”
c. how Tc cells recognize infected cells that need to be destroyed
d. how the perforin-granzyme cytotoxic pathway works

Answer 51

Cell-Mediated Immune Response:

The cell-mediated immune response is primarily carried out by T cells (Th1 and Tc cells) to defend against infected cells and cancer cells.

a. How Th1 and Tc Cells Are Activated:
- Th1 Cells: Dendritic cells or macrophages present processed antigens on MHC II molecules to CD4+ Th1 cells, activating them. This requires cytokine signals like IL-12 from dendritic cells.

• Tc Cells: Dendritic cells also activate CD8+ cytotoxic T cells (Tc cells) by presenting antigens on MHC I molecules. Tc cells require a second signal from co-stimulatory molecules (e.g., CD80/86) and cytokines (like IL-2) from Th1 cells to be fully activated.

b. Role of Dendritic Cells, MHC-I, CD8, Cytokines, “Second Signals”:
- Dendritic Cells: Act as the main antigen-presenting cells, capturing and presenting antigens to activate T cells.

• MHC-I: Present on all nucleated cells, used by Tc cells to recognize and respond to endogenous antigens (like viral proteins).
• CD8: A receptor on Tc cells that binds to MHC I, allowing Tc cells to recognize infected or abnormal cells.
• Cytokines: IL-2 and other cytokines help activate Tc cells and promote their clonal expansion.
• “Second Signals”: Co-stimulatory signals (like CD80/86) from antigen-presenting cells are necessary to fully activate T cells.

c. How Tc Cells Recognize Infected Cells:
- Tc cells use their TCR to recognize foreign antigens presented on MHC I molecules on the surface of infected cells.

• CD8 binds to MHC I, allowing Tc cells to identify and target infected cells for destruction.

d. How the Perforin-Granzyme Cytotoxic Pathway Works:
- Once a Tc cell identifies an infected cell, it releases perforin, a protein that forms pores in the target cell’s membrane.

• Granzyme is then delivered through the pores into the infected cell. Granzyme triggers apoptosis (programmed cell death) in the infected cell, eliminating the threat.

Question 52

Compare & contrast humoral vs. cell-mediated immunity

Answer 52

Humoral Immunity deals with extracellular pathogens and involves B cells and antibodies.

Humoral Immunity is essential for fighting infections in bodily fluids

Cell-Mediated Immunity handles intracellular pathogens and involves T cells (especially Tc cells for killing infected cells).

cell-mediated immunity is critical for dealing with infections inside cells.

Question 53

Are humoral and cell-mediated immunity interrelated? Explain your answer.

Answer 53

Yes, humoral and cell-mediated immunity are interrelated and work together:

• Th2 cells (part of cell-mediated immunity) help B cells (in humoral immunity) produce antibodies by releasing cytokines that activate B cells.
• Cytokines from Th1 cells help activate macrophages, which can assist in clearing pathogens from tissues, supporting both immune responses.
• Both types of immunity depend on antigen-presenting cells (APCs) (like dendritic cells), which activate both T cells and B cells.

Question 54

Compare and contrast primary vs. secondary antibody immune response.

Answer 54

Primary Immune Response:

First Exposure to Antigen
Lag Phase: There is a delay of several days to weeks as the body recognizes the antigen, activates B cells, and starts producing antibodies.
Memory Cells
- Slower, produces IgM first, then IgG.

Secondary immune response
Subsequent Exposure to Antigen
Faster Response: Memory B cells are quickly activated, leading to a faster and stronger immune response.
Antibody Production: Rapid production of IgG antibodies, and sometimes IgA or IgE, often at higher levels
Higher Affinity: The antibodies produced have a higher affinity for the antigen due to affinity maturation in memory B cells.

Question 55

Given a graphical representation of a specific response, be able to identify which type of response it is and label the types of Ab involved.

Answer 55

In a graph of antibody levels over time, the primary response will show a delayed rise in IgM, followed by a slower increase in IgG.

The secondary response will show a rapid and higher increase in IgG antibodies, often with a minimal lag phase and much higher levels than the primary response.

Question 56

What allows for a faster & more efficient secondary response?

Answer 56

Prior exposure

Higher affinity because of maturation

Question 57

Naturally acquired active immunity:

Naturally acquired passive immunity:

Answer 57

Naturally acquired active immunity: the body responds to antigens that enter naturally, such as during infections (get the disease)

Naturally acquired passive immunity: antibodies are transferred from mother to offspring, either across the placenta (IgG) or in breast milk (secretory IgA)

Question 58

Artificially acquired active immunity:

Artificially acquired passive immunity:

Answer 58

Artificially acquired active immunity: health care workers introduce antigens in vaccines; the body responds with antibody or cell-mediated immune responses, including the production of memory cells

Artificially acquired passive immunity: health care workers give patients antisera or antitoxins, which are preformed antibodies obtained from immune individuals or animals

Question 59

What is a vaccine?

Answer 59

A vaccine is a biological preparation that stimulates the immune system to recognize and fight specific pathogens (such as bacteria or viruses) without causing the disease.

It contains a form of the antigen (the part of the pathogen that triggers an immune response) that is harmless but still recognizable by the immune system.

Question 60

Explain what a vaccine does in the body with regards to immunity.

Answer 60

Immune System Activation: A vaccine introduces a harmless version of an antigen (such as a dead or weakened pathogen or its components) into the body.

Immune Response: The body recognizes the antigen as foreign and activates the immune system. This involves the production of antibodies and the activation of memory cells.

Memory Cells: These memory cells remain in the body long after vaccination and are prepared to respond quickly and effectively if the body encounters the actual pathogen in the future.

Immunity: As a result, the person becomes immune to the disease because their immune system can recognize and fight off the pathogen more quickly during subsequent exposures.

Question 61

Explain why routine vaccinations are important.

Answer 61

Prevention of Disease: Vaccines prevent infectious diseases, many of which can be deadly or cause long-term health problems.

Herd Immunity: When a large portion of a population is vaccinated, it reduces the spread of disease, protecting those who cannot be vaccinated (e.g., people with weakened immune systems).

Eradication of Diseases: Vaccination can lead to the complete eradication of certain diseases (e.g., smallpox) and reduce the prevalence of others (e.g., polio).

Cost-Effective: Vaccines save lives and money by preventing outbreaks, reducing the need for treatment, and preventing complications associated with diseases.

Question 62

Describe the three types of vaccines (attenuated, inactivated, toxoid) include how it is made, how it affects the immune system and an example.

Answer 62

1. Attenuated (Live) Vaccines:
   • Made By: The pathogen is weakened so it cannot cause disease but can still replicate in the body.
   • How it Affects the Immune System: The immune system recognizes and responds to the live but weakened pathogen, producing antibodies and memory cells, providing long-lasting immunity.
   • Example: Measles, Mumps, and Rubella (MMR) vaccine.
   • Pros: Often provides long-lasting immunity after one or a few doses.
   • Cons: Not suitable for people with weakened immune systems because the live virus could potentially cause disease.

Question 63

Describe the three types of vaccines (attenuated, inactivated, toxoid) include how it is made, how it affects the immune system and an example.

Answer 63

2. Inactivated (Killed) Vaccines:
   • Made By: The pathogen is killed or inactivated (e.g., by heat or chemicals) so it cannot replicate or cause disease.
   • How it Affects the Immune System: The immune system reacts to the inactivated pathogen, producing antibodies and memory cells, but typically requires booster shots to maintain immunity.
   • Example: Polio vaccine (IPV), Hepatitis A vaccine.
   • Pros: Safe for people with weakened immune systems because the pathogen cannot cause disease.
   • Cons: May require more doses to maintain immunity.

Question 64

Describe the three types of vaccines (attenuated, inactivated, toxoid) include how it is made, how it affects the immune system and an example.

Answer 64

3. Toxoid Vaccines:
   • Made By: The toxins produced by certain bacteria are inactivated (e.g., by chemical treatment) to make them harmless, but still stimulate an immune response.
   • How it Affects the Immune System: The immune system recognizes the inactivated toxin (toxoids) and produces antibodies specifically against the toxin, providing protection against the effects of the toxin rather than the pathogen itself.
   • Example: Tetanus vaccine, Diphtheria vaccine.
   • Pros: Provides protection against bacterial toxins that cause illness.
   • Cons: Often requires boosters to maintain immunity.

Question 65

What are natural killer cells and what role does it play in immunity?

Answer 65

Natural killer (NK) cells are a subset of lymphocytes that are part of the innate immune system

They play a critical role by detecting and destroying infected cells and tumor cells through the recognition of abnormal or missing self-molecules, particularly those with reduced expression of MHC I molecules.

Question 66

Describe ABO and Rh blood typing

Answer 66

ABO blood typing classifies blood into four groups (A, B, AB, and O) based on the presence or absence of A and B antigens on red blood cells

O is the universal donor and type AB is the universal recipient

Rh blood typing identifies the presence or absence of the Rh factor (also called the Rh antigen or D antigen), where Rh-positive means the antigen is present, and Rh-negative means it is absent, affecting compatibility in blood transfusions and pregnancies

Question 67

Explain why giving the wrong blood type to a patient is bad

Answer 67

Giving the wrong blood type to a patient can trigger an immune response, where the recipient’s immune system recognizes the foreign blood cells as harmful and attacks them, leading to hemolysis

This can cause severe complications such as organ failure, shock, or even death due to the release of toxic substances from the destroyed cells.

Question 68

What is the role of Rh in hemolytic disease of the newborn?

Answer 68

Rh incompatibility occurs when an Rh-negative mother carries an Rh-positive fetus, leading to the potential for the mother’s immune system to produce antibodies against the Rh antigen.

These antibodies can cross the placenta in subsequent pregnancies, attacking and destroying the fetal red blood cells, causing hemolytic disease of the newborn (HDN), which can lead to anemia, jaundice, and severe complications for the baby.

Question 69

Explain how an allergic reaction induces an immune response. How do allergy shots work?

Answer 69

An allergic reaction occurs when the immune system mistakenly identifies a harmless substance, like pollen or pet dander, as a threat, triggering an immune response that involves the release of histamines and other chemicals from mast cells and basophils, causing symptoms like swelling, itching, and inflammation.

Allergy shots work by gradually desensitizing the immune system to the allergen, stimulating the production of IgG antibodies that block the allergen from triggering the release of histamines and thus reducing the severity of allergic reactions over time.

Question 70

LAB EX 20: Perform the lab exercise with your lab group, fill in the document with your lab partners, and upload the document on Canvas in the assigned discussion board. Make sure that all partners check that the answers on the final document turned in for a grade.