Chapter 19

Question 1

Difference between Hypersensitivity and Autoimmunity:

Answer 1

Hypersensitivity: Exaggerated immune response to a harmless antigen, leading to tissue damage.
Autoimmunity: Immune response against self-antigens, where the immune system targets its own tissues.

Question 2

Is the immune system functioning normally during hypersensitivity?

Answer 2

Hypersensitivity: Yes, the immune system is functioning normally, but the response is exaggerated.

Question 3

Is the immune system functioning normally during autoimmunity sensitivity?

Answer 3

Autoimmunity: No, the immune system is not functioning normally; it is targeting self-antigens.

Question 4

What are the details of four types of hypersensitivity?

Answer 4

Type I: Immediate hypersensitivity, mediated by IgE. Examples include hay fever, asthma, and anaphylaxis.
Type II: Cytotoxic hypersensitivity, involving antibodies targeting cells. Examples include blood transfusion reactions.
Type III: Immune complex hypersensitivity, where immune complexes cause tissue damage. Example: Serum sickness.
Type IV: Delayed hypersensitivity, mediated by T cells. Examples include contact dermatitis and transplant rejection.

Question 5

What types of hypersensitivity requires B cell activity?

Answer 5

Hypersensitivity Requiring B Cell Activity:

Types I, II, and III hypersensitivity involve B cell activity.

Question 6

How does the body normally respond to an injected antigen during a type I
hypersensitivity?

Answer 6

IgE antibodies bind to mast cells, leading to degranulation and the release of histamine. This causes rapid allergic reactions. Blood vessel dilation which leads to decreased blood pressure.

Question 7

What were some examples of type II hypersensitivity given in class?

Answer 7

Blood transfusion reactions (ABO incompatibility), hemolytic disease of the newborn (Rh factor), and drug-induced reactions.

Question 8

Which type of hypersensitivity can be linked specifically to IgG?

Answer 8

Type II hypersensitivity is commonly linked to IgG antibodies.

Question 9

Which type of hypersensitivity is dependent only on T cell activation?

Answer 9

Type IV hypersensitivity (Delayed hypersensitivity) is dependent only on T cell activation.

Question 10

Which type of hypersensitivity has the shortest wait time for the onset of a reaction after
exposure?

Answer 10

Type I hypersensitivity has the shortest wait time for the onset of a reaction after exposure.

Question 11

What are the four classes of autoimmunities and what are examples of each?

Answer 11

1. Type I: Cytotoxic reaction where antibodies bind to self antigens and cause cell death (Autoimmune hemolytic anemia)
2. Type II: Cytotoxic reaction where antibodies bind to self antigens but DO NOT kill cell, changes cell function (Graves Disease)
3. Type III: Immune complex reactions (Systemic lupus)
4. Type IV: Cell-mediated reactions (Insulin-dependent diabetes)

Question 12

How are TH17 CD 4+ T cells related to the autoimmunities?

Answer 12

TH17 CD4+ T cells are associated with autoimmune diseases, contributing to excessive inflammation.

Question 13

What are a few of the suspected causes of hypersensitivity and autoimmunity?

Answer 13

Genetic predisposition, molecular mimicry, failure of negative selection, and environmental factors.

Question 14

How does the hygiene hypothesis connect with hypersensitivities and autoimmunities?

Answer 14

Reduced exposure to infections and microbes (as a kid) may lead to an increased risk of hypersensitivity and autoimmunity.

Question 15

Is the immune system functioning normally during immunodeficiency?

Answer 15

No, the immune system is compromised and not functioning properly.

Question 16

What are the two most common immunodeficiencies?

Answer 16

Selective IgA deficiency and Common Variable Hypogammaglobulinemia.

Question 17

What does the abbreviation SCID stand for?How does SCID affect the immune system? Is SCID a serious condition?

Answer 17

SCID: Severe Combined Immunodeficiency.
SCID results in the complete loss of B cells and T cells, severely affecting the immune system. It is a serious condition.

Question 18

What are the structural characteristics of HIV?

Answer 18

Enveloped retrovirus with glycoprotein spikes, containing two pieces of ssRNA genome and reverse transcriptase.

Question 19

Which type of HIV is common in North America, for the United States and Mexico?

Answer 19

Clade B is the most common type of HIV in North America.

Question 20

What allows HIV to change over the course of an infection?

Answer 20

N/A

Question 21

What are the human host cell receptor and coreceptors that allow HIV to infect?

Answer 21

CD4 is the host cell receptor, and coreceptors include CCR5 or CXCR4.

Question 22

Which specific immune cell types are infected by HIV?

Answer 22

Macrophages, dendritic cells, and CD4+ T cells are infected by HIV.

Question 23

How is the life cycle of HIV distinct from other viral families?

Answer 23

HIV has gp120 attachment spike so that it can latch onto normal cells. UNSURE OF THIS ANSWER.

Question 24

Which body organ becomes infested with large amounts of HIV?

Answer 24

Lymph nodes become a chronic reservoir for HIV.

Question 25

How is HIV most likely to be transmitted?

Answer 25

Transfer of contaminated body fluids through intercourse, blood transfusions, and needle sharing.

Question 26

What are the names and descriptions of each phase of HIV infection?

Answer 26

Phase I: Asymptomatic Phase. Then start to develop flu-like symptoms
Phase II: Symptomatic Phase. Begin to show immune system failure.
Phase III: AIDS (Acquired Immunodeficiency Syndrome). CD4 count is less than 200 per uL (microleter).

Question 27

How does T cell number relate to disease progression? What is the normal value, before disease starts to affect the body?

Answer 27

T cell number decreases as disease progresses. A normal value is around 1,000 to 800 CD4+ T cells/uL before disease affects the body.

Question 28

What does the abbreviation ARS stand for? During which phase of HIV infection would ARS occur?

Answer 28

ARS: Acute Retroviral Syndrome.
ARS occurs during the early phases (phase1) of HIV infection, presenting flu-like symptoms.

Question 29

What is a noticeable indicator that HIV infection has progressed to phase 2?

Answer 29

Increased frequency of opportunistic infections and early signs of immune system failure.

Question 30

What does the abbreviation HAART stand for? Why is treatment with HAART a
challenge in developing countries?

Answer 30

HAART: Highly Active Antiretroviral Therapy.
Treatment with HAART is a challenge in developing countries due to cost, accessibility, and healthcare infrastructure limitations.

Question 31

Which state has the most new HIV infections?

Answer 31

Texas has the most new HIV infections.

Question 32

Which state contains the greatest number of people living with HIV infections?

Answer 32

New York has the greatest number of people living with HIV infections.

Question 33

In the US, who is most at risk for becoming infected with HIV?

Answer 33

Men who have sex with men (MSM) are most at risk for HIV infection.

Question 34

Globally, who is most at risk for becoming infected with HIV?

Answer 34

N/A

Question 35

Be able to explain the difference between a person that is HIV positive and a person
who has AIDS

Answer 35

HIV positive indicates the presence of the virus, while AIDS is the advanced stage of HIV infection with severe immune system damage.

Question 36

Be able to explain how and why HIV, if untreated, can lead to immunodeficiency (AIDS).

Answer 36

Untreated HIV leads to the progressive destruction of CD4+ T cells, compromising the immune system and resulting in immunodeficiency (AIDS).