Deck 37: Immunity

Question 1

The above figure represents

A) membrane attack complex; pores in bacterial cell
B) macrophage attack complex; fluids released from pores
C) pores for mucus secretion ciliated lung tissue
D) macrophages; muscle tissue
E) none of these

Answer 1

A

Question 2

The letter "A" in the above figure represents

A) keratin-filled, dead epithelial cells.
B) replicating epithelium.
C) mucus produced by underlying ciliated cells.
D) white blood cells attacking a bacterial cell.
E) all of these.

Answer 2

A

Question 3

The source of diversity for B and T cell receptors is

A) mitosis.
B) meiosis.
C) transcript processing.
D) random recombination of genes.
E) gene transcription.

Answer 3

D

Question 4

Antibodies can be produced against all of the following EXCEPT

A) viruses.
B) bacterial cell walls.
C) fungi.
D) toxins.
E) all of these can be bound by an antibody.

Question 5

The following questions refer to the figure above of antibody structure.
The variable region of a light chain is indicated by

A) A.
B) B.
C) C.
D) D.
E) E.

Question 6

Pre-cancerous and even early cervical cancer

A) can be removed if detected early enough.
B) may be caused by HPV, a type of papillomavirus.
C) can be detected by Pap tests.
D) can be prevented with a vaccine.
E) include all of these.

Question 7

Antibodies are

A) proteins.
B) steroids.
C) polysaccharides.
D) lipoproteins.
E) any of these.

Question 8

The first response in adaptive immunity is

A) the production of white blood cells.
B) the production of complement.
C) the production of interferon.
D) inflammation.
E) wound healing.

Question 9

The most abundant of the circulating white blood cells are the

A) neutrophils.
B) macrophages.
C) mast cells.
D) eosinophils.
E) lymphocytes.

Question 10

Histamine

A) causes blood vessels to contract.
B) causes capillaries to lose their permeability.
C) causes an outward flow of fluids from the capillaries.
D) reduces tissue swelling.
E) enhances the function of cytokines.

Question 11

The elimination of resident bacterial populations is

A) beneficial to animals.
B) beneficial to opportunistic pathogens.
C) difficult because they are resistant to antibiotics.
D) unlikely because of their large numbers.
E) all of these.

Question 12

The following questions refer to the figure above of antibody structure.
Antigens bind at

A) A.
B) B.
C) C.
D) D.
E) E.

Question 13

Innate immunity is

A) the body's first line of defense.
B) the body's second line of defense.
C) the body's third line of defense.
D) involved with the production of antibodies.
E) associated with all of these.

Question 14

Antibodies are classified as

A) nucleoproteins.
B) immunoglobulins.
C) polysaccharides.
D) steroids.
E) lipids.

Question 15

Which of the following is NOT involved in self versus nonself recognition?

A) complement
B) MHC markers
C) TCRs
D) plasma membranes
E) all of these are involved.

Question 16

Which of the following is(are) characteristic of acute inflammation?

A) warmth
B) swelling
C) redness
D) pain
E) all of these

Question 17

Normal bacterial inhabitants of the human body

A) are naturally resistant to antibiotics.
B) are able to out-compete some invading pathogens and thus are one of the body's initial defense mechanisms.
C) can be transformed into pathogenic forms if a person's resistance to disease is low.
D) are unable to survive the human body's defense mechanisms.
E) are able to out-compete some invading pathogens and thus are part of the body's innate immunity.

Question 18

Cervical cancer

A) kills about 3,600 U.S.women each year.
B) can affect young women.
C) death occurs more often in women who have not had a Pap smear.
D) can be caused by genital HPV.
E) includes all of these.

Question 19

Which system involves plasma proteins activated when an organism's pattern receptors become bound to anything?

A) cytokine
B) complement
C) suppressor
D) enhancer
E) coagulation

Question 20

Memory cell production is associated with

A) the body's first line of defense.
B) the body's second line of defense.
C) the body's third line of defense.
D) complement production.
E) acute inflammation.

Question 21

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
complement proteins

Question 22

Antihistamines dampen the effect of allergic reactions by

A) blocking the production of histamines.
B) blocking the release of histamines.
C) blocking the effect of histamines.
D) enzymatically destroying the histamines.
E) none of these.

Question 23

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
perforin

Question 24

Which of the following is true of AIDS?

A) It is equivalent to HIV.
B) It is highly contagious.
C) There is no cure for those afflicted.
D) It is caused by a bacterium.
E) It can be prevented by vaccination.

Question 25

The cell-mediated response involves all of the following EXCEPT

A) dendritic cells with antigen-MHC complexes.
B) production of helper T cells.
C) production of cytokines.
D) production of cytotoxic cells.
E) production of antibodies.

Question 26

The immune system's attack on the body's own cells

A) is an autoimmune response.
B) results in anaphylactic shock.
C) is a type of acquired immune deficiency syndrome.
D) is due to the inactivation of helper T cells.
E) is due to an error in the production of MHC markers.

Question 27

Use the figure above to answer the following questions.
The letter "B" from the above figure represents

A) complement.
B) MHC markers with antigen expressed to the surface of a cell.
C) lysosome with MHC molecule.
D) plasma membranes fusing.
E) MHC recycling.

Question 28

All of the following are autoimmune diseases EXCEPT

A) Graves' disease.
B) multiple sclerosis.
C) rheumatoid arthritis.
D) AIDS.
E) lupus.

Question 29

Which of the following is(are) false regarding B cells with antigen-MHC complexes?

A) They are stimulated by helper T cells to secrete cytokines.
B) Helper T cells signal them to divide and differentiate.
C) On signals from the helper T cells, they produce clones with identical receptors.
D) Once activated by signals from helper T cells, they produce IgG, IgA, or IgE immunoglobulins instead of membrane-bound IgM.
E) All of these are true.

Question 30

Approximately ____ million people are now infected with HIV.

A) 1
B) 6
C) 12
D) 20
E) 30

Question 31

In AIDS, the body's reduced capacity for adaptive immunity is due directly to the destruction of ____ cells.

A) NK
B) B
C) helper T
D) T
E) dendritic

Question 32

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
cytotoxic T lymphocytes

Question 33

Which antibody is most commonly associated with an allergic reaction?

A) IgG
B) IgA
C) IgD
D) IgM
E) IgE

Question 34

What are responsible for the rapid mobilization of the immune response after a subsequent attack by a pathogen?

A) naive B cells
B) naive T cells
C) NK cells
D) memory cells
E) macrophages

Question 35

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
antigens

Question 36

Which of the following statements is false?

A) HIV is the virus that causes AIDS.
B) The AIDS virus is a retrovirus.
C) The AIDS virus attacks macrophages, dendritic cells, and helper T cells.
D) HIV has several target cells
E) IgA antibodies can keep HIV levels low for decades.

Question 37

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
clone

Question 38

Most organ transplants fail because

A) of poor vascular connection between host and donor tissue.
B) the migrating leukocytes attack the tissue adjacent to the transplant.
C) of the activity of cytotoxic T cells.
D) introduced tissues produce antibodies that cause a massive reaction.
E) of all of these.

Question 39

Use the figure above to answer the following questions.
The letter "F" from the above figure represents

A) complement.
B) MHC markers with antigen expressed to the surface of a cell.
C) lysosome fusing with a phagosome.
D) plasma membranes fusing.
E) MHC recycling.

Question 40

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
B lymphocytes

Question 41

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
memory cells

Question 42

Classification.Respond to the following statements with reference to the five types of white cells listed below.
a.macrophages
b.helper T cells
c.B cells
d.cytotoxic T cells
e.natural killer cells
Antibody production occurs in these cells.

Question 43

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
vaccine

Question 44

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
natural killer cells

Question 45

Classification.Respond to the following statements in reference to the five items listed below.
a.antigens
b.antibodies
c.helper T cells
d.cytotoxic T cells
e.effector B cells
These produce immunoglobulins in response to the reinvasion by a virus.

Question 46

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
interleukins

Question 47

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
macrophages

Question 48

Classification.Respond to the following statements in reference to the five items listed below.
a.antigens
b.antibodies
c.helper T cells
d.cytotoxic T cells
e.effector B cells
These bind, as in a lock-and-key mechanism, to foreign proteins.

Question 49

Classification.Respond to the following statements with reference to the five types of white cells listed below.
a.macrophages
b.helper T cells
c.B cells
d.cytotoxic T cells
e.natural killer cells
These cells scavenge dead cells and attack bacteria directly.

Question 50

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
retroviruses

Question 51

Classification.Respond to the following statements with reference to the five types of white cells listed below.
a.macrophages
b.helper T cells
c.B cells
d.cytotoxic T cells
e.natural killer cells
These cells destroy cells infected by viruses.

Question 52

__________ immunity specifically targets billions of different antigens.

Question 53

Classification.Respond to the following statements in reference to the five items listed below.
a.antigens
b.antibodies
c.helper T cells
d.cytotoxic T cells
e.effector B cells
These directly attack the foreign cells of an incompatible skin graft.

Question 54

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
stem cells

Question 55

MATCHING
Matching.Match each term with the most appropriate statement.
a.cells that do not divide, die in less than a week, and secrete antibodies
b.cells that directly destroy body cells already infected by viral or fungal parasites, as well as mutant and cancerous cells
c.lymphocytes that are held in reserve, circulate in the bloodstream, and enable a rapid response to subsequent encounters with the same invader
d.able to lyse cells by forming pore complexes
e.cells that are produced in the bone marrow, are never changed by the thymus, and manufacture antibodies
f.able to destroy cells but not dependent on recognition of antigen-MHC complexes
g.a class of proteins that help cells of the immune system communicate
h."big eaters" that alert other lymphocytes to the invasion of specific antigens
i.immature cells that may or may not be committed to develop into one of several mature cell types
j.
a group of cells that are all produced asexually from one original parent cell
k.surface patterns of nonself molecules or particles
l.
proteins released by cytotoxic T cells to destroy target cell membranes
m.
preparation injected into the body to elicit a primary immune response
n.
one of this group has been identified as the causative agent of AIDS
B cells

Question 56

Classification.Respond to the following statements in reference to the five items listed below.
a.antigens
b.antibodies
c.helper T cells
d.cytotoxic T cells
e.effector B cells
Proteins produced by these attack bacteria and viruses in the blood.

Question 57

An antigen-bearing pathogen that breaches surface barriers triggers __________ immunity.

Question 58

Classification.Respond to the following statements with reference to the five types of white cells listed below.
a.macrophages
b.helper T cells
c.B cells
d.cytotoxic T cells
e.natural killer cells
These cells kill tumor cells but are not B or T lymphocytes.

Question 59

Classification.Respond to the following statements in reference to the five items listed below.
a.antigens
b.antibodies
c.helper T cells
d.cytotoxic T cells
e.effector B cells
An Rh+ molecule in the body of an Rh woman is an example of these.

Question 60

Classification.Respond to the following statements with reference to the five types of white cells listed below.
a.macrophages
b.helper T cells
c.B cells
d.cytotoxic T cells
e.natural killer cells
These cells recognize cell surface antigens and initiate the proliferation of lymphocytes.

Question 61

__________ are proteins, Y-shaped antigen receptors made only by __________ cells.

Question 62

There are five antibody classes: __________, __________, __________, __________, and __________.(Ig stands for __________.)

Question 63

__________ is the only disease to have been eradicated from causing natural infections.

Question 64

__________ refers to processes designed to induce immunity.

Question 65

Inflammation begins when mast cells in tissue release __________, which increases blood flow and also makes capillaries leaky to phagocytes and plasma proteins.

Question 66

Why is it beneficial to urinate after sexual activity?

Question 67

Antigen receptors are capable of producing large diversity due to the fact that there are __________ cassettes (versions) of each __________.

Question 68

__________ relieve allergy symptoms by dampening the effects of histamines.

Question 69

__________ fights infection by increasing the metabolic rate.

Question 70

Research on HIV vaccines is progressing, but success to date has been limited to vaccines that are of limited effectiveness against a few strains of the HIV virus.However, flu vaccines are similar in their limitations.Why are 'limited effectiveness' flu vaccines released, but not HIV vaccines?

Question 71

An individual is exposed to a pathogen and takes five days to recover.When exposed a year later they again take five days to recover.Would you suspect that adaptive immunity was involved?

Question 72

Some clones of the original immune cells are __________ cells, long-lived B and T cells reserved for future encounters with the antigen.

Question 73

Why is the destruction of helper T cells caused by HIV infection so crippling to adaptive immunity?