Parasitic

Question 1

are microorganisms that survive by living off of other organisms, referred to as
hosts.

Answer 1

Parasites

Question 2

Three types of organisms may cause parasitic infections:

Answer 2

protozoa, helminths, and
ectoparasites

Question 3

The immune response to parasitic infections differs from that associated with

Answer 3

Bacterial infection

Question 4

It is described that general concepts need to be considered in relation to host immune
responses to parasites:

Answer 4

(1) Heterogeneity with respect to life cycles and antigenic expression is a key feature of parasitic agents.
(2) Many parasitic infections are chronic in nature.
(3) The mechanisms of immune evasion are significantly different from those of bacterial infections.
(4) Many parasites develop significant genetic and antigenic variation in a relatively short period.
(5) The innate immunity in the natural hosts may be genetically determined.
(6) Humans, as well as animals, differ widely in their ability to handle the complex antigens found in parasites.

Question 5

Defenses to parasitic infection involve both

Answer 5

both innate and acquired (adaptive) immune
mechanisms

Question 6

may result in the destruction and removal
of the parasite, thus preventing establishment of an infection.

Answer 6

innate or nonspecific immune response

Question 7

The nonspecific immune defenses can include activation of cells that may destroy the
parasite by

Answer 7

Phagocytosis

Question 8

release of cytokines such as:

Answer 8

TNF-α, IL-1, IL-10, IL-12, type I
interferons, and chemokines that enhance the immune response, or activation of the
complement system, resulting in enhanced recognition by the immune system.

Question 9

No invasion of host by parasite

Answer 9

Natural resistance

Question 10

Colonization of host with parasite with benefit to both

Answer 10

Symbiosis

Question 11

Colonization of host with parasite with no benefit or harm

Answer 11

Commensalism

Question 12

Parasite invades host and causes disease; host develops immunity and is cured

Answer 12

Sterilizing immunity

Question 13

Parasite invades host and causes disease; host develops an immune response and has some resistance to the parasite but is not cured

Answer 13

Concomitant immunity

Question 14

Parasite invades host and causes disease; host does not develop resistance to the parasite and is not cured

Answer 14

Ineffective immunity

Question 15

are best known for their role in allergic reactions.

Answer 15

IgE

Question 16

IgE Antibodies and Parasites Play an important role in the defense against parasites such as __________ which are too large to be phagocytized.

Answer 16

Helminths

Question 17

Killing of the parasites is accomplished by

Answer 17

ADCC (Antibody-dependent
cellular cytotoxicity)

Question 18

bind to specific receptors on the surface of eosinophils, which are then
stimulated to release enzymes from their granules that destroy the parasite.

Answer 18

Fc portions of the parasite-specific IgE antibodies

Question 19

The concentration of IgE and the number of eosinophils in the peripheral
blood are

Answer 19

Increased or decreased

Question 20

represent a large heterogeneous group of
eukaryotic organisms that are ubiquitous in the
environment.

Answer 20

Fungi

Question 21

can either be considered as parasites,
deriving their nutrition from living matter, or
more commonly as saprophytes, living off of
dead and decaying matter.

Answer 21

Fungi

Question 22

The first line of innate defense includes

Answer 22

skin and the mucous membranes of the respiratory
gastrointestinal
genitourinary tracts

Question 23

structures and molecules of the organism that are conserved among microbial species.

Answer 23

pathogen-associated molecular patterns (PAMP)

Question 24

PRRs on the innate immune cells are

Answer 24

phagocytes
macrophages
dendritic cells [DCs]