Basic Concepts

Question 1

Innate Immunity

Answer 1

a non-specific immunity that has no memory such as natural killer cells, phagocytosis, exogenous factors like skin and endogenous like stomach acid

Question 2

Acquired Active Immunity

Answer 2

the specific response of the host to an infecting organism; divided into two categories: cell mediated and antibody mediated

Question 3

Cell-mediated immune responses

Answer 3

carried out by special lymphocytes of the T cell class

Question 4

Cytotoxic T lymphocytes (Tc)

Answer 4

specifically attack and kill microorganisms or host cells damaged or infected by pathogens

Question 5

Helper T lymphocytes (Th)

Answer 5

promote the maturation of B lymphocytes by producing activator cytokines that indue the B cells to produce antibodies and attach to and kill invading organisms

Question 6

Immunochemical tests

Answer 6

use antigens and antibodies as tools to detect microorganisms

Question 7

Antigens

Answer 7

substances recognized as foreign in the body; usually high-molecular weight proteins or carbohydrates that elicit the production of other proteins; can be part of the physical structure (ex: bacterial cell wall) or a chemical produced by the pathogen (ex: enzyme or toxin)

Question 8

Antibodies

Answer 8

the other proteins produced in response to antigens; attach to antigens and aid the host in removing the infectious agent

Question 9

Epitopes

Answer 9

Regions that are recognized by the immune system

Question 10

Antibody-mediated immune response

Answer 10

specific proteins (antibodies/immunoglobulins) are generated by lymphocytes of the B-cell (bone marrow derived) class in response to antigens or epitopes of a specific infectious agent

Question 11

Opsonizing antibodies

Answer 11

attach to the surface of pathogens and make the pathogens more amenable to ingestion by phagocytic cells

Question 12

Neutralizing antibodies

Answer 12

bind to and block surface receptors for host cells

Question 13

Complement-fixing antibodies

Answer 13

attach to the surface of pathogens and contribute to their destruction by lytic action of complement

Question 14

What are the different antibody classes?

Answer 14

IgM, IgG, IgA, IgD, and IgE
IgM and IgG are primarily used for diagnostic serology

Question 15

IgA

Answer 15

secretory antibody- is the predominant class in saliva, tears, and intestinal secretions; responds to localized infection as mucosal membranes

Question 16

IgD

Answer 16

attached to the surface of B cells and involved in immune regulations

Question 17

IgE

Answer 17

levels increase as a result of infections caused by several parasites or in response to allergic reactions

Question 18

IgM

Answer 18

produced as a first response to many antigens, indicating a recent or active exposure to an antigen; largest immunoglobulin molecule w/ 10 binding sites

Question 19

IgG

Answer 19

may persist long after an infection has run its course; more specific for the antigen w/ 2 antigen binding sites; the Fc region binds to phagocytes once an antigen is bound to the variable region

Question 20

Fourfold rise in titer

Answer 20

for most pathogens, an increase in the patient’s titer of two doubling dilutions (1:8 to 1:32) is considered to be diagnostic of a current infection