18 Immunology IV: Practical Aspects of Immunology (diagnostic tests, vaccines, etc.)

Question 1

What kind of test can be used to exploit the antibody-antigen interactions?

Answer 1

Serological assays (serology)

Question 2

What’s the principle of serological assays?

Answer 2

Since the Ab-Ag interaction is highly specific, if you have one, you can use it to detect the other

Question 3

Name a specific type of serological assay.

Answer 3

ELISA (Enzyme Linked Immunosorbent Assay)

Question 4

What does the presence of antibodies in someone’s blood tell you? [i.e. What does a positive ELISA test tell you?] (3)

Answer 4

1. Current active infection w/ microbe
2. Previous infection w/ the same microbe, but pt has recovered
3. Prev. vaccination w/ the same microbe

Question 5

Why can a person who’s infected w/ a microbe still give a negative ELISA result?

Answer 5

If testing is done during the “window period” b/w first contact w/ microbe and time at which first antibodies appear

Question 6

A negative ELISA result can mean…(2)

Answer 6

1. you don’t have antibodies for the microbe

2. you’re testing too early (during “window period”)

Question 7

T or F: ELISA tests can be used to detect antibodies OR antigens.

Answer 7

T

Question 8

How can ELISA tests be used to detect antigens:

Answer 8

1. Start w/ antibody
2. Submerge in soln w/ suspected antigen > antibody “captures” antigen
3. Use second (“detection”) antibody

Question 9

Name a common diagnostic test that uses ELISA “antibody-capture” technology.

Answer 9

Pregnancy tests

Question 10

Name a type of test that utilizes Ab-Ag interactions to test for the presence of specific bacteria. “Clumping” rxns b/w antibody+bacteria are being looked for in this test.

Answer 10

Agglutination Test

Question 11

What 3 broad categories of external agents can be used to alter immune sys fn via external manipulation?

Answer 11

1. Pharmaceuticals
2. Nutrients
3. Nutritional supplements

Question 12

Two types of pharmaceuticals that can alter immune sys fn?

Answer 12

1. Immunosuppressive drugs

2. Immunostimulatory drugs

Question 13

What’s the main problem w/ pharmaceuticals that can alter immune sys fn?

Answer 13

Most of them act NON-SPECIFICALLY > unwanted side effects

Question 14

How do immunosuppressive drugs work?

Answer 14

Inhibit cell-mediated immunity, either by blocking cell division (inc’l T-cells) or blocking synthesis of cytokines

Question 15

How do immunostimulatory drugs work?

Answer 15

Stimulate production of lymphocytes in bone marrow

Question 16

Deficiency in some nutrients ____ immune fn.

Answer 16

impairs

Question 17

Most studied nutrients wrt the immune sys? (5)

Answer 17

1. Zn
2. Selenium
3. Cu
4. Vitamins
5. folic acid

Question 18

What specific vegetable has been associated w/ immune sys boosting?

Answer 18

Broccoli

Question 19

What’s the problem w/ nutritional supplements?

Answer 19

Evidence for efficacy controversial

Question 20

What is “Cold-fX” made of?

Answer 20

Extract of North American Ginseng

Question 21

What’re Cold-fX’s claims?

Answer 21

1. Stimulates macrophage production/activity
2. Increased amts of cytokines
3. Increased production of B-cells and higher levels of circulating IgG

Question 22

Have studies showed evidence for Cold-fX’s benefits in boosting the immune system?

Answer 22

No

Question 23

Should we “boost” or “maintain” our immune sys?

Answer 23

Maintain (live healthy)

Question 24

How can we create a protective immune response against a microbe without having to go through a natural infection first?

Answer 24

By immunizing w/ VACCINES

Question 25

What is the principle of vaccination?

Answer 25

Memory B and/or T-cells are produced > future exposure > rapid immune response > rapid elimination of microbe before disease occurs

Question 26

What is PASSIVE immunization?

Answer 26

TEMPORARY, short-term immunity that results when a person receives pre-existing antibodies from someone else

Question 27

Two examples of passive immunization? What does ea. involve?

Answer 27

1. Immune globulin >IgG purified and collected from many donors carrying immunoglobulins against many diff pathogens 2. Maternal antibodies >IgG transferred from mom to fetus that gives partial protection against microbes for first 4-6 mths of live

Question 28

Two examples of immune globulin passive immunization?

Answer 28

1. Post-exposure prophylaxis (helps w/ recent exposures) | 2. Intravenous Immune Globulin ("IVIG") (helps w/ inds who have trouble producing their own antibodies)

Question 29

What influences the scheduling of early childhood vaccinations?

Answer 29

The disappearance of maternal antibodies

Question 30

Define "active immunization"

Answer 30

longer-term immunity due to a natural immune response following exposure to an antigen (eg. a microbe)

Question 31

How can active immunization be achieved?

Answer 31

by using VACCINES

Question 32

Define vaccine:

Answer 32

A microbe, or a part of a microbe, that by itself does not cause disease, but instead produces humoral &/or cell-mediated immunity

Question 33

Two major types of vaccines:

Answer 33

1. Whole-cell vaccines | 2. Sub-unit vaccines

Question 34

Two types of whole-cell vaccines:

Answer 34

1. Killed whole-cell vaccines | 2. Live, attenuated whole-cell vaccines

Question 35

What're whole-cell vaccines composed of?

Answer 35

ENTIRE microbe and all its antigenic parts

Question 36

What're sub-unit vaccines?

Answer 36

Parts of the microbe that're the most antigenic and/or needed to cause disease

Question 37

What's the risk of killed whole-cell vaccines?

Answer 37

Adverse rxns bc "toxic" bacterial components may still be present (e.g. LPS)

Question 38

T or F: There's a chance of getting a disease from killed whole-cell vaccines

Answer 38

F (the microbe is KILLED)

Question 39

What're live attenuated whole-cell vaccines?

Answer 39

Living microbes that've been weakened ("attenuated")

Question 40

How're live, attenuated whole-cell vaccines made?

Answer 40

Microbe is continuously grown in lab until it accumulates mutations that REDUCE its ability to grow inside human host

Question 41

What type of whole-cell vaccine results in life-long immunity?

Answer 41

Live, attenuated whole-cell vaccines

Question 42

What type of whole-cell vaccine requires repeated immunizations?

Answer 42

Killed, whole-cell vaccines

Question 43

Two probs w/ live, attenuated whole-cell vaccines?

Answer 43

1. Slight risk of "back-mutation" to the original, non-attenuated microbe 2. Immunocompromised inds are not advised to get them

Question 44

Synonym for "Sub-unit" vaccines?

Answer 44

Acellular

Question 45

What's used to make sub-unit vaccines?

Answer 45

Ind, purified bacterial components (instead of whole cells) that give a strong immune rxns/are known to be req'd for disease

Question 46

Give 3 e.g.'s of components used to make sub-unit vaccines:

Answer 46

1. Capsular polysaccharide 2. Pili 3. Bacterial toxins

Question 47

Probs w/ sub-unit vaccines?

Answer 47

1. Less likely to produce cell-mediated immunity | 2. Less likely to give life-long immunity (booster shots required)

Question 48

What type of vaccine is the tetanus vaccine?

Answer 48

Sub-unity vaccine

Question 49

What're adjuvants?

Answer 49

Non-antigenic components in vaccines that ENHANCE the immune response to the antigen

Question 50

What type of vaccines are adjuvants esp. useful for?

Answer 50

Sub-unit vaccines

Question 51

Possible side-effect of adjuvants?

Answer 51

Mild, adverse rxns at site of injection

Question 52

What is the most important strategy wrt vaccinations?

Answer 52

TIMING of vaccination

Question 53

What can occur if a vaccine is given to an infant too early while his maternal antibodies are still present?

Answer 53

The maternal antibodies will interfere w/ the immune response to the vaccine if the first dose is given too early

Question 54

What is "herd immunity"?

Answer 54

Protection achieved by being part of a lger gp that includes many immunized members

Question 55

T or F: It's necessary to vaccinate 100% of the pop in order to prevent the spread of infectious diseases.

Answer 55

F | this is due to "herd immunity"

Question 56

T or F: At least 90% of the pop MUST be vaccinated before herd immunity is achieved.

Answer 56

F It always varies depending on many factors (such as effectiveness of the vaccine, contagiousness of microbe, etc.)

Question 57

T or F: Side effects tend to be more of a concern w/ older vaccines compared to current ones.

Answer 57

T

Question 58

What was the prob w/ the older oral poliovirus vaccine?

Answer 58

It was a live, attenuated virus

Question 59

What're most side effects of vaccines due to?

Answer 59

The ADDITIVES included in the vaccine formulation (not the antigen itself)

Question 60

T or F: There's evidence to support links between vaccine usage and serious complications (eg. autism, etc.).

Answer 60

F

Question 61

Do vaccines actually work?

Answer 61

Yes (huge drop in disease cases in postvaccine era)

Question 62

List some challenges associated w/ vaccine development (7):

Answer 62

1. Finding the right microbial antigen > should give protective immunity and avoid adverse rxn 2. Getting better life-long immunity and reducing the need for "boosters" 3. Increasing vaccine stability under adverse conditions (e.g. those used in 3rd world settings) 4. Improving delivery systems 5. Increasing % of ppl vaccinated 6. Improving public perception/awareness of vaccine benefits 7. Maintaining high vaccination rates for "old" diseases

Question 63

What's the problem w/ "bundling" ind vaccines into one fmlation?

Answer 63

More components = weaker immune response to ea. ind component