Microbiology Chapter 15 part 2

Practical Applications of ImmunologyI. Vaccines

a. Substances that contain antigens to stimulate the immune system to produce antibodies specific for those antigens

b. Artificial acquired immunity c. Principles and Effects of Vaccination

i. The injection produces the primary response of the immune system leading to the formation of antibodies and long term memory cells ii. If a second exposure is encountered the memory cells are stimulated producing a rapid response (second response is quick and more intense than primary)

Microbiology Chapter 15 part 2

d. Types of Vaccines i. Attenuated whole agent vaccines: living, but weakened

1. more closely mimic an actual infection

2. lifelong immunity accomplished with boosters

3. Ex: MMR

4. Danger: live microbes can back mutate to virulent forms

ii. Inactivated whole agent vaccine: Microbes have been killed. Ex: rabies, influenza,

polio

Microbiology Chapter 15 part 2iii. Toxoids: inactivated toxins that are no

longer toxic but retain antigenic character that stimulates antibodiy response

1. Tetanus and Diphtheria 2. require boosters every 10 years

iv. Subunit vaccines: Use only an antigenic fragment of a microbe that best

stimulate an immune response 1. Recombinant vaccines: produced by

genetic engineering tech. (hep B) 2. inherently safer because can’t

reproduce in the recipient and contain little or no extraneous material that can produce side

effects; also, separate fractions of the disrupted bacterial cell and retain and use only the

fraction desired (ex:acellular vaccine for pertussis)

Microbiology Chapter 15 part 2

v. Conjugated vaccines: help deal with poor immune response in young children to vaccines based on capsular antigens (polysacch)

vi. Nucleic acid vaccines: DNA vaccines: actually inject plasmids of naked DNA into muscles to get production of proteins encoded in DNA (scary?)

OH DEER

15.19

Fig. 15.20

Microbiology Chapter 15 part 2

II. Immunological Tests A. Serology: based on blood serum tests to detect and quantify antigens and antibodies found in serum samples

B. Precipitin Test (precipitate) – precipitation reactions between soluble antigens and antibodies, when the meet they form a visible precipitate (tube – precipitin ring test, or plate – gel immunodiffusion ) pgs. 523

i. Can be used to determine the presence of more than one antigen in a serum sample ii. We will do one as an example in lab

Microbiology Chapter 15 part 2

C. Agglutination Reactions (Clumping) pg. ______

i. Particulate antigens (particles like cells, or artificial particles made in the lab with latex beads)

ii. Antigen Antibody reaction produces a distinct clumping as the Antigens and Antibodies react to link together and produce large easily seen clumps.

1. used to quantify the amount of antibody against an antigen (is it increasing? - antibody titer)

2. Hemagglutination reactions: clumping of RBC: blood typing - ABO blood groups

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16.10

Fig. 16.11

Microbiology Chapter 15 part 2

D. Neutralization Reactions

i. Neutralization: antigen-antibody reaction in which harmful effects of bacterial exotoxins or a virus are blocked by specific antibodies

ii. Can be used a s diagnostic test to identify viruses and ascertain viral antibody titer

Microbiology Chapter 15 part 2

E. Tagged antibody tests

i. Immunofluorescence: uses antibodies that fluorescent dye has been attached to, glow with green or orange color when exposed to UV light pg 516, 526, fig 17.4, fig 17.15

ii. Radio immunoassay: Uses a radioactive marker on the Antigen or antibody, and the amount of radiation is measured in the end; used to determine tiny amounts of antigen or antibody (problem these days of disposing of radioactive material)

Fig. 17.15

Fig. 17.4

Microbiology Chapter 15 part 2

• iii. ELISA (Enzyme Linked Immunosorbent Assay) very important, sometimes called EIA.

• Review your notes from last chapter and be sure you can illustrate for the test. See page 528, fig. 17.16 in text.

Fig. 17.16

Microbiology Chapter 15 part 2

*****WESTERN BLOT TEST – CONFIRMATORY TEST FOR HIV – DETECT SPECIFIC HIV PROTEINS – fig 17.13, pg 524

Fig. 17.13