1. Prevetion of Pathogenic
Microbial Infection

2. • Two Artificial Methods of Immunity
– Active immunization
• Administration of antigens so patient actively
mounts a protective immune response
– Passive immunization
• Individual acquires immunity through the transfer
of antibodies formed by immune individual or
animal
© 2012 Pearson Education Inc.

3. 3
Vaccines are antigens prepared fromVaccines are antigens prepared from
pathogens that can raise a protectivepathogens that can raise a protective
immune response, yet do not cause illness.immune response, yet do not cause illness.
These prepared antigens will stimulateThese prepared antigens will stimulate
both B cells and T cells and help to createboth B cells and T cells and help to create
memory cells that can later produce amemory cells that can later produce a
vigorous immune response whenvigorous immune response when
encountered with the real pathogen.encountered with the real pathogen.
Artificial active immunityArtificial active immunity
The strategies for prevention of bacterial infections

4.  Active Immunization
 Vaccine types
 Attenuated (live) vaccines
 Use pathogens with reduced virulence
 Can result in mild infections
 Active microbes stimulate a strong immune response
 Can provide contact immunity
 Modified microbes may retain enough residual virulence
to cause disease

5.  Active Immunization
 Vaccine types
 Inactivated (killed) vaccines
 Whole-agent vaccines
 Subunit vaccines
 Both safer than live vaccines
 Microbes don’t provide many antigenic molecules to
stimulate the immune response
 Often contain adjuvants['æd v nt]ʒə ə
 Chemicals added to increase effective antigenicity

6.  Active Immunization
 Vaccine types
 Toxoid vaccines
 Chemically or thermally modified toxins used to stimulate
immunity
 Useful for some bacterial diseases
 Stimulate antibody-mediated immunity
 Require multiple doses because they possess few antigenic
determinants

7.  Active Immunization
 Vaccine types
 Combination vaccines
 Administration of antigens from several pathogens
 Vaccines using recombinant gene technology (DNA vaccine)
 Attempts to make vaccines more effective, cheaper, safer
 Variety of techniques used to improve vaccines

9. 9
Artificial passive immunityArtificial passive immunity
※※ Antitoxin: e.g. Tetanus antitoxin and diphtheria antitoxin. It isAntitoxin: e.g. Tetanus antitoxin and diphtheria antitoxin. It is
raised in the horse.It is most important to give an intentedraised in the horse.It is most important to give an intented
recipient of equine serum a prior test dose to excluderecipient of equine serum a prior test dose to exclude
hypersensitivity subjects who may have been sensitized by ahypersensitivity subjects who may have been sensitized by a
previous dose of equine serum.previous dose of equine serum.
※※ Pooled immunoglobulin: It contains the normal repertoire ofPooled immunoglobulin: It contains the normal repertoire of
antibodies for an adult, and can protect against hepatitis A, andantibodies for an adult, and can protect against hepatitis A, and
measles.measles.
※※ Specific immunoglobulin: Preparations of specificSpecific immunoglobulin: Preparations of specific
immunoglobulin are available for passive immunization againstimmunoglobulin are available for passive immunization against
tetanus, hepatitis B, rabies, varicella-zoster.tetanus, hepatitis B, rabies, varicella-zoster.
※※ CytokinesCytokines

10. 10
Active-passive immunityActive-passive immunity
Involves giving both a vaccine to provide long-termInvolves giving both a vaccine to provide long-term
protection (preventive infection) and immune globulin toprotection (preventive infection) and immune globulin to
provide immediate protection (therapeutic and preventiveprovide immediate protection (therapeutic and preventive
infectious disease).infectious disease).

11. Exercises:
1. What are the the two artificial methods of
immunity ?
2. What’s the DNA vaccine?