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Immunoprophylaxis
• Types of immunization
• Immunoglobulins and vaccines
• Strategies in vaccine preparation
• Mechanisms of action of different types of vaccines
NATURAL
ARTIFICIAL (PROPHYLACTIC)
ACTI
VE
PASS
IVE
IMMUNIZATION
Immunity after infectionTransplacental transfer of IgG
Immunoglobulines in milk (breast feeding)
Immunoglobulins and antisera (antitoxins)
Vaccination
Pasive immunization(Administration of immunoglobulins/antisera)
For prophylaxis or therapy
Human immunoglobulins (from blood donors)
Animal (horse) sera (antisera, antitoxins)
e.g. for snake venoms, botulism, diphteria...
immediate effect
temporary immunity (weeks, months)
Antibodies-Immunoglobulins (Ig)
- human serum (gama)globulin (Ig of various specificity)
- specific immune globulins (high-titre of specific Ig)
serum disease!!!
e.g. for hepatitis B, tetanus, rabies...
e.g. for immunodeficiencies...
Active immunization(Vaccination)
Requires time (weeks) for induction of immune response
Administration
Long-lasting immunity
- prior to exposure to pathogen (exception: rabies vaccine)
- post-exposure (in combination with specific Ig)
- multiple doses needed for most vaccines
Herd immunity
Primarily for prophylaxis
Adjuvant
- increases immunogenicity
Vaccine types
Live (attenuated) vaccines
Inactivated (killed) vaccines
- contain killed whole infectious agents
Conjugate vaccines
- contain structural parts/products of infectious agents
New approches for vaccines
obtained from pathogens by isolation and purification
synthetic (genetic engineering)
Subunit (antigenic) vaccines
- contain live, attenuated (weakend) infectious agents
Combined (polyvalent) vaccines
- contain T-independent antigen bound to T-dependent antigen
- contain several antigens of one or more different pathogens
Live (attenuated) vaccines
Examples
AdvantagesInduction of both humoral (Abs) and cellular response (CTLs)
Several viral vaccines (against polio (oral-Sabin), mumps, measles, rubella, varicella) and some bacterial (BCG for tuberculosis)...
Long-lasting immunity (administered in one or two doses)
LimitationsRisk in immunocompromised persons
Instability (termolabile)
PrincipleImunization with attenuated (weakened) pathogen
BCG (limited efficacy)
Inactivated (killed) vaccines
Greater stability
Vaccines against pertussis, typhoid, polio (Salk), influenza...
Safety (no risk of infection)
Shorter immunity (multiple, booster administration required)
Low immunogenicity (only Ab induced, adjuvant required)
Examples
Advantages
Limitations
Principle
Imunization with killed (inactivated) whole infective agents
Subunit (antigenic) vaccines
Vaccine against pertussis (acellular), tetanus and diphteria (toxoid),influenza (Hemagglutinin and Neuraminidase), hepatitis B (HBsAg) andhuman papilloma virus (L1 protein) – so-called virus-like particles (VLP),pneumococcal and meningococcal polysaccharide vaccines...
Same as for inactivated vaccines (lower immunogenecity)
Examples
Advantages
Limitations
Principle
Same as for inactivated vaccines (greater safety)
Immunization with structural antigens (protein or polysaccharide) of pathogens or their products (e.g. toxoid)
Conjugate vaccinesPrinciple
Immunization with capsular polysaccharide antigen of one pathogen (weak immunogen in children) conjugated to protein antigen of another pathogen (strong immunogen)
Conjugate vaccines
Good immune response to capsular antigens
Vaccines against pneumococcus, menigococcus and H. influenzae type B(capsular polysaccharide bound to diptheria toxoid )
Efficient in children in the first two years of life and asplenic persons
Relatively high cost
Same as for subunit vaccines
Example
Advantages
Limitations
PrincipleImmunization with capsular polysaccharide antigen of one pathogen (weak immunogen in children) conjugated to protein antigen of another pathogen (strong immunogen)
Same as for subunit vaccines
Combined (polyvalent) vaccines
Practical (fewer administration, fewer visits of doctor...)
Vaccines against tetanus, diphtera and pertussis (DTP), measles, mumps and rubella (MMR), polysaccharide or conjugate pneumococcal vaccines...
Same as for single vaccines
Examples
Advantages
Limitations
PrincipleSimultaneous immunization with several serotypes of one pathogen (either attenuated strains or antigens) or several different pathogens
The same as for appropriate single vaccines
Good immune response to every component in vaccine
New approaches for vaccines(Hybride vaccines with live viral vectors)
Immunization with live viral vectors (e.g. vaccinia virus) withintroduced genes for immunodominant peptides of different pathogens
Repeated administration not possible
Ongoing clinical trials for several vaccines (e.g. against HIV)
Examples
Advantages
Limitations
Principle
Induction of both humoral (Abs) and cellular immune response (CTLs)
Possibility of polyvalent vaccine preparation
Injection of bacterial plasmid with DNA containing genes for various microbial antigenes
Mechanism of action and possible adverse effects not well understood
Ongoing clinical trials for several pathogens
Simple handling, possibility of polyvalent vaccines preparation
Example
Advantages
Limitations
Principle
Induction of both humoral (Abs) and cellular immune response (CTLs)
New approaches for vaccines(DNA vaccines)
transplacental transfer of IgGj.Adjuvants increase 10.
immunogenicity of antigens in vaccinesi.Conjugate vaccines induce production of9.
immunity after recovery from infectious disease
h.Combined vaccines contain8.
high-affinity antibodies to polysaccharidesg.Inactivated vaccines contain7.
parts of infective agents or their productsf.
Subunit vaccines contain6.
induce production of mucosal IgAe.Live attenuated vaccine against polio5.
whole killed microorganisms d.Example of natural passive immunization is
4.
immunity to tetanus after injection ofantitetanus immunoglobulins
c.Example of natural active immunization is
3.
immunity to tetanus after injection of tetanus toxoid
b.Example of artificial passive immunization is
2.
antigens from different infectious agentsa.Example of artificial active immunization is
1.
1.____ 2.____ 3.____ 4.____ 5.____ 6.____ 7.____ 8.____ 9.____ 10.___b c h j e f d a g h
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