MICR 201 Microbiology for Health Related Sciences

Report
Lecture 11: Practical applications of immunology ; vaccinations
Edith Porter, M.D.
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 Major applications of immunology
▪ Vaccines
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Immunological memory
Types of adaptive immunity
Types of vaccines
Development of new vaccines
Safety of vaccines
▪ Generation of antibodies for research and diagnostic
▪ Anti-sera
▪ Monoclonal antibodies
▪ Diagnostic immunology
▪ Precipitation and agglutination reactions
▪ Complement fixation
▪ ELISA, western blot, immunofluorescence
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Once lymphocytes have encountered their specific
antigen they undergo clonal expansion
 Some of these cells develop further into memory cells
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 Can circulate for many years
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Upon re-contact with the same antigen they quickly
proliferate and resume effector function
 B cells: antibody production
 T cells: cytokine production (TH, Treg) and cytotoxicity (CTL)
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Instead of requiring 10 – 14 days for a full response
measurable effects appear within 2 days
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Primary Response
Secondary Response
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IgM is always the first
antibody
IgG follows IgM
IgG level does not go back to
baseline
Re-exposure to the same
antigen will lead to an
augmented and accelerated
immune response, increased
IgG response and with higher
residual antibody levels
Presence of antibodies is not
equivalent to sickness
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Vaccines do not always target B cells and antibodies but some target T cells.5
Artificially acquired
 Active immunity
Naturally acquired
 Active immunity
 Resulting from
 Injection of Ag
Long Lasting
(vaccination)
infection
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Passive immunity
 Transplacental
Short Lasting
Passive immunity
 Injection of Ab
 Colostrum
Vaccines: toxoid, killed microorganisms, live attenuated microorganisms
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1) What type of immunity results from
vaccination?
A) Innate immunity
B) Naturally acquired active immunity
C) Naturally acquired passive immunity
D) Artificially acquired active immunity
E) Artificially acquired passive immunity
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3) What type of immunity results from
recovery from mumps?
A) Innate immunity
B) Naturally acquired active immunity
C) Naturally acquired passive immunity
D) Artificially acquired active immunity
E) Artificially acquired passive immunity
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15) The antibodies found in mucus, saliva, and
tears are
A) IgG.
B) IgM.
C) IgA.
D) IgD.
E) IgE.
26) The best definition antibody is
A) A serum protein.
B) A protein that inactivates or kills an antigen.
C) A protein made in response to an antigen
that can combine with that antigen.
D) An immunoglobulin.
E) A protein that combines with a protein or
carbohydrate.
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Induce active immune response with a related or
inactivated agent that does not cause major disease
 Induce cross-reactive antibodies or T cells
 Herd immunity is sufficient to prevent epidemic
diseases
 Must weigh the benefit of protection versus the
danger of vaccine associated disease
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Attenuated whole agent vaccines
 Live, weakened microbes
 Generated through long term culture
 Mimic most closely actual infection
 Caution: danger of backmutation to a virulent form
 Dangerous for immunocompromised patients!
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Inactivated whole agent vaccines
Toxoid
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Subunit or acellular vaccines
 Use of antigenic subunit that triggers an immune
response.
 Inherent safer as it cannot reproduce in the host
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Conjugated vaccine
 Combine as antigen poorly immunogenic material (e.g.
capsules) with an immunogenic protein
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Nucleic acid vaccines (DNA vaccines)
 Introduce genes for protein targets into the host
 Host will express the protein and mount an immune
response to this foreign protein
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Classical
 Bacterial culture
 (Animal extract)
 Cell culture
 Embryonated eggs
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New Developments
 Recombinant vaccines
 Plants
Influenza virus grown in
embryonated eggs
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Improve effectiveness of
vaccines/immunizations by providing costimulatory signals for T and B cells
 In humans
▪ Alum
▪ Oil based substance MF59 and virosomes
 In animals
▪ Freund’s complete adjuvants
▪ Mycobacterium extract
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Diphtheria: Purified diphtheria toxoid
Pertussis: Acellular fragments of B. pertussis or
antigenic acellular fragments
Tetanus: Purified tetanus toxoid
Meningococcal meningitis: Purified polysaccharide
from N. meningitidis
Haemophilus influenzae type b meningitis:
Polysaccharides conjugated with protein
Pneumococcal conjugate vaccine: S. pneumoniae
antigens conjugated with protein
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Influenza: Inactivated or attenuated virus
Measles: Attenuated virus
Mumps: Attenuated virus
Rubella: Attenuated virus
Chickenpox: Attenuated virus
Poliomyelitis: Inactivated virus
Hepatitis B: Antigenic fragments (recombinant)
Smallpox: Live vaccinia virus
Rabies: Inactivated virus
Hepatitis A: Inactivated virus
Human papilloma virus: Antigenic fragments
Selected patients
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Re-administration of vaccine to boost
immune defense ( )
 Increased antibody production
 Increased memory cell development
Time
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HIV
Malaria
Tuberculosis
Cholera
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Safety
 Sometimes illness follows vaccination
▪ Risk benefit analysis
 Autism had been linked to vaccination
▪ Most recent studies conclude that there is no link but
instead a genetic disposition
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Weaning protection
 Bordetella pertussis
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Patients antibodies
 indicate that patient had contact with the
agent before
 “serology”
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Commercial antibodies
 used to detect patient antigen
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In research
 Detection of antigen
 Purification
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Study of reactions between antibodies and
antigens
 Globulins
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 Serum proteins
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Gamma () globulin
 Serum fraction containing Antibodies (immunoglobulin)
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Antiserum
 Generic term for serum when it contains specific Ab
 Polyclonal
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Monoclonal antibodies
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Prepare antigen
Inoculate animal with antigen and adjuvants
Administer several boosts
Draw blood and let it coagulate
Remove cells by centrifugation and collect
supernatant = serum with high titers of
specific antibodies
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Precipitation
Agglutination
 Hemagglutination
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Fluorescent-antibody technique
ELISA
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Involve soluble antigens
and antibodies
Upon cross linking a
visible interlocking
molecular aggregate is
formed (lattice)
Only in equivalence zone
precipitates are formed
Example
 Ouchterlony
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Involve particulate antigens
and antibodies
 IgM are most efficient
 Direct agglutination
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 Antibodies against large cellular
antigens
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Indirect agglutination
 Antibodies against soluble
antigen adsorbed to a particle or
erythrocytes
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Relates to the
concentration of
antibodies against a
particular antigen
 Gives a guide to how
active the patient’s
immune response is.
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Labeled
Specific Antibody
To detect difficult to grow pathogens (e.g. Legionella)
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Specific
Primary Antibody
Labeled
Secondary Antibody
Figure 18.10b
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To detect Ag
To detect Ab
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Vaccination (against disease) and immunizations
(for antibody production) require administration
of attenuated or inactivated antigen
Ab:Ag reaction is the fundamental reaction in
immunology
Precipitation: ab--soluble ag
Agglutination: ab--particulate ag
Presence of antibodies does not mean illness
High titer means high concentration of ab
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4) In an agglutination test, eight serial dilutions to
determine antibody titer were set up: tube #1
contained a 1:2 dilution; tube #2, a 1:4, etc. If
tube #6 is the last tube showing agglutination,
what is the antibody titer?
A) 6
B) 1:6
C) 64
D) 1:32
E) 32
15) What type of vaccine is live measles virus?
A) Conjugated vaccine
B) Subunit vaccine
C) Nucleic acid vaccine
D) Attenuated whole-agent vaccine
E) Toxoid vaccine
16) A test used to identify antibodies against
Treponema pallidum in a patient is the
A) Direct fluorescent-antibody test.
B) Indirect fluorescent-antibody test.
C) Direct agglutination test.
D) Direct ELISA test.
E) Hemagglutination-inhibition test.
13) What type of vaccine involves host synthesis of
viral antigens?
A) Conjugated vaccine
B) Subunit vaccine
C) Nucleic acid vaccine
D) Attenuated whole-agent vaccine
E) Toxoid vaccine
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