Transcript Vaccination

2.
Manipulation of the immune
response:
 Antigen specific
•Immunostimulation
•Immunosuppression
 Non-antigen specific
-Immunostimulation
-Immunosuppression
 Immunomodulation
Targets of immunotherapies:
elements of the immune response: cytokines, adhesion
molecules, cell membrane molecules, receptors,
antibodies
Antibodies as drugs:
specificity  antigenicity
humanized antibodies, „targeting”
Immunotherapies
Immunostimulation
-Induction of immune response against
pathogenic microbes
-Inducing immunreponse against tumor cells
Immunosuppression
-inhibition of autoimmun processes
-inhibition of allergy
-inducing transplantion tolerance
-fight against newborn haemolytic aenemia
Immunomodulation
-shifting TH1 / TH2 balance in autoimmune
diseases or allergy
-modulation of antibody isotype in allergy
Fighting against infections
After infection 
Traditional drugs (antibiotics, anti-viral drugs)
Passive immunization (antibodies, cells)
Aktive vaccination
Before infection  vaccination 
1) increase the ratio of antigen specific cells
2) inducing specific immunological memory
IMMUNOSTIMULATION vaccination
Infectious diseases, epidemics
Edward Jenner, 1796, smallpox
„A landmark was discovery of
the germ theory, which included
small parasites, bacteria and
viruses. This theory was mainly
based on the studies of Robert
Koch (1843-1910), Louis
Pasteur (1822-1895) and many
others.”
What will happen next.......
Vaccine approaches
Type of vaccine
Examples
Live attannuated or killed bacteria
BCG, cholera
Live attennuated viruses
Polio, rabies
Subunit (antigen) vaccine
Tetanus toxoid, diphteria toxoid
Conjugate vaccines
Haemophilus influenzae
Pneumococcus
Synthetic vaccines
Hepatitis (recombinant proteins)
Viral vectors
linical trials of HIV ags in
canarypox vector
DNA vaccines
Clin trials ongoing for several
infections
Antigen specific immunostimulation:
Increase of the bodys’ specific protecting capability

Active immunization:
killed microbes
attenuated microbes
crossreactive microbe
non-pathogenic live microbes
non-toxic modified form
modified microbial toxin
Results:
antibody production + effector T cells
Adjuvants:
support immunostimulation
concentrating ag
prolonged contact with ag
stimulation ofAPC
Passive immunization: rapid treatment of potentially fatal disease
antigen specific IgG from hyperimmunized animal (or human)
advantage: immediate protection, but transient,
disadvantage: no memory,
elimination of IgG, hypersensitivity, neutralization,
species specific immune response
application: antitetanic sera, snakebite
human IgG: antibody defficiency
Adaptive immunization:
therapy with immunocompetent cells
- immunodeficiency:
congenital cellular immunodeficieny
bone marrow (MHC compatibility!) or immunocompetent
cells from fetal liver, thymus
-enzyme deficiency: adenosin deaminase,
nucleosid phosphorylase
somatic gene therapy: bone marrow stem cells
transfected with a viral vector containing the
desired gene
Vaccination – antigen specific immunostimulation
Vaccine: against the microbe, or toxin produced by the microbe
Live, attennuated virus are more efficient compared to killed virus
(effector mechanisms, CD8+T cells higher ) – but: risk!
 New techniques:
Recombinant DNA technologies
Immunization with dendritic cells – new type vaccines
Attennuation of pathogenic microbes:
Culturing virus in monkey cells  mutations  virus growth in monkey
cells, but  does not growth in human cells  vaccine
In vitro mutagenesis: irreversible modification of virus gene
influensa- changes every year - antigén shift
directed mutagenezis
Attenuation of the pathogenic virus by culturing in non-human
cells
Mechanisms of the changes of surface antigens on influensa virus
– antigen-drift and antigen-shift
human
virus
antigen drift
lung epithel cells
human
virus
lung epithel cells
bird
virus
antigen shift
lung epithel cells
lung epithel cells
Antigen drift: continous small changes in viral genes
Antigen shift: genes from two different virus strains are mixed -> new virus
Antigenic Drift
Each year’s flu vaccine contains three
flu strains -- two A strains and
one B strain -- that can change
from year to year.
After vaccination, your body produces
infection-fighting antibodies
against the three flu strains in
the vaccine.
If you are exposed to any of the three
flu strains during the flu season,
the antibodies will latch onto
the virus’s HA antigens,
preventing the flu virus from
attaching to healthy cells and
infecting them.
Influenza virus genes, made of RNA,
are more prone to mutations
than genes made of DNA.
If the HA gene changes, so can the
antigen that it encodes, causing
it to change shape
If the HA antigen changes shape,
antibodies that normally would
match up to it no longer can,
allowing the newly mutated
virus to infect the body’s cells.
This type of genetic mutation is
called “antigenic drift.”
Pathogenic virus
Mutation or deletion
of virulence gene
Immunogenic but
avirulent virus ->
vaccine
Development of non-pathogenic mutants:
 Virus: polio, mumps, rubella, measles, etc. – deletion or mutation of
gene (s) necessery for virulence
 Bacterium: Salmonella typhy : non virulent mutants were selected
- UDP galactose epimerase enzyme mutation --LPS synthesis
LPS low in mutants
-Targeting: enzyme  Tyr, Phe syinthesis, 
slow proliferation -  vaccination
chiken salmonella – vaccination important

Conjugate vaccine:
B and helper T cells recognize different epitopes in the same molecular complex
•Haemophilus influenzae B:
T cell-independent B cell response, to polysacharide chain of
bacteria
tetanusz toxoid + polysacharide conjugate - > T dependent, efficient
response even below two years age
Tetanusz toxoid specific T cells produce cytokines
B cell: antibody against bactaerial polysacharide
Haemophilus influenzae type B vaccine
Conjugate vaccine :
•B and helper T cells recognize
different epitopes in the same
molecular complex
Reverse immunogenetics
Determination of T cell epitopes
HLAB53 protects against fatal cerebral malaria.
HLAB53–binding peptides are identified:
nonapeptide with proline at position 2
From pathogen infected cells -> identification of
the bound peptide with X Pro sequence
Plasmodium falciparum
Strong T cell proliferation
Peptide -> terapy

Attennuated live microorganisms, as vector
combined vaccine:
Salmonella: tetanus toxoid ag,
+ Listeria monocytogenezis
Leishmania
Yersinia pestis
Schistosoma mansoni genes
virus: non-pathogenic (plant), – many genes in one
„microbe” as carrier: antigene built in,
cannot be repeated

Synthetic peptides
identification of T cell epitopes,
Disadvantage: variability
 peptide synthesis
ISCOM: immune stimulatory complex
liposomes with peptides – sejtbe bejut
Immunstimuláló
komplex
peptiddel
Fúzió
Peptid transzport
az ER -be
Peptid
bemutatása az
MHCI-en
keresztül a T
sejtek számára
Succesful vaccinations
SSPE stands for subacute
sclerosing panencephalitis,
a brain disease that is a
late consequence of
measles infection in a few
patients.
Diseases for which effective vaccines are still needed. *The number
of people infected is estimated at ~200 million, of which 20 million have
severe disease. †Current measles vaccines are effective but heatsensitive, which makes their use difficult in tropical countries. Estimated
mortality data for 1999 from World Health Report 2000 (World Health
Organization).
Types of virus infection
polio,
influenza,
mumps,
Yellow fever
herpes,
varicella,
EBV
HIV,
hepatitis B,
hepatitis C
Immune response after infection
Kinetics of antibody response
Targets of virus specific antibodies
PROBLEMS with vaccines:
Specificity, isotype, localization of antibody response is not correct
Antibody response does not provide protection
Adaptation mechanisms of pathogens inhibit the immune reponse
Antibody production + citotoxic T cells activation –protection against the virus
DNA targeting:
·
·
·
·
the right ligand,
internalization and direction to endosome
fusion with lysosomes
lysosomal enzymes degrade enzimek
Synthetic virus
Intranasal, intrarectal, intravaginal immunization mucosal immunization
TL induction in Peyer plaques, lamina propria
Adjuvants : pl. cholera toxin B: cAMP induction, IL-12 production
suitable for mucosal immunization
DNA based vaccination:
Delivery: in vivo electroporation, gene gun 
whole protein gene, or peptide
MHCI, MHCII presentation
Viral vector (vaccinia, poxvirus) strengthen the efficiency of rec DNA
ligand
Endosomal
lyzis, or
bypass
Nuclear transzlocation
signál
Tissue specific
regulated promoter
Therapic gene
DNA
plasmid
?
Vaccine design
epitope
adjuvant
delivery, site of delivery
Selection of the epitope
T
B
APC
conformation
Selection of the epitope
limited
proteolysis
N
linear
C
denaturation
N
C
NC
new determinant
N
C
hidden linear
determinant
Strategies to develop new generation of vaccines
Virus – do not express suitable T cell epitopes
evolution)
(selection during
Tumor – suitable T cells are deleted
„Epitope enhancement”
 increase peptide- MHC binding affinity - MHCII –TH cells
repair of anchoring aa.
 combinatorial peptide libraries
 peptide-MHC complex – increase TCR- binding affinity :
activation of both small and large affinity T cells 
epitope
increase the number of T cells that recognize tumor
 increase TCR crossreactivity: peptid chimera – recognition of
different virus strains
Design of new peptides
Efficiency can be increased by modifying peptide sequence
VACCINE DESIGN
To increase immunogenicity of antigen
/carrier and adjuvant
particularisation (Al-hidroxid/phosphate, liposome, virosome
polimerisation ( mannose polimerek, MAP)
emulsion (oil / water)
microcapsula ( polymers degrading with different kinetics)
bacterial products
chemical adjuvants ( polinucleotides, CpG )
cytokines ( IL-2, IL-4, IL-6, IL-10, IL-12, GM-CSF, TNF-, IFN-)
Targeting ( CR , FcR , MR, TLR )
COMPARISON OF VARIOUS TYPES OF VACCINES
VACCINE TYPES
live, attennuated
killed / subunit
DNA / RNA
TYPE OF IMMUNE RESPONSE
Antibody mediated
B- cells
+++
+++
+++
cellular
CD4+ T-cells
+/- TH1
+/-TH1*
+++ TH1*
CD8+ T-sejtek
+++
-
++
antigen presentation
MHC I / II
MHC II
MHC I / II
humoral
+++
+++
+++
sejtes
+++
+/-
++
Difficulty of
development
+
++
++++
price
+
+
+++
Transportation
storage
+
+++
+++
++
++++
+++
memory
production
safety
AGE
memory
naive
naive
age
memória
TOXICITY
Effect of adjuvant (TH1/TH2)
autoimmuny (molecular mimicri)
impurities (virus, prion)
build into genom / activation of oncogenes
The efficient vaccine:
- safe –can be applied to everyone including children
- efficient to protect against infection or disease (less efficient)
- protection for life long – memory
- induce neutralizing antibodies
- induce T cell response
- stabile, cheap, no/few side effect
- easy applicable (oralis vaccine, e.g. Sabin dropp)
- acceptable and applicable everywhere (developing world)
Adjuvants: non-specific signal, stimulation of APC
cytokine induction,
antigén-depo: slow felszívódás
aluminium hidroxid, or oil emulsion.
mixed vaccines - one can activate the other ( e.g. Bordatella
Pertussis+ tetanus+difteria)
cytokines : IL-12 - TH1 response
The way of immunization
Important: the site of infection/ immunizations
Oral vaccines – the role of mucosa (MALT)
Dendritikus sejtek mint vakcina hordozók