Transcript Why HHV vaccines

“Challenges and dilemmas
about vaccines against the
Herpesviruses : the case of EBV”
Emmanuel DROUET
Université de Grenoble-Alpes
Eurovaccines 2016
Human Herpesviruses to date
Virinae
Common
abreviation
Common name
Common manifestation
Antiviral
therapy
Alpha
Alpha
Alpha
HSV-1
HSV-2
VZV
Herpes simplex virus type 1
Herpes simplex virus type 2
Varicella Zoster Virus
Cold sores, keratitis, encephalitis
Genital sores
Chicken pox; shingles
+++
+++
+++
Beta
CMV
Cytomegalovirus
Severe diseases in
immunocompromised patients
++
Beta
Beta
HHV-6
HHV-7
Human Herpesvirus-6
Human Herpesvirus-7
Roseola infantum; rash and fever
Roseola infantum; rash and fever
-
Gamma
Gamma
EBV
HHV-8
Epstein-Barr Virus
Human Herpesvirus-8
Infectious mononucleosis
Kaposi’s sarcoma
+
-
(+++) widely used and successful ; (++) widely used and quite successful
(+) occasionally used with limited success ; (-) rarely used with uncertain outcome
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Human Herpesviruses to date
Herpesvirus
Site of latency and
persistence
Pathology
Vaccine trials
Antivirals
Prevalence
Transmission
HHV1 (HSV1)
Neurones (sensory ganglia)
Widespread vesicular
lesions and
neurological diseases
No ongoing
vaccine research
YES
High
Skin contact
HHV2 (HSV2)
Neurones (sensory ganglia)
One of the most
prevalent sexually
transmitted infections
worldwide
In clinical trials
no regulatoryapproved
vaccines
YES
High
Sexual
HHV3 (VZV)
Neurones (sensory ganglia)
Chickenpox
Live vaccine
available
YES
High
Respiratory tract
HHV4 (EBV)
B Lymphocytes
(oropharyngeal epithelium)
IM, lymphoid
& epithelial tumors
In clinical trials
no regulatoryapproved
vaccines
YES
Very high
Saliva
HHV5 (CMV)
Blood monocytes /bone
marrow precursors
(probably epithelial cells)
Significant disease in
pregnancy and in
immunocompromised
patients
In clinical trials
YES
High
Sexual, blood,
saliva, urine
Monocytes, T lymphocytes
Roseola infantum
-
Not relevant
Monocytes, T lymphocytes
Roseola infantum
Not relevant
Uncertain
Kaposi’s sarcoma
No ongoing
vaccine research
Moderate
Sexual
HHV6
HHV7
HHV8 (KSHV)
no regulatoryapproved
vaccines
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Not relevant
Gene layout in Herpesvirus genomes
152kb
140kb
230 kb
DJ Mc Geoch Virus research 117 2006
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During this longstanding coevolution
HV develop a multitude of strategies to escape from and counteract a
number of the host responses
•
•
•
Many captured genes are involved in manipulation of host defenses, with immune
evasion and anti-apoptotic functions
– Viral IL-10 (CMV, EBV)
– Viral MHC class I (CMV)
– Viral Bcl-2, viral mitochondrion-localised inhibitor of apoptosis (vMIA) (EBV,
CMV)
– Viral FLIP (inhibitor of caspase-8 - KSHV)
– Viral cyclines (EBV)
– Viral chemokines….(CMV)
– Viral chemokine receptor (CMV)
Duplication of genes
Genes exhibiting unsual high levels of variation (CMV ) (gB polymorphism)
– This phenomenon reflects the evolutionnary outcome of a greater overall
exposure of CMV to the host’s immune system, than in the case of the alpha
and gamma
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Herpes viruses persist because
they do know their own host
So their goal is to live with!
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Herpes virus - How do they persist?
Anti-immunology strategies of Herpesviruses
Strategy
Examples
Hide from immune surveillance
Latency
Infect immunopriviledged tissues (skin,
neurons)
Subvert or kill immune cells/phagocytes
Infect and kill immune cells (DCs, APCs,
lymphocytes, macrophages)
Inhibit CTL/NK killing pathways
Block acquired immunity
Downregulate MHC-I or –II
Block antigen presentation/proteasome
Prevent induction of immune response
genes
Inhibit complement
Inhibition of complement cascade
Inhibit cytokines/interferon chemokines
Modulate apoptosis/autophagy
Interfere withTLRs
Inhibit cell death
Block death signalling pathways
Downregulate death receptors or ligands
Block or hijack TLR signalling
Prevent TLR recognition
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The size of CD4+ CD8+ T cell response to CMV is enormous:
This response is definitely important in the control of virus
replication, and hence in protection against disease.
MK Gandhi & R Khanna
Lancet Infect Dis 2004; 4: 725–38c
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Re-encounter model linking CD8+ T cell response
to various persistent viruses
In spite of this broad range of antiviral immune effector mechanisms, CMV/EBV persists for life and continues to
replicate.
Long term memory T cell responses are maintained at high frequency and are thought to prevent clinical disease
following periodic reactivation of the virus.
As such, a balance is established between the immune response and viral reactivation (CMV is regarded as a low-load
persistent infection of Immunocompetent host
.
CMV-induced
Immunosenescence?
As long as the hosts encounter viral antigens, they increase the
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size of the response
Klenermann
& Hill, Nature Immunology, 2005
Why HHV vaccines ?
The Varicella-Zoster vaccine represents the paradigm of a successful Herpesvirus vaccine.
This live-attenuated vaccine demonstrates unequivocally that it is possible to develop vaccines
against the HHVs
BUT: DOES NOT PREVENT THE ACQUISITION OF VZV
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“This 10-year review of spontaneous reporting after distribution of 155 million
doses of Varivax demonstrates that the interpretation of postmarketing adverse
experience reports has been enhanced by the VZVIP (identification program) and
that Varivax is generally well tolerated”
Moreover, mild Varicella (wild VZV) episodes in vaccinated inviduals increase the
protection
No study about asymptomatic episodes after vaccination
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The VZV case (neutropic and disseminating)
Arvin, A. M. 1996. Varicella-zoster virus, p. 2547–2586.
In B. Fields (ed.), Virology, 3rd ed. Raven Press, New York.
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Over the years, the development of HHV vaccines has
been a story of mixed fortunes, especially for HSV-2
and HCMV.
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Origin of the glycoprotein subunit
vaccine approach
• gD (the 80s)
– Watson et al. Science 1982 (expression in E coli HSV1 gD)
– Weis et al. Nature HSV1 gD is immunogenic)
– Cremer et al. Science 1985(expression in vaccinia HSV1
gD)
– Berman et al. Science 1985 1st vaccination HSV2 gD)
• gB & gD(the 90s)
–
–
–
–
Mertz et al. JID 1990
Straus et al. Lancet 1994 (immunotherapy)
Straus et al. JID 1997 (immunotherapy)
Corey et al. JAMA 1999 (vaccine)
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The goals of the vaccines under development are rather to prevent the establishment
of latent infection by blocking access of the virus to sensory ganglia, to reduce the
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severity of the symptoms, and/or to reduce
the frequency
of recurrences.
Anti HHV vaccines : a risky business
The lesson of HSV2
Efficacy results of a trial of a herpes simplex vaccine. Belshe RB, Leone PA, Bernstein DI, Wald A, Levin MJ,
Stapleton JT, Gorfinkel I, Morrow RL, Ewell MG, Stokes-Riner A, Dubin G, Heineman TC, Schulte JM, Deal CD;
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Herpevac Trial for Women. N Engl J Med. 2012
Jan 5;366(1):34-43.
Anti HHV: a risky business
The lesson of HSV2
Efficacy results of a trial of a herpes simplex vaccine. Belshe RB, Leone PA, Bernstein DI, Wald A, Levin
MJ, Stapleton JT, Gorfinkel I, Morrow RL, Ewell MG, Stokes-Riner A, Dubin G, Heineman TC, Schulte JM,
Deal CD; Herpevac Trial for Women. N Engl J Med. 2012 Jan 5;366(1):34-43.
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Failed herpes vaccine puzzles virologists
“Enough vaccines have failed that companies are seeing herpes vaccines as a
risky business,”
David Knipe, Harvard Medical School in Boston
“We need to understand the immunobiology of HSV acquisition,”
“What are the immune responses in the genital tract and how do we develop those
immune responses through vaccination?”
Lawrence Corey, Fred Hutchinson Cancer
Research Center in Seattle, Washington.
“The fact that the gB- and/or gD-based vaccines have failed in six clinical trials spanning
22 years and involving nearly 15,000 human participants does not seem to have
dampened the enthusiasm of scientists for continuing to take this same basic approach,
repackaging it, renaming it, and trying it yet again”
Bill Halford,
Southern
Illinois University School of Medicine
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The saga of HCMV vaccine
Strain CMV Towne: latency-deficient live-attenuated Towne strain CMV vaccine (which lacks more than a dozen viral genes), prevented
severe disease in renal transplant recipients
Strain CMV Toledo : more immunogenic
The history of vaccination against cytomegalovirus
Med Microbiol Immunol (2015) 204:247–254 Stanley Plotkin
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The saga of HCMV vaccine
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MK Gandhi & R Khanna
Lancet Infect Dis 2004; 4: 725–38c
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***
***
Induced broadly crossreactive
complement-independent Nabs
Not suitable
Clinical Seronegative and
seropositive adults
Phase II: Transplant patients
Clinical and preclinical trials: challenges and the dilemmas
Not suitable
Not suitable
Clinical Seronegative adults
Phase II Children
Seronegative young women
Seropositive women
Transplant patients
Not suitable
***
Vijayendra Dasari, Corey Smith & Rajiv Khanna (2013) Recent advances inEurovaccines
designing an effective
2016 vaccine to prevent cytomegalovirus-associated clinical diseases, Expert
Review of Vaccines, 12:6, 661-676, DOI: 10.1586/erv.13.46
gH/gL/gO and Pentamer form mutually exclusive complexes
exposing neutralizing sites. gH/gL complex interacts either with
gO or with the ULs to form gH/gL/gO and Pentamer, respectively.
Claudio Ciferri et al. PNAS 2015;112:1767-1772
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©2015 by National Academy of Sciences
The need and challenges for
development of a CMV vaccine
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In spite of extensive efforts over the last 40 years, a clinically licensed vaccine
formulation with convincing clinical efficacy remains elusive
R Khanna Queensland Institute of Medical Research, Brisbane, Australia
Recent advances in designing an effective vaccine to prevent
cytomegalovirus-associated clinical diseases
Expert Rev. Vaccines 12(6), 661–676 (2013)
The final concern with all current CMV vaccine candidates is the durability
of the immune response and protective efficacy.
Emery VC.
Could a vaccine against immune-evading cytomegalovirus become a reality?
Expert Rev. Vaccines 10(8), 1109–1111 (2011).
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Comprehensive layout
of cytomegalovirus-encoded immune –evasion gene products
Griffiths
Lancet Infect Dis 2012
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Burden of disease associated with EBV
Inflammatory disease: IM
Malignant diseases BL & NPC
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EBV cycle: Despite such a robust primary immune response, EBV is still able
to establish latency.
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EBV entry in both epithelial cells and
primary B cells
•
•
•
•
•
Attachment mediated by the major envelope
gp350 (primarily CR2 or CD21)
gp350 : Principal target of neutralizing
antibodies in naturally infected individuals*
Role of integrins on the surface of epithelial
cells (gH/gL +++)
Fusion triggered by gp42
BUT : EBV can enter CD21 negative
lymphocytes (T cells, NK cells)
B cells
Epithelial cells
*Epstein MA, Morgan AJ, Finerty S, Randle BJ, Kirkwood JK. Protection of cottontop tamarins against Epstein-Barr virusEurovaccines 2016
induced malignant lymphoma by a prototype subunit vaccine. Nature 1985;318:287–9.
The complexity of EBV entry
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The EBV vaccines designed so far fall into two categories
• Those preventing any kind of infection (including prophylaxis
of EBV associated malignancies)
• Those designed for therapeutic purposes (to be used in
subjects already infected) (only EBV maligancies).
EBV is associated with nearly 200,000 new malignancies each year worldwide
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Cohen JI et al. Vaccine 31S (2013) B194–
B196 – Cohen JI et al. Sci Transl Med (2011)
The EBV vaccines designed so far fall
into two categories
• Preventive vaccines protecting against acute disease
(such as IM) contain, as a rule, the gp350
polypeptide(s) encoded by the BLLF1 gene.
– generates antibodies preventing virus entry
• Vaccines destined for tumor prevention rather consist
of peptides derived from latency associated nuclear
proteins (EBNA 2, 3 and 6) and/or from oncogenic
latent membrane proteins (LMP1/LMP2a).
– potentiate the cell mediated response
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In a phase 2, randomized, double-blind, placebocontrolled trial, the vaccine reduced the rate of IM by 78%
According to protocol
Intention to treat
Sokal EM et al. J Infect Dis. 2007 Dec 15;196(12):1749-53
Recombinant gp350 vaccine for infectious mononucleosis:
Evaluation of the safety, immunogenicity, and efficacy of an Epstein-Barr virus
vaccine in healthy young adults
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The need and challenges for development of an EBV
vaccine
Balfour HH. Current Opinion in Virology 2014 & Cohen JI Vaccine 2013
Prospects
Progress
Problems
Prevention of infectious
mononucleosis
IM was prevented in a phase 2 study with a subunit
gp350 vaccine (Sokal et al. JID 2007)
A CD8+ T-cell peptide (EBNA3-TT) vaccine was
immunogenic with a hint of efficacy (Elliott et al. J
Virol 2008)
Duration of protection unknown. Viral loads and
T-cell specific responses were not evaluated. The
ideal age’ which to vaccinate may differ according
race/ethnicity and socioeconomics
Prevention of Nasopharyngeal
Carcinoma
A vaccinia construct expressing EBV membrane
glycoprotein BNLF-1 MA (gp 220-340) was
immunogenic and may have reduced incidence of EBV
infection in Chinese children
CD8+ T-cell peptide vaccine : HLA restricted.
Long incubation period from EBV infection to
development of NPC makes efficacy trials
impractical.
Prevention of lymphomas
A subunit gp 350 vaccine was safe in pediatric renal
transplant candidates (Rees et al. Transplantation
2009)
Vaccine was poorly immunogenic probably due to
the low dose and weak adjuvant; trial could not
assess protection from PTLD
Treatment of NPC
A vaccinia recombinant vector expressing the tumorassociated viral antigens EBNA-1 and LMP2 was safe
and immunogenic (Hui et al. Cancer Res 2013)
Therapeutic efficacy has not yet been assessed
Prevention of multiple sclerosis
(Linkage between the occurrence of IM
and MS) (Munger et al. Mult. Scler
2011)
Evidence that a vaccine could work: EBV-specific CD8+ Long incubation period from EBV infection to MS
T cell responses are elevated during active MS
makes vaccine efficacy trials impractical except
(Angelini et al. Plos Pathogens 2013). Monoclonal
perhaps in first-degree relatives
antibodies that deplete the B cell reservoir of latent
EBV were beneficial in MS (Hauser et al. New Eng J
Med 2008)
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Kanekuyo et al. Cell 2015
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Development of Nano-particle-based vaccine
expressing EBV gp350
Kanekuyo et al. Cell 2015
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Development of Nano-particle-based
vaccine expressing EBV gp350
Kanekuyo et al. Cell 2015
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This new Nano-particle-based vaccine induces ~100 fold higher
levels of B cell neutralizing antibody in mice compared with
soluble gp350
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Kanekuyo et al. Cell 2015
“The true definition of madness is repeating the same
action, over and over, hoping for a different result”.
Albert Einstein
The Epstein-Barr virus encodes approximately 80
proteins, from which 15 possess at least 90 antigenic
epitopes. Many of them stimulate the T cell
receptors (TCR), but a few interact with the B cell
receptors (BCR).
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gp 55/78
Gp85/gH
A. D. Hislop et al. Ann Rev Immunol 2007
gp350 & gp 220/gB
BZLF1 /ZEBRA is a highly immunogenic IE antigen
and elicits robust CD4+ and CD8+ responses
The majority of EBV epitopes (over 80) inducing either cytotoxic and/or helper T lymphocytes were located on non-structural and/or
latency associated polypeptides. In particular the EBV-specific CD4+ and CD8+ memory T lymphocytes can respond within hours, potentially
destroying the virus-producing cells before viral replication is completed and viral particles have been released.
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T cell epitope clustering in the highly immunogenic BZLF1 antigen of
Epstein-Barr virus.
RAKFKQLL
FSAPQPAPENAY
BZLF1 T cell epitopes: Rist et al. 2015 J Virol
BZLF1 B cell epitopes Drouet. EP2101177 & EP1163516 (N-ter), EP-801744 (C-ter)
In acute infectious mononucleosis (IM) patients (about 40 %) a considerable proportion
of HLA B8 restricted CTL reactivity is directed against a single peptide (RAKFKQLL) of
transactivator protein BZLF1/Zta
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The DNA-binding domain (RAK) of the
trans-activator ZEBRA is a major target antigen for IgM antibody response
in EBV primary infection
AD
1
BD
140
176
bZIP
194
221
245
V A S R K C R A K F K Q
« Small is beautiful »
Drouet et al. 6th EBV International Symposium on EBV and associated diseases
Stockholm 1998
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ZEBRA/BZLF1 gene expression in
human EBV lymphoma samples
EBV-LPD tumor sample obtained from hu-PBL-SCID mouse
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The ZEBRA/BZLF1 paradox
Expression of ZEBRA in biopsies of EBV+ lymphomas (abortive cycles?)
Weak Expression of ZEBRA
Strong Expression of ZEBRA
(immunoperoxidase staining with anti-Z mAb)
In a context of malignant lymphoproliferation, cells with EBV under a lytic form contribute
to the tumor progression, leading to an overt disease (lymphoma)
Ma et al. J Virol, 2011
Hong et al. J Virol 2005,
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Recombinant BZLF1 vaccination promotes antigen-specific Tcell expansion and function in vitro and in vivo
Hartlage et al. Cancer Immunol Res 2015
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EBV immediate-early protein BZLF1, can induce
a protective effect against the development of fatal EBV-LPD in
SCID mice engrafted with PBMCs from an HLA-B8 individual
Hartlage et al. Cancer Immunol Res 2015
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Issues regarding HHV
• The entry pathways of HHV are not fully understood ex. CMV
pentameric gH complex, EBV gp350/220 gp 42 gH/gL
• The acquisition through the mucosas (HSV2) as well
(replication-defective HSV2 or live attenuated HSV2 vaccines
expressing a broad array of viral antigens)
• Recently described and purified individual recombinant
immunogenic polypeptides and/or their mixes (Combination of
lytic/latent proteins)
Rajcáni et al. Survey of Epstein Barr Virus (EBV) Immunogenic Proteins and their Epitopes: Implications for Vaccine
Preparation Recent Pat Anti-infect Drug Discovery 2014;9(1):62-76.
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Challenges in EBV vaccine strategies (1)
EBV vaccine for the prevention of IM – and what else ? Balfour HH. JID 2007
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Challenges in EBV vaccine strategies
and priorities for the future (1)
- Identification of surrogate markers that predict the
development of EBV-related malignancies
- Determination of immune correlates of protection
against EBV infection and diseases in animals models
and in humans
- Definition of a goal for an EBV vaccine and criteria for
licensure to prevent diseases rather than infection
- Planning of additional epidemiological studies
designed to predict the likelihood of benefit of a
specific EBV vaccine and development of a strategy to
determine an EBV vaccine’s efficacy in preventing
human cancers
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• Primary Cell Transformation : EBV LATENT FORM
 EBV DNA quantification (qPCR) in blood samples corresponds to the burden of memory B cells
(not proliferating lymphoblasts) infected by EBV Yang et al. Blood 2000 96:4055-4063
Normal cells
Transformed & tumor cells
Dividing cells
Blood vessels
Apoptotic cells
• Tumor Progression: EBV REPLICATIVE FORM
ZEBRA : EBV-encoded immediate-early protein, expressed at the very beginning of the replicative cycle.
Because ZEBRA is the master transcription factor of EBV, it activates viral and cellular promoters; ZEBRA is
now considered as critical in the tumor progression.
 The measurement of the soluble ZEBRA (ZEBRAs) corresponds to the tumor progression
Ma et al. J Virol 2011 An Epstein-Barr Virus (EBV) Mutant with Enhanced BZLF1
Expression Causes Lymphomas with Abortive Lytic EBV Infection in a Humanized
Mouse Model
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sBZLF1/ZEBRA : a new biomarker of PTLD
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Follow-up of four PTLD-patients by soluble ZEBRA in peripheral
blood (serum)
1st episode of PTLD
Treatment with anti-CD20
Relapse of PTLD
Detection threshold 40 ng/ml
Time
Months after transplantation
Patient #1 100ng/ml (d56) PTLD Day 56 PT
Patient #2 2000ng/ml (d88) PTLD Day 159 PT
Patient #3 80ng/ml (d18) PTLD Day 39 PT
Patient #4 70ng/ml (d35) PTLD Day 35 PT
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Relapse 95ng/ml Day 110
Challenges in EBV vaccine strategies
and priorities for the future (1)
- Identification of surrogate markers that predict the
development of EBV-related malignancies
- Determination of immune correlates of protection
against EBV infection and diseases in animals models
and in humans
- Definition of a goal for an EBV vaccine and criteria for
licensure to prevent diseases rather than infection
- Planning of additional epidemiological studies
designed to predict the likelihood of benefit of a
specific EBV vaccine and development of a strategy to
determine an EBV vaccine’s efficacy in preventing
human cancers
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Thank you !!
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