M A J O R A R T I C L E
Potent CD81T-Cell Immunogenicity in Humans
of a Novel Heterosubtypic Influenza A Vaccine,
Tamara K. Berthoud, Matthew Hamill, Patrick J. Lillie, Lenias Hwenda, Katharine A. Collins, Katie J. Ewer,
Anita Milicic, Hazel C. Poyntz, Teresa Lambe, Helen A. Fletcher, Adrian V. S. Hill, and Sarah C. Gilbert
The Jenner Institute, Oxford University, Oxford, United Kingdom
(See the editorial commentary by Hambleton on pages 8–9.)
vaccines that induce high antibody titers to the highly polymorphic viral surface antigen hemagglutinin must be re-
formulated and readministered annually. A vaccine providing protective immunity to the highly conserved internal
antigens could provide longer-lasting protection against multiple influenza subtypes.
Methods. We prepared a Modified Vaccinia virus Ankara (MVA) vector encoding nucleoprotein and matrix
protein 1 (MVA2NP1M1) and conducted a phase I clinical trial in healthy adults.
Results. The vaccine was generally safe and well tolerated, with significantly fewer local side effects after
intramuscular rather than intradermal administration. Systemic side effects increased at the higher dose in both
frequency and severity, with 5 out of 8 volunteers experiencing severe nausea/vomiting, malaise, or rigors. Ex vivo
T-cell responses to NP and M1 measured by IFN-c ELISPOT assay were significantly increased after vaccination
(prevaccination median of 123 spot-forming units/million peripheral blood mononuclear cells, postvaccination
peak response median 339, 443, and 1443 in low-dose intradermal, low-dose intramuscular, and high-dose
intramuscular groups, respectively), and the majority of the antigen-specific T cells were CD81.
Conclusions. We conclude that the vaccine was both safe and remarkably immunogenic, leading to frequencies
of responding T cells that appear to be much higher than those induced by any other influenza vaccination
approach. Further studies will be required to find the optimum dose and to assess whether the increased T-cell
response to conserved influenza proteins results in protection from influenza disease.
Influenza A viruses cause occasional pandemics and frequent epidemics. Licensed influenza
Licensed influenza vaccines, whether inactivated or live
attenuated, are designed to induce humoral immunity
to hemagglutinin (HA). Seasonal influenza vaccines are
a mixture of A/H1N1, A/H3N2, and B antigens. Vaccine
effectiveness is 70%–90% when the circulating virus is
well matched to the vaccine, but may fall below 50%
when the circulating strain has drifted significantly from
the vaccine strain , particularly in people over 60
years of age . Annual revaccination is required to
maintain immunity against seasonal influenza viruses.
Fears of an H5N1 pandemic resulted in the genera-
tion and testing of H5-specific vaccines, which may re-
quire the use of an adjuvant or multiple doses to achieve
a protectivelevel of immunity following vaccination .
H5N1 viruses have continued to mutate in avian pop-
ulations, and in clinical trials of an unadjuvanted H5
vaccine, serological cross-reactivitytovariant H5 viruses
even within the same clade was only 20%–30% , al-
though use of an adjuvant may improve this. Since
swine origin H1N1 began to circulate in humans in
April 2009, vaccine manufacturers have produced pan-
demic-specific vaccines, and the first doses became
Received 22 June 2010; accepted 19 August 2010.
Correspondence: Dr Sarah C. Gilbert, Jenner Institute, Old Road Campus
Research Building, Oxford, OX3 7DQ, UK (email@example.com).
Clinical Infectious Diseases
? The Author 2011. Published by Oxford University Press on behalf of the
Infectious Diseases Society of America. 2011. All rights reserved. This is an Open
Access article distributed under the terms of the Creative Commons Attribution
Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/)
which permits unrestricted non-commercial use, distribution, and reproduction in
any medium, provided the original work is properly cited.
A Phase 1 Study of MVA2NP1M1
d CID 2011:52 (1 January)
available in October 2009, 6 months after the virus was first
Clearly, a vaccine that could provide heterosubtypic
protection against all influenza A viruses would be of great
benefit, and, if effective and widely used, could prevent an-
other pandemic from occurring. The efficacy of influenza
vaccines designed to induce subtype cross-reactive T cells to
internal influenza antigens such as nucleoprotein (NP),
which is highly conserved between all influenza A subtypes,
has been demonstrated in many species of animal model [5–
8], and this approach has the potential to replace or sup-
plement seasonal and pandemic-specific vaccination in hu-
mans. Influenza challenge studies in humans with low
neutralizing antibody titers to the challenge virus (measured
by the HA inhibition assay) have demonstrated a negative
correlation between T-cell response to viral antigens and
influenza disease and virus shedding . Protection is
thought to be mediated chiefly by CD81T cells, but pro-
tective immunity is short-lived , although reexposure to
influenza virus within a few years of the first infection may
result in a subclinical infection and boosting of the T-cell
response. Lee et al  reported that memory T cells rec-
ognizing influenza antigens were detected in over 90% of
those tested, and showed cross-recognition of at least one
H5N1 internal protein. The magnitude of the responses
varied considerably, and is presumably related to the time
elapsed since the most recent exposure to influenza virus.
However, low-level memory T-cell responses to influenza
antigens have the potential to be boosted to protective levels,
by further exposure to the virus or by vaccination. Live at-
tenuated influenza vaccines have been shown to induce
modest T-cell responses in children, but did not significantly
boost T-cell responses to influenza in adults with T-cell re-
sponses induced by natural exposure .
Modified Vaccinia virus Ankara (MVA) is a highly attenuated
virus that has been used to boost T-cell responses to recombi-
nant antigens encoded by the virus in many clinical studies
aimed at developing new vaccines for malaria, human immu-
nodeficiency virus (HIV), and tuberculosis (TB). MVA has an
excellent safety profile, and has been tested in children  as
well as HIV-positive  and latently TB-infected individuals
. MVA has been used to boost both CD41and CD81re-
Bacille Calmette-Guerin immunization , or HIV infection
. Since adults have been primed by prior exposure to in-
fluenza, MVA expressing conserved internal antigens of in-
fluenza such as NP and matrix protein 1 (M1) could be used to
boost cross-reactive T-cell responses to protective levels, pro-
viding broad immunity to all subtypes of influenza A. An il-
lustration of the conservation of the vaccine antigens is given in
Table 1, showing the identity and divergence of the amino acid
sequences of NP and M1 in the vaccine MVA2NP1M1 and
human isolates of H3N2, H1N1, H5N1, and swine origin H1N1.
The identity and divergence of HA are given for comparison.
vaccine antigens are derived from the H3N2 virus A/Panama/
2007/99, but both antigens are more than 90% identical with
homologues from seasonal H1N1, swine origin H1N1, and
H5N1 viruses, whereas identity drops as low as 43% between the
HA proteins of the same 4 viruses.
We now report on the safety and immunogenicity of MVA2
NP1M1, a vaccine designed to boost preexisting T-cell responses
to conserved influenza antigens in a Phase I clinical study in
healthy adult volunteers.
MATERIALS AND METHODS
Sequences were obtained from the National Center for Bio-
technology Information GenBank and aligned using Lasergene
DNAStar 8.0 MegAlign, Jotun Hein method.
Between Antigens in MVA-NP1M1 and Other Influenza A Viruses
Sequence Identity (top) and Divergence (Bottom)
Vaccine H3N2H1N1H5N1 SO H1N1
VaccineX 98.091.891.4 90.2
H3N22.0X 91.4 90.889.8
H1N1 8.7 9.2X 92.0 90.0
H5N19.2 9.9 8.5X 93.6
SO H1N110.5 11.010.8 6.7X
B: Matrix protein 1
Vaccine H3N2 H1N1H5N1 SO H1N1
VaccineX99.2 94.9 92.992.1
H3N20.8X 95.792.9 92.1
H1N15.3 4.5X 93.393.7
H5N1 7.57.5 7.1X 96.0
SO H1N1 8.4 8.4 6.64.1X
VaccineH3N2 H1N1 H5N1SO H1N1
VaccineX N/AN/A N/A N/A
H3N2N/AX 42.6 44.042.8
H1N1 N/A 100.0X 79.3 63.1
H5N1 N/A 97.324.2X 63.8
SO H1N1N/A 100.0 50.449.1X
ment. Percent identity 5 (Matches x 100)/Length of aligned region (with gaps);
divergence is calculated by comparing sequence pairs in relation to the
reconstructed phylogeny. Viruses are H3N2: A/Pennsylvania/PIT08/2008 (NP:
CY035057, M1: CY035055, HA: CY035054), H1N1: A/Washington/AF06/2007
(NP: CY037330, M1: CY037328, HA: CY037327), H5N1: A/Beijing/01/2003
(NP: EF587278, M1: EF587280, HA: EF587277), SO H1N1: A/Canada-NS/
RV1535/2009 (NP: FJ998216, M1: FJ998210, HA: FJ998207).
Calculated using DNAStar MegAlign 8.0 after Jotun Hein align-
d CID 2011:52 (1 January)
d Berthoud et al.
Vaccine Design and Manufacture
The vaccine antigen expressed from MVA consists of the com-
plete NP and M1 from A/Panama/2007/99 joined by a 7 amino
acid linker sequence, and is expressed from the Vaccinia
P7.5 promoter inserted at the thymidine kinase locus of MVA.
Generation of the recombinant virus and subsequent Good
embryo fibroblast (CEF) cells. GMP manufacture and release
testing of the vaccine were carried out by Impfstoffwerk
Twenty-eight subjects were recruited for immunization studies
under a protocol approved by the United Kingdom’s Medicines
and Healthcare products Regulatory Agency and Gene Therapy
Advisory Committee and were enrolled only after obtaining
written informed consent (www.clinicaltrials.gov, identifier:
18–50 years, resident in the Oxford area, and seronegative for
HIV antibodies, hepatitis B surface antigen, and hepatitis C
antibodies. Women who were pregnant or lactating, and vol-
unteers who had previously received an MVA (but not vaccinia)
vaccine, or who had a history of egg allergy or anaphylaxis fol-
lowing vaccination, were excluded. No information about prior
seasonal influenza vaccination was recorded, but volunteers did
not fall into the target population for vaccination within the UK
and were unlikely to have received vaccination.
Vaccination and Follow-up Regime
Following receipt of information about the study, volunteers
attended a screening visit to assess their suitability for the study.
Each group was completed and vaccine safety assessed before
enrolling the next group. All eligible volunteers were enrolled
into the next available group. A single vaccination was admin-
istered at a subsequent visit, with the dose and route of vacci-
nation varying between the study groups. Group 1 received 5 3
107pfu intradermally (dose volume 385 microliters), group 2
received the same dose intramuscularly, and group 3 received
2.5 3 108pfu intramuscularly (dose volume 1920 microliters).
Blood was drawn to assess the T-cell response to NP and M1 on
day of vaccination and 1, 3, 8, 12, 24, and 52 weeks after vac-
cination. Volunteers also attended a follow-up visit 2 days after
vaccination; adverse events were elicited by open questions at
that visit and all visits up to week 12 and were also recorded on
a diary card by the volunteer for the first week after vaccination.
Mild events were defined as awareness of a symptom that was
easily tolerated, moderate as discomfort enough to cause in-
terference with usual activity, and severe as incapacitating, in-
ability to perform usual activities, requiring absenteeism or bed
rest. Information about influenza-like illness was also recorded,
with no volunteer reporting symptoms within the first 3 weeks
following vaccination, and very few reports of coryzal illness at
later time points. Vaccinations were carried out from August to
November 2008 (group 1), February to March 2009 (group 2),
and March to May 2009 (group 3). Circulating seasonal in-
fluenza A strains during this period were H3N2—A/Brisbane/
10/2007 and H1N1—A/Brisbane/59/2007.
Ex Vivo IFN-g ELISPOT
Ex vivo interferon-gamma enyzyme-linked immunosorbent
spot (IFN-c ELISPOT) assays were performed using cry-
opreserved peripheral blood mononuclear cells (PBMCs).
PBMCs were cryopreserved in fetal calf serum (FCS) (Biosera
Ltd) with 10% dimethyl sulfoxide (Sigma) at 280?C in a
Mr Frosty container, then transferred and stored in liquid
nitrogen. PBMCs were thawed quickly in warm R10 (R10:
RPMI 1640 with 10% FCS, 100 IU/mL penicillin, .1 mg/mL
streptomycin (all Sigma), and 2 mM L-glutamine (GIBCO/
Invitrogen), washed and resuspended in R10 with 2 ll/mL of
25 U/mL Benzonase nuclease (Novagen) and left to rest
overnight at 37?C. The following day the cells were washed
and counted for use in the assays. The ex vivo IFN-c ELISPOT
was carried out as previously described . Fifteen- to 20-
mer peptides overlapping by 10 amino acid residues, spanning
the whole of the NP1M1 insert, were used to stimulate
PBMCs at a concentration of 10 lg/ml. The peptides were split
into 8 pools of 10 peptides; pools 1–6 contained peptides from
the NP sequence and pools 6–8 contained peptides from the
M1 sequence. Fifty microliters of PBMCs (2 3 105cells) and
50 ll of the peptides were added in triplicate. R10 was used as
a negative control and phytohaemagglutinin (PHA) at a final
concentration of 10 lg/mL was used as a positive control.
Following a 18–20-hour incubation at 37?C, the ELISPOT
plates were dried and read with an AID ELISPOT reader (AID
Diagnostika). The results are expressed as spot-forming units
(SFUs) per million PBMCs calculated by subtracting the mean
R10 negative control response from the mean peptide pool
response. To determine the ELISPOT response to the vaccine
insert, the response to each peptide pool was summed fol-
lowing background subtraction. Plates were excluded if a re-
sponse over 100 SFUs per million was seen in the R10 wells or
under 1000 SFU in the PHA wells.
Intracellular Cytokine Staining
One to 2 million cryopreserved PBMCs were stimulated with
a single pool of all NP1M1 peptides at a final concentration of
4 lg/mL and 1 lg/mL of co-stimulatory antibodies aCD28 and
aCD49d (BDPharmingen). Cells were incubated for 18 hours at
37?C. After the first 2 hours of incubation, 10 lg/mL brefeldin
A and monensin (eBiosciences) was added. PBMCs were
stained with: CD3 Alexa Fluor 700 (eBioscience-UCHT1), CD8-
APC-AF780 (eBioscience-RPAT8), CD4-QD655 (Invitrogen-
S3.5), IFN-c FITC (eBioscience-4S.B3), CD14 Pacific Blue
(Invitrogen-TuK4), CD19 Pacific Blue (Invitrogen-SJ25-C1),
A Phase 1 Study of MVA2NP1M1
d CID 2011:52 (1 January)
and VIVID Pacific Blue (Invitrogen). Over 300,000 gated lym-
phocyte events were acquired on a Beckton Dickinson LSRII
flow cytometer using FACSDiva software (BD Biosciences) and
analyzed using Flow Jo, Version 8.3 (Tree Star Inc). Unstained
cells and single stained anti-human compensation beads (BD
Biosciences) were used as controls to automatically calculate
compensation. All antibodies were titrated for optimal staining.
Fisher’s exact test was used to detect significant differences in
adverse events between the 3 vaccine groups. If such a difference
existed, groups 1 and 2 were compared and the difference in
proportions presented, and similarly for groups 2 and 3. Non-
parametric tests were used to determine differences in the ELI-
SPOT data; Wilcoxon signed rank test was performed to test for
differences in the ELISPOT responses between time points
within a vaccine group, and Mann-Whitney U test was per-
formed to detect differences in ELISPOT responses between
different vaccine groups.
MVA2NP1M1 Is Safe in Healthy Volunteers
Volunteers were given a single dose 5 3 107pfu intradermally
(group 1, 12 subjects), 5 3 107pfu intramuscularly (group 2, 8
subjects) or 2.5 3 108pfu intramuscularly (group 3, 8 subjects).
Adverse events are presented in Figure 1. Volunteers receiving
the vaccine via the intramuscular route, at either dose, experi-
enced significantly less erythema, itch, swelling, and warmth at
the injection site than those vaccinated intradermally, regardless
of the vaccine dose. All local adverse events were grade 1 severity
apart from 1 volunteer in group 1 and 2 volunteers in group 2,
who each experienced one grade 2 adverse event. No significant
differences in systemic adverse events were reported by the
volunteers receiving the low-dose vaccine by either route (no
grade 3 adverse events in either group), but there was a signifi-
cant increase in malaise, nausea/vomiting, and rigors in the
group receiving the high-dose vaccination with 5 volunteers
experiencing 1 or more severe adverse events (Figure 1B).
MVA2NP1M1 Vaccination Boosts IFN-g Secreting Antigen-
Specific T Cells
Ex vivo IFN-c ELISPOT responses to the whole NP and M1
vaccine insert were measured in cryopreserved PBMCs at base-
line (week 0) and at 1, 3, 8, 12, 26, and 52 weeks after immu-
to NP and M1 prior to vaccination (median 123 SFU/million
PBMC). A significant increase in the number of SFUs detected
following vaccination was seen in all 3 groups as measured by
Wilcoxon signed rank test at weeks 1 and 3. Responses were also
significantly above the prevaccination level at weeks 8 and 12 for
group 1, and weeks 8, 12, and 24 for group 3. The route of
immunization did not appear to affect the magnitude of the
immune response at low dose (no significant difference between
(n 5 8). (A) Local adverse events. Significantly less (P ,.05, Fisher's exact test) erythema, itch, swelling, and warmth at the injection site were detected
in those receiving intramuscular vaccine than those vaccinated intradermally, regardless of the vaccine dose. Significantly less scaling was recorded in
the low-dose compared with the high-dose intramuscular group. (B) Systemic adverse events. No significant differences in systemic adverse events were
reported by the volunteers receiving the low-dose vaccine by either route, but there was a significant increase in malaise, nausea/vomiting, and rigors in
the group receiving the high dose (P ,.05, Fisher's exact test). Severe adverse events only occurred in the high-dose group, with 2 volunteers reporting
severe pain at the injection site, 1 reporting malaise, 1 vomiting, 2 rigors, and 1 sweating. All severe adverse events resolved within 48 hours of
vaccination, apart from 1 volunteer reporting severe pain at the injection site on the 3 days following vaccination. The majority of mild and moderate
adverse events also took place within 48 hours of vaccination, although mild erythema at the injection site lasted for up to 49 days for those receiving
Local and systemic adverse events recorded after vaccination. Black: group 1 (n 5 12). White: group 2 (n 5 8). Striped: group 3
d CID 2011:52 (1 January)
d Berthoud et al.
groups 1 and 2) whereas the increase in dose from 5 3 107pfu
(group 2) to 2.5 3 108pfu (group 3) resulted in significant
increase in immune response at weeks 1, 3, 8, 12, and 24.
Vaccination Boosts Both CD41and CD81Antigen-Specific
Intracellular cytokine staining (ICS) analysis was carried out to
determine whether the IFN-c detected in the ex vivo ELISPOT
was produced by CD31CD41or CD31CD81T cells. ICS was
carried out at week 0, week 1, and week 8 on cryopreserved
PBMCs from all volunteers in group 3. The CD41and
CD81T-cell responses following background subtraction
are shown in Figure 3. A significant increase in IFN-c
production from CD81T cells was detected following vacci-
nation at week 1 and week 8. The percentage of antigen-specific
CD81cells producing IFN–c was higher than the corresponding
volunteers at baseline (week 0), and weeks 1, 3, 8, 12, 24, and 52 weeks after immunization. (A) group 1; (B) group 2; (C) group 3. Wilcoxon signed rank
test was used to determine significant differences in the post- and prevaccination time points. (A) week 1, P 5 .0059; week 3, P 5 .0098; week 8, P 5
.0078; week12, P5 .0049. (B) week 1, P 5.0313; week 3, P 5 .0313. (C) week 1, P 5 .0078; week 3, P5 .0078; week 8, P5 .0078; week 12, P5 .0078;
week 24, P 5 .023. Significant differences were detected between groups 2 (B) and 3 (C) at all postvaccination time points apart from week 52 (Mann-
Whitney U test: week 1, P 5 .006; week 3, P 5 .04; week 8, P 5 .01; week 12, P 5 .02; week 24, P 5 .012).
Ex vivo IFN-g ELISPOT responses to the vaccine insert. Median with individual ex vivo IFN-c ELISPOT responses from vaccinated
responses after background subtraction in (A) CD31CD81and (B) CD31CD41cell populations stimulated with 1 pool of peptides spanning the complete
NP1M1vaccineinsert. Volunteers ingroup 3weretestedatweeks 0,1,and8.Median% IFN-c1 withinCD31CD81cells atweek 15 .4%and week8 5
.33%; median % IFN-c1 cells within CD31CD41population at week 1 5 .098% and week 8 5 .039%.
CD31CD41and CD31CD81IFN-g responses to vaccine insert as measured by intracellular cytokine staining. Intracellular IFN-c
A Phase 1 Study of MVA2NP1M1
d CID 2011:52 (1 January)
population of CD41T cells both before and after vaccination.
Interleukin-2 and tumour necrosis factor alpha (IL-2 and
TNF-a) production and CD107a expression were also analyzed
double, and single functional cells in both populations
(Figure 4). CD107a, a marker of degranulation and cytotoxicity,
was present both with and without IFN-c.
We report here the first clinical study of a novel influenza vac-
cine designed to boost cross-reactive immune responses to all
influenza A subtypes. Many studies have reported intradermal
vaccination with MVA, and the side effect profile seen with
MVA2NP1M1 is comparable . The same dose adminis-
tered by the intramuscular route resulted in significantly fewer
local, but not systemic, adverse events. At the higher dose of
2.5 3 108pfu administered as an intramuscular injection, there
was an increase in both the frequency and severity of systemic
adverse events compared withthelower dose of 5 3 107pfu. For
future studies with this vaccine the dose will be reduced to 1.5 3
108pfu. The magnitude of the immune response to vaccination
determined by ex vivo IFN-c ELISPOT did not differ with the
route of administration, but increased at the higher dose.
ICS analysis for IFN-c production by CD31CD41and
CD31CD81cells was also carried out in the high-dose in-
tramuscular group and showed that more antigen-specific
CD31CD81T cells than CD31CD41T cells were present after
vaccination. IL-2, TNF-a, and CD107a were also produced by
antigen-specific cells. Further studies are required to determine
which T-cell phenotypes, whether lytic or cytokine-producing,
are capable of prevention of disease following exposure to in-
A vaccine that boosts cross-reactive T-cell responses to
conserved internal antigens of influenza has the potential to
modify or prevent disease and virus shedding in vaccinees,
thus reducing morbidity and transmission whether the virus
causing the infection is one that continually circulates in
humans or is a different subtype with the potential to cause
a pandemic. Vaccines based on HA protein must be produced
not only for each virus subtype, but for the continually
evolving sequences within each subtype. MVA-vectored vac-
cines can be produced at large scale for human vaccination,
and are safe for use. MVA2NP1M1 could be used alone, or
in combination with an anti-HA antibody inducing compo-
nent, to provide broad protection against all influenza A vi-
ruses, thereby improving vaccine efficacy over that currently
achieved, particularly in influenza seasons when the circu-
lating virus has drifted from the vaccine strain, and to provide
protection when a global pandemic occurs, regardless of the
Currently the magnitude of T-cell response to NP and M1
required to prevent influenza disease in humans is not known.
However, the magnitude of the induced T-cell responses mea-
sured here are noteworthy. A median response of 1443 SFU/
million PBMCs at the peak time point substantially exceeds the
T-cell responses induced in any of large numbers of phase I and
phase II trials of potent vectored vaccines in HIV, malaria, and
cancer [21, 22]. In the STEP trial of an adenovirus vectored
vaccine against HIV-1, the geometric mean T-cell response at
peak was around 300 SFU/million PBMCs to the vaccine anti-
gens. The much higher immunogenicity identified here likely
results from the level of T-cell response prior to vaccination
attributable to natural influenza virus exposure, combined with
the remarkable boosting ability of MVA-vectored vaccines. A
similar potent boosting of preexisting T-cell responses and
percentage of quadruple (black), triple (dark gray), double (light gray), and single (white) functional cells detected within the CD81(A) and CD41
(B) populations. Within the CD81population, the most frequently detected triple positive cells were CD107a1IFN-c1TNF-a1; the most frequently
detected double positive cells were CD107a1TNF-a1; and CD107a1cells were the most frequently detected single positive cells. Within the CD41cells,
the most frequently detected triple positive cells were CD107a1IFN-c1IL-21; the most frequently detected double positive cells were IFN-c1IL-21; and
TNF-a1cells were the most frequently detected single positive cells. At all time points the frequency of antigen-specific cytokine positive cells was greater
in the CD81population (week 0, CD815 1.92% and CD415 .12%; week 1, CD815 2.43% and CD415 .58%; week 8, CD815 3.96% and
IFN-g, IL-2, TNF-a, and CD107a multifunctional cells detected by ICS in CD31CD81and CD31CD41populations. Mean
d CID 2011:52 (1 January)
d Berthoud et al.
induction of polyfunctional T-cell responses is observed with an Download full-text
MVA vector encoding a TB antigen . In contrast, a trial of
the cold-adapted influenza virus vaccine, FluMist, found that
although it could induce modest T-cell responses in children, it
did not significantly boost T-cell responses to influenza in adults
with T-cell responses induced by natural exposure .
A further notable finding is the greater CD81than CD41
T-cell response after vaccination. In the only previous example
of vaccine-induced T-cell response exceeding 1000 SFU/million
PBMCs to an antigenic insert, the response was predominantly
of CD41T cells . This reflects the proportions of CD41and
CD81T cells detected prior to vaccination in each case and adds
to the growingevidence that MVA vectors can boost bothCD41
and CD81T cells effectively in humans.
Further planned studies will address the ability of this MVA
vaccine to boost preexisting T-cell responses to the conserved
influenza antigens NP and M1 in an extended age range, as well
as the efficacy of the vaccine in preventing influenza disease and
virus shedding via influenza virus challenge studies.
We gratefully acknowledge Saroj Saurya and Matt Cottingham for as-
sistance with generating the recombinant MVA; Nicola Alder, Centre for
Statistics in Medicine, University of Oxford, in presenting the analysis of
the adverse events data; and Alison Lawrie, Katherine Gantlett, and Ian
Poulton for assistance with the clinical trial. SCG and AVSH are Jenner
Investigators, and are inventors on a patent covering use of MVA2
NP1M1. No potential conflicts of interest exist for the other authors. This
work was funded by the Wellcome Trust and by the NIHR Oxford Bio-
medical Research Centre.
Potential conflict of interest. All authors: no conflicts.
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A Phase 1 Study of MVA2NP1M1
d CID 2011:52 (1 January)