Papers of the Month – 2014

December, 2014

Vaccine 2015. 33(4): 559-567.

Joanne M. Langleya, Louise Frenetteb, Robert Jeanfreauc, Scott A. Halperina, Michael Kyled, Laurence Chue, Shelly McNeila, Mamadou Draméf, Philippe Morisg, Louis Friesh, David W. Vaughn

Background: Highly pathogenic avian influenza A/H5N1 viruses continue to circulate in birds and infect humans causing serious illness and death.

Methods: In this randomized, observer-blinded study, adults ≥18 years of age (n=841) received 3.75 or 7.5μg hemagglutinin antigen (HA) of an AS03-adjuvanted (AS03A or AS03B) A/Indonesia/5/2005 H5N1 (subclade 2.1) vaccine (priming), followed by the same HA dose of AS03-adjuvanted A/turkey/Turkey/1/05 H5N1 (clade 2.2) influenza vaccine as a booster 6 or 18 months after priming; an unprimed group received placebo at Day 0, and 3.75μg HA of AS03A-adjuvanted booster vaccine at 6 and 18 months. Antibody responses were assessed by hemagglutination-inhibition assay (HI). Microneutralization (MN) antibody and cellular immunoassays were assessed in a subset of participants.

Results: Geometric mean titers (GMTs) and seroconversion rates (SCRs) were higher in primed vs. unprimed subjects against the booster strain 10 days following booster vaccination at month 6 and month 18. After the booster at 18 months, the lower limit of the 97.5% confidence interval for the difference in SCR and GMT ratios between primed and unprimed subjects was >15% and >2.0, respectively, fulfilling the primary endpoint criteria for superiority against the booster strain. MN and cellular immune responses corresponded with the immunogenicity seen in HI measures.

Conclusions: Adults primed with a dose-sparing oil-in-water adjuvanted H5N1 subclade vaccine had rapid and durable antibody responses to a heterologous subclade boosting vaccine given 6 or 18 months later.

November, 2014

N Engl J Med. 2014 Nov 26. [Epub ahead of print]

Ledgerwood JE, DeZure AD, Stanley DA, Novik L, Enama ME, Berkowitz NM, Hu Z, Joshi G, Ploquin A, Sitar S, Gordon IJ, Plummer SA, Holman LA, Hendel CS, Yamshchikov G, Roman F, Nicosia A, Colloca S, Cortese R, Bailer RT, Schwartz RM, Roederer M, Mascola JR, Koup RA, Sullivan NJ, Graham BS; the VRC 207 Study Team.

Background The unprecedented 2014 epidemic of Ebola virus disease (EVD) has prompted an international response to accelerate the availability of a preventive vaccine. A replication-defective recombinant chimpanzee adenovirus type 3-vectored ebolavirus vaccine (cAd3-EBO), encoding the glycoprotein from Zaire and Sudan species that offers protection in the nonhuman primate model, was rapidly advanced into phase 1 clinical evaluation. Methods We conducted a phase 1, dose-escalation, open-label trial of cAd3-EBO. Twenty healthy adults, in sequentially enrolled groups of 10 each, received vaccination intramuscularly in doses of 2×1010 particle units or 2×1011 particle units. Primary and secondary end points related to safety and immunogenicity were assessed throughout the first 4 weeks after vaccination. Results In this small study, no safety concerns were identified; however, transient fever developed within 1 day after vaccination in two participants who had received the 2×1011 particle-unit dose. Glycoprotein-specific antibodies were induced in all 20 participants; the titers were of greater magnitude in the group that received the 2×1011 particle-unit dose than in the group that received the 2×1010 particle-unit dose (geometric mean titer against the Zaire antigen, 2037 vs. 331; P=0.001). Glycoprotein-specific T-cell responses were more frequent among those who received the 2×1011 particle-unit dose than among those who received the 2×1010 particle-unit dose, with a CD4 response in 10 of 10 participants versus 3 of 10 participants (P=0.004) and a CD8 response in 7 of 10 participants versus 2 of 10 participants (P=0.07). Conclusions Reactogenicity and immune responses to cAd3-EBO vaccine were dose-dependent. At the 2×1011 particle-unit dose, glycoprotein Zaire-specific antibody responses were in the range reported to be associated with vaccine-induced protective immunity in challenge studies involving nonhuman primates. Clinical trials assessing cAd3-EBO are ongoing. (Funded by the Intramural Research Program of the National Institutes of Health; VRC 207 number, NCT02231866 .)

October, 2014

Journal of Virology. 2014. 88(22):13333-43

D Hallengard, FJ Lum, BM Kummerer, A Lulla, J Garcia-Arriaza, JK Fazakerley, P Rogues, R Le Grand, A Merits, LF Ng, M Estaban, P Liljestrom.

Chikungunya virus (CHIKV) is a reemerging mosquito-borne alphavirus that causes debilitating arthralgia in humans. Here we describe the development and testing of novel DNA replicon and protein CHIKV vaccine candidates and evaluate their abilities to induce antigen-specific immune responses against CHIKV. We also describe homologous and heterologous prime-boost immunization strategies using novel and previously developed CHIKV vaccine candidates. Immunogenicity and efficacy were studied in a mouse model of CHIKV infection and showed that the DNA replicon and protein antigen were potent vaccine candidates, particularly when used for priming and boosting, respectively. Several prime-boost immunization strategies eliciting unmatched humoral and cellular immune responses were identified. Further characterization by antibody epitope mapping revealed differences in the qualitative immune responses induced by the different vaccine candidates and immunization strategies. Most vaccine modalities resulted in complete protection against wild-type CHIKV infection; however, we did identify circumstances under which certain immunization regimens may lead to enhancement of inflammation upon challenge. These results should help guide the design of CHIKV vaccine studies and will form the basis for further preclinical and clinical evaluation of these vaccine candidates.

Importance: As of today, there is no licensed vaccine to prevent CHIKV infection. In considering potential new vaccine candidates, a vaccine that could raise long-term protective immunity after a single immunization would be preferable. While humoral immunity seems to be central for protection against CHIKV infection, we do not yet fully understand the correlates of protection. Therefore, in the absence of a functional vaccine, there is a need to evaluate a number of different candidates, assessing their merits when they are used either in a single immunization or in a homologous or heterologous prime-boost modality. Here we show that while single immunization with various vaccine candidates results in potent responses, combined approaches significantly enhance responses, suggesting that such approaches need to be considered in the further development of an efficacious CHIKV vaccine.

September, 2014

mmunity. 2014 Sep 18;41(3):478-92. doi: 10.1016/j.immuni.2014.08.009. Epub 2014 Sep 11.

Oh JZ1, Ravindran R1, Chassaing B2, Carvalho FA3, Maddur MS1, Bower M4, Hakimpour P5, Gill KP1, Nakaya HI6, Yarovinsky F7, Sartor RB4, Gewirtz AT2,Pulendran B8.

Systems biological analysis of immunity to the trivalent inactivated influenza vaccine (TIV) in humans revealed a correlation between early expression of TLR5 and the magnitude of the antibody response. Vaccination of Trl5(-/-) mice resulted in reduced antibody titers and lower frequencies of plasma cells, demonstrating a role for TLR5 in immunity to TIV. This was due to a failure to sense host microbiota. Thus, antibody responses in germ-free or antibiotic-treated mice were impaired, but restored by oral reconstitution with a flagellated, but not aflagellated, strain of E. coli. TLR5-mediated sensing of flagellin promoted plasma cell differentiation directly and by stimulating lymph node macrophages to produce plasma cell growth factors. Finally, TLR5-mediated sensing of the microbiota also impacted antibody responses to the inactivated polio vaccine, but not to adjuvanted vaccines or the live-attenuated yellow fever vaccine. These results reveal an unappreciated role for gut microbiota in promoting immunity to vaccination.

August, 2014

N Engl J Med. 2014. 371(7):635-45.

Carlos A. DiazGranados, M.D., Andrew J. Dunning, Ph.D., Murray Kimmel, D.O., Daniel Kirby, B.Sc., John Treanor, M.D., Avi Collins, B.Sc.N., Richard Pollak, D.P.M., Janet Christoff, R.N., John Earl, M.D., Victoria Landolfi, M.Sc., M.B.A., Earl Martin, D.O., Sanjay Gurunathan, M.D., Richard Nathan, D.O., David P. Greenberg, M.D., Nadia G. Tornieporth, M.D., Michael D. Decker, M.D., M.P.H., and H. Keipp Talbot, M.D., M.P.H.

Background: As compared with a standard-dose vaccine, a high-dose, trivalent, inactivated influenza vaccine (IIV3-HD) improves antibody responses to influenza among adults 65 years of age or older. This study evaluated whether IIV3-HD also improves protection against laboratory-confirmed influenza illness.

Methods: We conducted a phase IIIb-IV, multicenter, randomized, double-blind, active-controlled trial to compare IIV3-HD (60 μg of hemagglutinin per strain) with standard-dose trivalent, inactivated influenza vaccine (IIV3-SD [15 μg of hemagglutinin per strain]) in adults 65 years of age or older. Assessments of relative efficacy, effectiveness, safety (serious adverse events), and immunogenicity (hemagglutination-inhibition [HAI] titers) were performed during the 2011-2012 (year 1) and the 2012-2013 (year 2) northern-hemisphere influenza seasons.

Results: A total of 31,989 participants were enrolled from 126 research centers in the United States and Canada (15,991 were randomly assigned to receive IIV3-HD, and 15,998 to receive IIV3-SD). In the intention-to-treat analysis, 228 participants in the IIV3-HD group (1.4%) and 301 participants in the IIV3-SD group (1.9%) had laboratory-confirmed influenza caused by any viral type or subtype associated with a protocol-defined influenza-like illness (relative efficacy, 24.2%; 95% confidence interval [CI], 9.7 to 36.5). At least one serious adverse event during the safety surveillance period was reported by 1323 (8.3%) of the participants in the IIV3-HD group, as compared with 1442 (9.0%) of the participants in the IIV3-SD group (relative risk, 0.92; 95% CI, 0.85 to 0.99). After vaccination, HAI titers and seroprotection rates (the percentage of participants with HAI titers ≥ 1:40) were significantly higher in the IIV3-HD group. Conclusions: Among persons 65 years of age or older, IIV3-HD induced significantly higher antibody responses and provided better protection against laboratory-confirmed influenza illness than did IIV3-SD. (Funded by Sanofi Pasteur; number, NCT01427309.).

July, 2014

Lancet. 2014 Jul 10. [Epub ahead of print]

Capeding MR, Tran NH, Hadinegoro SR, Ismail HI, Chotpitayasunondh T, Chua MN, Luong CQ, Rusmil K, Wirawan DN, Nallusamy R, Pitisuttithum P, Thisyakorn U, Yoon IK, van der Vliet D, Langevin E, Laot T, Hutagalung Y, Frago C, Boaz M, Wartel TA, Tornieporth NG, Saville M, Bouckenooghe A; the CYD Study Group.

Background: An estimated 100 million people have symptomatic dengue infection every year. This is the first report of a phase 3 vaccine efficacy trial of a candidate dengue vaccine. We aimed to assess the efficacy of the CYD dengue vaccine against symptomatic, virologically confirmed dengue in children.

Methods: We did an observer-masked, randomised controlled, multicentre, phase 3 trial in five countries in the Asia-Pacific region. Between June 3, and Dec 1, 2011, healthy children aged 2-14 years were randomly assigned (2:1), by computer-generated permuted blocks of six with an interactive voice or web response system, to receive three injections of a recombinant, live, attenuated, tetravalent dengue vaccine (CYD-TDV), or placebo, at months 0, 6, and 12. Randomisation was stratified by age and site. Participants were followed up until month 25. Trial staff responsible for the preparation and administration of injections were unmasked to group allocation, but were not included in the follow-up of the participants; allocation was concealed from the study sponsor, investigators, and parents and guardians. Our primary objective was to assess protective efficacy against symptomatic, virologically confirmed dengue, irrespective of disease severity or serotype, that took place more than 28 days after the third injection. The primary endpoint was for the lower bound of the 95% CI of vaccine efficacy to be greater than 25%. Analysis was by intention to treat and per procotol. This trial is registered with, number NCT01373281.

Findings: We randomly assigned 10 275 children to receive either vaccine (n=6851) or placebo (n=3424), of whom 6710 (98%) and 3350 (98%), respectively, were included in the primary analysis. 250 cases of virologically confirmed dengue took place more than 28 days after the third injection (117 [47%] in the vaccine group and 133 [53%] in the control group). The primary endpoint was achieved with 56·5% (95% CI 43·8-66·4) efficacy. We recorded 647 serious adverse events (402 [62%] in the vaccine group and 245 [38%] in the control group). 54 (1%) children in the vaccine group and 33 (1%) of those in the control group had serious adverse events that happened within 28 days of vaccination. Serious adverse events were consistent with medical disorders in this age group and were mainly infections and injuries.

Interpretation: Our findings show that dengue vaccine is efficacious when given as three injections at months 0, 6, and 12 to children aged 2-14 years in endemic areas in Asia, and has a good safety profile. Vaccination could reduce the incidence of symptomatic infection and hospital admission and has the potential to provide an important public health benefit.

June, 2014

Nature Medicine 20:655–658.

1 1] Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA. [2] Graduate Program in Pathobiology, Department of Global Health, University of Washington, Seattle, Washington, USA.

2 Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.

3 Department of Pediatrics, University of Nairobi, Nairobi, Kenya.

4 1] Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA. [2] Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.

Eliciting protective neutralizing antibodies (NAbs) against HIV-1 is daunting because of the extensive genetic and antigenic diversity of HIV-1. Moreover, broad and potent responses are uncommon even during persistent infection, with only a subset of adults developing broadly neutralizing antibodies (bNAbs) that recognize viral variants from different HIV-1 clades. It is not known whether bNAbs can also arise in HIV-1-infected infants, who typically progress to disease faster than adults, presumably in part due to an immature immune system. Here, we show that bNAbs develop at least as commonly in infants as in adults. Cross-clade NAb responses were detected in 20/28 infected infants, in some cases within 1 year of infection. Among infants with breadth of responses within the top quartile, neutralization of tier 2 or 3 variants from multiple clades was detected at 20 months after infection. These findings suggest that, even in early life, there is sufficient B cell functionality to mount bNAbs against HIV-1. Additionally, the relatively early appearance of bNAbs in infants may provide a unique setting for understanding the pathways of B cell maturation leading to bNAbs.

May, 2014

J Virol. 2014 in press.

Gartland AJ, Li S, McNevin J, Tomaras GD, Gottardo R, Janes H, Fong Y, Morris D, Geraghty DE, Kijak GH, Edlefsen PT, Frahm N, Larsen BB, Tovanabutra S, Sanders-Buell E, deCamp AC, Magaret CA, Ahmed H, Goodridge JP, Chen L, Konopa P, Nariya S, Stoddard JN, Wong K, Zhao H, Deng W, Maust BS, Bose M, Howell S, Bates A, Lazzaro M, O’Sullivan A, Lei E, Bradfield A, Ibitamuno G, Assawadarachai V, O’Connell RJ, deSouza MS, Nitayaphan S, Rerks-Ngarm S, Robb ML, Sidney J, Sette A, Zolla-Pazner S, Montefiori D, McElrath MJ, Mullins JI, Kim JH, Gilbert PB, Hertz T.

Statistical Center for HIV/AIDS Research & Prevention, Vaccine & Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA

Summary: The RV144 HIV-1 vaccine trial demonstrated partial efficacy of 31% against HIV-1 infection. Studies into possible correlates of protection found that antibodies specific to the V1/V2 region of envelope correlated inversely with infection risk and that viruses isolated from trial participants contained genetic signatures of vaccine-induced pressure in the V1/V2 region. We explored the hypothesis that the genetic signatures in V1/V2 could be partly attributed to selection by vaccine primed T cells. We performed a T-cell based sieve analysis of breakthrough viruses in the RV144 trial and found evidence of predicted HLA binding escape that was greater in vaccine versus placebo recipients. The predicted escape depended on class I HLA A*02 and A*11 restricted epitopes in the MN-strain rgp120 vaccine immunogen. Though we hypothesized that this was indicative of post-acquisition selection pressure, we also found that vaccine efficacy (VE) was greater in A*02+ compared to A*02- participants (VE=54% vs. 3%, p=0.05). Vaccine efficacy against viruses with a lysine residue at site 169, important to antibody binding and implicated in vaccine-induced immune pressure, was also greater in A*02+ participants (VE=74% vs. 15%, p=0.02). Additionally, a reanalysis of vaccine-induced immune responses focused on those that were shown to correlate with infection risk, suggested that the humoral response may have differed in A*02+ participants. These exploratory and hypothesis-generating analyses indicate there may be an association between a class I HLA allele and vaccine efficacy, highlighting the importance of considering HLA alleles and host immune genetics in HIV vaccine trials.

IMPACT: The RV144 trial was the first to show efficacy against HIV-1 infection. Subsequently, much effort has been directed towards understanding the mechanisms of protection, including this T-cell based sieve analysis which compared the genetic sequences of viruses isolated from infected vaccine and placebo recipients. Though we hypothesized that the observed sieve effect indicated post-acquisition T-cell selection, we also found that vaccine efficacy was greater for participants who expressed HLA A*02, an allele implicated in the sieve analysis. Though HLA alleles have been associated with disease progression and viral load in HIV-1 infection, these data are the first to suggest the association of a class I HLA allele and vaccine efficacy. While these statistical analyses do not provide mechanistic evidence of protection in RV144, they generate testable hypotheses for the HIV vaccine community and they highlight the importance of assessing the impact of host immune genetics in vaccine-induced immunity and protection.

April, 2014

Pediatrics 2014;133;577

Fangjun Zhou, Abigail Shefer, Jay Wenger, Mark Messonnier, Li Yan Wang, Adriana Lopez, Matthew Moore, Trudy V. Murphy, Margaret Cortese and Lance Rodewald

Objectives: To evaluate the economic impact of the 2009 routine US childhood immunization schedule, including diphtheria and tetanus toxoids and acellular pertussis, Haemophilus influenzae type b conju- gate, inactivated poliovirus, measles/mumps/rubella, hepatitis B, varicella, 7-valent pneumococcal conjugate, hepatitis A, and rotavirus vaccines; influenza vaccine was not included.

Methods: Decision analysis was conducted using population-based vaccination coverage, published vaccine efficacies, historical data on disease incidence before vaccination, and disease incidence reported during 2005 to 2009. Costs were estimated using the direct cost and societal (direct and indirect costs) perspectives. Program costs included vaccine, administration, vaccine-associated adverse events, and parent travel and work time lost. All costs were inflated to 2009 dollars, and all costs and benefits in the future were discounted at a 3% annual rate. A hypothetical 2009 US birth cohort of 4261494 infants over their lifetime was followed up from birth through death. Net present value (net savings) and benefit-cost ratios of routine childhood immunization were calculated.

Results: Analyses showed that routine childhood immunization among members of the 2009 US birth cohort will prevent ∼42 000 early deaths and 20 million cases of disease, with net savings of $13.5 billion in direct costs and $68.8 billion in total societal costs, respec- tively. The direct and societal benefit-cost ratios for routine childhood vaccination with these 9 vaccines were 3.0 and 10.1. CONCLUSIONS: From both direct cost and societal perspectives, vaccinating children as recommended with these vaccines results in substantial cost savings.

March, 2014

Emerging Infectious Diseases. 2014. 20:4. 643-648.

Jussi Sane, Sigrid Gouma, Marion Koopmans, Hester de Melker, Corien Swaan, Rob van Binnendijk, and Susan Hahné

National Institute for Public Health and the Environment, Bilthoven, the Netherlands; European Programme for Intervention Epidemiology Training, European Centre for Disease Prevention and Control, Stockholm, Sweden; and Erasmus Medical Centre, Rotterdam, the Netherlands.

To analyze the epidemiology of a nationwide mumps epidemic in the Netherlands, we reviewed 1,557 notified mumps cases in persons who had disease onset during September 1, 2009–August 31, 2012. Seasonality peaked in spring and autumn. Most case-patients were males (59%), 18–25 years of age (67.9%), and vaccinated twice with mea- sles-mumps-rubella vaccine (67.7%). Nearly half (46.6%) of cases occurred in university students or in persons with student contacts. Receipt of 2 doses of vaccine reduced the risk for orchitis, the most frequently reported complication (vaccine effectiveness [VE] 74%, 95% CI 57%–85%); complications overall (VE 76%, 95% CI 61%–86%); and hospitalization (VE 82%, 95% CI 53%–93%). Over time, the age distribution of case-patients changed, and proportionally more cases were reported from non-university cities (p<0.001). Changes in age and geographic distribution over time may reflect increased immunity among students result- ing from intense exposure to circulating mumps virus.

February, 2014

New England Journal of Medicine. 2014. 370:9.

Rongcheng Li, B.S., Longding Liu, Ph.D., Zhaojun Mo, M.Sc.,
Xuanyi Wang, M.D., Ph.D., Jielai Xia, Ph.D., Zhenglun Liang, M.D., Ph.D., Ying Zhang, Ph.D., Yanping Li, B.S., Qunying Mao, M.Sc., Jingjing Wang, M.Sc., Li Jiang, B.S., Chenghong Dong, B.S., Yanchun Che, M.Sc., Teng Huang, M.Sc., Zhiwei Jiang, Ph.D., Zhongping Xie, B.S., Lichun Wang, B.S., Yun Liao, B.S., Yan Liang, Ph.D., Yi Nong, B.S., Jiansheng Liu, M.Sc., Hongling Zhao, B.S., Ruixiong Na, B.S., Lei Guo, Ph.D., Jing Pu, B.S., Erxia Yang, B.S., Le Sun, M.Sc., Pingfang Cui, B.S., Haijing Shi, M.Sc., Junzhi Wang, Ph.D., and Qihan Li, M.D., Ph.D.

Background: Enterovirus 71 (EV71) is a major cause of hand, foot, and mouth disease in children and may be fatal. A vaccine against EV71 is needed.

Methods: We conducted a randomized, double-blind, placebo-controlled phase 3 trial involving healthy children 6 to 71 months of age in Guangxi Zhuang Autonomous Region, China. Two doses of an inactivated EV71 vaccine or placebo were administered intramuscularly, with a 4-week interval between doses, and children were monitored for up to 11 months. The primary end point was protection against hand, foot, and mouth disease caused by EV71.

Results: A total of 12,000 children were randomly assigned to receive vaccine or placebo. Serum neutralizing antibodies were assessed in 549 children who received the vaccine. The seroconversion rate was 100% 4 weeks after the two vaccinations, with a geometric mean titer of 170.6. Over the course of two epidemic seasons, the vaccine efficacy was 97.4% (95% confidence interval [CI], 92.9 to 99.0) according to the intention-to-treat analysis and 97.3% (95% CI, 92.6 to 99.0) according to the per- protocol analysis. Adverse events, such as fever (which occurred in 41.6% of the participants who received vaccine vs. 35.2% of those who received placebo), were significantly more common in the week after vaccination among children who received the vaccine than among those who received placebo.

Conclusions: The inactivated EV71 vaccine elicited EV71-specific immune responses and protection against EV71-associated hand, foot, and mouth disease. (Funded by the National Basic Research Program and others; number, NCT01569581.)

January, 2014

Sci Transl Med. 2014. 6(221):221ra13

Leonel Maldonado, Jessica E. Teague, Matthew P. Morrow, Iveta Jotova, T. C. Wu, Chenguang Wang, Cindy Desmarais, Jean D. Boyer, Benjamin Tycko, Harlan S. Robins, Rachael A. Clark and Cornelia L. Trimble

About 25% of high-grade cervical intraepithelial neoplasias (CIN2/3) caused by human papillomavirus serotype 16 (HPV16) undergo complete spontaneous regression. However, to date, therapeutic vaccination strategies for HPV disease have yielded limited success when measured by their ability to induce robust peripheral blood T cell responses to vaccine antigen. We report marked immunologic changes in the target lesion microenvironment after intramuscular therapeutic vaccination targeting HPV16 E6/E7 antigens, in subjects with CIN2/3 who had modest detectable responses in circulating T lymphocytes. Histologic and molecular changes, including markedly (average threefold) increased intensity of CD8(+) T cell infiltrates in both the stromal and epithelial compartments, suggest an effector response to vaccination. Postvaccination cervical tissue immune infiltrates included organized tertiary lymphoid-like structures in the stroma subjacent to residual intraepithelial lesions and, unlike infiltrates in unvaccinated lesions, showed evidence of proliferation induced by recognition of cognate antigen. At a molecular level, these histologic changes in the stroma were characterized by increased expression of genes associated with immune activation (CXCR3) and effector function (Tbet and IFNβ), and were also associated with an immunologic signature in the overlying dysplastic epithelium. High-throughput T cell receptor sequencing of unmanipulated specimens identified clonal expansions in the tissue that were not readily detectable in peripheral blood. Together, these findings indicate that peripheral therapeutic vaccination to HPV antigens can induce a robust tissue-localized effector immune response, and that analyses of immune responses at sites of antigen are likely to be much more informative than analyses of cells that remain in the circulation.

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