30-day morbidity and mortality of revisional bariatric surgery - An international multi-centre collaborative (BROAD) study.

INTRODUCTION: Revisional bariatric surgery (RBS) for insufficient weight loss/weight regain or metabolic relapse is increasing worldwide. There is currently no large multinational, prospective data on 30-day morbidity and mortality of RBS. In this study, we aimed to evaluate the 30-day morbidity and mortality of RBS at participating centres. METHODS: An international steering group was formed to oversee the study. The steering group members invited bariatric surgeons worldwide to participate in this study. Ethical approval was obtained at the lead centre. Data were collected prospectively on all consecutive RBS patients operated between 15th May 2021 to 31st December 2021. Revisions for complications were excluded. RESULTS: A total of 65 global centres submitted data on 750 patients. Sleeve gastrectomy (n = 369, 49.2 %) was the most common primary surgery for which revision was performed. Revisional procedures performed included Roux-en-Y gastric bypass (RYGB) in 41.1 % (n = 308) patients, One anastomosis gastric bypass (OAGB) in 19.3 % (n = 145), Sleeve Gastrectomy (SG) in 16.7 % (n = 125) and other procedures in 22.9 % (n = 172) patients. Indications for revision included weight regain in 615(81.8 %) patients, inadequate weight loss in 127(16.9 %), inadequate diabetes control in 47(6.3 %) and diabetes relapse in 27(3.6 %). 30-day complications were seen in 80(10.7 %) patients. Forty-nine (6.5 %) complications were Clavien Dindo grade 3 or higher. Two patients (0.3 %) died within 30 days of RBS. CONCLUSION: RBS for insufficient weight loss/weight regain or metabolic relapse is associated with 10.7 % morbidity and 0.3 % mortality. Sleeve gastrectomy is the most common primary procedure to undergo revisional bariatric surgery, while Roux-en-Y gastric bypass is the most commonly performed revision.

From Bands to Bypasses: Navigating Safety of Band Conversions to Roux-en-Y Gastric Bypass and Single Anastomosis Duodenoileostomy Versus Sleeve Gastrectomy.

INTRODUCTION: Revisional bariatric surgery is associated with higher perioperative complications over primary procedures. Adjustable gastric bands (AGB) continue to be the most frequently converted bariatric configuration. This study examines trends in current clinical indication and safety profile of the most frequently pursued AGB conversions. MATERIALS AND METHODS: MBSAQIP data from 2020 to 2022 was retrospectively analyzed in a cohort study examining 30-day postoperative outcomes after AGB conversion to sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), or single anastomosis duodenoileostomy (SADI). Descriptive statistics were used, including multivariable and 2:1 nearest neighbor matching analysis. RESULTS: This study included 19,335 AGB conversions, of which most were to SG (n = 11,736) followed by RYGB (n = 7442) and SADI (n = 157). While a majority were completed for weight loss, there were differences in distribution of primary indication for each conversion cohort, such as higher proportion of RYGB conversion for gastroesophageal reflux disease (18.7%) compared to SG (7.92%) and SADI (5.10%). Multivariable analysis demonstrates conversion to RYGB has significantly higher odds of 30-day major complications (OR 1.75, p < 0.001), reoperation (OR 2.08; p = 0.001), readmission (OR 1.69; p = 0.001), and emergency department visits (OR 1.50; p = 0.001) over SG. These risks and odds of reintervention (OR 1.75; p < 0.001) remained significantly higher after conversion to RYGB versus SG on matched analysis. None of these risks is significantly different between conversions to SADI versus SG in either multivariable or matched analysis. CONCLUSIONS: Compared to AGB conversion to SG, single-stage conversion to RYGB had increased odds of perioperative complications while risks of conversion to SADI were not significantly different.

Early Successful Experiences of Surgical Conversion of Endoscopic Gastric Plication to Roux-en-Y Gastric Bypass.

BACKGROUND: The primary obesity surgery endoluminal (POSE) procedure is an innovative incision-less endoscopic bariatric procedure that is increasingly used. However, variable weight loss response and recurrence post-endoscopic bariatric procedures have at times necessitated laparoscopic bariatric conversion. The safety and approach of conversion to laparoscopic sleeve gastrectomy (LSG) or Roux-en-Y gastric bypass (RYGB), however, have been an active point of discussion within revisional bariatric surgery. METHODS: This retrospective review of four consecutive patients is the largest description of medium-term postoperative outcomes and technical highlights of a laparoscopic conversion of POSE to RYGB. Chart review was completed to evaluate patients' post-POSE clinical course and perioperative outcomes after surgical conversion. RESULTS: Early data suggests varied weight loss trajectory with POSE and marked improvement in weight response after surgical conversion. Qualitative review reveals successful single-staged conversions contrary to previous smaller case series describing staged conversions involving endoscopic removal of plications followed by RYGB. Review additionally reveals key perioperative considerations for successful conversions to include intraoperative endoscopy, upper gastrointestinal fluoroscopic studies, and at times computed tomography. The latter study and laparoscopic view of the post-POSE stomach challenge the prior notion that distal POSE allows for easy revision to LSG. CONCLUSIONS: Our case series underscores the complex multifactorial nature of metabolic disease and the increasing importance of a conscientious approach to conversion bariatric surgery as the adoption of POSE and the bariatric patient population continues to grow.

The SAGES MASTERS program bariatric surgery pathway selects 10 seminal publications on revisional bariatrics.

BACKGROUND: The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) Masters Program designated bariatric surgery as a clinical pathway. Among the tiers of the Masters Program, revisional bariatric surgery is the highest tier of "mastery" within the pathway. This article presents the top 10 seminal studies representing the current landscape of revisional bariatrics. METHODS: The literature was systematically searched and seminal articles designated by consensus agreement of the SAGES Metabolic and Bariatric Surgery committee using multiple criteria, including impact on the field, citation frequency, and expert opinion. Articles were reviewed by committee members and presented in summarized fashion. RESULTS: The top 10 papers are presented in grouped thematic categories covering the early evolution of revisional bariatrics, changing criteria for reoperative bariatric surgery, divergence of revision versus conversion bariatric surgery, and recent technologic innovations in revisional bariatric surgery. Each summary is presented with expert appraisal and commentary. CONCLUSION: These seminal papers represent a snapshot of the dynamic field of revisional bariatric surgery and emphasize the need to not only remain current with contemporary trends but also keep a patient-oriented perspective on patient and intervention selection for optimal success.

Esophageal and gastric malignancies after bariatric surgery: a retrospective global study.

BACKGROUND: Bariatric surgery can influence the presentation, diagnosis, and management of gastrointestinal cancers. Esophagogastric (EG) malignancies in patients who have had a prior bariatric procedure have not been fully characterized. OBJECTIVE: To characterize EG malignancies after bariatric procedures. SETTING: University Hospital, United Kingdom. METHODS: We performed a retrospective, multicenter observational study of patients with EG malignancies after bariatric surgery to characterize this condition. RESULTS: This study includes 170 patients from 75 centers in 25 countries who underwent bariatric procedures between 1985 and 2020. At the time of the bariatric procedure, the mean age was 50.2 ± 10 years, and the mean weight 128.8 ± 28.9 kg. Women composed 57.3% (n = 98) of the population. Most (n = 64) patients underwent a Roux-en-Y gastric bypass (RYGB) followed by adjustable gastric band (AGB; n = 46) and sleeve gastrectomy (SG; n = 43). Time to cancer diagnosis after bariatric surgery was 9.5 ± 7.4 years, and mean weight at diagnosis was 87.4 ± 21.9 kg. The time lag was 5.9 ± 4.1 years after SG compared to 9.4 ± 7.1 years after RYGB and 10.5 ± 5.7 years after AGB. One third of patients presented with metastatic disease. The majority of tumors were adenocarcinoma (82.9%). Approximately 1 in 5 patients underwent palliative treatment from the outset. Time from diagnosis to mortality was under 1 year for most patients who died over the intervening period. CONCLUSION: The Oesophago-Gastric Malignancies After Obesity/Bariatric Surgery study presents the largest series to date of patients developing EG malignancies after bariatric surgery and attempts to characterize this condition.

Robotic versus laparoscopic median arcuate ligament (MAL) release: a retrospective comparative study.

BACKGROUND: Multiple retrospective studies have demonstrated the safety and feasibility of laparoscopic median arcuate ligament division with celiac neurolysis for the definitive management of median arcuate ligament syndrome (MALS). This study queries the clinical equipoise of robotic (RMALR) versus laparoscopic MAL release (LMALR) at a high-volume center. METHODS: A retrospective analysis of consecutive 26 RMALR and 24 LMALR between March 2018 and August 2019 by a single surgeon at a quaternary academic institution was completed. Primary endpoint was postoperative decrease in celiac trunk expiratory peak systolic velocities (PSVs) measured by mesenteric duplex ultrasonography. Secondary outcomes included reported improvement in MALS-related clinical symptoms, distribution of first assistant seniority level, and involvement of second assistants in RMALR versus LMALR. RESULTS: Mean operative times for LMALR and RMALR were 86 and 134 min, respectively (p < 0.0001). There were no open conversions and mean length of hospital stay was 1 day for both cohorts. Both groups provided an equally effective decrease in postoperative peak systolic velocities (PSVs) (LMALR p = 0.0011; RMALR p = 0.0022; LMALR vs. RMALR p = 0.7772). While RMALR had significantly higher reduction of chronic abdominal pain postoperatively, there were no significant differences in other postoperative symptom relief between groups. However, RMALR patients reported significant relief of postprandial abdominal pain (p < 0.0001) and chronic nausea (p = 0.0002). RMALR had significantly more junior first assistants (p = 0.0001) and less frequently required second assistants compared to LMALR (p = 0.0381). CONCLUSIONS: In this study comparing RMALR to LMALR, postoperative chronic abdominal pain relief was significantly less in the former while other outcomes were equivalent. In comparison with LMALR, RMALR cases were associated with more junior first assistants, fewer second assistants, and longer operative times. Both approaches are safe and feasible for well-selected patients in experienced centers.

TLE4 Is a Critical Mediator of Osteoblast and Runx2-Dependent Bone Development.

Healthy bone homeostasis hinges upon a delicate balance and regulation of multiple processes that contribute to bone development and metabolism. While examining hematopoietic regulation by Tle4, we have uncovered a previously unappreciated role of Tle4 on bone calcification using a novel Tle4 null mouse model. Given the significance of osteoblasts in both hematopoiesis and bone development, this study investigated how loss of Tle4 affects osteoblast function. We used dynamic bone formation parameters and microCT to characterize the adverse effects of Tle4 loss on bone development. We further demonstrated loss of Tle4 impacts expression of several key osteoblastogenic genes, including Runx2, Oc, and Ap, pointing toward a potential novel mechanism for Tle4-dependent regulation of mammalian bone development in collaboration with the RUNX family members.

Bariatric Surgery is Safe for Patients After Recovery from COVID-19.

BACKGROUND: Studies of patients who have undergone surgery while infected with COVID-19 have shown increased risks for adverse outcomes in both pulmonary complications and mortality. It has become clear that the risk of complications from perioperative COVID-19 infection must be weighed against the risk from delayed surgical treatment. Studies have also shown that prior bariatric surgery conveys protection against mortality from COVID-19 and that obesity is the biggest risk factor for mortality from COVID-19 infection in adults under 45 years of age. Studies in patients who have fully recovered from COVID-19 and underwent elective surgery have not become widely available yet. OBJECTIVES: This multi-institutional case series is presented to highlight patients who developed COVID-19, fully recovered, and subsequently underwent elective bariatric surgery with 30-day outcomes available. SETTING: Nine bariatric surgery centers located across the United States. METHODS: This multicenter case series is a retrospective chart review of patients who developed COVID-19, recovered, and subsequently underwent bariatric surgery. Fifty-three patients are included, and 30-day morbidity and mortality were analyzed. RESULTS: Thirty-day complications included esophageal spasm, dehydration, and ileus. There were no cardiovascular, venous thromboembolism (VTE) or respiratory events reported. There were no 30- day mortalities. CONCLUSIONS: Bariatric surgery has been safely performed in patients who made a full recovery from COVID-19 without increased complications due to cardiovascular, pulmonary, venous thromboembolism, or increased mortality rates.

Efficacy of Virtual Case-Based General Surgery Clerkship Curriculum During COVID-19 Distancing.

OBJECTIVE: The COVID-19 pandemic created a paradigm shift in medical education with a reliance upon alternative teaching methods to deliver meaningful surgery clerkship content. This study examines the efficacy of a novel, case-based virtual surgery clerkship curriculum to determine its impact on student experience during quarantine. STUDY DESIGN: Sixteen third-year medical students enrolled in the General Surgery clerkship between April through June 2020 during COVID-19 distancing at a quaternary medical center (Cleveland Clinic, Cleveland, OH) participated in this study. Course surveys, including a 10-question curriculum-based multiple-choice assessment, were administered before and after the clerkship. Analyses include student self-perception of readiness to see a surgical consult independently, students' interest in pursuing a General Surgery residency, and improvement of surgical knowledge. RESULTS AND CONCLUSION: On a 5-point Likert scale, students felt significantly more assured in their ability to independently assess a surgical consult by the end of the course. Five (31%) students reported an influence of the curriculum on their personal interest in a career in General Surgery. Mean scores on the curriculum-based knowledge assessment increased. These findings highlight that a virtual platform can be a reliable alternative adjunct that delivers surgical content and positively impacts student experience. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40670-020-01126-5.

Effect modification of resident autonomy and seniority on perioperative outcomes in laparoscopic cholecystectomy.

BACKGROUND: Resident operative involvement is an integral aspect of general surgery residency training. However, current data examining the effect of resident autonomy on perioperative outcomes remain limited. METHODS: Patient and operator-specific data were collected from 344 adult laparoscopic cholecystectomies at a tertiary academic institution and its regional affiliates between 2018 and 2019. Multivariate modeling compared postoperative outcomes between cases completed with or without resident involvement and its effect modification by resident seniority and autonomy per Zwisch scale. Outcomes include 30-day postoperative complications, hospital readmission rate, and operative time. RESULTS: Multivariate analysis revealed resident involvement in laparoscopic cholecystectomy did not significantly change odds of 30-day postoperative complications (OR 2.52, p = 0.185, 95% CI 0.64-9.92) or hospital readmission (OR 1.61, p = 0.538, 95% CI 0.36-7.23). Operative time is significantly increased compared to faculty-only cases (IRR 1.37, p < 0.001, 95% CI 1.26-1.48). While accounting for case difficulty and resident performance evaluated by SIMPL criteria, stratification by resident autonomy measured by Zwisch scale or seniority reveal no effect modification on 30-day postoperative complications, readmissions, or operative time. The effect of resident involvement on longer relative rates of operative time loses its significance in supervision-only cases (IRR 1.18, p = 0.069, 95% CI 0.99-1.41). CONCLUSION: While resident involvement and autonomy are associated with significantly longer operative times in laparoscopic cholecystectomy, their lack of significant effect on postoperative outcomes argues strongly for continued resident involvement and supervised operative independence.

Beyond Medical Knowledge and Patient Care: A Program Director's Perspective for the Role of General Surgery Subinternships.

OBJECTIVE: Established primary goals of general surgery subinternships are improvement in patient care and medical knowledge. However, the secondary gains such as obtaining recommendation letters and forming relationships are apparent but poorly defined. We sought the opinion of general surgery program directors (PDs) on the secondary purposes of subinternships. Our aim is to aide mentors and students to optimize the subinternship experience relative to the residency application process. DESIGN: A survey was administered in July 2019. This questionnaire consisted of 11 items and was broken down into 3 sections: demographics, PD perspective on the secondary goals of a general surgery subinternship, and the role of general surgery subinternships on the students' residency application. SETTING: An online, national survey through the Association for Program Directors listserv. PARTICIPANTS: United States general surgery PDs affiliated with the Association for Program Directors listserv. RESULTS: Sixty-one PDs completed the survey from 42 (69%) academic and 14 (23%) community programs. The majority of PDs (n = 33, 54%) reported that assessment of a subintern's suitability for their residency was the most important secondary purpose. Furthermore, PDs (n = 24, 39%) valued a letter of recommendation from faculty the student worked with during a subinternship as the most important criteria in the interview selection process. Away rotations were perceived as of equal value to subinternships completed at the student's home institution. Overall, PD opinions were similar at academic and community programs. CONCLUSIONS: Our study suggests subinternships significantly impact a student's application to general surgery residency, clarifying a secondary role for these rotations. Subinternships are important for PDs to assess a student for ranking at their program. All students should pursue a letter of recommendation from subinternship faculty, when possible, as they can heavily influence the interview selection process. Away rotations should only be recommended for those students who need to strengthen their application.

Effects of laparoscopic vs open abdominal surgery on costs and hospital readmission rate and its effect modification by surgeons' case volume.

BACKGROUND: Laparoscopy provides a minimally invasive alternative to open abdominal surgery. Current data describing its association with hospital readmission and costs in relation to surgeon laparoscopic case volume is limited to smaller databases and subsets of operations. METHODS: This retrospective cohort study of 23,285 adult abdominal operations from 2007 to 2015 compares 30-day readmission rate and costs between laparoscopic and open abdominal operations and examines effect modification by surgeon laparoscopic case volume. Outcomes were all-cause hospital readmission within 30 days after discharge and index hospital admission cost. RESULTS: All-cause hospital readmission rates were significantly lower after laparoscopic abdominal operations compared with open operations (adjusted odds ratio [aOR] 0.56, 95% CI 0.46-0.69, p < 0.001) with a difference in readmission risk attributable to laparoscopic approach of - 4.0% (95% CI - 5.4 to - 2.6%) in complete-case analysis. Among surgeons with a high laparoscopic case volume, the estimated difference in readmission risk through laparoscopy was magnified (- 5.8%, 95% CI - 7.5 to - 4.1%) compared to low surgeon laparoscopic case volume (- 2.9%, 95% CI - 4.8 to -1.1%, p for interaction = 0.005). The estimated difference in costs of the index hospital admission attributable to laparoscopic approach was - $3869 (95% CI - $4200 to - $3538; adjusted incidence rate ratio 0.77, 95% CI 0.75-0.79, p < 0.001). Laparoscopy was followed by significantly lower rates of readmissions related to gastrointestinal (aOR 0.68, 95% CI 0.55-0.85, p = 0.001), wound complications (infection: aOR 0.33, 95% CI 0.23-0.47, p < 0.001; non-infectious: aOR 0.47, 95% CI 0.30-0.74, p = 0.001), and malignancy (aOR 0.68, 95% CI 0.55-0.85, p < 0.001). The findings remain robust after multiple imputation and sensitivity analyses. CONCLUSIONS: Laparoscopy versus open abdominal surgery is associated with reduced hospital readmissions related to malignancy, gastrointestinal, and wound complications. Effect modification by higher laparoscopy case volume argues for continued proliferation of laparoscopy in abdominal surgeries.

Tumor Lysis Syndrome After Bilobectomy for Typical Carcinoid Tumor of the Lung.

Tumor lysis syndrome is a life-threatening complication comprising hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia attributed to release of intracellular contents. Although traditionally associated with leukemia and lymphoma after chemotherapy, it is known to occur in solid malignancies. We herein report a rare case of this syndrome after resection of bulky carcinoid tumor of the lung.

TLE4 regulation of wnt-mediated inflammation underlies its role as a tumor suppressor in myeloid leukemia.

The presence of AML1-ETO (RUNX1-CBF2T1), a fusion oncoprotein resulting from a t(8;21) chromosomal translocation, has been implicated as a necessary but insufficient event in the development of a subset of acute myeloid leukemias (AML). While AML1-ETO prolongs survival and inhibits differentiation of hematopoietic stem cells (HSC), other contributory events are needed for cell proliferation and leukemogenesis. We have postulated that specific tumor suppressor genes keep the leukemic potential of AML1-ETO in check. In studying del(9q), one of the most common concomitant chromosomal abnormalities with t(8;21), we identified the loss of an apparent tumor suppressor, TLE4, that appears to cooperate with AML1-ETO to confer a leukemic phenotype. This study sought to identify the molecular basis of this cooperation. We show that the loss of TLE4 confers proliferative advantage to leukemic cells, simultaneous with an upregulation of a pro- inflammatory signature mediated through aberrant increases in Wnt signaling activity. We further demonstrate that inhibition of cyclooxygenase (COX) activity partly reverses the pro-leukemic phenotype due to TLE4 knockdown, pointing towards a novel therapeutic approach for myeloid leukemia.

The corepressor Tle4 is a novel regulator of murine hematopoiesis and bone development.

Hematopoiesis is a complex process that relies on various cell types, signaling pathways, transcription factors and a specific niche. The integration of these various components is of critical importance to normal blood development, as deregulation of these may lead to bone marrow failure or malignancy. Tle4, a transcriptional corepressor, acts as a tumor suppressor gene in a subset of acute myeloid leukemia, yet little is known about its function in normal and malignant hematopoiesis or in mammalian development. We report here that Tle4 knockout mice are runted and die at around four weeks with defects in bone development and BM aplasia. By two weeks of age, Tle4 knockout mice exhibit leukocytopenia, B cell lymphopenia, and significant reductions in hematopoietic stem and progenitor cells. Tle4 deficient hematopoietic stem cells are intrinsically defective in B lymphopoiesis and exhaust upon stress, such as serial transplantation. In the absence of Tle4 there is a profound decrease in bone mineralization. In addition, Tle4 knockout stromal cells are defective at maintaining wild-type hematopoietic stem cell function in vitro. In summary, we illustrate a novel and essential role for Tle4 in the extrinsic and intrinsic regulation of hematopoiesis and in bone development.

Highly optimized DNA vaccine targeting human telomerase reverse transcriptase stimulates potent antitumor immunity.

High levels of human telomerase reverse transcriptase (hTERT) are detected in more than 85% of human cancers. Immunologic analysis supports that hTERT is a widely applicable target recognized by T cells and can be potentially studied as a broad cancer immunotherapeutic, or a unique line of defense against tumor recurrence. There remains an urgent need to develop more potent hTERT vaccines. Here, a synthetic highly optimized full-length hTERT DNA vaccine (phTERT) was designed and the induced immunity was examined in mice and non-human primates (NHP). When delivered by electroporation, phTERT elicited strong, broad hTERT-specific CD8 T-cell responses including induction of T cells expressing CD107a, IFN-γ, and TNF-α in mice. The ability of phTERT to overcome tolerance was evaluated in an NHP model, whose TERT is 96% homologous to that of hTERT. Immunized monkeys exhibited robust [average 1,834 spot forming unit (SFU)/10(6) peripheral blood mononuclear cells (PBMC)], diverse (multiple immunodominant epitopes) IFN-γ responses and antigen-specific perforin release (average 332 SFU/10(6) PBMCs), suggesting that phTERT breaks tolerance and induces potent cytotoxic responses in this human-relevant model. Moreover, in an HPV16-associated tumor model, vaccination of phTERT slows tumor growth and improves survival rate in both prophylactic and therapeutic studies. Finally, in vivo cytotoxicity assay confirmed that phTERT-induced CD8 T cells exhibited specific cytotoxic T lymphocyte (CTL) activity, capable of eliminating hTERT-pulsed target cells. These findings support that this synthetic electroporation-delivered DNA phTERT may have a role as a broad therapeutic cancer vaccine candidate.

Induction of robust cellular immunity against HPV6 and HPV11 in mice by DNA vaccine encoding for E6/E7 antigen.

Due to the strong relationship between the Human Papillomavirus (HPV) "high-risk" subtypes and cervical cancers, most HPV-related studies have been focusing on the "high-risk" HPV subtypes 16 and 18. However, it has been suggested that the "low-risk" subtypes of HPV, HPV6 and HPV11, are the major cause of recurrent respiratory papillomatosis and genital warts. In addition, HPV 6 and 11 are also associated with otolaryngologic malignancies, carcinoma of the lung, tonsil, larynx and low-grade cervical lesions. Therefore, development of HPV therapeutic vaccines targeting on subtypes 6 and 11 E6 or E7 are in great need. In this report, we describe two novel engineered DNA vaccines that encode HPV 6 and 11 consensus E6/E7 fusion proteins (p6E6E7 and p11E6E7) by utilizing a multi-phase strategy. Briefly, after generating consensus sequences, several modifications were performed to increase the expression of both constructs, including codon/RNA optimization, addition of a Kozak sequence and a highly efficient leader sequence. An endoproteolytic cleavage site was also introduced between E6 and E7 protein for proper protein folding and for better CTL processing. The expressions of both constructs were confirmed by western blot analysis and immunofluorescence assay. Vaccination with these DNA vaccines could elicit robust cellular immune responses. The epitope mapping assay was performed to further characterize the cellular immune responses induced by p6E6E7 and p11E6E7. The HPV 6 and 11 E6 or E7-specific immunodominant and subdominant epitopes were verified, respectively. The intracellular cytokine staining revealed that the magnitude of IFN-γ and TNF-α secretion in antigen-specific CD8(+) cells was significantly enhanced, indicating that the immune responses elicited by p6E6E7 and p11E6E7 was heavily skewed toward driving CD8(+) T cells. Such DNA immunogens are interesting candidates for further studies on HPV 6 and 11-associated diseases.

Clinical applications of DNA vaccines: current progress.

It was discovered almost 20 years ago that plasmid DNA, when injected into the skin or muscle of mice, could induce immune responses to encoded antigens. Since that time, there has since been much progress in understanding the basic biology behind this deceptively simple vaccine platform and much technological advancement to enhance immune potency. Among these advancements are improved formulations and improved physical methods of delivery, which increase the uptake of vaccine plasmids by cells; optimization of vaccine vectors and encoded antigens; and the development of novel formulations and adjuvants to augment and direct the host immune response. The ability of the current, or second-generation, DNA vaccines to induce more-potent cellular and humoral responses opens up this platform to be examined in both preventative and therapeutic arenas. This review focuses on these advances and discusses both preventive and immunotherapeutic clinical applications.