Generalizability of a Musculoskeletal Therapist Electronic Health Record for Modelling Outcomes to Work-Related Musculoskeletal Disorders

PURPOSE

Electronic Health Records (EHRs) can contain vast amounts of clinical information that could be reused in modelling outcomes of work-related musculoskeletal disorders (WMSDs). Determining the generalizability of an EHR dataset is an important step in determining the appropriateness of its reuse. The study aims to describe the EHR dataset used by occupational musculoskeletal therapists and determine whether the EHR dataset is generalizable to the Australian workers' population and injury characteristics seen in workers' compensation claims.

METHODS

Variables were considered if they were associated with outcomes of WMSDs and variables data were available. Completeness and external validity assessment analysed frequency distributions, percentage of records and confidence intervals.

RESULTS

There were 48,434 patient care plans across 10 industries from 2014 to 2021. The EHR collects information related to clinical interventions, health and psychosocial factors, job demands, work accommodations as well as workplace culture, which have all been shown to be valuable variables in determining outcomes to WMSDs. Distributions of age, duration of employment, gender and region of birth were mostly similar to the Australian workforce. Upper limb WMSDs were higher in the EHR compared to workers' compensation claims and diagnoses were similar.

CONCLUSION

The study shows the EHR has strong potential to be used for further research into WMSDs as it has a similar population to the Australian workforce, manufacturing industry and workers' compensation claims. It contains many variables that may be relevant in modelling outcomes to WMSDs that are not typically available in existing datasets.

SARS-CoV-2 caused a surge in antibiotic consumption causing a silent pandemic inside the pandemic. A retrospective analysis of Italian data in the first half of 2022

BACKGROUND

The phenomenon of antibiotic resistance shows no sign of stopping, despite global policies to combat it that have been in place for several years. The risk of forms of pathogenic microorganisms that are increasingly resistant to common antibiotics has led health authorities around the world to pay greater attention to the phenomenon. The worrying situation, has led to further recommendations from the World Health Organization (WHO) and national recommendations in Italy through the new National Plan against Antibiotic Resistance 2022-2025 (PNCAR 2022-2025).

AIM

This manuscript aims to raise the awareness of all health professionals to follow what is suggested by regulatory agencies and scientific societies.

METHOD

We conducted a retrospective study of antibiotic pharmacoutilization in Italy, in the Campania region at the Azienda Sanitaria Locale (ASL) Napoli 3 Sud, on consumption in the first half of 2022 in a population of more than 1 million people.

RESULT

The results indicate that consumption, based on defined daily doses (DDDs), is above the national average. Probably the COVID-19 pandemic has influenced this growth in prescriptions.

CONCLUSIONS

Our study suggests an informed and appropriate use of antibiotics, so as to embark on a virtuous path in the fight against antibiotic resistance.

Pharmacological approach for the reduction of inflammatory and prothrombotic hyperactive state in COVID-19 positive patients by acting on complement cascade

The novel Coronavirus SARS-CoV-2 is the viral pathogen responsible for the ongoing global pandemic, COVID-19 (Coronavirus disease 2019). To date, the data recorded indicate 1.62 Mln deaths and 72.8 Mln people infected (WHO situation report Dec 2020). On December 27, the first anti-COVID-19 vaccinations started in Europe. There are no direct antivirals against SARS-CoV-2. Understanding the pathophysiological and inflammatory/immunological processes of SARS-CoV-2 infection is essential to identify new drug therapies. In the most severe COVID-19 cases, an unregulated immunological/inflammatory system results in organ injury that can be fatal to the host in some cases. Pharmacologic approaches to normalize the unregulated inflammatory/immunologic response is an important therapeutic solution. Evidence associates a non-regulation of the “complement system” as one of the causes of generalized inflammation causing multi-organ dysfunction. Serum levels of a complement cascade mediator, factor “C5a”, have been found in high concentrations in the blood of COVID-19 patients with severe disease. In this article we discuss the correlation between complement system and COVID-19 infection and pharmacological solutions directed to regulate.

Comparison between LigaSure™ and Harmonic® in Laparoscopic Sleeve Gastrectomy: A Single-Center Experience on 422 Patients

BACKGROUND

New laparoscopic devices, such as electrothermal bipolar-activated devices (LigaSure™ (LS)) or ultrasonic systems (Harmonic® scalpel (HS)), have been applied recently to bariatric surgery allowing to reduce blood loss and surgical risks. The aim of this study was to retrospectively compare intraoperative performance of HS and LS, postoperative results, and clinical outcomes in a large cohort of patients undergoing LSG.

METHODS

Data from 422 morbidly obese patients undergoing LSG in our Bariatric Unit at the Advanced Biomedical Sciences Department of the "Federico II" University of Naples (Italy) between January 2009 and December 2017 were retrospectively analyzed. Subjects were divided into two groups (HS and LS), and operative time, intraoperative complications, and postoperative (within 30 days from surgery) complications were compared. Bleeding from the omentum or from the staple line, use of hemostatic clips, and absorbable hemostat were recorded as intraoperative complications; hemorrhages, abscess formation, gastric leaks, fever, and mortality were considered as postoperative complications.

RESULTS

Statistical analysis showed no difference in terms of baseline demographics between the two cohorts. Operative time (48 ± 9 vs 49 ± 6 min, p=0.646) and the rates of intraoperative and postoperative complications did not significantly differ between groups.

CONCLUSION

Harmonic® and LigaSure™ are both useful tools in bariatric surgery, and these two advanced power devices are user-friendly and can facilitate surgeon work; from this point of view, the choice of the energy device should be based on the preference of the surgeon and on the hospital costs policy and availability.

IFSO Worldwide Survey 2016: Primary, Endoluminal, and Revisional Procedures

BACKGROUND AND AIM

The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO), being a Federation of 62 national societies, is the ideal network to monitor the number and type of procedures at a global level. The IFSO survey, enriched with a special section on revisional procedures, aims to report the number and types of bariatric procedures performed worldwide in 2016 and analyzes the surgical trends from 2008 to 2016.

METHODS

The 2016 IFSO Survey form was emailed to all IFSO societies. Each Society was requested to indicate the number and type of bariatric procedures performed in the country. Trend analyses from 2008 to 2016 were also performed.

RESULTS

The total number of bariatric/metabolic procedures performed in 2016 was 685,874; 634,897 (92.6%) of which were primary and 50,977 were revisional (7.4%). Among the primary interventions, 609,897 (96%) were surgical and 25,359 (4%) were endoluminal. The most performed primary surgical bariatric/metabolic procedure was sleeve gastrectomy (SG) (N = 340,550; 53.6%), followed by Roux-en-Y gastric bypass (N = 191,326; 30.1%), and one-anastomosis gastric bypass (N = 30,563; 4.8%).

CONCLUSIONS

In 2016, there was an increase in the total number both of surgical and endoluminal bariatric/metabolic procedures. Revisional procedures represent about 7% of the total bariatric interventions. SG remains the most performed surgical procedure in the world.

Bariatric Surgery and Endoluminal Procedures: IFSO Worldwide Survey 2014

BACKGROUND AND AIM

Several bariatric surgery worldwide surveys have been previously published to illustrate the evolution of bariatric surgery in the last decades. The aim of this survey is to report an updated overview of all bariatric procedures performed in 2014.For the first time, a special section on endoluminal techniques was added.

METHODS

The 2014 International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) survey form evaluating the number and the type of surgical and endoluminal bariatric procedures was emailed to all IFSO societies. Trend analyses from 2011 to 2014 were also performed.

RESULTS

There were 56/60 (93.3%) responders. The total number of bariatric/metabolic procedures performed in 2014 consisted of 579,517 (97.6%) surgical operations and 14,725 (2.4%) endoluminal procedures. The most commonly performed procedure in the world was sleeve gastrectomy (SG) that reached 45.9%, followed by Roux-en-Y gastric bypass (RYGB) (39.6%), and adjustable gastric banding (AGB) (7.4%). The annual percentage changes from 2013 revealed the increase of SG and decrease of RYGB in all the IFSO regions (USA/Canada, Europe, and Asia/Pacific) with the exception of Latin/South America, where SG decreased and RYGB represented the most frequent procedure.

CONCLUSIONS

There was a further increase in the total number of bariatric/metabolic procedures in 2014 and SG is currently the most frequent surgical procedure in the world. This is the first survey that describes the endoluminal procedures, but the accuracy of provided data should be hopefully improved in the next future. We encourage the creation of further national registries and their continuous updates taking into account all new bariatric procedures including the endoscopic procedures that will obtain increasing importance in the near future.

Bariatric Surgery and Endoluminal Procedures: IFSO Worldwide Survey 2014

BACKGROUND AND AIM

Several bariatric surgery worldwide surveys have been previously published to illustrate the evolution of bariatric surgery in the last decades. The aim of this survey is to report an updated overview of all bariatric procedures performed in 2014.For the first time, a special section on endoluminal techniques was added.

METHODS

The 2014 International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) survey form evaluating the number and the type of surgical and endoluminal bariatric procedures was emailed to all IFSO societies. Trend analyses from 2011 to 2014 were also performed.

RESULTS

There were 56/60 (93.3%) responders. The total number of bariatric/metabolic procedures performed in 2014 consisted of 579,517 (97.6%) surgical operations and 14,725 (2.4%) endoluminal procedures. The most commonly performed procedure in the world was sleeve gastrectomy (SG) that reached 45.9%, followed by Roux-en-Y gastric bypass (RYGB) (39.6%), and adjustable gastric banding (AGB) (7.4%). The annual percentage changes from 2013 revealed the increase of SG and decrease of RYGB in all the IFSO regions (USA/Canada, Europe, and Asia/Pacific) with the exception of Latin/South America, where SG decreased and RYGB represented the most frequent procedure.

CONCLUSIONS

There was a further increase in the total number of bariatric/metabolic procedures in 2014 and SG is currently the most frequent surgical procedure in the world. This is the first survey that describes the endoluminal procedures, but the accuracy of provided data should be hopefully improved in the next future. We encourage the creation of further national registries and their continuous updates taking into account all new bariatric procedures including the endoscopic procedures that will obtain increasing importance in the near future.

Acinic cell carcinoma of the breast: review of the literature

INTRODUCTION

The breast and salivary gland tissue share embryologic and thus pathological similarities. Acinic cell carcinoma (ACC) is a typical tumor in salivary glands, but rarely arises in breast too. We reviewed 38 cases of mammary ACC reported in literature and our case, the first ACC born within a fibroadenoma.

MATERIALS AND METHODS

Data were collected by a research for the key words acinic cell carcinoma breast on Pubmed in March 2014, including a case treated in our department. All reviewed cases were compared for clinical approach and histological pattern.

RESULTS

To date 23 articles presenting cases of ACC of the breast are reported in literature. We included in our review 38 cases previously described and one new case. The histological pattern was predominantly solid with a microglandular structure. All the tumor cells were cytologically characterized by monotonous round cells with a finely granular, weakly eosinophilic, or clearly vacuolated cytoplasm. The most of the cells were intensely stained with anti-lysozime, anti-amylase, anti-α1-chimotripsin, anti-EMA and anti-S100 protein antisera. Immunohistochemistry was also performed to point out: estrogen receptor (ER), progesterone receptor (PR), androgen receptors (AR), human epidermal growth factor receptor 2 overexpression (HER2/neu), E-cadherin (E-cad), cytokeratin-7 (CK7), gross cystic disease fluid protein 15 (GCDFP15), smooth muscle actin (SMA).

CONCLUSION

ACC of the breast is a rare tumor, showing similarities with the salivary gland counterpart, above all in terms of good prognosis, and differences from the ordinary invasive breast carcinoma. Further investigations are needed to elucidate the true histogenesis and the correct treatment.

Positive findings in preoperative testing prior to gastric banding: their real value

AIM

Relations between laparoscopic adjustable gastric banding (LAGB), gastroesophageal reflux (GER) and hiatal hernia (HH) are controversial. In this context the role of preoperative investigations to assess upper gastrointestinal (GI) function and its impact on the approach to LAGB and outcomes remains unclear. The aim was to define the value of preoperative upper GI testing, and to relate the findings with postoperative outcomes.

METHODS

Seventy-eight cases were enrolled among 250 patients undergoing LAGB from January 2010 to December 2011 in our Center for the Multidisciplinary treatment of severe obesity. Patients were submitted preoperatively to endoscopy and radiologic series with oral contrast to assess the state of upper GI mucosa, the presence of HH, GER or cardias incontinence. According to the findings, patients were assigned to group A, if one or both exams showed positive results; or to the control group B if both exams were negative.

RESULTS

GI series showed GER in 14.1% of patients, HH in 6.4%, altered motility in 5.1%, gastritis in 3.1%and were negative in 75.6%. Endoscopy showed gastritis in 71.8%of patients, HH in 30.8%, esophagitis in 7.7%, duodenitis in 7.7%, LES incontinence in 8%; while only 21.8% of patients had a negative exam. Differences between group A and B are not statistically significant in terms of pre- and post-operative BMI, EBWL%, long-term complications, time and number of regulations.

CONCLUSION

Positive findings in preoperative testing rarely postpone or change the surgical approach and postoperative outcomes. Our results encourage the omission of upper GI series from routine evaluation protocol prior to LAGB.

Gastric emptying after sleeve gastrectomy: statistical evidence of a controlled prospective study with gastric scintigraphy

AIM

Laparoscopic sleeve gastrectomy (LSG) is a stand-alone bariatric procedure, its feasibility and efficacy being confirmed by long-term data. The effect of the procedure is believed to be based on the gastric restriction and reduction of ghrelin. Nevertheless it remains still controversial the role of LSG on gastric emptying and the impact that this may have on weight loss outcomes. Our aim is to assess gastric emptying after LSG using gastric scintigraphy.

METHODS

For this prospective randomized study, 45 patients undergoing LSG at our Centre for the Multidisciplinary Treatment of Severe Obesity from April 2009 to April 2011 were enrolled and observed prospectively (Group A). The inclusion criteria followed the guidelines for bariatric surgery. All patients performed gastric emptying scintigraphy through a standard semisolid meal (250 kcal), marked with 0.5 mCiTc 99. Group A performed the exam before (A1) and after the operation (A2). A control group (Group B) included 20 patients undergoing scintigraphic assessment for other reasons.

RESULTS

LSG was performed following a standardized technique. No complications were observed. The scintigraphic study showed a reduced half-life tracer (A1 vs. A2: 80.4±16.5 min vs. 64.3±22 min P=0.06), without a significant difference. Comparing the two groups no differences occurred before operation (B vs. A1). Gastric emptying time resulted significatively reduced in group A2 rather than in group A1 and B.

CONCLUSION

Gastric motility plays a role in the pathogenesis of obesity. Our experience suggests that LSG reduces gastric emptying time, but further studies are necessary to reach statystical significativity.

Rheumatoid arthritis, Klippel-Feil syndrome and Pott's disease in Cardinal Carlo de' Medici (1595-1666)

OBJECTIVE

A paleopathological study was carried out on the she skeletal remains of Cardinal Carlo de' Medici (1595-1666), son of the Grand Duke Ferdinando I (1549-1609) and Cristina from Lorraine (1565-1636), to investigate the articular pathology described in the archival sources.

METHODS

The skeletal remains of Carlo, buried in the Basilica of San Lorenzo in Florence, have been exhumed and submitted to macroscopic and radiological examination.

RESULTS

The skeleton of Carlo revealed a concentration of different severe pathologies. Ankylosis of the cervical column, associated with other facial and spine anomalies suggests a diagnosis of congenital disease: the Klippel-Feil syndrome. In addition, the cervical segment presents the results of the tuberculosis (Pott's disease) from which the Cardinal suffered in his infancy. The post-cranial skeleton shows an ankylosing disease, mainly symmetrical and extremely severe, involving the large as well as small articulations, and characterized by massive joint fusion, that totally disabled the Cardinal in his last years of life.

CONCLUSIONS

The final diagnosis suggests an advanced, ankylosing stage of rheumatoid arthritis.

Ex vivo priming for long-term maintenance of antileukemia human cytotoxic T cells suggests a general procedure for adoptive immunotherapy

Adoptive cellular immunotherapy has proven to be a successful approach in preventing and curing cytomegalovirus infection and Epstein-Barr virus-associated lymphomas after bone marrow transplantation. Translation of this approach for preventing leukemia relapse after bone marrow transplantation might require ex vivo priming and long-term maintenance of leukemia blast-specific T cells. To accomplish this goal, procedures were optimized for the in vitro priming of naive CD8 using dendritic cells activated by CD40 ligation, interleukin-12 (IL-12), and IL-7. Using T lymphocytes and dendritic cells obtained from HLA-matched allogeneic bone marrow transplantation donors and leukemia blasts as a source of tumor antigens, anti-acute myeloid leukemia cytotoxic T lymphocytes (CTLs) were induced. In these experiments, it was found that though it is possible to induce CTLs using immature dendritic cells, IL-12, and IL-7, obtaining long-term CTLs requires the presence of CD4 T cells in the priming phase. Using this approach, long-term antileukemia CTL lines could be generated from 4 of 4 bone marrow donors. Because this procedure does not require definition of the target antigen and because it selects responding cells from a virgin T-cell repertoire, its general application is suggested in adoptive immunotherapy and in the definition of tumor rejection antigens.

Regulation of transporter associated with antigen processing by phosphorylation

The ATP-binding cassette transporter associated with antigen processing (TAP) is required for transport of antigenic peptides, generated by proteasome complexes in the cytoplasm, into the lumen of the endoplasmic reticulum where assembly with major histocompatibility complex class I molecules takes place. The TAP transporter is a heterodimer of TAP1 and TAP2. Here we show that both TAP1 and TAP2 are phosphorylated under physiological conditions. Phosphorylation induces formation of high molecular weight TAP complexes that contain TAP1, TAP2, tapasin, and class I heterodimers. In addition, a 43-kDa phosphoprotein, which appears to be a kinase, is contained in the phosphorylated TAP-containing complexes. Phosphorylated TAP complexes are able to bind peptides and ATP, however, they are not capable of transporting peptides. After de-phosphorylation, TAP complexes regain the ability to transport peptides. Interestingly, phosphorylation levels of TAP complexes induced by viral infection inversely correlates with a significant reduction in TAP-dependent peptide transport activity. Enhanced TAP phosphorylation appears to be one of several strategies that viruses have exploited to better escape from host immune surveillance. These results demonstrate that major histocompatibility complex class I antigen processing and presentation is modulated by reversible TAP phosphorylation, and implicate the importance of TAP phosphorylation in the regulation of cytotoxic immune response.

Impaired immunoproteasome assembly and immune responses in PA28-/- mice

In vitro PA28 binds and activates proteasomes. It is shown here that mice with a disrupted PA28b gene lack PA28a and PA28b polypeptides, demonstrating that PA28 functions as a hetero-oligomer in vivo. Processing of antigenic epitopes derived from exogenous or endogenous antigens is altered in PA28-/- mice. Cytotoxic T lymphocyte responses are impaired, and assembly of immunoproteasomes is greatly inhibited in mice lacking PA28. These results show that PA28 is necessary for immunoproteasome assembly and is required for efficient antigen processing, thus demonstrating the importance of PA28-mediated proteasome function in immune responses.

Adoptive immunotherapy prevents prostate cancer in a transgenic animal model

Cancer-related mortality can be decreased by prevention, early detection and improved therapies. Although animal models should be used to evaluate the success of cancer therapies, their usefulness is controversial. Many cancer therapies that have cured tumors in mice have not met with similar success when attempted in humans. Current animal models rely mainly on inoculating cell lines into animals, a method that does not reproduce the natural development of the tumor, both for the kinetics of induction and the anatomical site concerned. In this study, we have used an SV40 T-antigen-transgenic mouse model of prostate cancer in which the tumor spontaneously develops orthotopically with a disease progression that closely resembles the progression of human prostate cancer. We have used this model to test the suitability of adoptive cellular immunotherapy. Transfer of naive cells obtained from a T-antigen-negative congenic animal had significant but partial effects: it prevented development of malignant tumors, leaving just minor foci of residual tumor and/or hyperplasia. Adoptive transfer of memory lymphocytes specific for T-antigen, which is a prostatic self antigen in this model, prevented tumor development and progression without affecting the morphology and function of involved tissues. Treated animals were able to breed, and their survival was greatly increased. These results strongly suggest that adoptive immunotherapy should be successful in treating early stages of human prostate cancer.

Pure cutaneous relapsing langerhans cell histiocytosis in an adult

The histiocytic syndromes represent a group of rare diseases characterized by the proliferation of the mononuclear phagocyte system cells. We report a case of recurrent class I histiocytosis with exclusive cutaneous localization in an adult. Our patient had a 3 cm ulcerated nodule located on the right cheek. Subsequently, new lesions appeared, all having the same clinical evolution characterized by spontaneous resolution with scarring. After a five year follow up no more lesions were observed. The histopathological examination, immunohistochemical profile and electron microscopy of the lesions indicated Langerhans cell histiocytosis.

Application of an artificial neural network to predict specific class I MHC binding peptide sequences

Computational methods were used to predict the sequences of peptides that bind to the MHC class I molecule, K(b). The rules for predicting binding sequences, which are limited, are based on preferences for certain amino acids in certain positions of the peptide. It is apparent though, that binding can be influenced by the amino acids in all of the positions of the peptide. An artificial neural network (ANN) has the ability to simultaneously analyze the influence of all of the amino acids of the peptide and thus may improve binding predictions. ANNs were compared to statistically analyzed peptides for their abilities to predict the sequences of K(b) binding peptides. ANN systems were trained on a library of binding and nonbinding peptide sequences from a phage display library. Statistical and ANN methods identified strong binding peptides with preferred amino acids. ANNs detected more subtle binding preferences, enabling them to predict medium binding peptides. The ability to predict class I MHC molecule binding peptides is useful for immunolological therapies involving cytotoxic-T cells.

Findings in vivo of Sarcoptes scabiei with incident light microscopy

Parasites, especially Sarcoptes scabiei, may represent a difficult diagnostic problem. In many cases, the results of the usual methods for the diagnosis of scabies, such as microscopic identification, can be negative owing to the small number of parasites present in the cornified layer. Moreover, tape stripping or removal of mites with a needle is difficult and sometimes painful, and therefore, not well accepted. We have evaluated the applicability and usefulness of epiluminescence microscopy, a new technique frequently used for the study of pigmented lesions of the skin. Thirty seven patients with the presumptive clinical and/or anamnestic diagnosis of scabies were enrolled in our study. With this method many suspicious sites may be examined within a few minutes without causing any harm or discomfort to the patient.

Expression and regulation of the neural cell adhesion molecule L1 on human cells of myelomonocytic and lymphoid origin

The neural cell adhesion molecule L1 has been implicated in a variety of neurologic processes, including neuritogenesis and cerebellar cell migration. Here we propose an expanded role for this cell adhesion molecule in the human immune system based on its expression on cells of myelomonocytic and lymphoid origin. Freshly isolated circulating monocytes had minimal L1 expression; however, activation of these effector cells by IFN-gamma, or as a result of density gradient isolation, resulted in a significant induction of L1 expression. Constitutive L1 expression was further evident on myelomonocytic cell lines but was absent on mature tissue macrophages. In further studies, positive selection with a L1-specific Ab enriched both B cells and dendritic precursor cells from peripheral blood. Significantly, L1 expression was not detected on mature dendritic cells but could be induced by treatment with LPS, PHA, and TNF-alpha. Immunohistochemical analysis further demonstrated significant L1 expression on follicular dendritic cells and on endothelial cells associated with the arterioles and red pulp of normal spleen. Based on these observations and known functions of L1, we propose that this cell adhesion molecule may contribute to cell-cell adhesion events associated with the effector function or extravasation of these immune effector cells. In support of the latter, we present evidence that L1 can be recognized by endothelial cells via the integrin alpha(v)beta3.

Expression and regulation of the neural cell adhesion molecule L1 on human cells of myelomonocytic and lymphoid origin

The neural cell adhesion molecule L1 has been implicated in a variety of neurologic processes, including neuritogenesis and cerebellar cell migration. Here we propose an expanded role for this cell adhesion molecule in the human immune system based on its expression on cells of myelomonocytic and lymphoid origin. Freshly isolated circulating monocytes had minimal L1 expression; however, activation of these effector cells by IFN-gamma, or as a result of density gradient isolation, resulted in a significant induction of L1 expression. Constitutive L1 expression was further evident on myelomonocytic cell lines but was absent on mature tissue macrophages. In further studies, positive selection with a L1-specific Ab enriched both B cells and dendritic precursor cells from peripheral blood. Significantly, L1 expression was not detected on mature dendritic cells but could be induced by treatment with LPS, PHA, and TNF-alpha. Immunohistochemical analysis further demonstrated significant L1 expression on follicular dendritic cells and on endothelial cells associated with the arterioles and red pulp of normal spleen. Based on these observations and known functions of L1, we propose that this cell adhesion molecule may contribute to cell-cell adhesion events associated with the effector function or extravasation of these immune effector cells. In support of the latter, we present evidence that L1 can be recognized by endothelial cells via the integrin alpha(v)beta3.

Comparison of cytotoxic T lymphocyte responses induced by peptide or DNA immunization: implications on immunogenicity and immunodominance

To study the mechanisms that influence the immunogenicity and immunodominance of potential cytotoxic T lymphocyte (CTL) epitopes, we conducted a systematic analysis of the CTL response raised in HLA-A*0201/Kb (A2/Kb) transgenic mice against the viral antigen, hepatitis B virus polymerase (HBV pol). From a pool of 26 nonamer peptides containing the HLA-A*0201-binding motif, we selected A2-binding peptides, immunized A2/Kb animals, and tested the CTL raised against the peptide for recognition of HBV pol transfectants. Of nine immunogenic CTL epitopes, only four were recognized on HBV pol transfectants, whereas the other five were cryptic. Characterization of the peptide-specific CTL lines indicated that crypticity may result from either poor processing or low T cell receptor (TCR) avidity. To identify the immunodominant epitopes, we determined the CTL specificities induced in A2/Kb animals in response to priming with HBV pol cDNA. We obtained a response against three epitopes that were contained with the set of four epitopes recognized by peptide-specific CTL on HBV pol transfectants. Comparative analysis of cDNA priming and peptide priming revealed, therefore, the presence of a subdominant epitope. We conclude that for the HBV pol antigen, the repertoire of CTL specificities is shaped by major histocompatibility complex class I peptide binding capacity, antigen processing, and TCR availability.

Immunodominance analysis of CTL responses to influenza PR8 virus reveals two new dominant and subdominant Kb-restricted epitopes

In the present study, a systematic analysis of the influenza (Flu) PR8 determinants recognized by H-2b mice was undertaken. A single Db-restricted immunodominant epitope (NP(366)) was previously known in this system. Twenty-three different Flu PR8-derived peptides that bound either Kb or Db molecules in vitro were identified. Sixteen were immunogenic following peptide immunization of C57BL/6 mice, yet CTL induced by peptide immunization recognized PR8-infected target cells only in the case of the NP(366) and NS2(114) epitopes. Similarly, CTL responses following whole-PR8 virus immunization were detected only for the same two determinants. CTL recognizing these dominant epitopes had high avidity for peptide-pulsed target cells, with 5 to 200 pM of peptide required for 30% specific lysis. In contrast, most (80%) of the remaining epitopes were recognized with lower avidity (30% effective concentration in the range of 0.4-50 nM). Repeated in vitro stimulation of primary CTL cultures revealed one additional Kb-restricted epitope (M1(128)). This peptide bound Kb with high affinity (4.6 nM) and induced CTL that effectively recognized PR8-infected cells. These results suggest that 1) this epitope is produced by natural processing in relatively high amounts and 2) low precursor frequency might be related to the subdominant status of the M1(128) epitope. Taken together, these results illustrate the crucial contributions of MHC-binding capacity, and T cell repertoire availability, to the shaping of the repertoire of CTL specificities for Flu Ag virus.

Immunodominance analysis of CTL responses to influenza PR8 virus reveals two new dominant and subdominant Kb-restricted epitopes

In the present study, a systematic analysis of the influenza (Flu) PR8 determinants recognized by H-2b mice was undertaken. A single Db-restricted immunodominant epitope (NP(366)) was previously known in this system. Twenty-three different Flu PR8-derived peptides that bound either Kb or Db molecules in vitro were identified. Sixteen were immunogenic following peptide immunization of C57BL/6 mice, yet CTL induced by peptide immunization recognized PR8-infected target cells only in the case of the NP(366) and NS2(114) epitopes. Similarly, CTL responses following whole-PR8 virus immunization were detected only for the same two determinants. CTL recognizing these dominant epitopes had high avidity for peptide-pulsed target cells, with 5 to 200 pM of peptide required for 30% specific lysis. In contrast, most (80%) of the remaining epitopes were recognized with lower avidity (30% effective concentration in the range of 0.4-50 nM). Repeated in vitro stimulation of primary CTL cultures revealed one additional Kb-restricted epitope (M1(128)). This peptide bound Kb with high affinity (4.6 nM) and induced CTL that effectively recognized PR8-infected cells. These results suggest that 1) this epitope is produced by natural processing in relatively high amounts and 2) low precursor frequency might be related to the subdominant status of the M1(128) epitope. Taken together, these results illustrate the crucial contributions of MHC-binding capacity, and T cell repertoire availability, to the shaping of the repertoire of CTL specificities for Flu Ag virus.

Identification of A2-restricted hepatitis C virus-specific cytotoxic T lymphocyte epitopes from conserved regions of the viral genome

We have focused on conserved regions of the hepatitis C Virus (HCV) genome to identify viral peptides that contain HLA class I binding motifs and bind with high affinity to the corresponding purified HLA molecules. Accordingly, we have identified 31 candidate epitopes in the HCV that have the potential to be recognized by either HLA-A1, A2.1-, A3, A11- or A24-restricted cytotoxic T lymphocytes (CTL). Twelve conserved peptides that bind HLA-A2.1 with high or intermediate affinity were tested for immunogenicity in vitro in human primary CTL cultures and in vivo by direct immunization of HLA-A2.1/Kb transgenic mice. Six HLA-A2.1-restricted CTL epitopes were immunogenic in both systems. At least three of these peptide epitopes were endogenously processed and presented for CTL recognition. Overall, these data illustrate the value of this approach for the development of virus-specific, peptide-based vaccines.

Differences and similarities in the A2.1-restricted cytotoxic T cell repertoire in humans and human leukocyte antigen-transgenic mice

HLA-A2.1-binding peptides (n = 38) were screened for immunogenicity with human peripheral blood mononuclear cells in cytotoxic T lymphocyte (CTL) induction experiments in vitro and with splenocytes from HLA-A2.1/Kb transgenic mice following immunization in vivo. These data were compiled and analyzed to determine the level of overlap between the A2.1-restricted CTL repertoire of A2.1/Kb-transgenic mice and A2.1+ humans. In both humans and mice, a major histocompatibility complex affinity threshold of approximately 500 nM appears to determine the capacity of a peptide to elicit a CTL response. Good concordance between the human data in vitro and mouse data in vivo was observed with 85% of the high-binding peptides, 58% of the intermediate binders, and 83% of the low/negative binders. Although some peptides immunogenic for mouse CTL but not for humans (and vice versa) could be identified, the data as a whole suggest an extensive overlap between T cell receptor repertoires of mouse and human CTL and support the use of HLA-transgenic mice for the identification of potential human CTL epitopes.

Development of a lipopeptide-based therapeutic vaccine to treat chronic HBV infection. I. Induction of a primary cytotoxic T lymphocyte response in humans

Our goal is to use peptide epitopes that are recognized by cytotoxic T lymphocytes (CTL) as immunogens for the development of prophylactic and therapeutic vaccines with chronic hepatitis B virus (HBV) infection being our first therapeutic target. Because most CTL peptide epitopes are poor immunogens, we specifically modified them by covalently attaching two additional components: a T helper peptide epitope and two lipid molecules. Using the murine influenza virus CTL epitope NP 147-155 as a model system, we found this construct to be highly immunogenic, and a single injection resulted in memory CTL induction that persisted for > 1 yr. Based on the animal studies, a vaccine was designed and tested for both safety and its ability to induce a primary CTL response in normal subjects. The three vaccine components included HBV core antigen peptide 18-27 as the CTL epitope, tetanus toxoid peptide 830-843 as the T helper peptide, and two palmitic acid molecules as the lipids. A dose escalation trial (5, 50, and 500 micrograms) carried out in 26 normal subjects showed that the vaccine was safe and able to induce a primary HBV-specific CTL response. A dose-response curve was observed and five out of five subjects responded to the 500-micrograms dose.

The relationship between class I binding affinity and immunogenicity of potential cytotoxic T cell epitopes

The relationship between binding affinity for HLA class I molecules and immunogenicity of discrete peptide epitopes has been analyzed in two different experimental approaches. In the first approach, the immunogenicity of potential epitopes ranging in MHC binding affinity over a 10,000-fold range was analyzed in HLA-A*0201 transgenic mice. In the second approach, the antigenicity of approximately 100 different hepatitis B virus (HBV)-derived potential epitopes, all carrying A*0201 binding motifs, was assessed by using PBL of acute hepatitis patients. In both cases, it was found that an affinity threshold of approximately 500 nM (preferably 50 nM or less) apparently determines the capacity of a peptide epitope to elicit a CTL response. These data correlate well with class I binding affinity measurements of either naturally processed peptides or previously described T cell epitopes. Taken together, these data have important implications for the selection of epitopes for peptide-based vaccines, and also formally demonstrate the crucial role of determinant selection in the shaping of T cell responses. Because in most (but not all) cases, high affinity peptides seem to be immunogenic, our data also suggest that holes in the functional T cell repertoire, if they exist, may be relatively rare.

The relationship between class I binding affinity and immunogenicity of potential cytotoxic T cell epitopes

The relationship between binding affinity for HLA class I molecules and immunogenicity of discrete peptide epitopes has been analyzed in two different experimental approaches. In the first approach, the immunogenicity of potential epitopes ranging in MHC binding affinity over a 10,000-fold range was analyzed in HLA-A*0201 transgenic mice. In the second approach, the antigenicity of approximately 100 different hepatitis B virus (HBV)-derived potential epitopes, all carrying A*0201 binding motifs, was assessed by using PBL of acute hepatitis patients. In both cases, it was found that an affinity threshold of approximately 500 nM (preferably 50 nM or less) apparently determines the capacity of a peptide epitope to elicit a CTL response. These data correlate well with class I binding affinity measurements of either naturally processed peptides or previously described T cell epitopes. Taken together, these data have important implications for the selection of epitopes for peptide-based vaccines, and also formally demonstrate the crucial role of determinant selection in the shaping of T cell responses. Because in most (but not all) cases, high affinity peptides seem to be immunogenic, our data also suggest that holes in the functional T cell repertoire, if they exist, may be relatively rare.

HLA A2 restricted cytotoxic T lymphocyte responses to multiple hepatitis B surface antigen epitopes during hepatitis B virus infection

Inasmuch as the hepatitis B virus (HBV) is not directly cytopathic for the infected hepatocyte, it is generally presumed that viral clearance and liver cell injury during viral hepatitis are due to a CTL response to HBV encoded Ag presented by HLA class I molecules. We have previously examined the peripheral blood CTL response to two HBV nucleocapsid epitopes in patients with acute and chronic viral hepatitis, one of which is restricted by HLA-A2, whereas the other is dually restricted by HLA-A31 and Aw68. In this study, we defined the HLA-A2-restricted CTL response to the hepatitis B surface Ag (HBsAg) by using a panel of HBsAg-derived synthetic peptides containing the ideal HLA-A2.1 binding motif (-L------V). Several novel aspects of HBV immunobiology and pathogenesis are evident from this study. First, the peripheral blood CTL response to HBV-encoded Ag is remarkably polyclonal and multispecific in most patients with acute hepatitis. Indeed, HLA-A2-restricted CTL specific for as many as four envelope epitopes and one nucleocapsid epitope were found to be present simultaneously in individual patients with acute viral hepatitis. Second, HBV-specific CTL are not detectable in the peripheral blood in a minority of patients with acute hepatitis, nor have we detected a CTL response in any of the patients with chronic hepatitis that we have studied thus far. Although the cellular and molecular basis for CTL nonresponse remains to be determined, the data suggest that it may contribute to viral persistence. Third, the diversity and the specificity of the CTL response is determined in part by the coding sequence of the viral genome present in each infected patient. Indeed, the apparent nonresponse of some acutely infected patients to at least one HBsAg-specific CTL epitope actually reflects infection by a viral variant that contains a critical substitution in one of the anchor residues within the epitope. Finally, at a fundamental level, the data suggest that the presence of the HLA-A2.1-binding motif in a peptide may not be sufficient for binding; and the capacity of a peptide to bind the class I molecule does not guarantee that it will be immunogenic.

HLA A2 restricted cytotoxic T lymphocyte responses to multiple hepatitis B surface antigen epitopes during hepatitis B virus infection

Inasmuch as the hepatitis B virus (HBV) is not directly cytopathic for the infected hepatocyte, it is generally presumed that viral clearance and liver cell injury during viral hepatitis are due to a CTL response to HBV encoded Ag presented by HLA class I molecules. We have previously examined the peripheral blood CTL response to two HBV nucleocapsid epitopes in patients with acute and chronic viral hepatitis, one of which is restricted by HLA-A2, whereas the other is dually restricted by HLA-A31 and Aw68. In this study, we defined the HLA-A2-restricted CTL response to the hepatitis B surface Ag (HBsAg) by using a panel of HBsAg-derived synthetic peptides containing the ideal HLA-A2.1 binding motif (-L------V). Several novel aspects of HBV immunobiology and pathogenesis are evident from this study. First, the peripheral blood CTL response to HBV-encoded Ag is remarkably polyclonal and multispecific in most patients with acute hepatitis. Indeed, HLA-A2-restricted CTL specific for as many as four envelope epitopes and one nucleocapsid epitope were found to be present simultaneously in individual patients with acute viral hepatitis. Second, HBV-specific CTL are not detectable in the peripheral blood in a minority of patients with acute hepatitis, nor have we detected a CTL response in any of the patients with chronic hepatitis that we have studied thus far. Although the cellular and molecular basis for CTL nonresponse remains to be determined, the data suggest that it may contribute to viral persistence. Third, the diversity and the specificity of the CTL response is determined in part by the coding sequence of the viral genome present in each infected patient. Indeed, the apparent nonresponse of some acutely infected patients to at least one HBsAg-specific CTL epitope actually reflects infection by a viral variant that contains a critical substitution in one of the anchor residues within the epitope. Finally, at a fundamental level, the data suggest that the presence of the HLA-A2.1-binding motif in a peptide may not be sufficient for binding; and the capacity of a peptide to bind the class I molecule does not guarantee that it will be immunogenic.

Definition of a minimal optimal cytotoxic T-cell epitope within the hepatitis B virus nucleocapsid protein

Residues 11 to 27 of the hepatitis B virus nucleocapsid antigen contain a cytotoxic T-cell epitope that is recognized by cytotoxic T cells from virtually all HLA-A2-positive patients with acute hepatitis B virus infection. Using panels of truncated and overlapping peptides, we now show that the optimal amino acid sequence recognized by cytotoxic T cells is a 10-mer (residues 18 to 27) containing the predicted peptide-binding motif for HLA-A2 and that this peptide can stimulate cytotoxic T cells able to recognize endogenously synthesized hepatitis B core antigen. Since patients with chronic hepatitis B virus infection fail to mount an efficient cytotoxic T-cell response to it, this epitope might serve as the starting point for the design of synthetic peptide-based immunotherapeutic strategies to terminate persistent viral infection.

Random association between the peptide repertoire of A2.1 class I and several different DR class II molecules

The interaction between synthetic peptides and A2.1 class I MHC molecules has been investigated using an inhibition of Ag presentation assay and unbiased peptide sets derived of either viral or eucaryotic origin. For the various sets, strong binding (defined as significant inhibition at the 30 micrograms/ml level) was detected in 7 to 46% of the peptides tested, with an overall frequency of 26%. A set of self-peptides derived from human beta 2 microglobulin was also included in the study. In this case, strong binding was detected in 3 of 15 peptides (20%), thus formally demonstrating a lack of self-/non-self-discrimination at the level of class I molecules. When the whole A2.1-binding database of 105 peptides thus generated was examined by sequence analysis, a significant correlation was found with a recently proposed A2.1-binding motif, whereas no particular positive or negative association was detected between the capacity to bind A2.1 and three different class II alleles (DR1, DR5, and DR7). Finally, using this approach, several peptides capable of binding both A2.1 and multiple DR alleles have been identified, suggesting possible candidates for development of peptide vaccines eliciting both class I and class II restricted responses.

Random association between the peptide repertoire of A2.1 class I and several different DR class II molecules

The interaction between synthetic peptides and A2.1 class I MHC molecules has been investigated using an inhibition of Ag presentation assay and unbiased peptide sets derived of either viral or eucaryotic origin. For the various sets, strong binding (defined as significant inhibition at the 30 micrograms/ml level) was detected in 7 to 46% of the peptides tested, with an overall frequency of 26%. A set of self-peptides derived from human beta 2 microglobulin was also included in the study. In this case, strong binding was detected in 3 of 15 peptides (20%), thus formally demonstrating a lack of self-/non-self-discrimination at the level of class I molecules. When the whole A2.1-binding database of 105 peptides thus generated was examined by sequence analysis, a significant correlation was found with a recently proposed A2.1-binding motif, whereas no particular positive or negative association was detected between the capacity to bind A2.1 and three different class II alleles (DR1, DR5, and DR7). Finally, using this approach, several peptides capable of binding both A2.1 and multiple DR alleles have been identified, suggesting possible candidates for development of peptide vaccines eliciting both class I and class II restricted responses.

Analysis of the HLA-restricted influenza-specific cytotoxic T lymphocyte response in transgenic mice carrying a chimeric human-mouse class I major histocompatibility complex

Transgenic murine lines have been constructed that express a chimeric class I molecule composed of the alpha 1 and alpha 2 domains of HLA-A2.1 and the alpha 3, transmembrane, and cytoplasmic domains of H-2Kb. Upon immunization with influenza virus, transgenic mice developed a strong A2.1Kb-restricted cytotoxic T lymphocyte (CTL) response specific for the same matrix protein epitope that serves as the dominant A2.1-restricted determinant in the equivalent human response. Fine specificity analysis of CTL clones using truncated peptides revealed strong similarity between the response repertoire of transgenic mice and that previously reported using influenza-specific A2.1-restricted CTL clones from humans. This suggests that even when considering T cell responses by different species, the alpha 1 and alpha 2 domains of the restriction element play a dominant role in determining the CTL specific repertoire. Thus, substituting the alpha 3 domain of A2.1 with a murine counterpart has permitted development of a transgenic strain that should serve as an excellent model system in studies of HLA-restricted responses.

The role of beta 2-microglobulin in peptide binding by class I molecules

Efficient transport of class I major histocompatibility complex molecules to the cell surface requires association of the class I heavy chain with endogenous peptide and the class I light chain, beta 2-microglobulin (beta 2M). A mutant cell line deficient in beta 2M transports low amounts of nonpeptide-associated heavy chains to the cell surface that can associate with exogenously provided beta 2M and synthetic peptide antigens. Normal beta 2M-sufficient cells grown in serum-free media devoid of beta 2M also require an exogenous source of beta 2M to efficiently bind synthetic peptide. Thus, class I molecules on normal cells do not spontaneously bind or exchange peptides.

Mapping of epitopes recognized by alloreactive cytotoxic T lymphocytes using inhibition by MHC peptides

To identify epitopes recognized by alloreactive CTL we have examined H-2Kb-specific CTL for their recognition of synthetic peptides with sequences derived from the native Kb class I molecule. Consecutive nested peptides spanning the immunogenic alpha 1 and alpha 2 domains of Kb were tested for their capacity to inhibit CTL clones in their recognition of cells expressing the native Kb molecule. Inhibition by these peptides was found to be an extremely rare event. One peptide (Kb.111-122) did inhibit recognition by one particular CTL clone, clone 13. Upon further investigation it was observed that clone 13 also recognized peptide Kb.111-122 when presented in the context of the syngeneic MHC molecule, Kd. Considering that residues 111 to 122 are located at the base of the antigen groove, and clone 13 is able to recognize Kb.111-122 when presented by syngeneic target cells, we suggest that inhibition of this CTL clone may be due to MHC restricted, self-presentation of peptide rather than to direct binding of free peptide to the TCR. Taken together, these results suggest inhibition of allospecific CTL by MHC peptides is a rare event at least for Kb recognition. Furthermore, they demonstrate the need for caution when interpreting inhibition by peptide as evidence for recognition by the TCR of the corresponding region on the native molecule.

Consequences of self-presentation of peptide antigen by cytolytic T lymphocytes

We have used H-2Db-restricted CTL clones specific for peptide 365 to 380 of the influenza nucleoprotein to seek evidence for interaction between the TCR and peptide Ag. Preincubation of these CTL with peptide 365 to 380 resulted in inhibition of target cell lysis. In addition, CTL lysed allogeneic targets in the presence of soluble peptide Ag. Investigation of the basis of these two phenomena revealed a requirement for expression of H-2Db molecules by the effector cells. Either preincubation with anti-Db mAb or the use of chimera-derived H-2d CTL specific for Db plus peptide ablated both peptide-dependent inhibition and lysis of allogeneic cells, suggesting these activities are a consequence of self-presentation of peptide Ag by CTL. Lysis of allogeneic cells appears to represent bystander lysis by CTL in response to recognition of peptide on other effector cells. Lysis inhibition is attributable to a highly potent form of cold target inhibition in which CTL serve as their own cold targets.

Consequences of self-presentation of peptide antigen by cytolytic T lymphocytes

We have used H-2Db-restricted CTL clones specific for peptide 365 to 380 of the influenza nucleoprotein to seek evidence for interaction between the TCR and peptide Ag. Preincubation of these CTL with peptide 365 to 380 resulted in inhibition of target cell lysis. In addition, CTL lysed allogeneic targets in the presence of soluble peptide Ag. Investigation of the basis of these two phenomena revealed a requirement for expression of H-2Db molecules by the effector cells. Either preincubation with anti-Db mAb or the use of chimera-derived H-2d CTL specific for Db plus peptide ablated both peptide-dependent inhibition and lysis of allogeneic cells, suggesting these activities are a consequence of self-presentation of peptide Ag by CTL. Lysis of allogeneic cells appears to represent bystander lysis by CTL in response to recognition of peptide on other effector cells. Lysis inhibition is attributable to a highly potent form of cold target inhibition in which CTL serve as their own cold targets.

Mapping of epitopes recognized by alloreactive cytotoxic T lymphocytes using inhibition by MHC peptides

To identify epitopes recognized by alloreactive CTL we have examined H-2Kb-specific CTL for their recognition of synthetic peptides with sequences derived from the native Kb class I molecule. Consecutive nested peptides spanning the immunogenic alpha 1 and alpha 2 domains of Kb were tested for their capacity to inhibit CTL clones in their recognition of cells expressing the native Kb molecule. Inhibition by these peptides was found to be an extremely rare event. One peptide (Kb.111-122) did inhibit recognition by one particular CTL clone, clone 13. Upon further investigation it was observed that clone 13 also recognized peptide Kb.111-122 when presented in the context of the syngeneic MHC molecule, Kd. Considering that residues 111 to 122 are located at the base of the antigen groove, and clone 13 is able to recognize Kb.111-122 when presented by syngeneic target cells, we suggest that inhibition of this CTL clone may be due to MHC restricted, self-presentation of peptide rather than to direct binding of free peptide to the TCR. Taken together, these results suggest inhibition of allospecific CTL by MHC peptides is a rare event at least for Kb recognition. Furthermore, they demonstrate the need for caution when interpreting inhibition by peptide as evidence for recognition by the TCR of the corresponding region on the native molecule.

Cytolytic T-lymphocyte response to isolated class I H-2 proteins and influenza peptides

T cells recognize antigenic peptides in the context of major histocompatibility complex (MHC) proteins. Peptide binding to class II MHC proteins, and T-cell recognition of these complexes at the functional level has been demonstrated. Although considerable evidence suggests that class I-restricted cytotoxic T lymphocytes (CTL) recognize class I-peptide complexes, this has not yet been directly demonstrated. Chen and Parham have recently detected a low level of direct binding of radiolabelled influenza peptides to class I HLA proteins, but the relevance of this binding to T-cell recognition remains uncertain. We report here that purified class I proteins pulsed with influenza peptides can trigger antigen-specific, TCR-mediated degranulation by CTL. Effective pulsing depends on both peptide concentration and time, and can occur within 60 minutes. These results provide strong support for the formation of an antigenic complex that is recognized by CTL in which peptide antigens are bound to isolated class I proteins.