Effects of a Brief Team Training Program on Surgical Teams' Nontechnical Skills: An Interrupted Time-Series Study

BACKGROUND

Up to 60% of adverse events in surgery are the result of poor communication and teamwork. Nontechnical skills in surgery (NOTSS) are critical to the success of surgery and patient safety. The study aim was to evaluate the effect of a brief team training intervention on teams' observed NOTSS.

METHODS

Pretest-posttest interrupted time-series design with statistical process control analysis was used to detect longitudinal changes in teams' NOTSS. We evaluated NOTSS using the revised NOTECHS weekly for 20 to 25 weeks before and after implementation of a team training program.

RESULTS

We observed 179 surgical procedures with cardiac, vascular, upper gastrointestinal, and hepatobiliary teams. Mean posttest NOTECHS scores increased across teams, showing special cause variation. There were also significant before and after improvements in NOTECHS scores in respect to professional role and in the use of the Surgical Safety Checklist.

CONCLUSIONS

Our results suggest associated improvements in teams' NOTSS after implementation of the team training program.

The molecular origin and taxonomy of mucinous ovarian carcinoma

Mucinous ovarian carcinoma (MOC) is a unique subtype of ovarian cancer with an uncertain etiology, including whether it genuinely arises at the ovary or is metastatic disease from other organs. In addition, the molecular drivers of invasive progression, high-grade and metastatic disease are poorly defined. We perform genetic analysis of MOC across all histological grades, including benign and borderline mucinous ovarian tumors, and compare these to tumors from other potential extra-ovarian sites of origin. Here we show that MOC is distinct from tumors from other sites and supports a progressive model of evolution from borderline precursors to high-grade invasive MOC. Key drivers of progression identified are TP53 mutation and copy number aberrations, including a notable amplicon on 9p13. High copy number aberration burden is associated with worse prognosis in MOC. Our data conclusively demonstrate that MOC arise from benign and borderline precursors at the ovary and are not extra-ovarian metastases.

Keratin-14 (KRT14) Positive Leader Cells Mediate Mesothelial Clearance and Invasion by Ovarian Cancer Cells

Epithelial ovarian cancer metastasis is driven by spheroids, which are heterogeneous cancer cell aggregates released from the primary tumour mass that passively disseminate throughout the peritoneal cavity to promote tumour spread, disease recurrence, and acquired chemoresistance. Despite their clinical importance, the molecular events that control spheroid attachment and invasion into underlying healthy tissues remain poorly understood. We examined a novel in vitro invasion model using imaging mass spectrometry to establish a “snapshot” of the spheroid/mesothelial interface. Amongst numerous adhesion-related proteins, we identified a sub-population of highly motile, invasive cells that expressed the basal epithelial marker KRT14 as an absolute determinant of invasive potential. The loss of KRT14 completely abrogated the invasive capacity, but had no impact on cell viability or proliferation, suggesting an invasion-specific role. Our data demonstrate KRT14 cells as an ovarian cancer “leader cell” phenotype underlying tumor invasion, and suggest their importance as a clinically relevant target in directed anti-tumour therapies.

Evaluation of a Brief Team Training Intervention in Surgery: A Mixed-Methods Study

The aim of this study was to evaluate a brief team training program in relation to teams' observed nontechnical skills (NTSs) in surgery, teams' perceptions of safety culture, and the training implementation. We used mixed methods to analyze structured observations of 179 surgeries, semistructured interviews with surgical team members from four selected surgical specialties, and a survey. There were significant (P < .001) improvements in surgical teams' observed NTSs and in the use of the World Health Organization's Surgical Safety Checklist after participation in the training program. Nonsignificant results included increased perceived safety climate and decreased perceived teamwork climate. From participant interviews, we identified that production pressure and time constraints were the biggest barriers to implementation and the greatest enabler was the organization's support for staff education initiatives. Most participants perceived the content of the program to be useful. These results highlight the complexities inherent in the development and evaluation of interdisciplinary patient safety interventions.

Changes in surgical team performance and safety climate attitudes following expansion of perioperative services: a repeated-measures study

Objective The aim of the present study was to describe process changes in surgical team performance and team members’ attitudes to safety culture following hospital relocation and expansion of perioperative services. Methods The study was a naturalistic study using structured observations and surveys to assess non-technical skills (NTS; i.e. communication, teamwork, situational awareness, decision making and leadership) in surgery. This interrupted time series design used mixed-linear regression models to examine the effect of phase (before and after hospital relocation) on surgical teams’ NTS and their processes that may affect performance. Differences in self-reported teamwork and safety climate attitudes were also examined. Results In all, 186 procedures (100 before and 81 after hospital relocation) were observed across teams working in general, paediatric, orthopaedic and thoracic surgeries. Interobserver agreement ranged from 86% to 95%. An effect of phase was found, indicating that there were significant improvements after relocation in the use of NTS by the teams observed (P=0.020; 95% confidence interval 1.9–4.7). Conclusions The improvements seen in surgical teams’ NTS performance and safety culture attitudes may be related to the move to a new state-of-the-art perioperative department. What is known about the topic? Patient safety in surgery relies on optimal team performance, underpinned by effective NTS. What does this paper add? The NTS of surgical teams may be improved through ergonomic innovations that promote teams’ shared mental models. What are the implications for practitioners? Effective multidisciplinary teamwork relies on a combination of NTS and ergonomic factors, which inherently contribute to team performance and safety climate attitudes.

Correlates of non-technical skills in surgery: a prospective study

BACKGROUND

Communication and teamwork failures have frequently been identified as the root cause of adverse events and complications in surgery. Few studies have examined contextual factors that influence teams' non-technical skills (NTS) in surgery. The purpose of this prospective study was to identify and describe correlates of NTS.

METHODS

We assessed NTS of teams and professional role at 2 hospitals using the revised 23-item Non-TECHnical Skills (NOTECHS) and its subscales (communication, situational awareness, team skills, leadership and decision-making). Over 6 months, 2 trained observers evaluated teams' NTS using a structured form. Interobserver agreement across hospitals ranged from 86% to 95%. Multiple regression models were developed to describe associations between operative time, team membership, miscommunications, interruptions, and total NOTECHS and subscale scores.

RESULTS

We observed 161 surgical procedures across 8 teams. The total amount of explained variance in NOTECHS and its 5 subscales ranged from 14% (adjusted R² 0.12, p<0.001) to 24% (adjusted R² 0.22, p<0.001). In all models, inverse relationships between the total number of miscommunications and total number of interruptions and teams' NTS were observed.

CONCLUSIONS

Miscommunications and interruptions impact on team NTS performance.

Abstract POSTER-TECH-1105: Assessment of ovarian cancer spheroid attachment and invasion of mesothelial cells in real time to profile the molecular signature of the invasive interface

Background and Aims: Ovarian cancer is the most common cause of death from gynaecological cancer worldwide (1). Often called the “silent killer”, the high mortality rate is associated with the late stage in which the disease is diagnosed (2). Unlike other solid cancers, ovarian cancer cells rarely spread via the vasculature, instead shed from the primary tumor and disseminate within the peritoneal fluid or ascites (2). The formation of spheroids within the non-adherent peritoneal environment is a barrier to effective treatment, due to the enhanced ability of spheroids to survive chemotherapies and seed distal metastases (3-5).

Invading ovarian cancer cells interact with mesothelial cells lining the peritoneal surface, attach to, and invade the underlying basement membrane to establish secondary lesions (6). The molecular events at the interface between invading ovarian cancer and peritoneal cells at the onset of invasion have been poorly studied, existing methods capture events after invasion is well-underway. Therefore, the regulatory signals which govern the initiation of a metastatic lesion are poorly understood. We aimed: i) to develop an innovative method to co-culture ascites-derived primary ovarian cancer cells to measure invasion through peritoneal mesothelial cell layers in real time (7); ii) identify the unique protein expression profile at the ovarian cancer spheroid-peritoneal interface during early invasion using proteomics.

Methods: Real Time Cell Analysis (RTCA) technology (xCELLigence, ACEA) was adapted to establish a three-dimensional co-culture model of the tumor microenvironment of the peritoneum (7). RTCA wells were coated with Matrigel (basement membrane matrix) and a confluent monolayer of human mesothelial cells. Multicellular spheroids were generated from primary ovarian cancer lines (high-grade serous carcinoma, leiomysarcoma, adenocarcinoma, carcinosarcoma) or benign ascites derived cells cultured under non-adherent conditions. Spheroids were added to the RTCA plate and real time measurements were conducted to determine the precise period when invasion commenced. Parallel cultures were histologically-preserved at invasion initiation and processed for assessment by Matrix-Assisted Laser Desorption/Ionization (MALDI) imaging.

Results: We assessed invasion in a panel of ovarian cancer samples, benign ascites cells and the mesothelial cell line. Continuous real time measurements revealed that individual ovarian cancer samples exhibited differences in the timing of the onset of invasion. High-grade serous carcinoma samples initiated invasion rapidly after addition, with some samples detected in under 30 min, a time period not captured by traditional Transwell assays. The benign and mesothelial cells themselves did not invade. MALDI imaging allowed for the identification of peptides expressed at the tumor-mesothelial interface during early invasion. These molecules represent novel molecules involved in the initiation of the metastatic process and are the subject of further characterisation.

Conclusion: This method represents a high-throughput quantitative analysis of ovarian cancer spheroid invasion of mesothelial and ECM barriers. The study has provided an unprecedented insight into the molecular mechanisms and molecules involved in the initiation of ovarian cancer invasion of the mesothelium, identifying new therapeutic targets.

References: 1. Marsha Rivkin Center for Ovarain Cancer Research - Facts and Figures Survival Rates. 2014. 2. Ahmed N et al., Front Oncol. 2013;3(256). 3. Aguilar-Gallardo C et al., Stem Cell Rev. 2012 Sep;8(3):994-1010. 4. Burleson KM et al., Gynecol Oncol. 2004 Apr;93(1):170-81. 5. Liao J et al., PLoS One. 2014;9(1):e84941 6. Kenny HA et al., Int J Cancer. 2007 Oct 1;121(7):1463-72. 7. Bilandzic M et al., Journal of Visual Experimentation. 2014 20/05/2014 (87).

Citation Format: Maree Bilandzic, Adam Rainczuk, Andrew Stephens, Nicole Fairweather, Thomas Jobling, Kaye L Stenvers. Assessment of ovarian cancer spheroid attachment and invasion of mesothelial cells in real time to profile the molecular signature of the invasive interface [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-TECH-1105.

Team communications in surgery - creating a culture of safety

As a key department within a healthcare organisation, the operating room is a hazardous environment, where the consequences of errors are high, despite the relatively low rates of occurrence. Team performance in surgery is increasingly being considered crucial for a culture of safety. The aim of this study was to describe team communication and the ways it fostered or threatened safety culture in surgery. Ethnography was used, and involved a 6-month fieldwork period of observation and 19 interviews with 24 informants from nursing, anaesthesia and surgery. Data were collected during 2009 in the operating rooms of a tertiary care facility in Queensland, Australia. Through analysis of the textual data, three themes that exemplified teamwork culture in surgery were generated: "building shared understandings through open communication"; "managing contextual stressors in a hierarchical environment" and "intermittent membership influences team performance". In creating a safety culture in a healthcare organisation, a team's optimal performance relies on the open discussion of teamwork and team expectation, and significantly depends on how the organisational culture promotes such discussions.

Building shared situational awareness in surgery through distributed dialog

BACKGROUND

Failure to convey time-critical information to team members during surgery diminishes members' perception of the dynamic information relevant to their task, and compromises shared situational awareness. This research reports the dialog around clinical decisions made by team members in the time-pressured and high-risk context of surgery, and the impact of these communications on shared situational awareness.

METHODS

Fieldwork methods were used to capture the dynamic integration of individual and situational elements in surgery that provided the backdrop for clinical decisions. Nineteen semistructured interviews were performed with 24 participants from anesthesia, surgery, and nursing in the operating rooms of a large metropolitan hospital in Queensland, Australia. Thematic analysis was used.

RESULTS

The domain "coordinating decisions in surgery" was generated from textual data. Within this domain, three themes illustrated the dialog of clinical decisions, ie, synchronizing and strategizing actions, sharing local knowledge, and planning contingency decisions based on priority.

CONCLUSION

Strategies used to convey decisions that enhanced shared situational awareness included the use of "self-talk", closed-loop communications, and "overhearing" conversations that occurred at the operating table. Behaviors that compromised a team's shared situational awareness included tunneling and fixating on one aspect of the situation.

Factors that influence the expected length of operation: results of a prospective study

BACKGROUND

In the operating room, factors such as interruptions, communication failures, team familiarity and the unpredictability of unplanned cases can prolong the length of an operation, and lead to inefficiency and increased costs. However, little is known about the extent to which such factors contribute to extending the expected length of an operation. Aim To describe factors that prolong the expected length of an operation.

METHODS

Structured observations were performed on a purposive sample of 160 surgical procedures across 10 specialties of planned and unplanned surgeries. During the 6-month period, a trained observer structured observations. Bivariate correlations and a standard multiple regression model were developed to describe associations among unplanned operations, interruptions, prebriefings, team familiarity, communication failures and the outcome, and deviation from expected operation time.

RESULTS

Of the three explanatory variables entered into the regression model, the only significant predictor of deviation in expected length of operation was the number of communication failures (p=0.013). This model explained 4.5% of the variance in deviation in expected length of operation (p=0.018).

CONCLUSIONS

The results of this study validate the role of prospective observational research methods in unveiling critical factors that contribute to deviation in expected length of operation. These results have the potential to inform evidence-based interventions aimed at ameliorating the effects of miscommunications, hence improve patient safety.

Abstract 3993: Characterisation of early ovarian cancer biomarkers

Around 22,000 new cases and 15,500 deaths from ovarian cancer are expected in the US in 2008, and currently women run an estimated 1/67 risk of developing ovarian cancer during their lifetime. Approximately 70% of patients present with late stage disease (stages III - IV; FIGO classification) and have a poor prognosis, with only a ∼30% 5 year survival rate. By contrast, patients diagnosed with early (stage I) disease exhibit survival rates above 90%, with disease often cured by surgery alone. The key issue is that early detection is hampered by a lack of sensitive and specific markers. The aim of this ongoing study was to apply 8-plex isobaric tags for relative and absolute quantitation (iTRAQ) for the proteomic investigation for early stage markers of ovarian cancer.

Plasma was collected from patients and pooled as follows: G1-early stage cancers (stage I/II), G2-late stage cancers (stage III), G3-ascites fluid, G4-benign adenomas, G5-benign adenofibromas, G6-controls and G7-pool of all samples. Pooled patient samples were immuno-depleted of 12 abundant, disease-unrelated proteins and concentrated using reverse phase chromatography. Equal protein concentrations of each of the 7 pools were reduced, denatured, alkylated and digested using trypsin. Peptides from G1 through G7 were labelled with iTRAQ labels −113 to −119 respectively. Samples were combined and analysed using two-dimensional liquid chromatography (2D-LC) and mass spectrometry (4700 MALDI-TOF/TOF or QStar Elite, Applied Biosystems). Data were analysed using Protein Pilot (version 3.0, Applied Biosystems).

Initial studies have identified 111 proteins with quantitation of 71 proteins, including numerous proteins that have been patented as candidate early markers for ovarian cancer. Of those identified, many are involved in inflammation/immunity and coagulation. Of considerable interest was the quantitative identification of numerous low abundance proteins not previously associated with early stage ovarian cancer.

This proteome analysis has generated a catalogue of proteins that display potential as early markers for ovarian cancer. In addition, this study will assist in our understanding of the pathways potentially involved in the onset and progression of ovarian cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3993.

Molecular characterization of the surface layer proteins from Clostridium difficile

Many bacteria express a surface-exposed proteinaceous layer, termed the S-layer, which forms a regular two-dimensional array visible by electron microscopy. Clostridium difficile is unusual in expressing two S-layer proteins (SLPs), which are of varying size in a number of strains. In an approach combining molecular biology with mass spectrometric sequencing strategies, we have identified the structural gene (slpA) for the S-layer from three strains of C. difficile. Both proteins are derived from a common precursor, and processing involves the removal of a signal peptide and a second cleavage to release the two mature SLPs. To our knowledge, this is the first example in which two SLPs have been shown to derive from a single gene product through post-translational processing, rather than from the expression of separate genes. The higher molecular weight (MW) SLP is highly conserved among the three strains, whereas the lower MW SLP shows considerable sequence diversity, reflecting the results from Western blotting. The high-MW SLP shows weak homology to N-acetyl muramoyl-L-alanine amidase from Bacillus subtilis, and both the native SLP from C. difficile and a recombinant protein expressed in Escherichia coli were found to display amidase activity by zymography. The high-MW SLPs showed evidence of glycosylation, whereas the lower MW proteins did not. A family of genes with sequence homology to the amidase domain of the high-MW SLP was identified in the C. difficile strain 630 genome, some of which are located in the same region of the genome as slpA and were shown by reverse transcription-polymerase chain reaction (RT-PCR) analysis to be transcribed.

Influence of codon usage on the immunogenicity of a DNA vaccine against tetanus

Two related DNA vaccine vector plasmids, harbouring either wild-type (pcDNA3/ntetC) or synthetic codon optimised (pcDNA3/stetC) DNA encoding fragment C (TetC) of tetanus toxin were constructed. COS-7 cells transformed with pcDNA3/stetC reproducibly expressed higher levels of TetC than similar cells transformed with pcDNA3/ntetC. BALB/c mice immunised intramuscularly with pcDNA3/stetC produced significantly higher levels of anti-TetC antibodies in their serum in the weeks following vaccination compared to mice immunised with pcDNA3/ntetC, even when differences in the CpG content between the two sequences were controlled for using non-expressing DNA.

Analysis of mutants of tetanus toxin Hc fragment: ganglioside binding, cell binding and retrograde axonal transport properties

Tetanus toxin binds neuronal tissue prior to internalization and trafficking to the central nervous system. Binding of the carboxy-terminal 50 kDa HC fragment of tetanus toxin to polysialogangliosides is important for this initial cell binding step. Using the three-dimensional structure of HC, mutants were designed to investigate the role of individual residues in ganglioside binding. Mutant proteins were tested for binding to GT1b gangliosides, to primary motoneurons and for their ability to undergo retrograde transport in mice. Two classes of mutant were obtained: (i) those containing deletions in loop regions within the C-terminal beta-trefoil domain which showed greatly reduced ganglioside and cell binding and did not undergo retrograde transport and (ii) those that showed reduced ganglioside binding, but retained primary neuronal cell binding and retrograde transport. The second class included point mutants of Histidine-1293, previously implicated in GT1b binding. Our deletion analysis is entirely consistent with recent structural studies which have identified sugar-binding sites in the immediate vicinity of the residues identified by mutagenesis. These results demonstrate that ganglioside binding can be severely impaired without abolishing cell binding and intracellular trafficking of tetanus toxin.

Manipulation of pathogen-derived genes to influence antigen presentation via DNA vaccines

To gain insight into the routes of presentation of pathogen sequences via DNA vaccines, we have compared the abilities of sequences encoding fragment C of tetanus toxin (FrC) and influenza A virus nucleoprotein (NP) to induce antibody or cytotoxic T-cell (CTL) responses in vivo. Strong antibody and CTL responses were induced against FrC targeted to the endoplasmic reticulum (ER) and both were reduced by removal of the leader sequence. In contrast, targeting of NP to the ER generated only a modest antibody response, likely due to misfolding in this site. Removal of the leader sequence led to anti-NP antibodies via cross-priming. For NP, induction of CTLs was not influenced by the leader sequence. Exogenous FrC or NP delivered as proteins were unable to induce CTLs. Routes to induction of optimal immune responses via DNA evidently differ according to the nature of the encoded pathogen sequence. Understanding processing pathways for pathogen sequences should assist rational design of DNA vaccines.

Non-viral neuronal gene delivery mediated by the HC fragment of tetanus toxin

Many inherited neurological diseases and cancers could potentially benefit from efficient targeted gene delivery to neurons of the central nervous system. The nontoxic fragment C (HC) of tetanus toxin retains the specific nerve cell binding and transport properties of tetanus holotoxin. The HC fragment has previously been used to promote the uptake of attached proteins such as horseradish peroxidase, beta-galactosidase and superoxide dismutase into neuronal cells in vitro and in vivo. We report the use of purified recombinant HC fragment produced in yeast and covalently bound to polylysine [poly(K)] to enable binding of DNA. We demonstrate that when used to transfect cells, this construct results in nonviral gene delivery and marker gene expression in vitro in N18 RE 105 cells (a neuroblastoma x glioma mouse/rat hybrid cell line) and F98 (a glioma cell line). Transfection was dependent on HC and was neuronal cell type specific. HC may prove a useful targeting ligand for future neuronal gene therapy.

Novel genes mapping to the critical region of the 5q- syndrome

The 5q- syndrome is a myelodysplastic syndrome with specific hematological features and a good prognosis. Using molecular mapping techniques, we have previously defined the critical region of gene loss of the 5q- chromosome in the 5q- syndrome as the approximately 5-Mb region at 5q31-q33 flanked by the genes for FGF1 and IL12B. This region is completely represented by a series of overlapping YACs, and we are currently generating a transcription map with the aim of identifying the tumor-suppressor gene associated with the development of the 5q- syndrome. In this study two techniques have been used: first, the screening of full-length cDNA libraries with radiolabeled YACs and second, the mapping of chromosome 5-specific expressed sequence tags (ESTs) to a YAC contig. A 1-Mb YAC contig encompassing the CSF1R gene has been used to screen a fetal brain cDNA library, and this has resulted in the identification of two genes comprising one known gene previously localized to the region (ADRB2) and one known gene previously unlocalized. Six of 135 chromosome 5-specific ESTs were localized by PCR screening to the YAC contig mapping to the critical region of the 5q- syndrome. IMAGE cDNA clones for each of the six ESTs have been obtained. These seven (excluding ADRB2) newly assigned cDNA clones were subjected to further analysis. The expression patterns of each of the cDNA clones have been established in a range of human tissues, including bone marrow. Six of seven cDNAs are expressed in human bone marrow. Six of seven cDNAs have no known homology to any deposited human sequences, and one (C29) is dihydropyrimidinase-related protein-3, a member of a novel gene family. Genomic localization and expression patterns would suggest that these newly assigned cDNAs represent potential candidate genes for the 5q- syndrome.

Immunization of mice with DNA encoding fragment C of tetanus toxin

Immunization of mice with Fragment C protein, the non-toxic C-terminal domain of tetanus toxin, will protect mice against lethal challenge with tetanus toxin. A plasmid, pcDNA3/tetC, which encodes a synthetic tetC gene expressed under the control of the human cytomegalovirus major intermediate early promoter/enhancer region, was constructed. Fragment C expression was observed in Chinese hamster ovary cells following transfection with pcDNA3/tetC. The immune response induced by intramuscular immunization with pure pcDNA3/tetC DNA was evaluated in a murine model. Anti-Fragment C serum immunoglobulin and proliferative responses in splenocytes were observed following two immunizations with pcDNA3/tetC. The major IgG subclass that recognized Fragment C was IgG2a and the stimulated splenocytes secreted high levels of interferon-gamma. Sufficient anti-Fragment C serum immunoglobulins were induced by DNA-mediated immunization to protect mice against lethal challenge with tetanus toxin.

Cloning and characterisation of the rabbit 5-HT1D alpha and 5-HT1D beta receptors

The genes encoding the rabbit 5HT1D alpha and 5HT1D beta receptors have been cloned. The deduced amino acid sequence of these receptors shows 91-92% amino acid sequence identity with their human homologues, and similar high sequence identity with homologues from other species. The receptors were transiently expressed in COS-7 cells and exhibit a pharmacological profile closely resembling their human homologues, including a higher affinity of ketanserin for the 5-HT1D alpha subtype. However, sumatriptan had a lower affinity for both the rabbit receptors compared to their human counterparts. This may be accounted for by differences between the primary amino acid sequences of these species homologues.

Characterization of recombinant tetanus toxin derivatives suitable for vaccine development

Recombinant derivatives of tetanus toxin (TeTx) were isolated and used to immunize mice. Recombinant TeTx light chain, a derivative of fragment C that had lost the ability to bind neurons, and a recombinant TeTx holotoxoid that could protect mice against TeTx challenge were identified.

Modulation of antigen processing by bound antibodies can boost or suppress class II major histocompatibility complex presentation of different T cell determinants

Bound antibodies can modulate antigen processing but it is not clear to what extent this affects antigen presentation. Here we show that presentation of T cell determinants in tetanus toxin can be either enhanced or suppressed as a direct consequence of antibody modulation of antigen processing in human B lymphoblastoid cells. Remarkably, a single bound antibody or its Fab fragment can simultaneously enhance the presentation of one T cell determinant by more than 10-fold while strongly suppressing the presentation of a different T cell determinant. Biochemical analysis demonstrates that both the suppressed and boosted determinants fall within an extended domain of antigen stabilized or "footprinted" by this antibody during proteolysis. These results demonstrate that bound antibodies can modulate the capture of peptides by class II major histocompatibility complex (MHC), thus manipulating the T cell response towards or away from particular determinants. Altered processing of protein-protein complexes leading to enhanced loading of class II MHC and substantially lowered threshold for T cell activation suggests a novel mechanism that might reveal "cryptic" self determinants.

Expression of the Bordetella pertussis P.69 pertactin adhesin in Escherichia coli: fate of the carboxy-terminal domain

The mature pertactin protein (P.69) of Bordetella pertussis can be isolated from the bacterial cell surface as a polypeptide with an apparent molecular mass of 69,000 Da as determined by sodium dodecyl sulphate gel electrophoresis. However the open reading frame of prn, the pertactin gene, encodes a polypeptide with a predicted molecular mass of 93,478 Da, referred to as P.93. Expression of the prn gene in Escherichia coli leads to the synthesis of the full-length P.93 polypeptide, which is rapidly processed to the mature P.69 protein located at the cell surface. The P.93 precursor polypeptide is processed at both termini. A 34 amino acid long signal sequence is removed from the amino-terminus and a polypeptide sequence of about 30,000 Da (P.30) is cleaved from the carboxy-terminus. Deletion of the 3' region of prn, encoding P.30, results in the expression of an intracellular form of P.69. Antiserum which recognizes P.30 was raised using synthetic peptides based on the primary amino acid sequence of the region. This anti-P.30 serum was used in a Western blot analysis of fractionated cells of B. pertussis and E. coli harbouring the intact prn gene. The P.30 polypeptide was readily detected in outer membrane fractions prepared from both of these bacterial species, although it could not be shown to be exposed at the cell surface.

Construction, expression, and immunogenicity of the Schistosoma mansoni P28 glutathione S-transferase as a genetic fusion to tetanus toxin fragment C in a live Aro attenuated vaccine strain of Salmonella

A vector has been constructed to allow genetic fusions of guest antigens via a hinge domain to the C terminus of the highly immunogenic C fragment of tetanus toxin. A fusion has been constructed with the gene encoding the protective 28-kDa glutathione S-transferase (EC 2.5.1.18) from Schistosoma mansoni. The recombinant vector has been electroporated into the nonvirulent Salmonella typhimurium aroA live vaccine strain SL3261. The corresponding chimeric protein is stably expressed in a soluble form in Salmonella as evaluated by Western blotting with fragment C and glutathione S-transferase antisera. Mice immunized intravenously with a single dose of the live recombinant bacteria elicit antibodies to both fragment C and glutathione S-transferase as detected by enzyme-linked immunosorbent assays. Furthermore, all of the mice were solidly protected when challenged with lethal doses of either tetanus toxin or the virulent Salmonella typhimurium strain C5. Mice have also elicited antibodies to fragment C and glutathione S-transferase after oral immunization. It may be that a live trivalent vaccine against typhoid, tetanus, and schistosomiasis is feasible.

Processing and presentation of tetanus toxin by antigen-presenting cells from patients with chronic granulomatous disease (CGD) to human specific T cell clones are not impaired

The capacity of peripheral blood lymphocytes (PBL) or Epstein-Barr virus (EBV)-transformed B cell lines from CGD patients to process and present tetanus toxin (tt)-specific epitopes was assessed using various tt preparations and human tt-specific T cell clones. PBL from all of the donors were able to process and present either native tt and/or denatured tt to human T cell clones specific for various tt epitopes. Furthermore, no difference was found in the antigen requirement when normal or CGD EBV-B cell lines were used as antigen-presenting cells (APC). These results suggest that the deficiency in oxygen metabolism in CGD cells does not affect tt processing and presentation.

Mutations in the connexin 32 gene in X-linked dominant Charcot-Marie-Tooth disease (CMTX1)

X-linked dominant Charcot-Marie-Tooth disease (CMTX1) is a peripheral neuropathy which maps to Xq13 and is flanked by the loci DXS106 (Xq11.2-q12) and DXS559 (Xq13.1). Contained within this interval of approximately 2-3Mb of DNA is the gene, connexin 32 (locus designation GJ beta 1). This gene encodes a gap junction protein which is expressed in large quantities within the liver and throughout a range of other mammalian tissues. We have sequenced the coding region of exon 2 of this gene from affected individuals in nine families with CMTX 1 and have found mutations which segregate with the disease in eight of these families. The mutations detected include missense point mutations at codons 15, 60, 63, 208, and 215, a nonsense point mutation at codon 220, deletions of one base in codon 72/3 producing a stop codon 12 codons down stream and a three base pair deletion which can be predicted to result in the loss of a single amino acid. These findings are consistent with the disease CMTX1 being the result of mutations affecting the gene connexin 32 (Cx32).

Expression of P.69/pertactin from Bordetella pertussis in a baculovirus/insect cell expression system: protective properties of the recombinant protein

The surface antigen P.69/pertactin of Bordetella pertussis has been expressed using the polyhedron promoter of baculovirus in cultured insect cells. Either full-length or truncated prn DNA was used to express P.69 pertactin. The full-length gene gave rise to low levels of P.93 precursor protein, some of which was processed to P.69. The shortened prn expressed P.69 pertactin directly at levels up to 3.5 mg per litre. P.69 vaccinated animals were protected against aerosol challenge with virulent B. pertussis bacteria.

Fine mapping of the human SCIDX1 locus at Xq12-13.1

Previous linkage analysis of families with X-linked severe combined immunodeficiency (SCIDX1) mapped this locus to a large region encompassing about 10 to 20 cM at Xq12-21. We have analyzed in SCIDX1 families the segregation of 7 highly polymorphic microsatellites repeats localized to this region, including a new polymorphic microsatellite at the DXS135 locus described in this study, to refine the mapping of this disease locus. The observations of genetic recombinants within the previously defined SCIDX1-region allow us to establish new flanking markers at the DXS135 and DXS227 loci, which significantly reduce the region harboring the SCIDX1 locus to a distance estimated between 3 to 5 cM. The existence of multiple, highly polymorphic markers in the refined SCIDX1 region will greatly improve the accuracy of carrier detection and prenatal diagnosis for SCIDX1.

Crystallographic characterization of tetanus toxin fragment C

The C-terminal fragment from tetanus toxin has been crystallized. The 50 kDa protein forms prismatic crystals with an orthorhombic unit cell of dimensions a = 64.03 A, b = 76.31 A and c = 135.3 A. The space group is P2(1)2(1)2(1). Assuming one molecule per asymmetric unit, the solvent occupies 63% of the unit cell.

Characterization of a Salmonella typhimurium aro vaccine strain expressing the P.69 antigen of Bordetella pertussis

The P.69 Bordetella pertussis protective antigen was expressed by use of the trc promoter from the chromosome of a Salmonella typhimurium aro vaccine strain, BRD509, by integrating the prn gene, encoding the 93-kDa precursor of this protein, into the aroC locus. P.69 was detected on the cell surface of the S. typhimurium strain (BRD640) by agglutination and immunoelectron microscopy. BALB/c mice immunized orally or intravenously with BRD640 showed a significant level of protection against an aerosol challenge with virulent B. pertussis, compared with control animals. No anti-P.69 antibodies in the serum or anti-P.69 antibody-secreting cells in the lungs were detected in BRD640-vaccinated animals, although cells isolated from spleens showed a P.69-dependent cell proliferative response. In contrast, low levels of anti-P.69 antibodies in the serum and anti-P.69 antibody-secreting cells in the lungs were detected in immunized mice following a B. pertussis challenge.

Construction of a genetically defined Salmonella typhi Ty2 aroA, aroC mutant for the engineering of a candidate oral typhoid-tetanus vaccine

The construction of a Salmonella typhi Ty2 strain harbouring defined deletions in both the aroA and aroC genes is described. These deletions have been fully defined at the molecular level by DNA sequencing and have been introduced in such a way that no foreign DNA remains in the S. typhi genome. This strain is attenuated in mice when given by the intraperitoneal route suspended in hog gastric mucin and is attenuated to a similar level to strains harbouring deletions in aroA or aroC alone indicating that both lesions are capable of attenuating independently. We have used this defined S. typhi aroA aroC strain to express stably a non-toxic 50 kDa fragment of tetanus toxin (fragment C) from a gene incorporated into the chromosome. This strain has the advantage of harbouring no antibiotic-resistance markers and we consider it to be a candidate bivalent oral typhoid-tetanus vaccine.

Prenatal diagnosis for dystrophia myotonica using the polymerase chain reaction

The polymerase chain reaction has been used to detect an abundant class of short repeat DNA families of the form (dC-dA)n.(dG-dT)n, known as microsatellites. These units are found throughout the human genome and have been characterized for several loci including APOC2 on chromosome 19q12-q13.2. The locus APOC2 is linked to the gene for dystrophia myotonica and a microsatellite within this locus was used to derive polymorphisms in a family to predict the inheritance of the disease. Chorionic villus sampling (CVS) was performed at 15 1/2 weeks' gestation. Following DNA extraction from the CVS material and parental blood samples, microsatellite analysis was carried out by the polymerase chain reaction.

Molecular cloning and characterization of the aroD gene encoding 3-dehydroquinase from Salmonella typhi

The aroD gene from Salmonella typhi, encoding 5-dehydroquinate hydrolyase (3-dehydroquinase), has been cloned into Escherichia coli and the DNA sequence determined. The aroD gene was isolated from a cosmid gene bank by complementation of an S. typhimurium aroD mutant. Analysis of the DNA sequence revealed the presence of an open reading frame capable of encoding a protein of 252 amino acids with a calculated Mr of 27706. Comparison of the deduced S. typhi 3-dehydroquinase protein sequence with that elucidated for E. coli revealed 69% homology. Alignment of the S. typhi sequence and equivalent Aspergillus nidulans and Saccharomyces cerevisiae sequences showed that homology was lower, at 24%, but still significant. Use of a minicell expression system demonstrated that a polyclonal antibody raised against E. coli 3-dehydroquinase cross-related with its S. typhi counterpart.

Oral Salmonella typhimurium (AroA-) vaccine expressing a major leishmanial surface protein (gp63) preferentially induces T helper 1 cells and protective immunity against leishmaniasis

The gp63 gene of Leishmania major was transformed into the AroA- vaccine strain of Salmonella typhimurium (SL3261). The construct (SL3261-gp63), which stably expresses the gp63 Ag in vitro, was used to immunize CBA mice by the oral route. Spleen cells from mice inoculated with SL3261-gp63 developed antibody and proliferative T cell response to L. major. They did not express detectable delayed-type hypersensitivity reactivity. The activated T cells are mainly CD4+ and secrete IL-2 and IFN-gamma but no IL-4. The orally immunized mice developed significant resistance against a challenge L. major infection. We have, therefore, demonstrated the feasibility of oral vaccination against leishmaniasis and that the oral route of antigen delivery via the heterologous carrier may preferentially induce Th1 subsets of CD4+ cells.

Oral Salmonella typhimurium (AroA-) vaccine expressing a major leishmanial surface protein (gp63) preferentially induces T helper 1 cells and protective immunity against leishmaniasis

The gp63 gene of Leishmania major was transformed into the AroA- vaccine strain of Salmonella typhimurium (SL3261). The construct (SL3261-gp63), which stably expresses the gp63 Ag in vitro, was used to immunize CBA mice by the oral route. Spleen cells from mice inoculated with SL3261-gp63 developed antibody and proliferative T cell response to L. major. They did not express detectable delayed-type hypersensitivity reactivity. The activated T cells are mainly CD4+ and secrete IL-2 and IFN-gamma but no IL-4. The orally immunized mice developed significant resistance against a challenge L. major infection. We have, therefore, demonstrated the feasibility of oral vaccination against leishmaniasis and that the oral route of antigen delivery via the heterologous carrier may preferentially induce Th1 subsets of CD4+ cells.

Stable expression of foreign antigens from the chromosome of Salmonella typhimurium vaccine strains

A simple and versatile system has been developed using a new cloning vector which can serve as a vehicle for integrating DNA fragments, which direct the expression of heterologous antigens, into the aroC gene on the Salmonella chromosome. The system is based on Escherichia coli plasmid vectors which contain the DNA fragment, cloned from the chromosome of S. typhimurium C5, which encodes the aroC gene. The aroC gene was modified using synthetic oligodeoxyribonucleotides so that it contained several unique restriction sites into which DNA, directing the expression of heterologous antigens, could be cloned. DNA was integrated into the S. typhimurium chromosome at aroC by transferring the vectors into S. typhimurium polA mutants and allowing homologous recombination to occur between the cloned and chromosomal aroC genes. The vectors were used to integrate nucleotide sequences into the S. typhimurium chromosome which directed the expression of tetanus toxin fragment C and the Treponema pallidum lipoprotein. The expression of both antigens was detected by Western blotting.

Linkage in a family with X-linked Charcot-Marie-Tooth disease

The gene for the X-linked form of Charcot-Marie-Tooth disease (CMT Peroneal Muscular Atrophy, X-linked: McKusick No. 30280) has been shown in a single family to be linked to DXYS1 with a lod score of 4.55 at a recombination fraction of 0.03 and to PGK1 with a lod score of 3.34 at zero recombination. This is in agreement with previous work based on several families. Pooled data from this family and 7 previously reported families give a maximum lod score of 12.04 at theta max of 0.05 for linkage between CMTX and DXYS1 loci.