Immunogenicity and malaria transmission reducing potency of Pfs48/45 and Pfs25 encoded by DNA vaccines administered by intramuscular electroporation

Pfs48/45 and Pfs25 are leading candidates for the development of Plasmodium falciparum transmission blocking vaccines (TBV). Expression of Pfs48/45 in the erythrocytic sexual stages and presentation to the immune system during infection in the human host also makes it ideal for natural boosting. However, it has been challenging to produce a fully folded, functionally active Pfs48/45, using various protein expression platforms. In this study, we demonstrate that full-length Pfs48/45 encoded by DNA plasmids is able to induce significant transmission reducing immune responses. DNA plasmids encoding Pfs48/45 based on native (WT), codon optimized (SYN), or codon optimized and mutated (MUT1 and MUT2), to prevent any asparagine (N)-linked glycosylation were compared with or without intramuscular electroporation (EP). EP significantly enhanced antibody titers and transmission blocking activity elicited by immunization with SYN Pfs48/45 DNA vaccine. Mosquito membrane feeding assays also revealed improved functional immunogenicity of SYN Pfs48/45 (N-glycosylation sites intact) as compared to MUT1 or MUT2 Pfs48/45 DNA plasmids (all N-glycosylation sites mutated). Boosting with recombinant Pfs48/45 protein after immunization with each of the different DNA vaccines resulted in significant boosting of antibody response and improved transmission reducing capabilities of all four DNA vaccines. Finally, immunization with a combination of DNA plasmids (SYN Pfs48/45 and SYN Pfs25) also provides support for the possibility of combining antigens targeting different life cycle stages in the parasite during transmission through mosquitoes.

Human Polyclonal Antibodies Produced through DNA Vaccination of Transchromosomal Cattle Provide Mice with Post-Exposure Protection against Lethal Zaire and Sudan Ebolaviruses

DNA vaccination of transchromosomal bovines (TcBs) with DNA vaccines expressing the codon-optimized (co) glycoprotein (GP) genes of Ebola virus (EBOV) and Sudan virus (SUDV) produce fully human polyclonal antibodies (pAbs) that recognize both viruses and demonstrate robust neutralizing activity. Each TcB was vaccinated by intramuscular electroporation (IM-EP) a total of four times and at each administration received 10 mg of the EBOV-GP_co DNA vaccine and 10 mg of the SUDV-GP_co DNA vaccine at two sites on the left and right sides, respectively. After two vaccinations, robust antibody responses (titers > 1000) were detected by ELISA against whole irradiated EBOV or SUDV and recombinant EBOV-GP or SUDV-GP (rGP) antigens, with higher titers observed for the rGP antigens. Strong, virus neutralizing antibody responses (titers >1000) were detected after three vaccinations when measured by vesicular stomatitis virus-based pseudovirion neutralization assay (PsVNA). Maximal neutralizing antibody responses were identified by traditional plaque reduction neutralization tests (PRNT) after four vaccinations. Neutralizing activity of human immunoglobulins (IgG) purified from TcB plasma collected after three vaccinations and injected intraperitoneally (IP) into mice at a 100 mg/kg dose was detected in the serum by PsVNA up to 14 days after administration. Passive transfer by IP injection of the purified IgG (100 mg/kg) to groups of BALB/c mice one day after IP challenge with mouse adapted (ma) EBOV resulted in 80% protection while all mice treated with non-specific pAbs succumbed. Similarly, interferon receptor 1 knockout (IFNAR ^-/-) mice receiving the purified IgG (100 mg/kg) by IP injection one day after IP challenge with wild type SUDV resulted in 89% survival. These results are the first to demonstrate that filovirus GP DNA vaccines administered to TcBs by IM-EP can elicit neutralizing antibodies that provide post-exposure protection. Additionally, these data describe production of fully human IgG in a large animal system, a system which is capable of producing large quantities of a clinical grade therapeutic product.

Functional evaluation of malaria Pfs25 DNA vaccine by in vivo electroporation in olive baboons

Plasmodium falciparum Pfs25 antigen, expressed on the surface of zygotes and ookinetes, is one of the leading targets for the development of a malaria transmission-blocking vaccine (TBV). Our laboratory has been evaluating DNA plasmid based Pfs25 vaccine in mice and non-human primates. Previously, we established that in vivo electroporation (EP) delivery is an effective method to improve the immunogenicity of DNA vaccine encoding Pfs25 in mice. In order to optimize the in vivo EP procedure and test for its efficacy in more clinically relevant larger animal models, we employed in vivo EP to evaluate the immune response and protective efficacy of Pfs25 encoding DNA vaccine in nonhuman primates (olive baboons, Papio anubis). The results showed that at a dose of 2.5mg DNA vaccine, antibody responses were significantly enhanced with EP as compared to without EP resulting in effective transmission blocking efficiency. Similar immunogenicity enhancing effect of EP was also observed with lower doses (0.5mg and 1mg) of DNA plasmids. Further, final boosting with a single dose of recombinant Pfs25 protein resulted in dramatically enhanced antibody titers and significantly increased functional transmission blocking efficiency. Our study suggests priming with DNA vaccine via EP along with protein boost regimen as an effective method to elicit potent immunogenicity of malaria DNA vaccines in nonhuman primates and provides the basis for further evaluation in human volunteers.

A DNA vaccination regime including protein boost and electroporation protects cattle against foot-and-mouth disease

Protection against foot-and-mouth disease (FMD) using DNA technology has been documented for sheep and pigs but not for the highly susceptible species of cattle. Twenty-five Holstein Friesian cross-bred cattle were vaccinated twice, 21 days apart, with a DNA vaccine containing the capsid coding region (P1) along with the non-structural proteins 2A, 3C and 3D (pcDNA3.1/P1-2A3C3D) of O(1) Kaufbeuren alone or coated onto PLG (d,l-lactide-co-glycolide) microparticles. In some pcDNA3.1/P1-2A3C3D was also combined with an adjuvant plasmid expressing bovine granulocyte macrophage colony stimulating factor (GM-CSF). DNA vaccinations were administered intramuscularly with, or without, the use of electroporation and at 42 days post primary vaccination cattle received a protein boost of 146S FMD virus (FMDV) antigen and non-structural protein 3D. For comparison, four cattle were vaccinated with a conventional FMD vaccine and two more included as unvaccinated controls. Apart from those immunised with PLG microparticles all cattle were challenged with 10(5) TCID(50) cattle adapted O(1) Lausanne FMDV virus at day 93 post primary vaccination. All DNA vaccinated cattle regardless of regime developed good humoral and cell mediated responses prior to challenge. The best overall virus neutralising antibody, IFN-γ and clinical protection (75%) were seen in the cattle whereby the DNA was delivered by electroporation. In contrast, only 25% of cattle vaccinated with the DNA vaccine without electroporation were clinically protected. The addition of GM-CSF in combination with electroporation further improved the efficacy of the vaccine, as demonstrated from the reduction of clinical disease and virus excretions in nasal swabs. We thus demonstrate for the first time that cattle can be clinically protected against FMDV challenge following a DNA prime-protein boost strategy, and particularly when DNA vaccine is combined with GM-CSF and delivered by electroporation.

Delivery of a DNA vaccine for Alzheimer's disease by electroporation versus gene gun generates potent and similar immune responses

BACKGROUND

Induction of a humoral response against amyloid-β peptide may be beneficial for Alzheimer's disease (AD) patients and may alleviate the onset and progression of AD. DNA-based vaccination provides a unique alternative method of immunization for treatment and prevention of AD. Currently, the two major delivery methods used for enhancing DNA uptake and immune responses to DNA vaccines in humans are electroporation (EP) and gene gun (GG).

OBJECTIVE

The goal of this translational study was to evaluate the efficacy of an AD DNA epitope vaccine (DepVac) delivered intramuscularly by EP or intradermally by GG.

METHODS

Humoral and cellular immune responses to immunization with DepVac were evaluated by ELISA and ELISPOT, respectively. Functional activity of the antibodies was also assessed.

RESULTS

EP- and GG-mediated immunizations with DepVac induced similar anti-amyloid-β (Aβ) antibody and T cell responses. Anti-Aβ antibodies bound to amyloid plaques in AD brain tissue and to toxic forms of Aβ(42) peptide.

CONCLUSION

Both delivery methods are effective at promoting potent antibodies specific for Aβ.

Electroporation enhances immune responses and protection induced by a bovine viral diarrhea virus DNA vaccine in newborn calves with maternal antibodies

Bovine viral diarrhea virus (BVDV) is one of the major pathogens in cattle. In this study, newborn calves with maternal antibodies were vaccinated with a BVDV DNA vaccine, either by conventional intramuscular (IM) injection or with the TriGrid™ Delivery System for IM delivery (TDS-IM). The calves vaccinated with the TDS-IM developed more rapidly and effectively BVDV-specific humoral and cell-mediated immune responses in the presence of maternal antibodies. Overall, the immune responses induced by delivery with the TDS-IM remained stronger than those elicited by conventional IM injection of the BVDV DNA vaccine. Accordingly, electroporation-mediated delivery of the BVDV DNA vaccine resulted in close to complete protection from clinical signs of disease, while conventional IM administration did not fully prevent morbidity and mortality following challenge with BVDV-2. These results demonstrate the TDS-IM to be effective as a delivery system for a BVDV DNA vaccine in newborn calves in the presence of maternal antibodies, which supports the potential of electroporation as a delivery method for prophylactic DNA vaccines.

Enhancement of immune responses to an HBV DNA vaccine by electroporation

These studies document the ability of electroporation (EP)-based DNA vaccination to induce multi-specific CTL responses to hepatitis B virus (HBV) DNA vaccination in normal mice and marked immune responses to multivalent HBV DNA immunization in larger animal species. These results suggest that electroporation-mediated HBV DNA vaccination is worth pursuing as a treatment for chronic HBV infection.

The experience of collaboration: a comparison of health visiting in Scotland and Norway

This investigation compared health visiting in Scotland and Norway by focusing on collaboration in health visiting. The data are based upon in-depth interviews with a non-probability sample, with voluntary participation of nine health visitors from Scotland and 12 health visitors from Norway. The results showed that there were more similarities than differences between the Scottish and Norwegian health visitors' experience of collaboration in their work. Both groups had a complex role-set and experienced dependency on role partners. Collaborative strain was experienced through lack of recognition and system deficiencies. Tensions in collaboration evolved from the definition and question of responsibility in grey areas, jurisdictional threats and conflicts. Within these areas the degree and importance of collaboration differed. The Scottish health visitors were more dependent on client referrals to them and their referrals to other agencies, whereas the Norwegians health visitors experienced an asymmetrical relationship, as they were more dependent on the capacity of the agency to accept the referrals. Lack of recognition seemed to be a stronger experience in Norway than in Scotland. All of this had a marked influence on the performance of the health visitors. Further research should address the question of collaboration in health visiting work and to what degree it influences the quality of health visiting and consequences for clients, the community and health visiting service.

Health visiting in Scotland and Norway: commonalties and differences

This investigation compared health visiting in Scotland and Norway by focusing on health visitors' influence on management matters, work tasks and work conditions. The data are based upon in-depth interviews with nine health visitors from Scotland and 12 health visitors from Norway. The results showed more similarities than differences between the Scottish and Norwegian health visitors. Both groups experienced autonomy at work. The hardships of work were the lack of visibility for their work and an inability to demonstrate in measurable ways the effect of their work. Issues related to lack of time and priority of the newborn and young children were also similar as well as the experience of insecurity and strain at work. The differences were mostly within the area of organizational structure and its influence on management matters. While the Norwegian HV participated in plans for the service, employment and budget proposals, the Scottish HV was involved in these matters to a lesser degree. All in all, the similarity of the themes and the comparable units suggest the core of health visiting extends beyond the limits of cultural and national boundaries.

Changes in health visitors' work

AIMS

The purpose of this investigation is to describe Scottish health visitors (HVs) experience of changes in their work and compare these with their Norwegian counterparts.

BACKGROUND

The renewed emphasis on community health care, health promotion and illness prevention is a strong reason to focus on health visiting work. Knowledge about changes in practice are of special interest for nursing science as such knowledge could contribute to the development and advancement of the health visiting service.

DESIGN

The study used a comparative descriptive design. The data are based upon in-depth interviews with nine HVs from Scotland and 12 HVs from Norway.

RESULTS

The results showed similarities as well as differences. HVs in Scotland and Norway experienced changes in work load with decreases in some areas and increases in others, changes in work practice, approaches and techniques with more emphasis on clients' empowerment, and also fewer management positions held by nurses. The differences mainly related to the ways that the health visiting service had specialized and expanded. The aim of Scottish health visiting from 'cradle to grave' service was not adopted by the Norwegian HVs to the same extent. Scottish HVs specialized individually in some areas and used each other's competence to a much greater degree than the Norwegian HVs.

CONCLUSIONS

It appeared that the Scottish HVs had found a path where health visiting work aimed at illness prevention and health promotion for everyone was on the way to becoming a comprehensive service and a stronger and more integrated part of the health visiting service. This is a pathway that Norwegian HVs still have to pursue. The qualitative approach and the slightly different samples limited the possibility for generalizations. Further research should address the question of changes and patterns in health visiting work, of how the development came about, and what are the bases for the differences in specialization and expansion of the service. Secondly it should be asked to what degree the development influences the quality of health visiting and consequences for clients, community and health visiting service.

Empowered nurses? Nurses in Norway and the USA compared

This comparative study investigated to what degree nurses from two major university hospitals, one in the USA and one in Norway, experienced empowerment. Nurses' experiences of power were studied, as operationalized by Laschinger in her model and instruments. Laschinger's model is based on Kanter's theory of structural determinants of behaviour in organizations. The Norwegian sample consisted of 590 nurses with a response rate of 70.5%; the North American sample consisted of 135 nurses with a response rate of 55%. The results showed both similarities and differences. Formal power for both samples explained 51% of the variance of the overall empowerment, while informal and formal power explained 62%. The Norwegian nurses experienced slightly more informal power while the USA nurses experienced more formal power. There were significant differences, in each hospital, in items within the theoretical constructs, when cross-tabulated by demographic variables. Leadership position was the demographic variable that most clearly differentiated in both hospital samples, with more power for the leaders. The small differences between nurses from two hospitals in two different countries in developed parts of the world raises some questions. The importance, or lack of importance, of cultural and organizational differences might be one area for further exploration. Overall, the methodology is valuable for further testing of nurse empowerment in different settings, as well as in change and implementation studies.

Influence and leadership in community-based nursing in Norway

This study investigated the perception of influence and decision making among mid-level community-based nurses. Respondents were nurses and nurse leaders in public health nursing, home nursing, and nursing in nursing homes in the municipality. Nurses in three nursing services located within each municipality's Community Health Service in 72 municipalities were surveyed or interviewed. The results show that the leaders of the nursing service and nurses in the three services are regarded as having influence, and in fact, possess more influence on the decision process than the administrative leaders and political management. There are great differences in the perception of decision making among the leaders of the nursing service and nurses in the three services. The leader of the health visiting service has less influence on decision making than the leader of the nursing home, while the health visitor has more influence on decision making and autonomy in professional work than the nurse in the nursing home. These differences might be explained by contextual factors such as tradition, gender, and work process.

Jurisdiction in community nursing services

This article focuses on community-health nursing services and their jurisdiction in Norway. The aim of the study was to analyze and gain a better understanding of community-nursing services' jurisdiction and jurisdictional pressure. The areas of investigation were degree of jurisdictional control, pattern of pressure in the jurisdiction, and nurses' strategies to deal with this pressure. The respondents were nurses in public health nursing service, home nursing service, and nursing homes. The results showed that nurses in the three different community-nursing services had different degrees of formal and informal control in their jurisdictions. Patterns of pressure were visible both inside and outside of the jurisdiction. Jurisdictional pressure led to strategies that strengthened control of the work, fortified professional status, or both.

Re-mediastinoscopy in the assessment of resectability of lung cancer

OBJECTIVE

Thirty-one patients underwent re-mediastinoscopy in the diagnostic assessment of lung cancer. The reason for a repeat mediastinoscopy was either a negative result at the first operation in spite of CT indication of enlarged nodes or an incomplete first mediastinoscopy.

METHODS

All patients underwent a conventional mediastinoscopy.

RESULTS

In 22 patients with enlarged mediastinal lymph nodes at computed tomography, 10 had a positive lymph node histology at re-mediastinoscopy, while 12 were negative. In 9 patients with no enlarged mediastinal nodes at CT scan, but incomplete biopsies at the first mediastinoscopy, 1 patient had lymph node metastases. The median duration from the first to the second mediastinoscopy was 43 days. No major complications occurred. The staging of the patients was greatly affected by the re-mediastinoscopy. Of 31 patients judged as operable according to the initial mediastinoscopy only 60% were found to be operable following the second mediastinoscopy.

CONCLUSION

This study has demonstrated the value of re-mediastinoscopy in assessment of resectability of lung cancer.

Facial palsy in acute otitis media

During the 17-year period from 1977 to 1994 a total of 23 patients in Copenhagen County were admitted to hospital with facial palsy, developed during acute otitis media. This corresponds to an annual incidence of 2.3 per million inhabitants. In the pre-antibiotic era it was estimated that 0.5% of patients with acute otitis media developed facial palsy. Our figures indicate a decrease of this complication by a factor of 100, to 0.005%. Although fourteen of the patients were children, the risk of an acute otitis media being complicated by facial palsy seems to be highest in adults (who have a low incidence of acute otitis media). All the children were < or = 3 years of age and 2/3 of the adults > or = 50 years of age. Complete remission was seen in all patients, except one. The time interval to complete remission was correlated significantly with the degree of the facial palsy on admission, as it was longest in the most severe facial palsies.