Heterologous protection elicited by candidate monomeric recombinant HIV-1 gp120 vaccine in the absence of cross neutralising antibodies in a macaque model.

BACKGROUND: Current data suggest that an efficacious human immunodeficiency virus type 1 (HIV-1) vaccine should elicit both adaptive humoral and cell mediated immune responses. Such a vaccine will also need to protect against infection from a range of heterologous viral variants. Here we have developed a simian-human immunodeficiency virus (SHIV) based model in cynomolgus macaques to investigate the breadth of protection conferred by HIV-1W61D recombinant gp120 vaccination against SHIVsbg and SHIVSF33 challenge, and to identify correlates of protection. RESULTS: High titres of anti-envelope antibodies were detected in all vaccinees. The antibodies reacted with both the homologous HIV-1W61D and heterologous HIV-1IIIB envelope rgp120 which has an identical sequence to the SHIVsbg challenge virus. Significant titres of virus neutralising antibodies were detected against SHIVW61D expressing an envelope homologous with the vaccine, but only limited cross neutralisation against SHIVsbg, SHIV-4 and SHIVSF33 was observed. Protection against SHIVsbg infection was observed in vaccinated animals but none was observed against SHIVSF33 challenge. Transfer of immune sera from vaccinated macaques to naive recipients did not confer protection against SHIVsbg challenge. In a follow-up study, T cell proliferative responses detected after immunisation with the same vaccine against a single peptide present in the second conserved region 2 of HIV-1 W61D and HIV-1 IIIB gp120, but not SF33 gp120. CONCLUSIONS: Following extended vaccination with a HIV-1 rgp120 vaccine, protection was observed against heterologous virus challenge with SHIVsbg, but not SHIVSF33. Protection did not correlate with serological responses generated by vaccination, but might be associated with T cell proliferative responses against an epitope in the second constant region of HIV-1 gp120. Broader protection may be obtained with recombinant HIV-1 envelope based vaccines formulated with adjuvants that generate proliferative T cell responses in addition to broadly neutralising antibodies.

Advanced practice nursing students: pilot test of a simulation scenario.

In the current educational environment, increasing numbers of advanced practice nursing (APN) students compete for decreasing numbers of clinical sites where patient safety is paramount. Clinical simulations with high-fidelity human patient simulators provide APN students opportunities to demonstrate clinical skills and judgment in a safe supportive environment. Development, implementation, and preliminary evaluation of a scenario for APN students are discussed. Faculty and student evaluations are reviewed as well as recommendations for future simulations.

An optimised patient information sheet did not significantly increase recruitment or retention in a falls prevention study: an embedded randomised recruitment trial.

BACKGROUND: Randomised controlled trials are generally regarded as the 'gold standard' experimental design to determine the effectiveness of an intervention. Unfortunately, many trials either fail to recruit sufficient numbers of participants, or recruitment takes longer than anticipated. The current embedded trial evaluates the effectiveness of optimised patient information sheets on recruitment of participants in a falls prevention trial. METHODS: A three-arm, embedded randomised methodology trial was conducted within the National Institute for Health Research-funded REducing Falls with ORthoses and a Multifaceted podiatry intervention (REFORM) cohort randomised controlled trial. Routine National Health Service podiatry patients over the age of 65 were randomised to receive either the control patient information sheet (PIS) for the host trial or one of two optimised versions, a bespoke user-tested PIS or a template-developed PIS. The primary outcome was the proportion of patients in each group who went on to be randomised to the host trial. RESULTS: Six thousand and nine hundred patients were randomised 1:1:1 into the embedded trial. A total of 193 (2.8%) went on to be randomised into the main REFORM trial (control n = 62, template-developed n = 68; bespoke user-tested n = 63). Information sheet allocation did not improve recruitment to the trial (odds ratios for the three pairwise comparisons: template vs control 1.10 (95% CI 0.77-1.56, p = 0.60); user-tested vs control 1.01 (95% CI 0.71-1.45, p = 0.94); and user-tested vs template 0.92 (95% CI 0.65-1.31, p = 0.65)). CONCLUSIONS: This embedded methodology trial has demonstrated limited evidence as to the benefit of using optimised information materials on recruitment and retention rates in the REFORM study. TRIAL REGISTRATION: International Standard Randomised Controlled Trials Number registry, ISRCTN68240461 . Registered on 01 July 2011.

Clinical effectiveness and cost-effectiveness of a multifaceted podiatry intervention for falls prevention in older people: a multicentre cohort randomised controlled trial (the REducing Falls with ORthoses and a Multifaceted podiatry intervention trial).

BACKGROUND: Falls are a serious cause of morbidity and cost to individuals and society. Evidence suggests that foot problems and inappropriate footwear may increase the risk of falling. Podiatric interventions could help reduce falls; however, there is limited evidence regarding their clinical effectiveness and cost-effectiveness. OBJECTIVES: To determine the clinical effectiveness and cost-effectiveness of a multifaceted podiatry intervention for preventing falls in community-dwelling older people at risk of falling, relative to usual care. DESIGN: A pragmatic, multicentred, cohort randomised controlled trial with an economic evaluation and qualitative study. SETTING: Nine NHS trusts in the UK and one site in Ireland. PARTICIPANTS: In total, 1010 participants aged ≥ 65 years were randomised (intervention, n = 493; usual care, n = 517) via a secure, remote service. Blinding was not possible. INTERVENTIONS: All participants received a falls prevention leaflet and routine care from their podiatrist and general practitioner. The intervention also consisted of footwear advice, footwear provision if required, foot orthoses and foot- and ankle-strengthening exercises. MAIN OUTCOME MEASURES: The primary outcome was the incidence rate of falls per participant in the 12 months following randomisation. The secondary outcomes included the proportion of fallers and multiple fallers, time to first fall, fear of falling, fracture rate, health-related quality of life (HRQoL) and cost-effectiveness. RESULTS: The primary analysis consisted of 484 (98.2%) intervention and 507 (98.1%) usual-care participants. There was a non-statistically significant reduction in the incidence rate of falls in the intervention group [adjusted incidence rate ratio 0.88, 95% confidence interval (CI) 0.73 to 1.05; p = 0.16]. The proportion of participants experiencing a fall was lower (50% vs. 55%, adjusted odds ratio 0.78, 95% CI 0.60 to 1.00; p = 0.05). No differences were observed in key secondary outcomes. No serious, unexpected and related adverse events were reported. The intervention costs £252.17 more per participant (95% CI -£69.48 to £589.38) than usual care, was marginally more beneficial in terms of HRQoL measured via the EuroQoL-5 Dimensions [mean quality-adjusted life-year (QALY) difference 0.0129, 95% CI -0.0050 to 0.0314 QALYs] and had a 65% probability of being cost-effective at the National Institute for Health and Care Excellence threshold of £30,000 per QALY gained. The intervention was generally acceptable to podiatrists and trial participants. LIMITATIONS: Owing to the difficulty in calculating a sample size for a count outcome, the sample size was based on detecting a difference in the proportion of participants experiencing at least one fall, and not the primary outcome. We are therefore unable to confirm if the trial was sufficiently powered for the primary outcome. The findings are not generalisable to patients who are not receiving podiatry care. CONCLUSIONS: The intervention was safe and potentially effective. Although the primary outcome measure did not reach significance, a lower fall rate was observed in the intervention group. The reduction in the proportion of older adults who experienced a fall was of borderline statistical significance. The economic evaluation suggests that the intervention could be cost-effective. FUTURE WORK: Further research could examine whether or not the intervention could be delivered in group sessions, by physiotherapists, or in high-risk patients. TRIAL REGISTRATION: Current Controlled Trials ISRCTN68240461. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 24. See the NIHR Journals Library website for further project information.

The REFORM study protocol: a cohort randomised controlled trial of a multifaceted podiatry intervention for the prevention of falls in older people.

INTRODUCTION: Falls and fall-related injuries are a serious cause of morbidity and cost to society. Foot problems and inappropriate footwear may increase the risk of falls; therefore podiatric interventions may play a role in reducing falls. Two Cochrane systematic reviews identified only one study of a podiatry intervention aimed to reduce falls, which was undertaken in Australia. The REFORM trial aims to evaluate the clinical and cost-effectiveness of a multifaceted podiatry intervention in reducing falls in people aged 65 years and over in a UK and Irish setting. METHODS AND ANALYSIS: This multicentre, cohort randomised controlled trial will recruit 2600 participants from routine podiatry clinics in the UK and Ireland to the REFORM cohort. In order to detect a 10% point reduction in falls from 50% to 40%, with 80% power 890 participants will be randomised to receive routine podiatry care and a falls prevention leaflet or routine podiatry care, a falls prevention leaflet and a multifaceted podiatry intervention. The primary outcome is rate of falls (falls/person/time) over 12 months assessed by patient self-report falls diary. Secondary self-report outcome measures include: the proportion of single and multiple fallers and time to first fall over a 12-month period; Short Falls Efficacy Scale-International; fear of falling in the past 4 weeks; Frenchay Activities Index; fracture rate; Geriatric Depression Scale; EuroQoL-five dimensional scale 3-L; health service utilisation at 6 and 12 months. A qualitative study will examine the acceptability of the package of care to participants and podiatrists. ETHICS AND DISSEMINATION: The trial has received a favourable opinion from the East of England-Cambridge East Research Ethics Committee and Galway Research Ethics Committee. The trial results will be published in peer-reviewed journals and at conference presentations. TRIAL REGISTRATION NUMBER: Current Controlled Trials ISRCTN68240461 assigned 01/07/2011.

Resistance to superinfection by a vigorously replicating, uncloned stock of simian immunodeficiency virus (SIVmac251) stimulates replication of a live attenuated virus vaccine (SIVmacC8).

Vaccination with live attenuated simian immunodeficiency virus (SIVmacC8) confers potent, reproducible protection against homologous wild-type virus challenge (SIVmacJ5). The ability of SIVmacC8 to confer resistance to superinfection with an uncloned ex vivo derivative of SIVmac251 (SIVmac32H/L28) was investigated. In naïve, Mauritian-derived cynomolgus macaques (Macaca fascicularis), SIVmac32H/L28 replicated to high peak titres (>10(8) SIV RNA copies ml(-1)), persisted at high levels and induced distinctive pathology in lymphoid tissues. In cynomolgus macaques vaccinated with SIVmacC8, no evidence of detectable superinfection was observed in 3/8 vaccinates following challenge 3 or 20 weeks later with SIVmac32H/L28. Analyses after SIVmac32H/L28 challenge revealed a significant reduction in viral RNA (P<0.001) and DNA levels between 20 week vaccinates and challenge controls. Amongst 3 week vaccinates, less potent protection was observed. However, analysis of env from breakthrough virus indicated >99% sequence similarity with the vaccine virus. Highly sensitive PCR assays that distinguish vaccine and challenge virus stocks demonstrated restimulation of replication of the vaccine virus SIVmacC8 in the face of potent protection against a vigorous, homologous challenge virus. Vaccine-induced antiviral neutralizing antibodies and anti-Nef CD8+ cytotoxic T cell responses did not correlate with the outcome of the challenge. Defining the mechanism of vaccine protection will need to account for the effective control of a genetically closely related challenge virus whilst remaining unable to suppress replication of the pre-existing vaccine virus. The role of innate and intrinsic anti-retroviral immunity in the protection conferred by live attenuated SIV vaccines warrants careful study.

CD8+ lymphocytes do not mediate protection against acute superinfection 20 days after vaccination with a live attenuated simian immunodeficiency virus.

In order to test the hypothesis that CD8+ cytotoxic T lymphocytes mediate protection against acute superinfection, we depleted >99% of CD8+ lymphocytes in live attenuated simian immunodeficiency virus macC8 (SIVmacC8) vaccinees from the onset of vaccination, maintained that depletion for 20 days, and then challenged with pathogenic, wild-type SIVmacJ5. Vaccinees received 5 mg per kg of humanized anti-CD8 monoclonal antibody (MAb) 1 h before inoculation, followed by the same dose again on days 3, 7, 10, 13, and 17. On day 13, peripheral CD8+ T lymphocytes were >99% depleted in three out of four anti-CD8 MAb-treated vaccinees. At this time attenuated SIVmacC8 viral RNA loads in anti-CD8 MAb-treated vaccinees were significantly higher than control vaccinees treated contemporaneously with nonspecific human immunoglobulin. Lymphoid tissue CD8+ T lymphocyte depletion was >99% in three out of four anti-CD8 MAb-treated vaccinees on the day of wild-type SIVmacJ5 challenge. All four control vaccinees and three out of four anti-CD8 MAb-treated vaccinees were protected against detectable superinfection with wild-type SIVmacJ5. Although superinfection with wild-type SIVmacJ5 was detected at postmortem in a single anti-CD8 MAb-treated vaccinee, this did not correlate with the degree of preceding CD8+ T lymphocyte depletion. Clearance of attenuated SIVmacC8 viremia coincided with recovery of normal CD8+ T lymphocyte counts between days 48 and 76. These results support the view that cytotoxic T lymphocytes are important for host-mediated control of SIV primary viremia but do not indicate a central role in protection against acute superinfection conferred by inoculation with live attenuated SIV.

In situ hybridization and immunolabelling study of the early replication of simian immunodeficiency virus (SIVmacJ5) in vivo.

The distribution of virus-infected cells in cynomolgus macaques was determined at 4, 7, 14 and 28 days following intravenous challenge with 1000 TCID(50) of the wild-type simian immunodeficiency virus SIVmacJ5 (stock J5C). At each time-point, pairs of macaques were killed humanely and the presence of SIV was determined and quantified in blood, spleen, peripheral and mesenteric lymph nodes, thymus, lung and ileum by virus co-cultivation with C8166 cells, by quantitative DNA PCR or by in situ hybridization (ISH). At day 4 post-infection (p.i.), detection of the virus was sporadic. By day 7 p.i., however, significant SIV loads were detected in the blood and lymphoid tissues by DNA PCR and virus co-cultivation. Large numbers of cells expressing SIV RNA were detected in mesenteric lymph nodes by ISH and significantly fewer (P<0.05) in the spleen. Significant numbers of ISH-positive cells were also observed in sections of ileum. By day 14 p.i., the distribution of SIV was more even in all lymphoid tissues analysed. By day 28, most of the tissues were negative by ISH, but all remained positive by virus isolation and DNA PCR. Immunolabelling of sections of mesenteric lymph node with monoclonal antibodies specific for SIV envelope and Nef largely confirmed the observations from ISH. These results indicate that, even following intravenous challenge, a major site of the initial replication of SIV is gut-associated lymphoid tissue. Vaccines that induce protection at this site may therefore be superior, even against parenteral challenge.

Vaccination with live attenuated simian immunodeficiency virus for 21 days protects against superinfection.

The identification of mechanisms that prevent infection with human immunodeficiency virus (HIV) or simian immunodeficiency virus (SIV) would facilitate the development of an effective AIDS vaccine. In time-course experiments, protection against detectable superinfection with homologous wild-type SIV was achieved within 21 days of inoculation with live attenuated SIV, prior to the development of detectable anti-SIV humoral immunity. Partial protection against superinfection was achieved within 10 days of inoculation with live attenuated SIV, prior to the development of detectable anti-SIV humoral and cellular immunity. Furthermore, co-inoculation of live attenuated SIV with wild-type SIV resulted in a significant reduction in peak virus loads compared to controls that received wild-type SIV alone. These findings imply that innate immunity or non-immune mechanisms are a significant component of early protection against superinfection conferred by inoculation with live attenuated SIV.

Mechanisms of protection induced by attenuated simian immunodeficiency virus.

To determine whether attenuated simian immunodeficiency virus (SIV) vaccines confer protection against superinfection via secondary cellular immune responses, we searched for markers of immune activation following rechallenge. Productive infection with either attenuated SIVmacC8 or wild-type SIVmacJ5 resulted in a transient increase in T-lymphocyte CD25 and Mafa-DR expression. A pronounced increase in the frequency of FAS+ CD8+ lymphocytes was observed following SIVmacJ5 infection only. A transient increase in lymphocytes positive for intracellular IFN-gamma and IL-4 was observed following primary infection with either virus. In contrast, lymphocytes positive for intracellular IL-2 were reduced. Following SIVmacJ5 challenge of SIVmacC8-infected vaccinees, no evidence of detectable superinfection was obtained. Rechallenge of vaccinees did not alter the frequency of activated peripheral T-lymphocytes, perturb cytokine profiles, or generate an anamnestic antibody response. These data do not support the hypothesis that protection conferred by live attenuated SIV is mediated by the induction of vigorous T-cell responses upon rechallenge.