Development of a dual immunochromatographic test strip to detect E2 and Erns antibodies against classical swine fever

Background

It is essential to consider a practical antibody test to successfully implement marker vaccines and validate vaccination efficacy against classical swine fever virus (CSFV). The test should include a serological antibody assay, combined with a tool for differentiating infected from vaccinated animals (DIVA). The immunochromatographic test strip (ICS) has been exclusively designed for detecting CSFV E2 antibodies while lacking in detecting Erns antibodies, which can be employed and satisfy DIVA strategy. This study developed a novel ICS for detecting CSFV E2/Erns dual-antibody. The effectiveness of ICS in evaluating the DIVA capability of two novel chimeric pestivirus vaccine candidates was assessed.

Methods

Recombinant E2 or Erns protein was transiently expressed in the plant benthamiana using Agrobacterium tumefaciens. ICS was subsequently assembled, and goat anti-rabbit IgG and recombinant CSFV E2 or Erns protein were plated onto the nitrocellulose membrane as control and test lines, respectively. The sensitivity and specificity of ICS were evaluated using sera with different neutralizing antibody titers or positive for antibodies against CSFV and other pestiviruses. The coincidence rates for detecting E2 and Erns antibodies between ICS and commercial enzyme-linked immunosorbent assay (ELISA) kits were also computed. ICS performance for DIVA capability was evaluated using sera from pigs vaccinated with conventional vaccine or chimeric vaccine candidates.

Results

E2 and Erns proteins were successfully expressed in N. benthamiana-produced recombinant proteins. ICS demonstrated high sensitivity in identifying CSFV E2 and Erns antibodies, even at the low neutralizing antibody titers. No cross-reactivity with antibodies from other pestiviruses was confirmed using ICS. There were high agreement rates of 93.0 and 96.5% between ICS and two commercial ELISA kits for E2 antibody testing. ICS also achieved strong coincidence rates of 92.9 and 89.3% with two ELISA kits for Erns antibody detection. ICS confirmed the absence of CSFV Erns-specific antibodies in sera from pigs vaccinated with chimeric vaccine candidates.

Conclusion

E2 and Erns proteins derived from the plant showed great potential and can be used to engineer a CSFV E2/Erns dual-antibody ICS. The ICS was also highly sensitive and specific for detecting CSFV E2 and Erns antibodies. Significantly, ICS can fulfill the DIVA concept by incorporating chimeric vaccine candidates.

Generation and Efficacy of Two Chimeric Viruses Derived from GPE- Vaccine Strain as Classical Swine Fever Vaccine Candidates

A previous study proved that vGPE^- mainly maintains the properties of classical swine fever (CSF) virus, which is comparable to the GPE^- vaccine seed and is a potentially valuable backbone for developing a CSF marker vaccine. Chimeric viruses were constructed based on an infectious cDNA clone derived from the live attenuated GPE^- vaccine strain as novel CSF vaccine candidates that potentially meet the concept of differentiating infected from vaccinated animals (DIVA) by substituting the glycoprotein E^rns of the GPE^- vaccine strain with the corresponding region of non-CSF pestiviruses, either pronghorn antelope pestivirus (PAPeV) or Phocoena pestivirus (PhoPeV). High viral growth and genetic stability after serial passages of the chimeric viruses, namely vGPE^-/PAPeV E^rns and vGPE^-/PhoPeV E^rns, were confirmed in vitro. In vivo investigation revealed that two chimeric viruses had comparable immunogenicity and safety profiles to the vGPE^- vaccine strain. Vaccination at a dose of 10^4.0 TCID₅₀ with either vGPE^-/PAPeV E^rns or vGPE^-/PhoPeV E^rns conferred complete protection for pigs against the CSF virus challenge in the early stage of immunization. In conclusion, the characteristics of vGPE^-/PAPeV E^rns and vGPE^-/PhoPeV E^rns affirmed their properties, as the vGPE^- vaccine strain, positioning them as ideal candidates for future development of a CSF marker vaccine.

Unperceived treatment gaps in acute coronary syndromes

BACKGROUND

Despite a strong evidence-base for several therapies recommended in the management of acute coronary syndromes (ACS), many patients do not receive these therapies. The barriers preventing translation of evidence into practice are incompletely understood. The aim of this study was to survey clinicians regarding barriers to implementing recommendations of recently published national clinical guidelines and to determine the extent to which these impact clinical practice.

METHODS

A survey of clinicians at hospitals included in Australian Collaborative Acute Coronary Syndromes Prospective Audit (ACACIA, n = 3402, PML0051) was conducted, measuring self-stated knowledge, beliefs and guideline-concordant behaviours in relation to their care of ACS patients. Correlations between individual respondents' self-estimated rates and clinician's institutional rates of guideline-concordant behaviours were performed.

RESULTS

Most respondents (n = 50/86, 58%) were aware of current guidelines and their scope, achieving 7/10 (Interquartile Range (IQR) = 2) median score on knowledge questions. Belief in benefits and agreement with guideline-recommended therapy was high. However, none of these factors correlated with increased use of guideline therapies. Apart from clopidogrel (r(s) = 0.28, p < 0.01) and early interventional therapy for high-risk non-ST elevation myocardial infarction (r(s) = 0.31, p < 0.01), there were no significant correlations between individual clinicians' self-estimated rates of guideline-concordant practice and rates recorded in ACACIA data for their respective institution.

CONCLUSION

Beliefs about practice do not match actual practice. False beliefs regarding levels of evidence-based practice may contribute to inadequate implementation of evidence-based guidelines. Strategies such as continuous real-time audit and feedback of information for the delivery of care may help clinicians understand their levels of practice better and improve care.

Improving the management of acute coronary syndromes in Australia: translating evidence to outcomes

Cardiovascular disease imposes a heavy burden of morbidity and mortality on the Australian community. This situation is likely to exacerbate as the number of elderly Australians increase. Management of acute coronary syndromes (ACS) is underpinned by a robust evidence base, which is outlined in clinical practice guidelines. Yet, despite wide diffusion of guidelines, many Australians who experience acute coronary syndromes do not receive optimal care. This article reviews what we have learnt from previous quality improvement initiatives and discusses what we need to know to improve acute coronary syndromes management in Australia.

Visual outcomes following lensectomy and vitrectomy for combined anterior and posterior persistent hyperplastic primary vitreous

OBJECTIVE

To determine the visual outcome after surgery for persistent hyperplastic primary vitreous using modern vitreoretinal techniques.

DESIGN

Retrospective medical record review during a 5-year period (June 1992 to June 1997). Information recorded for each patient included age, medical history, sex, results of preoperative ocular examination, age at diagnosis, procedure performed, intraoperative and postoperative complications, location and number of sclerotomy sites, type of aphakic rehabilitation, amblyopic therapy given, final visual acuity, and length of follow-up.

RESULTS

Fourteen patients who underwent surgical management of combined anterior and posterior persistent hyperplastic primary vitreous were identified. Eleven patients underwent aphakic rehabilitation and aggressive amblyopic therapy consisting of occlusive therapy for several waking hours each day. One additional older patient received aphakic rehabilitation only. Ten eyes (71%) achieved a visual acuity of 20/300 or better, and 8 (57%) obtained a final visual acuity of 20/100 or better. Average length of follow-up was 22 months (range, 4-57 months). Nine patients were fitted with an aphakic soft contact lens, 2 older patients had a posterior chamber intraocular lens placed at the time of vitrectomy, and 1 patient wore aphakic spectacles.

CONCLUSIONS

With modern vitreoretinal techniques, aphakic rehabilitation, and aggressive amblyopic therapy, useful vision can be obtained in the majority of patients with combined anterior and posterior persistent hyperplastic primary vitreous.

Regeneration of T lymphocytes from human bone marrow cells after depletion with methylprednisolone

This study evaluates the propagation of T lymphocytes in bone marrow cells after in vitro methylprednisolone treatment. Previous studies from this laboratory showed that immunocompetent T lymphocytes could be eliminated from the bone marrow cells by incubation with 15 mg/ml (0.04 M) of methylprednisolone for 1 hr. The effectiveness of the chemoseparation was assessed by E-rosette forming cell assay, mitogen-induced lymphoblastogenic responses, and lymphocyte surface markers. In this study, bone marrow cells treated with different concentrations of methylprednisolone were cultured in the presence of PHA and Interleukin-2. The mitogen-induced lymphoblastogenesis was restored in the 15 mg/ml MP-treated bone marrow cells by the 8th day of culture in the presence of Interleukin-2. The cells in the culture were analyzed by E-rosette forming cell assay. It was shown that the predominant cells in the cultures were E-rosette forming cells. This study demonstrates that immunocompetent T lymphocytes can be regenerated in the presence of mitogen and Interleukin-2 from bone marrow cells treated with 15 mg/ml of methylprednisolone.