scholarly journals Recombinant Nipah Virus Vaccines Protect Pigs against Challenge

2006 ◽  
Vol 80 (16) ◽  
pp. 7929-7938 ◽  
Author(s):  
Hana M. Weingartl ◽  
Yohannes Berhane ◽  
Jeff L. Caswell ◽  
Sheena Loosmore ◽  
Jean-Christophe Audonnet ◽  
...  
Keyword(s):  
Real Time ◽  
Nipah Virus ◽  
Neutralizing Antibody ◽  
Rt Pcr ◽  
Challenge Virus ◽  
Virus Shedding ◽  
Challenge Control ◽  
Human Infections ◽  
Antibody Levels

ABSTRACT Nipah virus (NiV), of the family Paramyxoviridae, was isolated in 1999 in Malaysia from a human fatality in an outbreak of severe human encephalitis, when human infections were linked to transmission of the virus from pigs. Consequently, a swine vaccine able to abolish virus shedding is of veterinary and human health interest. Canarypox virus-based vaccine vectors carrying the gene for NiV glycoprotein (ALVAC-G) or the fusion protein (ALVAC-F) were used to intramuscularly immunize four pigs per group, either with 108 PFU each or in combination. Pigs were boosted 14 days postvaccination and challenged with 2.5 × 105 PFU of NiV two weeks later. The combined ALVAC-F/G vaccine induced the highest levels of neutralization antibodies (2,560); despite the low neutralizing antibody levels in the F vaccinees (160), all vaccinated animals appeared to be protected against challenge. Virus was not isolated from the tissues of any of the vaccinated pigs postchallenge, and a real-time reverse transcription (RT)-PCR assay detected only small amounts of viral RNA in several samples. In challenge control pigs, virus was isolated from a number of tissues (104.4 PFU/g) or detected by real-time RT-PCR. Vaccination of the ALVAC-F/G vaccinees appeared to stimulate both type 1 and type 2 cytokine responses. Histopathological findings indicated that there was no enhancement of lesions in the vaccinees. No virus shedding was detected in vaccinated animals, in contrast to challenge control pigs, from which virus was isolated from the throat and nose (102.9 PFU/ml). Based on the data presented, the combined ALVAC-F/G vaccine appears to be a very promising vaccine candidate for swine.

DETECTION AND DIFFERENTIATION OF THE VACCINE STRAIN AND FIELD ISOLATES OF DUCK HEPATITIS A VIRUS TYPE 1 USING REAL-TIME RT-PCR AND HIGH RESOLUTION MELTING ASSAYS

2015 ◽  
Vol 41 (04) ◽  
pp. 229-235
Author(s):  
Kuang-Po Li ◽  
Shan-Chia Ou ◽  
Jui-Hung Shien ◽  
Poa-Chun Chang
Keyword(s):  
High Resolution ◽  
Real Time ◽  
Virus Type ◽  
Vaccine Strain ◽  
Hepatitis A ◽  
High Resolution Melting ◽  
Hepatitis A Virus ◽  
Rt Pcr ◽  
Duck Hepatitis

Duck hepatitis A virus type 1 (DHAV-1) infection is a highly contagious and fatal disease of young ducklings. A live attenuated vaccine strain designated as 5886 has been used in Taiwan for the control of DHAV-1. Although several molecular biological methods are reported for diagnosis of DHAV-1 infection, none of them is able to discriminate between the vaccine strain and field viruses of DHAV-1. In the present study, a real-time reverse transcriptase polymerase chain reaction (RT-PCR) and high resolution melting (HRM) assay was developed for rapid detection and differentiation between the vaccine strain and field viruses of DHAV-1. This assay is highly specific for DHAV-1 and the detection limit is about 100 copies of the viral RNA. Experiments using fecal samples collected from ducklings experimentally infected with DHAV-1 showed that DHAV-1 could be detected in fecal samples as early as 6 h post-infection. In summary, a real-time RT-PCR and HRM assay is developed in this study and this assay could be valuable for diagnosis and surveillance of DHAV-1 infection in the field.

scholarly journals Multiplex real-time RT-PCR assay for bovine viral diarrhea virus type 1, type 2 and HoBi-like pestivirus

2016 ◽  
Vol 229 ◽  
pp. 1-7 ◽  
Author(s):  
Viviana Mari ◽  
Michele Losurdo ◽  
Maria Stella Lucente ◽  
Eleonora Lorusso ◽  
Gabriella Elia ◽  
...  
Keyword(s):  
Real Time ◽  
Bovine Viral Diarrhea Virus ◽  
Bovine Viral Diarrhea ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Diarrhea Virus ◽  
Viral Diarrhea ◽  
Viral Diarrhea Virus

scholarly journals SARS-CoV-2 Virus like Particles produced by a single recombinant baculovirus generate potent neutralizing antibody that protects against variant challenge

2021 ◽  
Author(s):  
Edward Sullivan ◽  
Po-yu Sung ◽  
Weining Wu ◽  
Neil Berry ◽  
Sarah Kempster ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Severe Disease ◽  
Expression System ◽  
Recombinant Baculovirus ◽  
Neutralizing Antibody ◽  
Structural Proteins ◽  
Lung Pathology ◽  
Challenge Virus ◽  
Virus Shedding ◽  
Virus Like Particles

The Covid-19 pandemic caused by SARS-CoV-2 infection has highlighted the need for the rapid generation of efficient vaccines for emerging disease. Virus-like particles, VLPs, are an established vaccine technology that produces virus-like mimics, based on expression of the structural proteins of a target virus that can stimulate strong neutralizing antibody responses. SARS-CoV-2 is a coronavirus where the basis of VLP formation has been shown to be the co-expression of the spike, membrane and envelope structural proteins. Here we describe the generation of SARS-CoV-2 VLPs by the co expression of the salient structural proteins in insect cells using the established baculovirus expression system. VLPs were heterologous ~100nm diameter enveloped particles with a distinct fringe that reacted strongly with SARS-CoV-2 convalescent sera. In a Syrian hamster challenge model, a non adjuvanted VLPs induced neutralizing antibodies to the VLP-associated Wuhan S protein, reduced virus shedding following a virulent challenge with SARS-CoV-2 (B.1.1.7 variant) and protected against disease associated weight loss. Immunized animals showed reduced lung pathology and lower challenge virus replication than the non-immunized controls. Our data, using an established and scalable technology, suggest SARS-CoV-2 VLPs offer an efficient vaccine that mitigates against virus load and prevents severe disease.

scholarly journals High prevalence of SARS-CoV-2 antibodies in care homes affected by COVID-19; a prospective cohort study in England

2020 ◽  
Author(s):  
Shamez N Ladhani ◽  
Anna J Jeffery-Smith ◽  
Monika Patel ◽  
Roshni Janarthanan ◽  
Jonathan Fok ◽  
...  
Keyword(s):  
Neutralizing Antibody ◽  
Care Homes ◽  
Rt Pcr ◽  
Staff Members ◽  
Institutional Settings ◽  
High Prevalence ◽  
Almost All ◽  
Antibody Levels ◽  
Very High

Background: We investigated six London care homes experiencing a COVID-19 outbreak and found very high rates of SARS-CoV-2 infection among residents and staff. Here we report follow-up serological analysis in these care homes five weeks later. Methods: Residents and staff had a convalescent blood sample for SARS-CoV-2 antibody levels and neutralising antibodies by SARS-COV-2 RT-PCR five weeks after the primary COVID-19 outbreak investigation. Results: Of the 518 residents and staff in the initial investigation, 208/241 (86.3%) surviving residents and 186/254 (73.2%) staff underwent serological testing. Almost all SARS-CoV-2 RT-PCR positive residents and staff were antibody positive five weeks later, whether symptomatic (residents 35/35, 100%; staff, 22/22, 100%) or asymptomatic (residents 32/33, 97.0%; staff 21/22, 95.1%). Symptomatic but SARS-CoV-2 RT-PCR negative residents and staff also had high seropositivity rates (residents 23/27, 85.2%; staff 18/21, 85.7%), as did asymptomatic RT-PCR negative individuals (residents 62/92, 67.3%; staff 95/143, 66.4%). Neutralising antibody was present in 118/132 (89.4%) seropositive individuals and was not associated with age or symptoms. Ten residents (10/108, 9.3%) remained RT-PCR positive, but with lower RT-PCR cycle threshold values; all 7 tested were seropositive. New infections were detected in three residents and one staff member. Conclusions: RT-PCR testing for SARS-CoV-2 significantly underestimates the true extent of an outbreak in institutional settings. Elderly frail residents and younger healthier staff were equally able to mount robust and neutralizing antibody responses to SARS-CoV-2. More than two-thirds of residents and staff members had detectable antibodies against SARS-CoV-2 irrespective of their nasal swab RT-PCR positivity or symptoms status.

scholarly journals Herpes Simplex Virus Type 1 Serum Neutralizing Antibody Titers Increase during Latency in Rabbits Latently Infected with Latency-Associated Transcript (LAT)-Positive but Not LAT-Negative Viruses

1999 ◽  
Vol 73 (11) ◽  
pp. 9669-9672 ◽  
Author(s):  
Guey-Chuen Perng ◽  
Susan M. Slanina ◽  
Ada Yukht ◽  
Homayon Ghiasi ◽  
Anthony B. Nesburn ◽  
...  
Keyword(s):  
Neutralizing Antibody ◽  
Wild Type Virus ◽  
Wild Type ◽  
Latently Infected ◽  
Antibody Titers ◽  
Simplex Virus ◽  
Antibody Levels ◽  
Spontaneous Reactivation ◽  
Hsv 1

ABSTRACT The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) gene is essential for efficient spontaneous reactivation in the rabbit ocular model of HSV-1 latency and reactivation. LAT is also the only viral gene abundantly expressed during latency. Rabbits were ocularly infected with the wild-type HSV-1 strain McKrae or the McKrae-derived LAT null mutantdLAT2903. Serum neutralizing antibody titers were determined at various times during acute and latent infection. The neutralizing antibody titers induced by both viruses increased and were similar throughout the first 45 days after infection (P > 0.05). However, by day 59 postinfection (approximately 31 to 45 days after latency had been established), the neutralizing antibody titers induced by wild-type virus anddLAT2903 diverged significantly (P = 0.0005). The dLAT2903-induced neutralizing antibody titers decreased, while the wild-type virus-induced neutralizing antibody titers continued to increase. A rescuant of dLAT2903, in which spontaneous reactivation was fully restored, induced wild-type neutralizing antibody levels on day 59 postinfection. A second LAT mutant with impaired spontaneous reactivation had neutralizing antibody levels comparable to those of dLAT2903. In contrast to the results obtained in rabbits, in mice, neutralizing antibody titers did not increase over time during latency with any of the viruses. Since LAT is expressed in both rabbits and mice during latency, the difference in neutralizing antibody titers between these animals is unlikely to be due to expression of a LAT protein during latency. In contrast, LAT-positive (LAT+), but not LAT-negative (LAT−), viruses undergo efficient spontaneous reactivation in rabbits, while neither LAT+ nor LAT−viruses undergo efficient spontaneous reactivation in mice. Thus, the increase in neutralizing antibody titers in rabbits latently infected with LAT+ viruses may have been due to continued restimulation of the immune system by spontaneously reactivating virus.

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