Serum from Nipah virus patients recognises recombinant viral proteins produced in Escherichia coli

The genes for Nipah virus (NiV) proteins were amplified from viral RNA, cloned into the plasmid pTriEx-3 Hygro, expressed, and purified using immobilized metal affinity chromatography. The recombinant N, F, and G NiV proteins (rNiV-N, rNiV-F, and rNiV-G), were successfully expressed in Escherichia coli and purified with a yield of 4, 16, and 4 mg/L, respectively. All 3 recombinant viral proteins reacted with all 19 samples of NiV-positive human sera. The rNiV-N and rNiV-G proteins were the most immunogenic. The recombinant viral proteins did not react with any of the 12 NiV-negative sera. However, serum from a patient with a late-onset relapsing NiV infection complication was found to be primarily reactive to rNiV-G only. Additionally, there is a distinctive variation in the profile of antigen-reactive bands between the sample from a case of relapsing NiV encephalitis and that of acute NiV infection. The overall findings of this study suggest that the recombinant viral proteins have the potential to be developed further for use in the detection of NiV infection, and continuous biosurveillance of NiV infection in resource-limited settings

Nipah Virus Infection of Immature Dendritic Cells Increases Its Transendothelial Migration Across Human Brain Microvascular Endothelial Cells

Nipah virus (NiV) can infect multiple organs in humans with the central nervous system (CNS) being the most severely affected. Currently, it is not fully understood how NiV spreads throughout the body. NiV has been shown to infect certain leukocyte populations and we hypothesized that these infected cells could cross the blood-brain barrier (BBB), facilitating NiV entry into the CNS. Here, three leukocyte types, primary immature dendritic cells (iDC), primary monocytes (pMO), and monocytic cell line (THP-1), were evaluated for permissiveness to NiV. We found only iDC and THP-1 were permissive to NiV. Transendothelial migration of mock-infected and NiV-infected leukocytes was then evaluated using an in vitro BBB model established with human brain microvascular endothelial cells (HBMEC). There was approximately a threefold increase in migration of NiV-infected iDC across endothelial monolayer when compared to mock-infected iDC. In contrast, migration rates for pMO and THP-1 did not change upon NiV infection. Across TNF-α-treated endothelial monolayer, there was significant increase of almost twofold in migration of NiV-infected iDC and THP-1 over mock-infected cells. Immunofluorescence analysis showed the migrated NiV-infected leukocytes retained their ability to infect other cells. This study demonstrates for the first time that active NiV infection of iDC and THP-1 increased their transendothelial migration activity across HBMEC and activation of HBMEC by TNF-α further promoted migration. The findings suggest that NiV infection of leukocytes to disseminate the virus via the "Trojan horse" mechanism is a viable route of entry into the CNS

Body weight and survival rate of immunized mice upon lethal challenge with influenza virus.

<p>Body weight and survival rate of immunized mice upon lethal challenge with influenza virus.</p

Body weight and survival rate of mice following lethal challenge with influenza virus.

<p>At 18 days following the last immunization, all mice in study group B were intranasally challenged with 10 LD₅₀ of H1N1/A/TN/1-560/2009-MA2 virus. (A) Body weight and (B) survival of mice orally immunized with PBS, LL-HA1/L/AcmA or HA1/L/AcmA, or subcutaneously immunized with HA1/L/AcmA-FA, was monitored daily for 14 days following virus challenge. The body weight of mice on the day of viral challenge was used as the baseline weight to determine the body weight changes post-viral challenge. Asterisks indicate statistically significant differences in comparison with the PBS-treated group (*p<0.05; **p<0.01; ***p<0.001).</p

MERS-CoV Seroconversion amongst Malaysian Hajj Pilgrims Returning from the Middle East, 2016-2018: Results from the MERCURIAL Multiyear Prospective Cohort Study

AbstractProspective cohort study to investigate the potential exposure to the Middle East Respiratory Syndrome-Coronavirus (MERS-CoV) following Hajj pilgrims is still very limited. Here, we report the antibody seroconversion study results obtained from successive three years cohort studies (2016-2018) involving the Malaysian Hajj pilgrims returning from the Middle East. A cohort study of Hajj pilgrims from Malaysia enrolled 2,863 participants from 2016-2018, all of whom consented to provide paired blood samples for both pre- and post-Hajj travel to the Middle East. ELISAs and micro-neutralization assays were performed to detect the presence of MERS-CoV IgG antibodies. Sociodemographic data, symptoms experienced during Hajj, and history of exposure to camels or camel products were recorded using structured pre- and post-Hajj questionnaires. A 4-fold increase in anti-MERS-CoV IgG between paired pre-Hajj and post-Hajj serum samples in twelve participants was observed. None of the twelve ELISA-positive sera had detectable levels of virus-neutralizing antibodies. All reportedly had mild symptoms of respiratory symptoms at a certain point during the pilgrimage, implying mild or asymptomatic infections. No association between post-Hajj serum positivity and a history of exposure to camels or camel products was obtained. Findings from the study suggest that serologic conversion to MERS-CoV occurred in at least 0.6% of the Hajj pilgrims returning from the Middle East. Since all the seroconvertants had mild to no symptoms during the sampling period, it highlights the likelihood of occurrence of only low infectivity spillover infections among the Hajj pilgrims