Understanding neutralising antibodies against SARS-CoV-2 and theirimplications in clinical practice

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) is a newly identified member of the coronavirus family that has caused the coronavirus disease 2019 (COVID-19) pandemic. This rapidly evolving and unrelenting SARS-CoV-2has disrupted the lives and livelihoods of millions worldwide. As of 23 August 2021, a total of 211,373,303 COVID-19cases have been confirmed globally with a death toll of 4,424,341. A strong understanding of the infection pathway of SARS-CoV-2, and how our immune system responds to the virus is highly pertinent for guiding the development and improvement of effective treatments. In this review, we discuss the current understanding of neutralising antibodies(NAbs) and their implications in clinical practice. The aspects include the pathophysiology of the immune response,particularly humoral adaptive immunity and the roles of NAbs from B cells in infection clearance. We summarise the onset and persistence of IgA, IgM and IgG antibodies, and we explore their roles in neutralising SARS-CoV-2, their persistence in convalescent individuals, and in reinfection. Furthermore, we also review the applications of neutralising antibodies in the clinical setting—from predictors of disease severity to serological testing to vaccinations, and finally in therapeutics such as convalescent plasma infusion.

Impact of lipids and lipoproteins on hepatitis C virus infection and virus neutralization

Hepatitis C virus(HCV)infections represent a major global health problem.End-stage liver disease caused by chronic HCV infection is a major indication for liver transplantation.However,after transplantation the engrafted liver inevitably becomes infected by the circulating virus.Direct acting antivirals are not yet approved for use in liver transplant patients,and limited efficacy and severe side effects hamper the use of pegylated interferon combined with ribavirin in a post-transplant setting.Therefore,alternative therapeutic options need to be explored.Viral entry represents an attractive target for such therapeutic intervention.Understanding the mechanisms of viral entry is essential to define the viral and cellular factors involved.The HCV life cycle is dependent of and associated with lipoprotein physiology and the presence of lipoproteins has been correlated with altered antiviral efficacy of entry inhibitors.In thisreview,we summarise the current knowledge on how lipoprotein physiology influences the HCV life cycle.We focus especially on the influence of lipoproteins on antibodies that target HCV envelope proteins or antibodies that target the cellular receptors of the virus.This information can be particularly relevant for the prevention of HCV re-infection after liver transplantation.

Optimization of L(+)-Lactic Acid Fermentation Without Neutralisation of Rhizopus Oryzae Mutant RK02 by Low-Energy Ion Implantation

In order to get an industrial strain which can yield a high concentration of lactic acid for ISPR （in situ product removal）, the original strain Rhizopus oryzae RE3303 was mutated by low-energy ion beam implantation. A mutant RK02 was screened, and the factors such as the substrate concentration, nitrogen source concentration, inoculum size, seed age, aeration and temperature that affect the production of lactic acid were studied in detail. Under optimal con- ditions, the maximum concentration of L（＋）-lactic acid reached 34.85 g/L after 30 h shake-flask cultivation without adding any neutralisation （5% Glucose added）, which was a 146% increase in lactic acid production after ion implantation compared with the original strain. It was also shown that RK02 can be used in ISPR to reduce the number of times of separation.

Field Trial of a Thermostable Peste des petits ruminants (PPR) Vaccine in a Semi-Arid Zone of Nigeria

The field trial of a candidate thermostable Peste des petits ruminants (PPR) vaccine was carried out in flocks of sheep and goats under the extensive system of management. The immune response of vaccinated animals was determined using the neutralisation test to detect PPR virus specific antibody. Vaccinated animals seroconverted and a four-fold or more rise in antibody titre were observed between pre-vaccination and post-vaccination antibodies. The vaccine elicited significant antibody response in goats through the different routes of administration (intramuscular, intranasal, intraocular, subcutaneous and orally), but was poorly transmitted between the vaccinees and in-contact animals. The sheep responded poorly to the vaccine administered through most of the routes, except for those vaccinated through intramuscular and subcutaneous routes that seroconverted significantly (≥4 fold rise). The vaccine retained a potent titre of 3.1 log10 TCID50 for more than 8 hours after reconstitution in PBS at room temperature. Based on the response of goats to oral vaccination, it is suggested that the vaccine could be administered on the field through the oral routes and has the potential to be adapted to a feed-based administration for wider application to the scattered livestock populations under the extensive system of management.