Perspective: Reducing SARS-CoV2 Infectivity and Its Associated Immunopathology

Can the triumph of mRNA vaccines against COVID-19 be extended to other viral infections of humans and domesticated animals?

The unprecedented success of mRNA vaccines in managing the COVID-19 pandemic raises the prospect of applying the mRNA platform to other viral diseases of humans and domesticated animals, which may lead to more efficacious vaccines for some agents. We briefly discuss reasons why mRNA vaccines achieved such success against COVID-19 and indicate what other virus infections and disease conditions might also be ripe for control using mRNA vaccines. We also evaluate situations where mRNA could prove valuable to rebalance the status of immune responsiveness and achieve success as a therapeutic vaccine approach against infections that induce immunoinflammatory lesions.

Robust anti-SARS-CoV2 single domain antibodies cross neutralize multiple viruses

We report robust SARS-CoV2 neutralizing sdAbs targeting the viral peptides encompassing the polybasic cleavage site (CSP) and in the receptor binding domain (RBD) of the spike (S) protein. Both the sdAbs inhibited infectivity of the CoV2 S protein expressing pseudoviruses (LV-CoV2S). Both anti-CSP and RBD intrabodies (IB) inhibited the output of LV(CoV2 S). Anti-CSP IB altered the proteolytic processing and targeted the viral S protein for degradation. Because of cross-reactive CSPs in the entry mediators, the anti-CSP sdAb neutralized in vitro and in vivo the infectivity of SARS-CoV2 unrelated viruses such as herpes simplex virus 1 (HSV1) and pestes des petits ruminants virus (PPRV). Conversely, anti-HSV1 and anti-PPRV sera neutralized LV(CoV2 S) owing to the presence of CSP reactive antibodies indicating that a prior infection with such pathogens could impact on the pattern of COVID-19.

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Anti-CSP and anti-RBD sdAb efficiently neutralized LV (SARS-CoV2 S) pseudoviruses

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Both intrabodies prevented the biogenesis of SARS-CoV2-S pseudovirions

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Anti-CSP sdAb neutralized viruses such as HSV1 and PPRV

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Anti-HSV1 and anti-PPRV sera neutralized LV(CoV2 S) pseudoviruses

A Novel Potent Carrier for Unconventional Protein Export in Ustilago maydis

Recombinant proteins are ubiquitously applied in fields like research, pharma, diagnostics or the chemical industry. To provide the full range of useful proteins, novel expression hosts need to be established for proteins that are not sufficiently produced by the standard platform organisms. Unconventional secretion in the fungal model Ustilago maydis is an attractive novel option for export of heterologous proteins without N-glycosylation using chitinase Cts1 as a carrier. Recently, a novel factor essential for unconventional Cts1 secretion termed Jps1 was identified. Here, we show that Jps1 is unconventionally secreted using a fusion to bacterial β-glucuronidase as an established reporter. Interestingly, the experiment also demonstrates that the protein functions as an alternative carrier for heterologous proteins, showing about 2-fold higher reporter activity than the Cts1 fusion in the supernatant. In addition, Jps1-mediated secretion even allowed for efficient export of functional firefly luciferase as a novel secretion target which could not be achieved with Cts1. As an application for a relevant pharmaceutical target, export of functional bi-specific synthetic nanobodies directed against the SARS-CoV2 spike protein was demonstrated. The establishment of an alternative efficient carrier thus constitutes an excellent expansion of the existing secretion platform.

Study review of camelid and shark antibodies for biomedical and biotechnological applications

The antibodies of camelids and sharks are about one–half of the conventional ones while regular antibodies have four protein chains: two light and two heavy, these small antibodies studied have just two heavy chains; they lack a light chain. In recent years, nanobodies have been the focus of attention because they can recognize epitopes that are usually not antigenic (hidden) for conventional antibodies. On the clinical side, researchers are testing nanobodies (Nbs) in the fight against diseases and disease diagnosis. Nanobodies also are attractive because they can prevent protein aggregation and clear the already existing aggregates. Furthermore, new treatments using these Nbs can neutralize the severe acute respiratory syndrome coronavirus (SARS-CoV-2) for preventing COVID-19. In this review, we sum up recent findings of the proposed nanobodies for their potential application.