scholarly journals Monoclonal Antibodies B38 and H4 Produced in Nicotiana benthamiana Neutralize SARS-CoV-2 in vitro

2020 ◽  
Vol 11 ◽  
Author(s):  
Balamurugan Shanmugaraj ◽  
Kaewta Rattanapisit ◽  
Suwimon Manopwisedjaroen ◽  
Arunee Thitithanyanont ◽  
Waranyoo Phoolcharoen

The ongoing coronavirus disease 2019 (COVID-19) outbreak caused by novel zoonotic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was initially reported in Wuhan city, Hubei Province of China, in late December 2019. The rapid global spread of the virus calls for the urgent development of vaccines or therapeutics for human applications to combat the coronavirus infection. Monoclonal antibodies (mAbs) have been utilized as effective therapeutics for treating various infectious diseases. In the present study, we evaluated the feasibility of plant expression system for the rapid production of recently identified therapeutically suitable human anti-SARS-CoV-2 mAbs B38 and H4. Transient co-expression of heavy-chain and light-chain sequences of both the antibodies by using plant expression geminiviral vector resulted in rapid accumulation of assembled mAbs in Nicotiana benthamiana leaves within 4 days post-infiltration. Furthermore, both the mAbs were purified from the plant crude extracts with single-step protein A affinity column chromatography. The expression level of mAb B38 and H4 was estimated to be 4 and 35 μg/g leaf fresh weight, respectively. Both plant-produced mAbs demonstrated specific binding to receptor binding domain (RBD) of SARS-CoV-2 and exhibited efficient virus neutralization activity in vitro. To the best of our knowledge, this is the first report of functional anti-SARS-CoV-2 mAbs produced in plants, which demonstrates the ability of using a plant expression system as a suitable platform for the production of effective, safe, and affordable SARS-CoV-2 mAbs to fight against the spread of this highly infectious pathogen.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kaewta Rattanapisit ◽  
Balamurugan Shanmugaraj ◽  
Suwimon Manopwisedjaroen ◽  
Priyo Budi Purwono ◽  
Konlavat Siriwattananon ◽  
...  

Abstract Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for the ongoing global outbreak of coronavirus disease (COVID-19) which is a significant threat to global public health. The rapid spread of COVID-19 necessitates the development of cost-effective technology platforms for the production of vaccines, drugs, and protein reagents for appropriate disease diagnosis and treatment. In this study, we explored the possibility of producing the receptor binding domain (RBD) of SARS-CoV-2 and an anti-SARS-CoV monoclonal antibody (mAb) CR3022 in Nicotiana benthamiana. Both RBD and mAb CR3022 were transiently produced with the highest expression level of 8 μg/g and 130 μg/g leaf fresh weight respectively at 3 days post-infiltration. The plant-produced RBD exhibited specific binding to the SARS-CoV-2 receptor, angiotensin-converting enzyme 2 (ACE2). Furthermore, the plant-produced mAb CR3022 binds to SARS-CoV-2, but fails to neutralize the virus in vitro. This is the first report showing the production of anti-SARS-CoV-2 RBD and mAb CR3022 in plants. Overall these findings provide a proof-of-concept for using plants as an expression system for the production of SARS-CoV-2 antigens and antibodies or similar other diagnostic reagents against SARS-CoV-2 rapidly, especially during epidemic or pandemic situation.


Author(s):  
Andrew G. Diamos ◽  
Joseph G. L. Hunter ◽  
Mary D. Pardhe ◽  
Sun H. Rosenthal ◽  
Haiyan Sun ◽  
...  

Parasitology ◽  
1997 ◽  
Vol 114 (1) ◽  
pp. 79-84 ◽  
Author(s):  
M. ROBINSON ◽  
T. R. GUSTAD ◽  
S. MEINHARDT

A characteristic feature of infections with the nematode parasite of mice Heligmosomoides polygyrus, is a marked IgG1 hypergammaglobulinaemia. A possible source for this immunoglobulin has recently been demonstrated, through evidence that H. polygyrus adult worm homogenate (AWH) can induce the in vitro production of non-specific IgG1 from mouse lymphocytes. To determine the interactions between this immunoglobulin and the parasite, the ability of IgG1 to bind to AWH of H. polygyrus was investigated. Protein (Western) blotting indicated that mouse monoclonal antibodies are able to bind non-specifically to selected parasite antigens. Furthermore, by binding H. polygyrus adult worm homogenate to cyanogen bromide (CNBr)-activated Sepharose CL-4B, an affinity column was prepared which could be used to efficiently purify mouse IgG1 monoclonal antibodies. These antibodies were eluted from the affinity column and still retained their original specificity. These results indicate that H. polygyrus not only induces the production of non-specific IgG1 by the host, it can also bind this immunoglobulin to its own specific proteins. Thus, it is possible that IgG1 produced during a primary infection with H. polygyrus may not entirely benefit the host.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Merricka C. Livingstone ◽  
Alexis A. Bitzer ◽  
Alish Giri ◽  
Kun Luo ◽  
Rajeshwer S. Sankhala ◽  
...  

AbstractPlasmodium falciparum malaria contributes to a significant global disease burden. Circumsporozoite protein (CSP), the most abundant sporozoite stage antigen, is a prime vaccine candidate. Inhibitory monoclonal antibodies (mAbs) against CSP map to either a short junctional sequence or the central (NPNA)n repeat region. We compared in vitro and in vivo activities of six CSP-specific mAbs derived from human recipients of a recombinant CSP vaccine RTS,S/AS01 (mAbs 317 and 311); an irradiated whole sporozoite vaccine PfSPZ (mAbs CIS43 and MGG4); or individuals exposed to malaria (mAbs 580 and 663). RTS,S mAb 317 that specifically binds the (NPNA)n epitope, had the highest affinity and it elicited the best sterile protection in mice. The most potent inhibitor of sporozoite invasion in vitro was mAb CIS43 which shows dual-specific binding to the junctional sequence and (NPNA)n. In vivo mouse protection was associated with the mAb reactivity to the NANPx6 peptide, the in vitro inhibition of sporozoite invasion activity, and kinetic parameters measured using intact mAbs or their Fab fragments. Buried surface area between mAb and its target epitope was also associated with in vivo protection. Association and disconnects between in vitro and in vivo readouts has important implications for the design and down-selection of the next generation of CSP based interventions.


1998 ◽  
Vol 143 (7) ◽  
pp. 1813-1830 ◽  
Author(s):  
Marcello Marelli ◽  
John D. Aitchison ◽  
Richard W. Wozniak

We have identified a specific karyopherin docking complex within the yeast nuclear pore complex (NPC) that contains two novel, structurally related nucleoporins, Nup53p and Nup59p, and the NPC core protein Nup170p. This complex was affinity purified from cells expressing a functional Nup53p–protein A chimera. The localization of Nup53p, Nup59p, and Nup170p within the NPC by immunoelectron microscopy suggests that the Nup53p-containing complex is positioned on both the cytoplasmic and nucleoplasmic faces of the NPC core. In association with the isolated complex, we have also identified the nuclear transport factor Kap121p (Pse1p). Using in vitro binding assays, we showed that each of the nucleoporins interacts with one another. However, the association of Kap121p with the complex is mediated by its interaction with Nup53p. Moreover, Kap121p is the only β-type karyopherin that binds Nup53p suggesting that Nup53p acts as a specific Kap121p docking site. Kap121p can be released from Nup53p by the GTP bound form of the small GTPase Ran. The physiological relevance of the interaction between Nup53p and Kap121p was further underscored by the observation that NUP53 mutations alter the subcellular distribution of Kap121p and the Kap121p- mediated import of a ribosomal L25 reporter protein. Interestingly, Nup53p is specifically phosphorylated during mitosis. This phenomenon is correlated with a transient decrease in perinuclear-associated Kap121p.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e14002-e14002
Author(s):  
Saverio Alberti ◽  
Marco Trerotola ◽  
Valeria Relli ◽  
Chiara Pedicone ◽  
Antonella D' Amore ◽  
...  

e14002 Background: Trop-2 is a calcium signal transducer that drives tumor cell growth. Trop-2 is overexpressed in the majority of carcinomas, where it associates with worse prognosis. The Trop-2 extracellular domain contains a N-terminal cysteine-rich globular domain followed by a stem-like cysteine-less region that connects to the transmembrane domain. Trop-2 engages in homophylic interactions between adjacent cells and interacts with tight-junction proteins, which may severely affect accessibility by therapeutic monoclonal antibodies (mAb). Available anti-Trop-2 mAb mostly recognize a single immunodominant epitope between the globular and stem regions, and have limited or no therapeutic efficacy. In order to untap the potential of anti-Trop-2 immunotherapy we generated novel anti-Trop-2 mAb with tailored specificity towards the globular versus stem regions. Methods: Balb-C mice were immunized with soluble human Trop-2 produced in human 293 and murine L cell lines and in baculovirus expression system. Domain-targeted anti-Trop-2 mAb were selected by flow cytometry using live 293 transfectants.Therapeutic potential was assessed in human cancer xenografts in murine models. mAb mode of action was investigated by Western blot, live-cell imaging and in vitro ADCC and cancer cell growth inhibition assays. Results: mAb were identified that were differentially directed against the Trop-2 stem versus globular regions. These mAb efficiently bound Trop-2 expressing cancer cells and inhibited cell growth in vitro. In vivo, naked anti-globular OX-G64 and anti-stem OX-S55 mAb were most effective in inhibiting the growth of colon, ovary, breast and prostate cancers as xenografts in nude mice. NSG mice and in vitro mechanism profiling indicated efficient ADCC, together with efficient internalization for ADC development. Differential efficacy for established tumors versus isolated-cell models of metastatic dissemination was shown. Most remarkably, OX-G64/OX-S55 co-administration demonstrated sinergic growth inhibition in vivo. Conclusions: The OX-G64 and OX-S55 anti-Trop-2 mAb are novel domain-targeted, sinergic therapeutic mAb for game-changing anti-cancer immunotherapy.


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