Biology subjects

Nagaraj, S. K.

Publications and source records attributed to Nagaraj, S. K..

3 recordsLinked to original sources

bioRxiv2026

Broad protection against Influenza A Viruses via an adjuvant-free mucosal microparticle vaccine with conserved CD8/CD4 bispecific peptides

Rapid antigenic evolution of Influenza A viruses (IAVs) enables their escape from strain-specific vaccine immunity and underscores the need for broadly protective strategies. Here, we describe a modular, adjuvant-free mucosal vaccine platform that elicits potent and cross-protective T cell immunity. The approach uses overlapping CD4+ and CD8+ epitope-dense regions from the consensus IAV M1 and NP proteins, identified through computational and functional screening. These peptides are delivered using polylactic-co-glycolic acid (PLGA) microparticles, engineered for selective uptake by antigen-presenting cells and enable sustained, pH-responsive antigen release. This design enhances antigen processing and MHC cross-presentation, functionally substituting for a conventional adjuvant. This formulation drives robust activation of primed human as well as murine CD4+ and CD8+ T cells and confers broad protection against homologous (H1N1, H3N2) as well as heterologous (H5N1) IAV strains in immunized mice. Overall, this adjuvant-free dose-sparing platform establishes an adaptable framework for next-generation broadly-protective vaccines against rapidly-evolving viruses. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/715080v2_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@19fafedorg.highwire.dtl.DTLVardef@d73109org.highwire.dtl.DTLVardef@1d486edorg.highwire.dtl.DTLVardef@1e663c8_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

An Oral Combination therapy against SARS-CoV-2 based on Synergistic Action of Auranofin and Remdesivir.

The combination of direct-acting and host-directed antivirals targeting SARS-CoV-2 represents an attractive treatment strategy to combat COVID-19. In our previous work, we showed that the FDA-approved anti-arthritis drug Auranofin restricts SARS-CoV-2 replication and pathology in an animal model. Here, we report that Auranofin inhibits SARS-CoV-2 by targeting viral entry and main protease (Mpro) activity without affecting viral transcription. Time-of-addition studies combined with functional assays of viral entry, protease activity, and cell-cell fusion delineated its inhibitory effects at both early and late stages of the viral life cycle. Molecular docking and isothermal titration calorimetry analyses of Auranofin and the known Mpro inhibitor Nirmatrelvir indicated competitive binding within the Mpro active-site pocket. In addition, Auranofin attenuated NF-{kappa}B-dependent signalling and suppressed proinflammatory cytokine production. Combination studies with SARS-CoV-2 targeting nucleoside analogues, revealed the strongest synergistic antiviral activity with remdesivir in vitro. Comparable synergy was observed between auranofin and GS-621763, the orally bioavailable derivative of remdesivir, and was further validated in a preclinical animal model. Collectively, these findings provide a rationale for the further development of auranofin-nucleoside analog combinations targeting SARS-CoV-2. FundingThis research has been supported by ICMR (IIRPIG-2023-0000978) and BIRAC grant (BT/CS0070/06/22) to ST. We acknowledge the infrastructure and research support provided to IISc by the Crypto Relief Fund, L&T Trust, DST-FIST program, Institute of Eminence Fund, Ministry of Education, and the DBT-IISc partnership program (Phase II). RN acknowledges DBT-RA fellowship, SK acknowledges PMRF fellowship, and RS acknowledges FICCI-PMRF fellowship. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSMultiple previous studies have provided evidence showing that auranofin is an antiviral agent targeting SARS-CoV-2 through a host-targeting mechanism, involving the inhibition of thioredoxin reductase and redox homeostasis. Mixed results have been reported regarding the effect of this drug on inhibiting virus-induced syncytia. A prior study from our lab demonstrated the drugs effectiveness in reducing SARS-CoV-2 viral loads in both cell and animal models. Added value of the studyOur study firmly establishes the synergistic use of Auranofin and Remdesivir GS 621763 in the treatment of SARS-CoV-2 infection.

microbiology↗

bioRxiv2023

A broadly protective CHO cell expressed recombinant spike protein subunit based vaccine (IMT-CVAX) against SARS-CoV-2

Protective immunity induced by COVID-19 vaccines is mediated mainly by spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we report the development of a recombinant prefusion stabilized SARS-CoV-2 spike protein-subunit-based COVID-19 vaccine produced in the mammalian cell line. The gene encoding ectodomain (ECD) of the spike protein was engineered and cloned into Freedom pCHO 1.0, a mammalian expression vector, and subsequently expressed in the Chinese Hamster Ovary suspension cell line (CHO-S). The recombinant S protein ectodomain (hereafter referred to as IMT-CVAX) was purified using a combination of tangential flow filtration and liquid chromatography. Biochemical and biophysical characterization of IMT-CVAX was done to ensure its vital quality attributes. Intramuscular immunization of mice with two doses of adjuvanted IMT-CVAX elicited a strong anti-Spike IgG response. In pseudovirus-based assays, IMT-CVAX- immune mice sera exhibited a broad-spectrum neutralization of several SARS-CoV-2 variants of concern (VoCs). Golden Syrian Hamster immunized with IMT-CVAX provided excellent protection against SARS-CoV-2 infection, and, hamster immune sera neutralized the live SARS-CoV-2 virus. The adjuvanted IMT-CVAX induced robust Tfh-cells response and germinal center (GC) reaction in human ACE2 receptor-expressing transgenic mice. The findings of this study may pave the way for developing next-generation protein subunit-based vaccines to combat the existing SARS-CoV-2 and its emerging VoCs. The IMT-CVAX is produced using a scalable process and can be used for large-scale vaccine production in an industrial setup.

microbiology↗