Biology subjects

Nath, H.

Publications and source records attributed to Nath, H..

6 recordsLinked to original sources

bioRxiv2026

Tumor-tropic E. coli engineered as living T and NK cell engagers

Despite advances in immunotherapy, most solid tumors remain resistant to treatment. Immune cell engagers redirect cytotoxic lymphocytes against cancer, but limited tumor access, immunosuppressive microenvironments and systemic immune activation limit efficacy. Here we develop live immune modulating engagers (LIME), a modular platform where non-pathogenic, tumor-tropic Escherichia coli display tandem single-chain variable fragments targeting a tumor-associated antigen and an activating receptor on T or natural killer cells. LIME bridged effector and tumor cells, induced transcriptional programs of T cell activation, metabolism and proliferation, and enhanced cytotoxicity across cancer cell lines and patient-derived organoids. In mouse models, LIME safely accumulated in tumors, outperformed tarlatamab in small cell lung cancer, and induced durable immunity in lymphoma. RAS inhibition and PD-L1 blockade enhanced LIME activity in pancreatic cancer and induced humoral responses. Multi-lineage immune modulation remained tumor-confined, without organ toxicity. These findings establish LIME as a versatile living therapeutic platform for programmable, tumor-restricted immune orchestration.

bioengineering↗

bioRxiv2026

A One-Shot Multivalent Live-Attenuated Candidate Influenza Vaccine against Divergent Zoonotic H5N1 Clades

The continued emergence of genetically diverse high pathogenicity avian influenza (HPAI) H5N1 viruses with zoonotic potential highlights the urgent need for developing vaccines capable of providing broad protection against multiple circulating clades. Here, we developed a one-shot, multivalent, live-attenuated influenza vaccine (LAIV) based on the temperature-sensitive (ts), cold-adapted (ca), and attenuated (att) influenza A/Ann Arbor/6/1960 master donor virus (MDV) that incorporates the hemagglutinin (HA) and neuraminidase (NA) glycoproteins from representative clades 2.3.4.4b (A/Louisiana/12/2024), 2.3.2.1a (A/Victoria/149/2024), and 2.3.2.1e (A/Cambodia/2302009/2023) H5N1 viruses. A single intranasal (IN) immunization of C57BL/6 mice with the multivalent LAIV elicited robust humoral immune responses, with immune sera exhibiting broad cross-reactivity against antigens from all three H5N1 clades included in the vaccine. Following homologous viral challenge, vaccinated C57BL/6 mice were completely protected from disease, demonstrating the immunogenicity and protective efficacy of the multivalent LAIV. By simultaneously targeting antigenically distinct H5N1 lineages with pandemic potential, this strategy expands antigenic coverage within a single LAIV to confirm pan-H5N1 protection. Together, these findings support the development and implementation of this multivalent LAIV as a broadly protective pan-H5N1 LAIV for pandemic preparedness. SignificanceThe increasing genetic diversity of zoonotic H5N1 viruses complicates vaccine design. We developed a multivalent live-attenuated influenza vaccine (LAIV) based on the temperature-sensitive, cold-adapted, and attenuated (ts, ca, att) master donor virus (MDV) influenza A/Ann Arbor/6/1960 backbone that expresses the hemagglutinin (HA) and neuraminidase (NA) glycoproteins of H5N1 clades 2.3.4.4b, 2.3.2.1a, and 2.3.2.1e. A single intranasal (IN) immunization with the multivalent LAIV induced broadly cross-reactive neutralizing antibody (NAb) responses and protected experimental vaccinated animals against homologous lethal viral challenge, demonstrating the feasibility of the multivalent LAIV to protect against H5N1 clades of highest concern to humans. These findings demonstrate the feasibility of developing and implementing this multivalent LAIV as a broad protective pan-H5N1 LAIV against divergent H5N1 viruses for human use.

microbiology↗

bioRxiv2026

A novel ISG15 transcript restricts influenza A virus infection

The interferon response orchestrates antiviral defense through the induction of interferon-stimulated genes (ISGs). Although nearly all human genes undergo alternative splicing, the identity and function of many ISG transcript isoforms remains poorly understood. Using long-read RNA sequencing of human cells that were undergoing an interferon response, we identified a previously unrecognized interferon-inducible ISG15 transcript. This non-canonical ISG15 (ncISG15) transcript contains a unique 5' untranslated region and encodes an N-terminally truncated protein in frame with ISG15. During interferon stimulation, ncISG15 produces an ISGylation pattern distinct from canonical ISG15 and potently inhibits influenza A virus polymerase activity. The influenza A viral interferon antagonist protein NS1 counteracts ncISG15-mediated restriction; however, endogenous ncISG15 executes modest antiviral activity against NS1-encoding viruses. Antiviral activity of ncISG15 is largely independent of its function as a cytokine, through ISG augmentation, or by ISGylation. This novel transcript adds a new layer of regulatory complexity to the ISG15-driven antiviral network.

microbiology↗

bioRxiv2025

Tandem split-GFP influenza A viruses for sensitive and accurate replication analyses

Reporter influenza A viruses (IAVs) are valuable tools for studying virus fitness, screening antivirals, and assessing host-virus interactions. However, the compact and segmented nature of the IAV genome presents major challenges for engineering genetically stable reporter viruses with minimal fitness defects. To address this, we developed a replication-competent IAV incorporating a tandem split-GFP reporter strategy. Specifically, we appended seven tandem repeats of the GFP11 peptide (GFP11x7) to the C-terminus of the PB2 or PA polymerase subunit. Viruses contained or lacked a self-cleaving 2A peptide between the viral and reporter genes to create polymerase fusion proteins or released GFP, respectively. These viruses are complemented in trans by cells expressing GFP1-10, allowing bright fluorescence with minimal disruption to viral function. The tandem GFP11 reporter viruses exhibit delayed replication kinetics, but are genetically stable over serial passages with a strong concordance between GFP signal and viral gene expression. We demonstrate their utility in high-throughput applications including fluorescence-based quantification of infection, neutralizing antibody titration, antiviral drug screening, and host factor identification, with results matching traditional assays but on an accelerated timeline. Furthermore, we engineered a battery of GFP1-10-expressing cell lines from multiple vertebrate species, illustrating the broad compatibility of this platform for comparative host studies. This system enables sensitive, scalable, and quantitative evaluation of influenza virus replication across diverse experimental contexts. The GFP11x7 reporter platform offers a versatile and robust tool for virology research and therapeutic screening, with potential for rapid adaptation to emerging IAV strains.

microbiology↗

bioRxiv2020

SARS-CoV-2 has observably higher propensity to accept uracil as nucleotide substitution: Prevalence of amino acid substitutions and their predicted functional implications in circulating SARS-CoV-2 in India up to July, 2020

SARS-CoV-2 has emerged as pandemic all over the world since late 2019. In this study, we investigated the diversity of the virus in the context of SARS-CoV-2 spread in India. Full-length SARS-CoV-2 genome sequences of the circulating viruses from all over India were collected from GISAID, an open data repository, until 25thJuly, 2020. We have focused on the non-synonymous changes across the genome that resulted in amino acid substitutions. Analysis of the genomic signatures of the non-synonymous mutations demonstrated a strong association between the time of sample collection and the accumulation of genetic diversity. Most of these isolates from India belonged to the A2a clade (63.4%) which has overcome the selective pressure and is spreading rapidly across several continents. Interestingly a new clade I/A3i has emerged as the second-highest prevalent type among the Indian isolates, comprising 25.5% of the Indian sequences. Emergence of new mutations in the S protein was observed. Major SARS-CoV-2 clades in India have defining mutations in the RdRp. Maximum accumulation of mutations was observed in ORF1a. Other than the clade-defining mutations, few representative non-synonymous mutations were checked against the available crystal structures of the SARS-CoV-2 proteins in the DynaMut server to assess their thermodynamic stability. We have observed that SARS-CoV-2 genomes contain more uracil than any other nucleotide. Furthermore, substitution of nucleotides to uracil was highest among the non-synonymous mutations observed. The A+U content in SARS-CoV-2 genome is much higher compared to other RNA viruses, suggesting that the virus RdRp has a propensity towards uracil incorporation in the genome. This implies that thymidine analogues may have a better chance to competitively inhibit SARS-CoV-2 RNA replication than other nucleotide analogues.

microbiology↗

bioRxiv2020

Dengue virus sustains viability of infected cells by counteracting apoptosis-mediated DNA breakage

NS1, a virotoxin, abundantly present in Dengue patients blood, is a major player behind disease patho-biogenesis including plasma leakage and damage to the liver. Despite the presence of NS1 in blood, Dengue is asymptomatic and self-limiting in [≥]80% Dengue virus (DV) infected people. We investigated this observation and found that plasmid-mediated NS1 expression and secretion in liver cells (Huh7) are sufficient to cause programmed cell death (apoptosis) and associated cellular DNA breakage. However, liver or kidney cell lines infected with DV and secreting equivalent amounts of NS1 didnt exhibit apoptotic DNA breakage. In fact, DV-infected cells showed better survival than cells in which only NS1 was transiently expressed by transfection. We also found that DV can even prevent chemical-induced apoptotic DNA damage in infected host cells. So, DV thwarts host antiviral defence i.e. apoptosis, by counteracting cellular DNA breakages and keeps the infected cells metabolically active to prolong virus replication.

microbiology↗