Anti #Matrix Protein 1 Monoclonal #Antibody Neutralizes #Influenza A Virus Subtypes

Abstract

Background:

Research on monoclonal antibodies (mAb) targeting conserved internal proteins of influenza is limited.The matrix protein 1 (M1), the most abundant and conserved internal protein, serves as an endoskeleton bridging cytoplasmic tails of envelope glycoproteins haemagglutinin (HA), neuraminidase (NA) and matrix protein 2 (M2) with viral ribonucleoprotein particles (vRNPs). Clinical studies reveal significant M1 antibody responses post-infection and vaccination, with demonstrated B and T cell recognition. Our study examines 2B-B10-G9, our lab-synthesized mAb targeting conserved linear epitope of M1 at the C-terminal domain (CTD).

Methods:

Binding of 2B-B10-G9 to the purified influenza A viruses (IAV) and influenza B viruses (IBV) were assessed using SDS-PAGE and Western blotting with Image J analysis. Purified viruses included IAV (H1N1, Pandemic (H1N1) 2009 (H1N1pdm09), and H3N2 subtypes) and IBV which was first isolated in 1940 (B/Lee/40), and B/Victoria lineage. Cytotoxicity of 2B-B10-G9 on the Madin-Darby canine kidney (MDCK) cells was studied by MTT (3-(4, 5-dimethylthiazol-2)-2, 5-diphenyltetrazolium bromide) cell proliferation assay to establish in vitro and in ovo treatment doses. In ovo studies involved injecting 2B-B10-G9 into the allantoic cavity of specific pathogen free (SPF) 10-day-old embryonated chicken eggs (ECE) immediately post-infection with influenza A/Puerto Rico/8/1934 (H1N1) followed by RT-qPCR analysis of the virulence genes HA, NA, and PB1 expressions in the allantoic fluid (AF) 48 hours post-infection.

Results:

mAb 2B-B10-G9 shows significantly stronger binding to the M1 protein of H1N1 subtype of IAV with respect to H3N2 subtype of IAV (p < 0.001), and it has significantly stronger binding to the M1 protein of H1N1 subtype of IAV with respect to H1N1pdm09 subtype, IBV including B/Lee/40, B/Victoria lineage. (p< 0.0001) mAb 2B-B10-G9 at dose of 40 ug/ml which was determined as an optimal dose according to the MTT assay, significantly reduced plaque-forming units (PFU)/ml of IAV H1N1 and H3N2 subtypes in vitro (p< 0.0001). In ovo treatment of IAV H1N1 subtype at the same dose 40 ug/ml, significantly suppressed the virulence genes HA, NA, and PB1 expressions compared to the untreated group (p< 0.0001, p< 0.001, p< 0.0001, respectively) and mouse isotype IgG1 mAb treated groups (p< 0.01).

Conclusions:

These findings highlight that anti-M1 mAb 2B-B10-G9, targeting conserved linear epitope at the CTD of M1 protein, might be considered as a possible therapeutic option for IAV H1N1 and H3N2 subtypes related to its significant recognition and binding, viral neutralization and suppression of expression of virulence genes including HA, NA and PB1.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.06.09.658662v1

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#Neuroinvasive #Oropouche virus in a patient with #HIV from extra-Amazonian #Brazil

{Excerpt} A novel reassortant Oropouche virus (OROV) lineage (with medium [M], large [L], and small [S] RNA segments : M1L2S2) has driven Brazil's largest and most geographically widespread OROV epidemic , expanding beyond the endemic Amazon basin to establish local transmission across multiple Brazilian states and other previously unaffected Latin American countries . The rapid spread of this lineage underscores its evolutionary potential and reinforces its significance as a public health threat .1 Similar to chikungunya and Zika viruses, expanding arboviruses can exhibit unexpected clinical and epidemiological shifts , including vertical transmissions , neuroinvasive effects, and potentially fatal outcomes.2–4 Although OROV typically causes self-limited febrile illness, accumulating clinical and experimental evidence suggests neurotropic potential .5 This Correspondence describes the first confirmed case of neuroinvasive OROV infection caused by the emergent M1L2S2 lineage in ext...

Stability of #influenza viruses in the #milk of #cows and #sheep

Abstract In late 2023, H5N1 high pathogenicity avian influenza (HPAIV) started circulating in dairy cattle in the USA . High viral titres were detected in milk from infected cows , raising concerns about onwards human infections . Although pasteurisation was shown to effectively inactivate influenza viruses in milk, unpasteurised milk still poses a risk of infection, both from occupational exposure in dairies and from the consumption of raw milk. We therefore assessed how long influenza viruses could remain infectious for in milk without heat inactivation. We examined the stability of a panel of influenza viruses in milk , including a contemporary H5N1 HPAIV and a variety of other influenza A and D viruses. We incubated viruses in cows' milk under laboratory conditions : at room temperature to simulate exposure in dairies and at 4°C to simulate exposure to refrigerated raw milk. Following an isolated report of H5N1 viral RNA being detected in milk from a sheep in the UK , we also c...

#Evidence of #Viremia in Dairy #Cows Naturally Infected with #Influenza A {#H5N1} Virus, #California, #USA

Abstract We confirmed influenza A virus (IAV) by PCR in serum from 18 cows on 3 affected dairy farms in California, USA . Our findings indicate the presence of viremia and might help explain IAV transmission dynamics and shedding patterns in cows. An understanding of those dynamics could enable development of IAV mitigation strategies. Source: US Centers for Disease Control and Prevention, https://wwwnc.cdc.gov/eid/article/31/7/25-0134_article ____

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