Longhorn Vaccines and Diagnostics to Present Late-Breaking Poster at ESCMID 2025 on LHNVD-303 to Treat and Prevent Antimicrobial Resistance

Poster highlights cross-reactive binding and opsonization of S.aureus and E.coli by a single antibody

The antibody represents the core of LHNVD-303, the cornerstone therapy for infection control and inflammation in Longhorn's Anti-PAMP platform and inflammaging/longevity portfolio

GAITHERSBURG, Md.--(BUSINESS WIRE)--Longhorn Vaccines and Diagnostics (“Longhorn”) today announced it will present a late-breaking poster at the 6th ESCMID Conference on Vaccines supporting the breath of a single, conserved-target antibody to address the bacteria associated with antimicrobial resistance (AMR) and inflammation from gram-positive and gram-negative pathogens. The presentation will feature the company’s anti-peptidoglycan (PGN) monoclonal antibody, the core of LHNVD-303, for the prevention of AMR bacterial infections, sepsis, and a wide range of medical conditions caused by chronic inflammation driven by bacterial toxins. The ESCMID Conference on Vaccines is taking place in Lisbon, Portugal from September 10–13, 2025.

Preclinical data will be presented showing that the antibody generates cross-reactive binding to PGN from S. aureus and E. Coli, recognizing the whole bacteria of each species. It also promotes significant opsonophagocytic killing of E. coli in vitro, with previous data reporting opsonophagocytic killing of S. aureus.

“This poster is a key milestone in our anti-pathogen-associated molecular pattern, or PAMP, platform,” said Longhorn Chief Executive Officer Gerald W. Fischer, MD. “By targeting conserved bacterial signatures and the circulating fragments that fuel inflammation, we aim to deliver a first-in-class, immune-sparing therapy that is relevant to AMR prevention and treatment, and to diseases driven by chronic low-grade inflammation, reducing inflammaging which plays a significant role in longevity.”

“Our data demonstrate that a single anti-PGN monoclonal antibody can bind conserved cell-wall motifs and drive opsonophagocytic killing across species, spanning Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli,” said Longhorn Vice President of Vaccine and Antibody Development at Clara J. Sei, MPH, who will present the poster at ESCMID. “We believe this breadth—combined with systemic PAMP neutralization—could translate into fewer infection crises and lower inflammatory burden without disrupting the microbiome.”

Poster Presentation Information:

• Title: A Broad-Spectrum Monoclonal Antibody Targeting Peptidoglycan from Staphylococcus aureus Demonstrates Cross-Reactivity Against Escherichia coli: A Novel Strategy to Combat Antimicrobial Resistance
• Poster number: P139
• Presenter: Clara J. Sei, MPH, Longhorn Vice President of Vaccine and Antibody Development
• Date/Time: September 12^th at 17:40 WEST

LHNVD-303 is the core asset of Longhorn’s anti-PAMP platform, which works by clearing bacteria and toxins that invade the bloodstream. It does this by neutralizing circulating PAMPs such as PGN, LPS and LTA to reduce maladaptive systemic inflammation while preserving the natural microbiome and normal immunity. This dual “clean and calm” strategy is intended to deliver clinical value in AMR-relevant infections and in chronic inflammation-linked conditions associated with aging (“inflammaging”).

As Longhorn looks to the next phase of development for its inflammaging/longevity portfolio, it is advancing LHNVD-303 and other monoclonal antibody combinations through its anti-PAMP platform. Therapies are administered subcutaneously in high-risk populations (e.g., dialysis, LVAD, central lines) and intravenously as an add-on therapy in bloodstream infections and sepsis. The company is designing current and future pre-clinical studies to explore other infections related to AMR.

For more information about Longhorn, visit www.LHNVD.com.

About Longhorn Vaccines and Diagnostics
Longhorn Vaccines and Diagnostics is a closely held One Health company based in Maryland that is developing broad coverage vaccines and diagnostic tools for worldwide public health concerns such as anti-microbial resistance, sepsis and to prevent future pandemics. Since its inception in 2006, Longhorn has focused on developing broad coverage vaccines and diagnostic tools that can impact a pandemic on a global scale and at all socio-economic levels. Since pandemics flow between humans and animals, Longhorn products play a significant role to surveil, diagnose, prevent and treat the next infectious disease.