Kling Bio Validates its Proprietary B-Cell Technology for Rapid Response Against Emerging Viral Variants

• Study demonstrated the use of immortalized B-cell libraries as a rapid and adaptable approach to therapeutic development against evolving viral threats
• Discovered 12 antibodies with potent neutralizing activity against multiple SARS-CoV-2 strains, including Delta and BA.5, through high-throughput B-cell screening
• Applied ex vivo directed evolution to B-cell clones to enhance antibody neutralizing breadth and potency against emerging infectious disease variants

AMSTERDAM, Sept. 9, 2025 /PRNewswire/ -- Kling Bio, the function-first biotech harnessing proprietary B-cell technology to discover novel targets and antibodies across multiple disease areas, today announced the publication of a peer-reviewed study titled 'Immune counter-evolution: Immortalized B cell clones can undergo ex vivo directed evolution to counteract viral escape' in the high impact journal Frontiers in Immunology, validating the company's proprietary primary B-cell platform technologies for rapidly developing adaptable antibody therapeutics against evolving viral threats.

The paper highlights the use of immortalized B-cell libraries to develop therapeutics that adapt to viral evolution and demonstrates how immortalized B-cells can undergo ex vivo directed evolution to generate antibody responses against emerging SARS-CoV-2 escape variants.

The study, conducted solely by Kling Bio, utilized immortalized B-cell libraries derived from human peripheral blood mononuclear cells (PBMCs) and tonsil tissue to identify B-cell clones with cross-reactive neutralization against SARS-CoV-2 variants. Immortalization was achieved via retroviral transduction with apoptosis inhibitors, resulting in the libraries retaining full immunoglobulin isotype representation, enabling broad functional screening. High-throughput screening of 40,000 B-cells per library resulted in the identification of broadly neutralizing clones, including monoclonal antibodies with strong, robust activity against the Delta and BA.5 variants. Ex vivo directed evolution further improved potency against emerging immune escape variants such as KP.3 and XEC. The study also reports on a neutralizing epitope on Spike-RBD that is fully conserved among all variants reported to date.

In addition, the Kling Bio team engineered a bi-paratopic antibody by combining a broadly neutralizing antibody targeting a conserved Spike-RBD epitope with a broadly binding non-neutralizing antibody, resulting in enhanced potency against the SARS-CoV-2 variants JN.1 and KP.3.

Stefano Gullà, Chief Scientific Officer, Kling Bio, said, "Our proprietary B-cell platform technologies work together to unlock the full potential of the human immune system to stay ahead of evolving viral threats. By combining high-throughput screening with ex vivo directed evolution, we can rapidly discover and optimize powerful antibodies in days, not months. This breakthrough approach is not just a tool for today's pandemics; it is a transformative platform for developing next-generation infectious disease therapeutics and redefining how the world responds to future outbreaks."

The publication follows Kling Bio's recent announcement of a collaboration and license option agreement with Sanofi. Leveraging Kling Bio's proprietary primary B-cell immortalization and screening platform technologies, the collaboration aims to identify neutralizing antibodies and respective epitopes against a clinically relevant human viral pathogen. Read the full press release here.

Citation:

Casper Marsman, Jurgen Heinen, Vanessa Clerico Mosina, Kelly Maijoor, Arjen Q. Bakker, Michael Koslowski, Alessandra Villa, Stefano Gullà - Kling Bio, Amsterdam, Netherlands

About Kling Bio

Kling Bio is redefining antibody discovery by harnessing the natural power of the human immune system. Through its proprietary primary B-cell platform technologies, the company combines high-efficiency B-cell immortalization with function-first screening to uncover novel antibody–antigen pairs. Kling Bio's method identifies highly specific antibodies directly from patients, enabling faster, target-agnostic, and de-risked drug development. The target-agnostic model reveals opportunities to discover previously unrecognized targets, uncovering functional epitopes and new biology across oncology, infectious diseases, and beyond.

Kling Bio operates a dual-track model: advancing its pipeline of first-in-class assets while partnering with pharma and biotech's to co-develop differentiated therapies. Its platform has produced assets in oncology and infectious diseases, with additional programs focusing on solid tumors and neuroinflammation underway. Notably, the platform has already delivered a billion-dollar RSV antibody, Beyfortus (nirzevimab), marketed by Sanofi and AstraZeneca, validating its commercial potential. With active partnerships and a growing pipeline, Kling Bio is positioned as both a discovery engine and a strategic collaborator.