Binding molecules

What is this patent about?

’179 is related to the field of antibody engineering and the production of therapeutic proteins. Specifically, it addresses the manufacture of heavy chain-only antibodies (HCAbs) in transgenic mammals. Traditional monoclonal antibodies require the complex assembly of two heavy and two light chains, which limits production efficiency and increases costs. The background context involves the need for high-affinity, soluble binding domains that can be produced in simpler expression systems while retaining the effector functions of a full antibody.

The underlying idea behind ’179 is that B-cell maturation and the production of high-affinity antibodies can occur in a transgenic system without the presence of light chains, provided the CH1 domain is entirely absent. By removing the CH1 exon from the heavy chain constant region, the invention prevents the heavy chain from requiring a light chain for stable folding and secretion. This allows the animal’s immune system to utilize natural VDJ recombination and somatic hypermutation to evolve high-affinity, soluble VH binding domains that function as autonomous units.

The claims of ’179 focus on a method for producing soluble, antigen-specific heavy chain-only antibodies by immunizing a transgenic rodent. The rodent is engineered with a heterologous locus containing at least one VH gene segment, at least five D segments, and at least one J segment, linked to a constant region that lacks a functional CH1 domain. The process specifically requires that the resulting antibodies undergo affinity maturation via somatic mutation within the rodent before being cloned and produced in a heterologous expression system.

In practice, the invention works by challenging the transgenic rodent with a target antigen, triggering a natural immune response. Because the CH1 domain is deleted, the heavy chains do not get trapped in the endoplasmic reticulum; instead, they are secreted as functional dimers or multimers. The inventor’s insight ensures that the resulting VH domains are naturally selected for solubility and stability in vivo, avoiding the aggregation issues typically seen with isolated human VH domains derived from synthetic libraries.

This approach differs from prior methods by leveraging the full power of the mammalian immune system to refine the antigen-binding repertoire. Unlike camelid-derived antibodies, which may be immunogenic in humans, or phage display techniques that lack in vivo maturation, this method produces fully humanized, high-affinity binders. By bypassing the need for light chain pairing, the invention simplifies the engineering of multispecific and multivalent complexes, significantly reducing the risk of chain mispairing during large-scale manufacturing.