Antibodies or fusion proteins multimerized via cysteine mutation and a mu tailpiece

Inventors

Tsurushita, Naoya • Tso, J. Yun

Assignees

JN Biosciences LLC

Abstract

The invention provides constant regions incorporating a cysteine mutation and linked to a μ tailpiece and antibodies or fusion proteins incorporating the same. The constant regions include at least CH2 and CH3 regions of an IgG heavy chain constant region including a cysteine mutation and μ tailpiece. Antibodies or fusion proteins incorporating the constant regions gains the ability to form multivalent complexes, e.g., pentameric or hexameric structures. Antibodies or fusion proteins incorporating the constant regions also retain IgG properties including specific binding to protein G, which facilitates purification and may exhibit pH-dependent FcRn binding, which is associated with a relatively long in vivo half-life. Depending on the isotype and subtype, the nature of the antigen and presence of an additional IgG hinge domain, such antibodies or fusion proteins may also have properties of specific binding to protein A, and effector functions such as ADCC, CDC and opsonization.

Core Innovation

The invention describes engineered IgG constant-region variants that contain Fc CH2 and CH3 cysteine mutations linked to an IgG heavy-chain μ tailpiece, in which antibody units can multimerize. The IgG hinge, CH2 and CH3 regions are arranged in N- to C-terminal order, and one or more positions in the CH2 region are mutated to introduce a cysteine residue. The CH3 region is linked to a μ tailpiece at its C-terminus.

Multimerization is achieved through disulfide bonding between cysteines at the mutated position in different antibody units and between μ tailpieces in different units. The constructs enable formation of multivalent pentameric and hexameric antibody complexes through the same disulfide/μ tailpiece logic and support antibody/fusion-protein multimerization while retaining IgG functional properties.

The constructs retain IgG functions such as protein G binding for purification and optionally protein A binding, and include pH-dependent FcRn binding for long half-life. Effector functions such as ADCC, CDC, and opsonization are described as dependent on IgG isotype/subtype and antigen context, and the invention is described as providing a framework for multispecific complexes and scFv-based bispecific multimeric IgG antibodies held together by the same disulfide/μ tailpiece multimerization logic.

Claims Coverage

The provided independent claims define engineered IgG antibodies that multimerize by disulfide bonding mediated by CH2 cysteine mutations and a μ tailpiece linkage, and they further specify particular IgG constant-region compositions and residue positions. The main inventive features focus on the CH2/CH3/μ tailpiece architecture and disulfide-mediated multimerization, together with specified isotypes and residue mutations.

Across the independent claims, the inventive core is an IgG hinge/CH2/CH3 antibody architecture where a CH2-region cysteine mutation and a CH3-linked μ tailpiece enable multimerization through inter-unit disulfide bonding between the mutated CH2 position and μ tailpieces. The claims further restrict the IgG isotypes and, in one case, specify an additional residue pattern at CH2 positions 309 and 310.

Stated Advantages

Documented Applications