Small modular immunopharmaceutical

Small modular immunopharmaceuticals, or SMIPs for short, are artificial proteins that are intended for use as pharmaceutical drugs.

SMIPs have similar biological half-life and, being smaller than antibodies, are reasoned to have better tissue penetration properties.

[2] Like ordinary monoclonal antibodies, SMIPs are monospecific, meaning they recognize and attach to a single antigen target to initiate their biological activity.

SMIP drug candidates are intended to target antigens with the same specificity and predictable biological activity as monoclonal antibodies.

A large number of different hinge regions and effector domains are taken from libraries of immunoglobulins, and the combined proteins are produced in genetically modified (transfected) cells and screened for clones with useful properties like high binding specificity.

Sketch of a SMIP monomer consisting of four domains . The antigen binding site is on the left edge.
scFv : modified single-chain variable fragment
Fc : one half of a fragment crystallizable region
V H : heavy chain variable domain
V L : light chain variable domain
C H 2 : constant domain 2
C H 3 : constant domain 3 (effector domain)
Arrows : linker peptide (left) and hinge region (right)
N : N-terminus
C : C-terminus