Collabody is a unique recombinant protein engineering platform, which utilizes a short triplex-forming collagenous peptide, derived from human serum collagens to make multivalent protein binders. The structure design of its first derivative, anti-CD3 Collabody is meant to resolve the narrow therapeutic window of the existing anti-human CD3 antibody products— teplizumab and otelixizumab, both of which were failed in clinical phase 3 trails in treating patients with type 1 diabetes mellitus disease. The trivalent F(ab’)3 structure in coltelizumab has been proven to enhance the T-cell receptor modulation activity (drug potency) more than the bivalent teplizumab antibody counterpart. Unlike the Fc-engineered existing anti-CD3 antibodies which can still activate T cells, resulting in mild cytokine release syndrome, coltelizumab does not contain the Fc fragment, without any Fc-receptor binding activity. Therefore, coltelizumab is a genuine non-mitogenic version of anti-CD3 antibody and can be used to treat acute allograft rejection and autoimmune diseases with greater drug potency and lower side effect than the current low-mitogenic versions in clinical trials.