Current therapeutic antibodies such as Trastuzumab, are typically of the blood circulatory IgG1 class (Cκ/ CHγ1). Due to the binding to Her2 also present on normal cell surfaces, side effects such as cardiac failure can sometimes be associated with such targeted therapy. Using antibody isotype swapping, it may be possible to reduce systemic circulation through increased tissue localization, thereby minimising unwanted side effects. However, the effects of such modifications have yet to be fully characterized, particularly with regards to their biophysical properties in antigen binding. To do this, we produced all light and heavy chain human isotypes/subtypes recombinant versions of Trastuzumab and Pertuzumab, and studied them with respect to recombinant production and Her2 binding. Our findings show that while the light chain constant region changes have no major effects on production or Her2 binding, some heavy chain isotypes, in particularly, IgM and IgD isotypes, can modulate antigen binding. This study thus provides the groundwork for such isotype modifications to be performed in the future to yield therapeutics of higher efficacy and efficiency.