This secondary antibody allows the detection of IgG1 from llamas and other camelids. It was produced in vitro and purified using protein G. It has low to no cross-reactivity toward IgG2 and IgG3.
Besides the conventional IgGs (IgG1, composed of heavy and light chains), llamas and other camelids produce single chain IgGs (IgG2 and IgG3). They are composed of heavy chains only and are lacking the light chains and the CH1 domains. The antigen binding domain of IgG2 and IgG3, called VHH, is the smallest naturally occurring antibody binding domain.