Using an anti Nanobody® secondary antibody for direct detection, rather than by adding a tag to the nanobody, can provide advantages in many applications. For example, in therapeutic applications, most pharmaceutical companies do not add tag proteins like FLAG® or His to nanobodies to avoid adding more risk factors. Some researchers may design Fc-fused nanobodies to aid detection and extend the half-life. However, Fc-fused nanobodies would lose their small size advantage and trigger non-specific binding (many cells have Fc receptors) as well as Fc-mediated complement reactions. Besides, anti-VHH antibody can reduce cross-reactivity with endogenous proteins that are homologous to some tag epitopes.
GenScript MonoRab™ Rabbit Anti-VHH antibodies specifically recognize heavy chain antibodies but not the conventional IgG1 type (Figure 7) found in camelid sera and have low cross-reactivity among other species (Figure 8). As a result, GenScript MonoRab™ Rabbit Anti-VHH antibodies can be used as an anti llama secondary antibody or anti alpaca secondary antibody and accurately detect the amount of VHH in a sample.
Figure 7. MonoRab™ Rabbit Anti-Camelid VHH Antibody, mAb (Cat. No. A01860) and MonoRab™ Rabbit
Anti-Camelid VHH Cocktail (Cat. No. A02014) are specific to the variable domain of camelid heavy chain
Figure 8. MonoRab™ Rabbit Anti-Camelid VHH Antibody, mAb (Cat. No. A01860) and MonoRab™ Rabbit Anti-Camelid VHH Cocktail (Cat. No. A02014) are specific to Camelid IgG, while MonoRab™ Rabbit Anti-Humanized VHH Antibody, mAb (Cat. No.A02165) is specific to Humanized VHH. All these three antibodies have no cross-reactivity with mouse, rat, rabbit, goat, and human immunoglobulins, so that they can be used for the detection of different species of blood samples.