Antibody Dependent Enhancements (ADE) refers to a phenomenon in immunology where the presence of certain antibodies can actually enhance the ability of a virus or infectious agent to enter host cells and propagate infection. This effect occurs when specific antibodies, instead of neutralizing the pathogen, facilitate its entry into cells that express Fc receptors.
Fc receptors are found on various immune cells, such as macrophages and dendritic cells, and are capable of binding to the Fc portion of antibodies. When a virus is opsonized, or coated, with these non-neutralizing antibodies, the Fc receptors recognize and bind to the antibodies, resulting in the internalization of the virus into these immune cells.
In cases of Antibody Dependent Enhancements, the virus gains entry into these immune cells more effectively compared to when neutralizing antibodies are present. Consequently, the virus can take advantage of these immune cells for replication and dissemination, leading to increased viral load and potentially more severe disease outcomes.
ADE has been observed in certain viral infections, such as dengue fever and Zika virus, where the presence of suboptimal levels of neutralizing antibodies can predispose individuals to more severe disease manifestations upon subsequent infections with different strains or serotypes of the same virus.
Understanding the mechanisms underlying Antibody Dependent Enhancements is crucial in the development of vaccines and therapeutics, as it highlights the importance of eliciting neutralizing antibodies and minimizing the risks associated with ADE in order to achieve effective immune protection against viral infections.
