IgE is only found in mammals. IgE is the least abundant isotype of all antibodies, but it is capable of triggering the most powerful immune reactions. IgE plays an important role in allergy, and leads to excessive activation of mast cells and basophils by binding to their Fc receptors, resulting in an extreme inflammatory response.
IgE is able to bind to to versions of Fcε receptors:
FcεRI (type I Fcε receptor), the high-affinity IgE receptor
FcεRII (type II Fcε receptor), also known as CD23, the low-affinity IgE receptor
Function in mammalian body
IgEs have co-evolved with basophils and mast cells in the defence against parasites like helminths (like Schistosoma) but may be also effective in bacterial infections. Epidemiological research shows that IgE level is increased when infected by Schistosoma mansoni and nematodes in humans. It is most likely beneficial in removal of hookworms from the lung.
Except its established function for allergy, there is still speculation about the physiological contributions of IgE. In animal models circumstantial evidence hints to IgE fighting gut parasites like parasitic worms, but this has not been conclusively proven in humans. IgE may play some role in the immune system's recognition of cancer. However, so far there is only circumstantial evidence for this hypothesis though, like for example the observation that the prevalence of several cancers is lower in individuals with allergies. Additionally, treatment with immunesystem-suppressing substances increases the cancer risk. Interestingly, individuals with allergies have lower level of toxins. It is thought possible, that IgE bind an help to destroy or excrete toxins.
Below you will find a list of anti- secondary antibodies.
Anti-Immunoglobulin E (IgE)
Links to other secondary antibody-types