IgG is usually implicated in fighting off pathogens like viruses and bacteria. It doesn't typically cause an allergic response. IgE is usually implicated in fighting off pathogens like parasitic worms or mosquito bites. It's the antibody that regularly get confused and binds to peanut proteins and pollen. There is speculation on why the IgE mediated immune response gets confused. One hypothesis is IgE evolved much more recently and "needs more work".
The immune response to IgE binding is intense. Allergic reaction is an IgE response to a harmless antigen. However, IgE can be downregulated by repeated exposure to the antigen in question. If the body uses IgE too much (eg. from repeated exposure), it starts to replace IgE antibodies with the more subtle IgG antibodies.
The immune system is very fascinating really. IgE might be the key to effective cancer immunotherapy. Imagine if we could program your immune system to fight a cancer as intensely as it fights a pollen grain or peanut in an allergic individual. There is a lot of research in this area these days.
I was unaware that IgE producing B cells transform to IgG after repeated exposure. My previous understanding was that IgE production was a terminal state and responded similarly to increased antigen on IgG presenting Bcells. The hygiene hypothesis makes a good bit more sense now, given that transformation.
The immune response to IgE binding is intense. Allergic reaction is an IgE response to a harmless antigen. However, IgE can be downregulated by repeated exposure to the antigen in question. If the body uses IgE too much (eg. from repeated exposure), it starts to replace IgE antibodies with the more subtle IgG antibodies.
The immune system is very fascinating really. IgE might be the key to effective cancer immunotherapy. Imagine if we could program your immune system to fight a cancer as intensely as it fights a pollen grain or peanut in an allergic individual. There is a lot of research in this area these days.