Which immunoglobulin has highest affinity?

The valency of IgM is five times greater than that of IgE, so the difference between the affinity and the avidity will be greater for IgM antibodies than IgE antibodies.

How do antibodies of the different classes IgM IgG IgA IgD and IgE differ from each other?

There are five immunoglobulin classes (isotypes) of antibody molecules found in serum: IgG, IgM, IgA, IgE, and IgD. They are distinguished by the type of heavy chain they contain. IgG molecules possess heavy chains known as γ-chains; IgMs have μ-chains; IgAs have α-chains; IgEs have ε-chains; and IgDs have δ-chains.

What is a high affinity antibody?

Antibody affinity refers to the strength with which the epitope binds to an individual paratope (antigen-binding site) on the antibody. High affinity antibodies bind quickly to the antigen, permit greater sensitivity in assays and maintain this bond more readily under difficult conditions.

Why do IgG and IgA have higher affinity than IgM?

B cells produce IgM first in response to microbial infection/antigen invasion. Although IgM has a lower affinity for antigens than IgG, it has higher avidity for antigens because of its pentameric/hexameric structure.