Question { IISc, 9955 }

if an individual was genetically unable to make j chains,which
immunoglobulin would be affected

Answer

The Joining chain (J chain) is a glycoprotein that is
associated with pentameric IgM and dimeric IgA.The J chain is
required to generate stable pentameric IgM and its absence IgM
will be assembled into hexamers. In the case of IgA J chain is
essential for the generation of dimeric IgA and its transport
onto mucosal surface, while serum IgA is also present in a
monomeric form that does not contain J chain protein. In the
absence of J chain, IgA will neither interact with poly-Ig
receptor nor form stable complexes with secretory component.
Kumudesh