The answer is IgM (Immunoglobulin M) and IgA (Immunoglobulin A).
In the antibodies of IgM and IgA, J chain is a protein component. This component is required for both immunoglobulins to be secreted into the mucosa. Initially, J chain is required in polymerization according to the hypothesis but was found out lately that IgM is able to polymerize without the J Chain.
