Which immunoglobulin class(es) has (have) a J chain?

Which immunoglobulin class(es) has (have) a J chain?

• A. IgM
• B. IgE and IgD
• C. IgM and sIgA
• D. IgG3 and IgA

Answer: (C)

The correct answer is that IgM and secretory IgA (sIgA) are associated with the presence of a J chain. The J chain is a small polypeptide that is crucial for the polymerization of immunoglobulin molecules. In the case of IgM, it exists as a pentamer in serum, where five monomeric subunits are linked together by the J chain, enhancing its ability to precipitate antigens and activate complement. Similarly, secretory IgA, found predominantly in mucosal areas such as the gastrointestinal and respiratory tracts, is formed as a dimer. The two IgA monomers are interconnected by the J chain, allowing for greater stability and protection from proteolytic enzymes in mucosal secretions. The association of the J chain with IgM and sIgA highlights its role in facilitating the structural integrity and functionality of these immunoglobulins in immune responses. In contrast, other immunoglobulin classes mentioned, such as IgE, IgD, and IgG3, do not incorporate a J chain in their structure. IgE is typically a monomer and does not require a J chain for its function. IgD is also a monomer and serves mainly as a receptor on B

The correct answer is that IgM and secretory IgA (sIgA) are associated with the presence of a J chain. The J chain is a small polypeptide that is crucial for the polymerization of immunoglobulin molecules. In the case of IgM, it exists as a pentamer in serum, where five monomeric subunits are linked together by the J chain, enhancing its ability to precipitate antigens and activate complement.

Similarly, secretory IgA, found predominantly in mucosal areas such as the gastrointestinal and respiratory tracts, is formed as a dimer. The two IgA monomers are interconnected by the J chain, allowing for greater stability and protection from proteolytic enzymes in mucosal secretions.

The association of the J chain with IgM and sIgA highlights its role in facilitating the structural integrity and functionality of these immunoglobulins in immune responses.

In contrast, other immunoglobulin classes mentioned, such as IgE, IgD, and IgG3, do not incorporate a J chain in their structure. IgE is typically a monomer and does not require a J chain for its function. IgD is also a monomer and serves mainly as a receptor on B