B cell receptor complex IgA immunoglobulin complex IgA B cell receptor complex An IgA immunoglobulin complex that is present in the plasma membrane of B cells and is composed of two identical immunoglobulin heavy chains of an IgA isotype and two identical immunoglobulin light chains and a signaling subunit, a heterodimer of the Ig-alpha and Ig-beta proteins. GO:0071747 Note that an IgA immunoglobulin complex has the function of antigen binding if a suitable antigen is available. protein