Final answer:
IgM and IgD are the immunoglobulins typically found on the surface of B lymphocytes, with IgM being the predominant one involved in the body's initial immune response.
Step-by-step explanation:
The immunoglobulins (Ig) that are almost always cell associated on the surface of B lymphocytes are IgM and IgD. Naïve B cells express IgM in a monomeric membrane-bound form which acts as the antigen-binding receptor.
Together with IgM, IgD is also found on the surface of B cells, however, it is present only in trace amounts in the serum and is mainly important for antigen recognition and B cell maturation. IgM, on the other hand, is secreted by plasma cells in a pentameric form after its initial response as a monomer on naive B cells, making it essential in the body's first line of defense against infections.