Antibody and Ig

Antibody noun - Any of a large variety of proteins normally present in the body or produced in response to an antigen which it neutralizes, thus producing an immune response.

Ig and antibody are semantically related. In some cases you can replace term "Ig" with "Antibody", this nouns are similar.

Ig noun - A class of proteins produced in lymph tissue in vertebrates and that function as antibodies in the immune response.

Antibody and Ig are semantically related. You can use "Antibody" instead a noun "Ig".