Gamma globulins are a series of globular proteins that have large molecular weights and are water soluble. Globulin proteins are ranked and classified by their relative positions in a gel electrophoresis separation. Gammas are on the higher end of the molecular weight scale. Many gamma globulins are basically antibodies, and so gamma globulins are often given as intravenous injections to help boost a person's immune system against a particular disease. It appears that gamma globulin injections have been around for almost 100 years, starting at the beginning of the 20th century.