Immunoglobulin M (IgM) antibodies are produced as a first response to a new non-self antigen, providing short-term protection. Then, immunoglobulin G (IgG) antibodies are produced during the initial infection. Around 70-80% of the immunoglobulins in the blood are IgG, and your body retains a catalogue of these antibodies to rapidly reproduce them whenever exposed to the same antigen. IgG antibodies form the basis of long-term protection against microorganisms. Immunoglobulin A (IgA) antibodies comprise about 15% of the total lung and stomach secretions and breast milk. IgA protects against infection in mucosal areas of the body, which are the soft tissue that lines your body's canals and organs in the digestive, respiratory, and reproductive systems.