<unk>  refers to all<unk> s endogenously produced by DNA-level transcription and translation within an organism of interest. This does not include<unk> s synthesized due to viral infection, but may include those synthesized by commensal bacteria within the intestines.<unk> s that are not created within the body of the organism of interest, but nevertheless enter through the bloodstream, a breach in the skin, or a mucous membrane, may be designated as “non-self” and subsequently targeted and attacked by the immune system. Tolerance to<unk>  is crucial for overall wellbeing; when the body erroneously identifies<unk> s as “non-self”, the subsequent immune response against endogenous<unk> s may lead to the development of an autoimmune disease.
Self-protein
Immunogen
Polysaccharide peptide
Protein 
Glycol nucleic acid
Polysulfated glycosaminoglycan
Antigen
Protelean