Modifiers matching peptide:

• psychoactive,
• addictive,
• endogenous,
• proinflammatory,
• active,
• natural,
• interesting,
• antigenic,
• foreign,
• analgesic,
• minor,
• anticancer,
• synthetic,

Simple categories matching antigenic:

• stimulation,
• substance,
• peptide,
• constituent,
• receptor,
• protein,
• agent,
• component,
• substrate,
• property,
• carrier,
• preparation,
• material,
• polymer,
• compound,
• macromolecule,
• molecule,