DER21

Der p 21 is secreted by Dermatophagoides pteronyssinus and travels in mite fecal particles that linger in indoor air. The protein can carry lipids, which likely protect it and help it interact with airway surfaces. In sensitized people, antigen-presenting cells show Der p 21 fragments that drive Th2 immunity and high IgE levels. The allergen also triggers epithelial alarm signals such as IL-33 and TSLP, which amplify inflammation. Neutralizing binders that capture Der p 21 before it hits immune sentinels could blunt these cascades. Stabilizing binders also make it easier to formulate precise immunotherapy doses that desensitize patients without provoking dangerous reactions.