Mannose-binding protein in the lectin pathway is most similar to which classical pathway component?

Mannose-binding protein in the lectin pathway is most similar to which classical pathway component?

• A. C3
• B. C1q
• C. C1rs
• D. C4

Answer: (B)

Mannose-binding lectin acts as a pattern-recognition molecule in the lectin pathway, binding pathogen surfaces with a structure that mirrors the classical pathway’s recognition unit. It’s a collectin with a collagen-like stalk that forms multimers, just like C1q. When MBP binds, it activates associated MASP proteases to cleave C4 and C2, kicking off the same downstream cascade that the C1q-containing complex initiates in the classical pathway. So, the component of the classical pathway MBP most closely resembles is C1q, the recognition molecule.

Mannose-binding lectin acts as a pattern-recognition molecule in the lectin pathway, binding pathogen surfaces with a structure that mirrors the classical pathway’s recognition unit. It’s a collectin with a collagen-like stalk that forms multimers, just like C1q. When MBP binds, it activates associated MASP proteases to cleave C4 and C2, kicking off the same downstream cascade that the C1q-containing complex initiates in the classical pathway. So, the component of the classical pathway MBP most closely resembles is C1q, the recognition molecule.