Which complement components are involved in the alternate pathway?

The alternate pathway of the complement system is primarily activated in response to pathogens, without the need for antibodies, and plays a crucial role in the innate immune response.

The components involved in the alternate pathway include Factor B, Properdin, and Factor D. Factor B is essential because it binds to C3b, which is part of the complex formed with an activating surface. Properdin stabilizes the C3b:B complex, allowing it to cleave more C3 into C3b, thus amplifying the response. Factor D is involved in the conversion of factor B into its active form, Ba and Bb, which is critical for the formation of the C3 convertase enzyme.

This interaction of these components demonstrates how the alternate pathway rapidly responds to infection and amplifies the immune response, making it vital for effective pathogen clearance.