Activation of the Alternative Pathway Soluble proteins of the Alternative Pathway (B,D,P)bind to repetitive structures on microbial surfaces,such as components of the cell wall. The complex of B,D and P forms the C3 convertase of the Alternative Pathway. Recognition is selective for microbes,but not highly specific(pattern recognition). Activation of the Alternative Pathway Soluble proteins of the Alternative Pathway (B,D,P) bind to repetitive structures on microbial surfaces, such as components of the cell wall. The complex of B, D and P forms the C3 convertase of the Alternative Pathway. Recognition is selective for microbes, but not highly specific (pattern recognition)