We have five different types of immunoglobulins. And two of these immunoglobulins that are capable of binding to this C One complex are immunoglobulin M and immunoglobulin G. So let's suppose immunoglobulin M. This antibody finds its complement antigen, it binds to it, and then that complex goes on and binds onto the C One Q portion of the C One protein. And then that activates C one R, and then that activates C one S. Now, C one X is actually C one S is actually a serene protease. And what that means is it can go on and activate other proteins that are part of the classical pathway by cleaving them at specific amino acid sequences. So to see what we mean, let's take a look at the following diagram. So this is the entire C One complex.