We have five different types of antibodies. And one of these antibodies is immunoglobulin M. And it's immunoglobulin M that is produced predominantly in the primary response. Now, immunoglobulin M forms a pentamer and what that means is five individual antibodies orient in the following format to basically create this pentamer structure and they are held together by disulfide bonds. So this is our primary response. Now, what about a secondary response? So let's suppose as soon as the primary response is over, our pathogen reinfects our body.