And so that's why eventually, over time we see a drop in our concentration of immunoglobulbulins until it drops to very low undetectable levels as shown in the following diagram. And so this process ultimately takes place about four weeks as shown in this particular case for this particular invading pathogen. Now, the primary immunoglobulin that is used for this particular primary response and in general, the major type of antibody that is used for all primary responses is immunoglobulin M. So remember, we have five different classes of antibodies. 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.