And so the concentration of the antibodies in our blood will begin to increase sharply. So if we plot the concentration of antibodies that are produced versus time, we basically get the following diagram. So the Y axis is the concentration of our antibodies, our immunoglobulins, and the X axis is the time given to us in weeks. So at week zero, we essentially have that pathogen invading our body. Infection takes place. Now, it's the first time that we are ever infected by that particular pathogenic antigen.