So the entire point of a B lymphocyte is to collect these antigens found inside our body and these antigens came from some type of pathogen. For example a bacterial cell. The next question is what happens once our antigen is bound onto the B cell receptor of our B cell? Well, a process known as cell mediated endocytosis begins to take place. And what this process does is it invaginates our cell membrane and it forms this vesicle that is brought into the cytoplasm of our cell as shown in this diagram. So the antigen shown in red binds onto the cell receptor of the B cell and then that initiates the cell mediated endocytosis process and that ultimately forms that internal vesicle.