I will explain the statement 'his B cells will take care of it in no time!
I will start by explaining to him what B cells are literally all about and how they function in the body to fight/wade off infections.
B-cells or B lymphocytes are type of white blood cell, they are made in the bone marrow and they belong to the lymphocytes subtype and plays a crucial role in
the humoral immunity component of the adaptive system,they do so by the making antibiotics to fight off invading bacteria and viruses. (Antigens).
The play the role of antigen presenting cells and further form memory cells after they are activated by antibody-antigen reaction.
B cells can develop into memory cells or plasma cells which produce the most antibodies.
So when there is a bacterial invasion like in the above question,the memory cells of the B lymphocytes identify the bacteria,attack it and mark it for destruction.