White blood cells (WBC) are like our body's guards patrolling our blood to look for any pathogens (bacteria and virus).WBC kills pathogens in the following ways before pathogens make us ill.Eating them: WBC come closer and surround the bacteria before they engulf and digest them. This is through a process called phagocytosis.Producing antibodies: WBC can produce antibodies (a protein) that can bind specifically to the antigens on the surface of bacteria. This acts like a key fitting into a lock. For example, only antibodies A can bind to antigen A but not antigen B. Antibodies are then produced rapidly to look for similar bacteria or virus around the body. If we get infected again by the same pathogen in the future, the white blood cells can produce the antibodies so quickly to kill the pathogens before they make us ill. Producing antitoxins: Invading bacteria can produce toxins to make us ill. WBC produce antitoxins to neutralise (make it less toxic) the toxins.