The characteristic of Nk cells is that they recognise the pathogen and always attack in troops.
As phagocytes or special cells cannot distinguish between pathogens so it is said that they engulf every pathogen present in the body . So my que is that, it is not necessary that all pathogens entering into the body are harmful some of them may be useful then are they also killed by these phagocytic cells?
Antibodies produced by B cells can attack both extracellular and intracellular pathogens