Final answer:
White blood cells recognize foreign material using pattern recognition receptors, including Toll-like receptors, to identify and respond to pathogens.
Step-by-step explanation:
White blood cells use their own membrane molecules called pattern recognition receptors which include kinases to identify foreign material in the body.
These receptors include Toll-like receptors (TLRs), which are a type of pattern recognition receptor that recognizes molecules shared by pathogens but distinguishable from host molecules. Once identified, these foreign materials, such as viruses, bacteria, or parasites, which express pathogen-associated molecular patterns (PAMPs), can be attacked and destroyed by the immune system.