Lymphocytes or natural killer is one of the component of innate immune system where it acts as defense mechanism of the body that are always present to mobilize and fight bacteria, viruses and microbes at the site of infection.
Moreover, innate immune system also refers to non-specific recognition of certain molecular shapes on pathogens. Other components of innate immune system includes physical epithelial barriers, phagocytic leukocytes, dendritic cells, and circulating plasma proteins.