GENERAL HISTOLOGY

Detailed explanation-1: -Natural killer (NK) cells. These are large granular lymphocyte-like cells with important functions in innate immunity. Although lacking antigen-specific receptors, they can detect and attack certain virus-infected cells.

Detailed explanation-2: -Cytotoxic T lymphocytes, natural killer (NK) cells and antiviral macrophages can recognize and kill virus-infected cells. Helper T cells can recognize virus-infected cells and produce a number of important cytokines.

Detailed explanation-3: -Bacteria (or their products) picked up from the tissues by cells called macrophages, or those that flow into the lymph, are forced to percolate through the lymph nodes. There, white blood cells called lymphocytes can attack and kill the bacteria.

Detailed explanation-4: -The two main types of lymphocytes are B lymphocytes and T lymphocytes. B lymphocytes make antibodies, and T lymphocytes help kill tumor cells and help control immune responses. A lymphocyte is a type of white blood cell.