Macrophages are more efficient and multi-purposed than neutrophils. However, more recently, secretory functions of macrophages have been elucidated. They are extremely important for antigen processing and presentation to lymphocytes. Many monokines have immunoregulatory functions. Macrophages can be cytotoxic and participate in antitumor and antiviral mechanisms.
Mononuclear phagocytes are a prominent component of chronic inflammation.
The two major types of lymphocytes are B cells and T cells. B lymphocytes are responsible for humoral immunity and are precursors to plasma cells. T lymphocytes are responsible for cell mediated immunity. T lymphocytes have various types of regulatory functions. Without special immunohistochemical stains, it is impossible to distinguish lymphocyte types morphologically.