Immunology is a source of continuous discoveries; Immunology was and still is a source of continuous discoveries. Immunomodulation encompasses all therapeutic interventions aimed at modifying the immune response. Immunostimulation is desirable to prevent infection in states of immunodeficiency and to fight infections and cancer. On the other hand, immunosuppressive agents inhibit the activity of the immune system, and they are used to prevent the rejection of transplanted organs and tissues and to treat autoimmune diseases or diseases that are most likely of autoimmune origin (e.g., rheumatoid arthritis, systemic lupus erythematosus, Crohn’s disease, ulcerative colitis, etc.), or other nonautoimmune inflammatory diseases (e.g., allergic asthma). The discovery of immunomodulatory agents from medicinal plants devoid of toxic side effects, with enhanced bioavailability and that can be used for a long duration, is of great actuality. Research on natural immunomodulators provides a therapeutic solution that addresses a multitude of disorders. Plant phenolic compounds already proved beneficial effects in cardiovascular diseases, diabetes, and cancer, exerting mainly antioxidant and anti-inflammatory effects. The concepts of “immunomodulatory,” “anti-inflammatory,” and “antioxidant” are often strongly related, and a review of phenolic compound action on immune system should be analyzed in a context, revealing their mechanism of action on effector cells and also on the system as a whole.
Part of the book: Phenolic Compounds
Macrophages play an important role in cancer development, as they represent almost half of the cells forming the tumor microenvironment. They are called tumor-associated macrophages (TAMs) and most of them are alternative activated macrophages (M2 polarized), promoting cancer progression, angiogenesis and local immunosuppression. Blocking the macrophages recruitment, preventing their activation or turning M2 cells toward M1 phenotype (classic activated macrophage promoting an efficient immune response) is a modern immunotherapeutic approach for fighting cancer. Several studies showed that plant compounds (phenolics, triterpenes, coumarins, etc.) exert antitumor properties, not only by a direct toxical effect to malignant cells but also by influencing macrophage phenotypic differentiation.
Part of the book: Macrophages