Immune system of the body normally protects from viruses, bacteria, fungi, toxic molecules and other foreign proteins that find their way into the body. The immune system executes its work through two different modes, which include Antibody-mediated immunity (humoral immunity) and Cell-mediated immunity. The antibody-mediated immunity usually operates through B-lymphocytes (B cells) by producing specific antibodies. The cell-mediated immunity, on the other hand, operates through various types of immune cells such as T-lymphocytes (T cells), natural killer cells (NK cells), lymphokine activated killer cells (LAK cells) and macrophages, which are empowered to eliminate viruses, bacteria, toxic molecules and other foreign proteins from the body either physically (by engulfing) or by secreting specific chemicals. It is the cell-mediated immunity that works against cancer. Most of the newly formed cancerous cells never grow beyond the microscopic stage because the immune system of the body is capable to nip these abnormal cells in the bud, before they grow to form a tumour. The transformation of a normal cell into the cancerous cells is probably not as critical an event in the development of cancer as the body’s inability to destroy the newly formed cancerous cells, when they are few in number.
When a cell becomes cancerous, it acquires new surface antigens and even loses some normal antigens. This makes the cancerous cell antigenically different from the normal cells of the body. Immune system of the body normally recognises and destroys these newly formed cancerous cells through the cell-mediated immunity. This work is usually executed by T-lymphocytes (T cells), natural killer cells (NK cells), lymphokine activated killer cells (LAK cells) and macrophages. The T cells and NK cells are capable to recognise and destroy the cancerous cells at the first sight. The NK cells are armed with more than 100 biochemicals to destroy the foreign proteins and they play an important role in inhibiting micrometastases by killing the circulating cancerous cells. The macrophages work by destroying and ingesting the cancerous cells.
There are three major types of lymphocytes, i.e. T lymphocytes (T cells), B lymphocytes (B cells) and large glandular lymphocytes (null cells). The null cells include natural killer cells (NK cells), lymphokine activated killer cells (LAK cells) and antibody dependent cellular cytotoxic lymphocytes (ADCC). All types of the lymphocytes are produced in bone marrow but are matured in different tissues, for example, T lymphocytes and natural killer cells are matured in the Thymus gland, while the B lymphocytes are matured in the Mucosa associated lymphoid tissue (MALT) such as Peyer’s patches. Macrophages are produced in the bone marrow as monocytes but these get transformed into macrophages after reaching various tissues.
Immune cells of the body produce certain anticancer agents, known as cytokines (Lymphokines and Monokines), which include Interleukins (IL-1 to IL-15), Interferons (alpha, beta and gamma), tumour necrosis factors (TNF) and colony stimulating factors (CSF). So the body is having its own immunotherapeutic regime in the form of cytokines, which can destroy and eliminate the cancerous cells from the body without harming healthy cells. If there is spontaneous regression of a tumour (as seen in a few cases), the credit should not be taken away from the cytokines.
It has been observed that the risk of developing cancer is multiplied manifold in those persons, whose immune system is suppressed due to any reason, for example, undernutrition, old age, HIV and other viral infections. Immune system of the body also gets suppressed by the frequent, widespread, chronic and habitual use of certain drugs such as antibiotics, corticosteroids, painkillers and the drugs used in chemotherapy. Most of the antibiotics, corticosteroids and painkillers (such as aspirin, acetaminophen and ibuprofen) inhibit the production of antibodies and suppress immune functions of the body. Antibiotics promote growth of Candida albicans in the intestines, which further suppresses the immunity. Vaccinations also suppress the immunity of the body for a couple of weeks. Studies have shown that the count of helper T cells decreases in the infants and children after receiving the dose of multiple vaccines (vaccine cocktail). Almost all the drugs used in chemotherapy are known to suppress immune functions of the body, which could lead to the development of a new cancer.
Studies have shown that the patients suffering from AIDS (HIV infection) have a very high incidence of cancer (such as Kaposi’s sarcoma, non-Hodgkin’s lymphoma, carcinoma of the cervix and carcinoma of the anus) due to the suppressed immunity. It has been observed that chronic stress leads to production of stress hormone (cortisone), which suppresses the immune system of the body, thus favouring the genesis of cancer. Scientists all over the world are concentrating on the use of herbal medicines to boost the immune system of the body against cancer.