TABLE OF CONTENTS Immune system guards body against infection and diseases. Important components of immune system are spleen, tonsils, bone marrow, lymph nodes, and white blood cells.
This appendix describes some important white blood cells such as lymphocytes and phagocytes, and bone marrow.
The lymphotic stem cells undergo transformation to:
T-lymphocytes, which provide cellular immunity.
B-lymphocytes, which form antibodies and provide humoral immunity.
Natural killer cells, which destroy infected cells.
T-lymphocytes produce cytokines, which are a type of proteins. Each type of B cell produces specific antibodies in response to specific antigens.
Immune system cells carry their communication with each other with the help of cytokines. These immune system communicators include lymphokines, interferons, interleukins and colony-stimulating factors. Some T cells release cytokines that directly attack the targetted cells. Such T cells are called cytotoxic T cells. Some T cells release cytokines that alert other immune system defenders. Such T cells are called helper T cells.
Interferons (IFNs) have been produced in the laboratory also. They are of three types called IFN ?, IFN ? and IFN ?. Use of IFN ? has been approved by Food and Drug Administration (FDA) for treatment of certain types of cancers including Kaposi's sarcoma, which is related to AIDS. Clinical trials are being conducted for using IFN ? in combination with BRMs and chemotherapy. IFNs retard the growth of cancer cells, some IFNs stimulate other components of immune system to activate anticancer function of the system.
Interleukins (ILs) can also be produced in laboratory.
