About author :
Department of Pharmacy,
Southern University Bangladesh, Chittagong, Bangladesh
Immunology is a very potential branch of biomedical science that deals with the details of about immune system & immunity of the human body. This branch has a great focus on different pathogens that are responsible to cause diseases. Pathogens actually show their detrimental response by suppressing the activity of immune system of individuals. Here the activity or the ability of immune system is the immunity. Body’s defense activity depends on immunity of the immune system to protect or prevent the entry foreign bodies to the human body (immune response). Immunity could be vary in person to person as it is sure that in every people, the cells & organs of immune system could be same.
Keywords: Immunology, Immunity, Immune system, Pathogens, Immuno response.
The immune system is a network of cells, tissues, and organs that work together to defend the body against attacks by “foreign” invaders. These are primarily microbes—tiny organisms such as bacteria, parasites, and fungi that can cause infections. Viruses also cause infections, but are too primitive to be classified as living organisms. The human body provides an ideal environment for many microbes. It is the immune system’s job to keep them out or, failing that, to seek out and destroy them.
Types of Immune System :
1. Innate Immuno system
2. Adaptive (Acquired) Immuno system
Innate Immuno system :
The innate immune system consists of cells and proteins that are always present and ready to mobilize and fight microbes at the site of infection. The main components of the innate immune system are
1) Physical epithelial barriers
2) Phagocytic leukocytes
3) Dendritic cells
4) A special type of lymphocyte called a natural killer (NK) cell, and
5) Circulating plasma proteins.
Adaptive immune system :
The adaptive immune system, on the other hand, is called into action against pathogens that are able to evade or overcome innate immune defenses. Components of the adaptive immune system are normally silent; however, when activated, these components “adapt” to the presence of infectious agents by activating, proliferating, and creating potent mechanisms for neutralizing or eliminating the microbes.
There are two types of adaptive immune responses:
Humoral immunity is mediated by antibodies produced by B lymphocytes.
Cell-mediated immunity is mediated by T lymphocytes.
1. The Humoral System :
The humoral system of immunity is also called the antibody-mediated system because of its use of specific immune-system structures called antibodies. The first stage in the humoral pathway of immunity is the ingestion (phagocytosis) of foreign matter by special blood cells called macrophages. The macrophages digest the infectious agent and then display some of its components on their surfaces. Cells called helper-T cells recognize this presentation, activate their immune response, and multiply rapidly. This is called the activation phase.
The next phase, called the effector phase, involves a communication between helper-T cells and B-cells. Activated helper-T cells use chemical signals to contact B-cells, which then begin to multiply rapidly as well. B-cell descendants become either plasma cells or B memory cells. The plasma cells begin to manufacture huge quantities of antibodies that will bind to the foreign invader (the antigen) and prime it for destruction. B memory cells retain a “memory” of the specific antigen that can be used to mobilize the immune system faster if the body encounters the antigen later in life. These cells generally persist for years.
2. The Cell-Mediated System :
The cell-mediated immune response involves cytotoxic T-cells, or killer-T cells. Body cells that have been infected by foreign matter often present components of that material on their surfaces. Killer-T cells recognize these displays and respond by ingesting or otherwise destroying the infected cell. Killer-T cells are also important in the body’s defenses against parasites, fungi, protozoans, and other larger cells that might have found their way into the body. The killer-T cells recognize these large invaders by their foreign proteins and then destroy them. Killer-T cells also produce T memory cells which “remember” a specific protein or antigen. The combination of T-cell and B-cell memory assures the body of familiarity with any antigens or foreign agents that have been present in the body within the last few years. A response to an agent against which the body has already formed memory cells is called a secondary response. All other responses are primary responses.
Problems of Immune System / Immunity :
As immune system is the defense system of human body & can control the disease caused by invaders by preventing or killing them, we should take care of our immune system. We can easily do it by boosting its power. Different vitamins (Vitamin C, Vitamin E etc.) Minerals , Dietary Suppliments etc. can be some of the boosters. Most of the seasonal diseases can prevent by boosting our immunity because prevention is more important than cure.