Overview Of Immune Response

INTRODUCTION

When a pathogen enters your body, it either survives or becomes ineffective. We will talk about the first scenario sometime later. In the second case, when I say the pathogen becomes ineffective, it refers to the competence of your immune response. The pathogen which was actually potential enough to cause illness in your body couldn’t cause any kind of harm. Why ?? It’s because of the functionality of your immune system which was capable of generating a perfect defence mechanism against the pathogen. By the above statement you can conclude that if you are fine doesn’t guarantees that you are not attacked. Now before we get deeper into the immune mechanism and physiology of the immune system, let’s take a look at the structure of an immune system.

STRUCTURE OF HUMAN IMMUNE SYSTEM

Our immune system is composed of various types of cells which are mostly derived from the bone marrow. Fundamentally, blood consists of three types of cells — Red Blood Cells, White Blood Cells and Platelets. WBCs are the cells which provides you the immunity. These cells can be classified as mentioned below.

Furthermore, T lymphocytes can be classified into 4 types namely, Hyper T cells, Cytotoxic T cells, Memory T cells and Regulatory T cells. All the cells of the immune system are found throughout the body, located either in the lymphoid tissues or body fluids. The lymphoid tissues are found around the mucosal surface of respiratory, gastrointestinal and urogenital tracts.

UNDERSTANDING IMMUNE RESPONSE

We can broadly classify human immune response into three different categories namely the physical barriers, innate immunity and adaptive immunity. Skin is an impenetrable barrier which provides defense against an infection. Any kind of skin defacement can make your body more vulnerable to microbial infection. Similarly, the enzymes in mucous, lysozyme in tears and saliva are some of the other physical barriers.

Innate immune response is the first defense mechanism against the pathogen after it enters the body crossing the physical barriers. By the word innate (which means inborn) it is clear that this kind of defense mechanism is naturally or genetically existing in your body which has a common way of functioning or responding to all invading pathogens.

Adaptive or Acquired immune response is a peculiar defense mechanism generated against a pathogen. The purpose of adaptive immune response is to develop long lasting immunity to the particular pathogen and avoid reinfection. It is initiated after the innate immunity signals the immune system to develop a specific response. These signals involve activation of phagocytes, production of specific antibodies and others.

MALFUNCTIONING OF IMMUNE SYSTEM

Inherited abnormality in the immune system can be explained as the existence of mutant genes which cause the immuno deficiency disease. These diseases are characterised by poor or incompetent defense mechanism. An immune deficiency can be caused due the absence of one or more immune system components. For eg: absence of antibodies or impaired functioning of B cells or T cells.

Unlike the previous scenario, the immune system can be hyper reactive. We know, the basic principle of immune response is recognition of foregin body and generating strong defense mechanism against it. Essentially the immune system must react against the “harmful” foreign body only. In everyday life we come in contact with several components through various means. Undoubtedly, these components are foreign bodies but not necessarily malignant. For eg: some food item, insects or pests, allergens, medicines, etc. This stimulation of immune response against the innocuous molecules is called hypersensitivity or allergic reactions.

The last and the most important category is the Autoimmune Disease. These diseases are caused by the immune system itself which attacks the target tissues or organs of the body. In other words an autoimmune disease is an abnormal condition in which the mechanisms preventing the immune system to attack its own cells and tissues are affected. Genetic factors, environmental factors ( for eg: exposure to chemicals) or consequences of an immune response can contribute to the cause of an autoimmune disease.

IMPROVING IMMUNITY

Improper nutrient intake or malnourishment can make you more susceptible to infection. Fever, chills, fatigue, anorexia, etc are some of the clinical manifestations of infection which clearly indicate the existence of nutrient imbalance in your body. Such imbalance or nutrient deficiency can impair the functioning of the defense mechanisms developed by the body. Through a balanced diet and proper nutrient supplementation the immune response can be enhanced and possibility of severity can reduced to a greater extent. Let’s take a brief look of such nutrients.

IRON

Studies have shown that iron deficiency can hinder cell mediated immunity, phagocyte microcidal function and mucosal immunity. Some of the other findings state that 1. iron deficiency has shown reduction in natural killer cell activity and the production of cytokines. 2. Presence of iron helps monocytes to suppress the growth of mycobacterium tuberculosis 3. Prevention of iron deficiency lowers the incidence of common infection. Provided all the statements mentioned above are true, oral iron supplementation within the recommended limits will prove to be beneficial.

ZINC

The role of zinc in the human body is vast. In addition to the existance of numerous zinc dependent enzymes, Zinc is essential to prevent deficiency symptoms like retarded growth, diarrhea, hair loss and others. Studies show that lower serum zinc levels are associated with impaired cell mediated immunity. Some other findings reveal that 1. Zinc deficiency was linked to poor functionality of phagocytes 2. Reduced natural killer cell function 3. And decreased antibody production.

VIT — A

According to studies, in some cases atrophy of lymphoid organs (spleen, thymus, lymph nodes) is the result of Vitamin A deficiency. Also some of the case studies have shown the abnormality in T lymphocytes subpopulation when experiments were conducted on a group of Vit A deficient individuals. Additionally, lack of Vit A has a great impact on the functionality of various cells of the immune system.

VIT — E

Studies have shown that Vit E supplementation has immunostimulatory effect and enhances both humoral and cell mediated responses. Also vitamin E supplementation has shown improvement in antibody production. Some of the other studies state that administration of Vit E increases the neutrophil phagocytic activity.

VIT — C

Vitamin C which is known for its anti-oxidizing properties absorbs free radicals and detoxifies the cells. Hence vitamin C proves to be of great help if you are exposed to any kind of infection, environmental pollution, or are subjected to toxins/ alcohol/ smoking.

SELENIUM

Selenium is another nutrient with anti-oxidizing properties that helps to reduce peroxides into compounds that can be easily eliminated. For eg: In the presence of selenium, hydrogen peroxide can be converted into water and oxygen.

In brief all the above statements are based on previously conducted studies which state that these nutrients enhance the immune response in the human body. Regular administration of these nutrients can strengthen the functionality of your immune system.

NOTE: Consult your dietician and doctor if you are planning to add supplements to your regular diet. Intervention of health experts will guide you to the right food sources and dietary allowances.

REFERENCES

Peter Parham (2000) The Immune System, : Routledge.

Nestle Nutrition Workshop 1999 (2001) Nutrition, Immunity, and Infection in Infants and Children, : Lippincott Williams & Wilkins Hardcover.

Carlson Wade (1990) Immune Power Boosters, Englewood Cliffs: Prentice Hall