IMMUNOLOGY

 

IMMUNOLOGY

INTRODUCTION

Our bodies are continually under attack by millions of unseen foes, including viruses, bacteria, fungus, parasites, and other disease-causing pathogens that can penetrate our bodies and cause disease. Fortunately, most of us have a massive army on constant alert with an effective armament ready to combat these intruders. The immune system is that army.

DEFINITION:

Immunology is the study of the immune system, which is made up of a complex network of cells, tissues, and organs that communicate via a sophisticated and sensitive system.

EXPLANATION:

 A variety of white blood cells (leukocytes) and antibodies are always on the lookout for infections, ready to leap into action and send out chemical instructions through the bloodstream. Immunologists can improve the immune system's performance by better knowing what these cells and molecules do and how they communicate with one another (for example, by developing new vaccines). They can also figure out how to inhibit the immune system from reacting to an inappropriate target, such as in allergies (a hyper reaction to pollen or other allergens) or autoimmune illnesses (when the immune system reacts against your own body).

Our bodies use three primary ways to defend ourselves from infection:

By erecting nonspecific barriers to prevent germs and viruses from taking hold. Skin, mucus discharges in the respiratory and gastrointestinal systems, saliva, tears, and stomach acid are all examples of these.

Beneficial bacteria that live in the intestines and help digest specific types of food (known as the normal flora) compete with pathogenic bacteria for food and space, reducing the likelihood of disease-causing pathogens multiplying and causing sickness.

By relying on our innate immune system to detect invaders that get past the first line of defense. Innate immunity cells and other systems sense and respond to infections in a nonspecific manner, and they do not provide long-term or protective immunity. They are phagocytic ("eating") cells that ingest and consume pathogens and particles. Phosphatic leukocytes include macrophages, polymorphonuclear cells, dendritic cells, and mast cells. The natural killer cell is a nonphagocytic member of the innate immune system (the part of the immune system with specialized cells that identify and typically eradicate a bodily invader before it can proliferate) (NK). The NK does not directly assault a disease; instead, it destroys contaminated cells. Tumor cells are also attacked by NK cells.

If pathogens get past the barriers and phagocytes and start multiplying, a unique adaptive immune response is activated. Adaptive immunity is based on our lymphocytes' unique ability to discriminate between the body's cells (self) and undesirable invaders (no-self) based on distinct self-markers on our cells. The natural killer cell is a nonphagocytic member of the innate immune system (the part of the immune system with specialized cells that identify and typically eradicate a bodily invader before it can proliferate) (NK). The NK does not directly assault a disease; instead, it destroys contaminated cells. Tumor cells are also attacked by NK cells.

If pathogens get past the barriers and phagocytes and start multiplying, a unique adaptive immune response is activated. Because of different self-markers on our cells, our lymphocytes have a remarkable ability to distinguish between the body's cells (self) and undesirable invaders (no-self), which is the foundation of adaptive immunity. When our immune self-defenses across organisms or cells with "foreign" marks, they initiate an attack right away. The adaptive immune response allows the immune system to detect a pathogen and mount a stronger and faster attack each time the disease is encountered.

An antigen is something that can cause an immunological reaction. A germ, such as a virus, or even a portion of a microbe, can be an antigen. Antigens are no self-indicators carried by tissues or cells from another person (excluding identical twins). This helps to understand why tissue transplants are sometimes rejected. B cells and T cells are the two main types of lymphocytes that make up our immune system. B cells primarily function by secreting antibodies into the body's fluids. Antibodies swoop down on antigens in the bloodstream. They are unable to penetrate cells, though. T cells and other immune cells are in charge of fighting target cells, whether they've been infected by viruses or have been warped by cancer.

T cells, unlike B cells, do not identify antigens that are floating in the air. Rather, they have specific antibody-like receptors on their surfaces that detect antigen fragments on the surfaces of infected or malignant cells. T cells aid immune defenses in two ways: some guide and regulate immunological responses, while others help to suppress them. The cells, or helper T cells, communicate with other cells to coordinate immune responses. Some activate surrounding T cells, while others summon in phagocytes and stimulate nearby B cells to generate antibodies.

Killer T cells, also known as CTLs or cytotoxic T lymphocytes, have a different purpose. By connecting to other cells and delivering a fatal blast of chemicals that they safely carry within small membrane "bags" called granules, these cells directly assault other cells containing particular foreign or aberrant molecules on their surfaces. CTLs are very effective against viruses that are developing within infected cells. Small bits of these viruses peeking out from the Some of the B cells and T cells that participated in the attack on a foreign invader go on to become memory cells with a long lifespan. They can reproduce to mount a faster and stronger immune response in a second encounter with the invader. The scientific basis for immunization is this phenomenon.

The immune system's diverse cells create and secrete a variety of chemicals that alert other cells to the presence of an invader and aid in the activation of an immune response. Histamine (which dilates blood vessels, produces inflammation, and draws neutrophils and macrophages), interferons (which are released when viruses and tumor cells are encountered), and interleukins (which are released when viruses and tumor cells are encountered) are among them (which are vital to the functions of the immune system). The cell membrane is recognized by CTLs, which start an attack to kill the cell.

IMMUNOLOGICAL SUBDISCIPLINES

 Immunogenetics

This includes research on the genetics (inheritance) of immunological responses, such as the Rh and ABO blood groups, or the HLA system, which is vital in kidney and other transplants. The field also looks into the genetics of an individual's antigen-response capabilities.

Immunology in Clinical Practice

From a medical standpoint, this is the study of diseases produced by the immune system and disorders of the immune system. The majority of these illnesses fall into one of three categories: immunodeficiency, in which parts of the immune system fail to respond adequately; autoimmunity, in which the immune system attacks its cells; and hypersensitivity, in which the immune system reacts inappropriately to harmless compounds (allergies and asthma) or responds inappropriately to harmful compounds (allergies and asthma).

AIDS (acquired immunodeficiency syndrome) is a classic example of an immune-system disorder. It is defined by the absence of T helper cells and macrophages, both of which are killed by HIV (human immunodeficiency virus).

Clinical immunologists also research techniques to reduce organ transplant rejection and increase the immune system's ability to combat cancer.

Immunology at the molecular level

This mostly entails investigating the chemicals released by cells that regulate immune cell migration and activity. Chemicals that attract cells to an infection location and start the inflammatory process are examples of such compounds.

Immunology of the Cells

T cells are the subject of this research.

Immunology of the Humoral

The focus of this research is on B cells and the antibodies they make.