A antibody is a protein what reacts against an antigen in an animal-like organism. Antibodies, which can be found in the blood or in other body fluids, are used by the immune system to recognize and block virus, bacteria, parasites or mushrooms.
Importantly, each type of antibody defends the body against a specific class of antigen. When the antibody mistakes healthy tissue for a harmful substance, it is called a autoimmune disorder.
The most common antibody is made up of basic structural units that have four chains: two light and two heavy. The B lymphocyte is in charge of synthesizing antibodies, which can be divided into five classes (isotypes) different in the case of mammals.
Although the general structure of antibodies is similar, a certain region of the protein is highly variable, resulting in the existence of millions of antibodies. This part of the protein is called as hypervariable region.
The wide variety of antibodies is produced by combinations of a set of genetic segments, responsible for encoding various antigen-binding sites. It then undergoes random mutations in this region of the gene of the antibody, increasing the diversity even more.
Among the many types of antibodies, mention may be made of the anti-histic antibodies (which react against tissue antigens), anti-nuclear antibodies (attack antigens on the surface of cell nuclei) and antigens bivalent antibodies (capable of fixing a pair of antigen molecules that correspond to its surface), among others.
Immune system diseases
There is a group of diseases that are due to disorders in the immune or immune system and whose consequences are the suffering of frequent infections. In some cases they are not very serious but their recurrence could mean a delicate complication for the patient.
Some of the causes of these diseases may lie in the existence of certain unusual infectious cancers, viruses, fungi or some type of bacteria that directly affect the immunity of the organism.
These disorders may be due to a decrease in the number of white blood cells, improper functioning (despite being the amount that the body needs) or other failures of the immune system.
It is worth mentioning that immunodeficiency can appear from the moment of birth, in cases where it is genetically inherited, or develop over the years due to certain external factors.
Acquired immunodeficiency, which manifests itself in advanced age, is usually caused by a certain disease. In some cases, a minor deterioration in the defense system is generated, but in others, the most severe, the body's ability to cope with infection can be destroyed.
One of the best known infections is caused by HIV (human immunodeficiency virus) that is produced by the disease or acquired immunodeficiency syndrome, known under the acronym AIDS. This virus destroys the white blood cells, which makes it impossible for them to respond to the threat of any external infection, turning any simple disease into a serious problem for that organism.
During childhood one of the main causes of disorders in the immune system is the malnutrition. If a child is malnourished that at a body weight is less than 80 percent of its proper weight, it is known that the immune system will be affected and if it is 70, the condition will be serious. This happens because the deficiency of nutrients caused by this poor diet prevents the body from creating antibodies, becoming weaker and weaker and becoming vulnerable to any threat from outside.