Immune System Disorders: Autoimmunity and Hypersensitivity
Autoimmunity is an error in the immune system where it is unable to recognize certain molecules. As a result, it may originate serious diseases and even cause the death of the animal due to autoantigens.
Molecular Mimicry and Autoimmune Diseases
Molecular mimicry occurs as many microbes, such as bacteria and viruses, have developed strategies to form molecular complexes (mainly proteins) that are very similar to those in the body of the infected animal. People suffer from autoimmune diseases when certain types of proteins associated with the MHC membrane affect their cells. Examples include:
- Multiple Sclerosis: Affecting brain tissue and the spinal cord.
- Psoriasis: Affecting the skin.
- Rheumatoid Arthritis: Affecting connective tissue.
- Juvenile Diabetes: Affecting the cellular functions of the pancreas.
Hypersensitivity and Allergic Reactions
Hypersensitivity in the immune system can act excessively against harmless or slightly dangerous molecules. Allergy refers to certain hypersensitivity reactions, while an allergen is an antigen that causes hypersensitivity. Anaphylaxis can produce serious damage and even death upon the first contact.
Immediate Hypersensitivity between an allergen and the immune system produces no external symptoms initially, but it induces biochemical mechanisms that remain in a latent state until the second contact, a fact known as sensitization (awareness). Histamine provokes more or less severe adverse effects that can even lead to the death of the animal; this is called anaphylactic shock, which occurs several minutes after the second exposure to the allergen.
Immunodeficiency and Lymphocytes
The inability of lymphocytes and the immune system to stop microbial infections may be caused by genetic disorders, errors in the normal development of primary or secondary lymphoid organs, or viral infections.
- Congenital Immunodeficiency: A kind of genetic immune anomaly present from birth and is hereditary.
- Acquired Immunodeficiency: Acquired after birth at some point in life. AIDS is a serious disease caused by a virus attacking immune system cells, which reduces their capacity and destroys them.
Transplants and Immunotherapy
A transplant is a medical procedure that can replace certain diseased tissues or organs of one person with another. The immune system may reject the implementation when receptor molecules recognize the organ transplant as a foreign body and attack it from multiple fronts.
Immunotherapy uses current knowledge of the immune system to implement procedures based on the defense system to beat infectious microorganisms, address immune system deficiencies, treat cancer, or prevent the rejection reaction in transplantation.
Advanced Medical Technologies
Monoclonal antibodies are antibodies produced by a cell fusion hybrid of a B cell and a cancerous cell type. Genetic Engineering is used to maximize the immune response against antigens of microorganisms with the design of vaccines that underscore humoral or cellular immunity, facilitating the body's production of antibodies. ARV agents are antiretroviral drugs that slow the progress of the disease and prolong survival in patients.
Key Immunological Definitions
- Autoantigens: The body's own molecules that cause lymphocytes to trigger an autoimmune response.
- Heteroantigens: Foreign antigens that the immune system recognizes as non-self.