Immune System Mechanisms and Vaccine Technology
Nonspecific Defense Mechanisms
The nonspecific defense mechanisms include the skin and mucous membranes. These are the epithelia that line the body cavities in contact with the outside, such as the respiratory and digestive apparatus. Inflammation is the body's response to microorganisms or any foreign particles that enter the interior.
Specific Mechanisms: The Immune System
The most important components of the immune system are white blood cells called lymphocytes. There are two types: B lymphocytes and T lymphocytes.
Antigens and Antibodies
Antigens trigger the immune response. Antibodies are proteins called immunoglobulins, which bind to antigens. T cells recognize proteins that act as antigens and destroy the cells they find.
Immune System Disorders
- Autoimmune diseases: These occur when the immune system recognizes our own body molecules as foreign.
- Allergies: These appear when the immune system responds to antigens that it should not respond to.
Treatments for Bacterial and Fungal Infections
Bacterial infections are treated with antibiotics, substances that are toxic to bacteria and safe for people at the doses used. These were discovered by Alexander Fleming. For infections involving protozoa and fungi, antiprotozoals and fungicides are used respectively. In general, these drugs are not always as effective as antibiotics and can also be somewhat toxic for people.
Viral Infections and Immunization
Viral infections are the most difficult to treat because once the virus is introduced into cells, it is difficult to remove them. In recent years, effective antiviral drugs have been developed.
Vaccines pursue the objective of immunizing people against a number of pathogenic microorganisms. To do this, the microorganism is injected either dead, weakened, or even just as fragments. Vaccines work by stimulating our immune system to develop antibodies that can counter a virus or bacterium that invades our body and produce memory cells.
Challenges in AIDS Vaccine Development
The reasons why there is no vaccine for all diseases, such as AIDS, include:
- Social and economic factors: Further research is often prioritized for diseases that affect people living in the developed world.
- Scientific nature: Organisms have defensive strategies, making the manufacture of vaccines against some diseases very complex.
A major problem found with AIDS is that the virus mutates very rapidly. When the virus mutates, it changes the protein in its cover. Virus diversity must be fought with diversity in the vaccine. Dozens of types of coat proteins of the virus are being used until a vaccine containing more than one hundred of these proteins, known as polyenv (poly-wrap), is developed.
Genetics and DNA Vaccines
One type of vaccine that is under evaluation is the DNA vaccine. In this method, DNA from the infectious agent is inserted into a plasmid to protect the individual. The plasmid does not replicate in the cells of the vaccinated person; it only causes the synthesis of protein, which induces the production of antibodies and memory cells.