HIV/AIDS - A Crash Course

Today, we all know, in a general sense, what AIDS is, and we know that it attacks and destroys the ability to fight infections, but how this happens and how it affects the human body is still a mystery to many people.

The journey toward full-blown AIDS begins as HIV (Human Immunodeficiency Virus), a condition that affects more than 40 million people worldwide, the greatest number of them residing in Africa.

HIV is known as a retrovirus, which medical dictionaries describe as a 'family of single stranded RNA that produce reverse transcriptase by means of which DNA is synthesized using their RNA as a template and incorporated into the genome of infected cells'. INormally, DNA is the source code for RNA in the production of proteins. With HIV, the process is reversed and the RNA inserts its code into the DNA before replication, hence the name 'retro-virus'.

HIV virus particles infect cells that have a certain kind of chemical receiver, or 'receptor' on their surface. Those receptors are known as CD4 lymphocytes, or macrophages. Lymphocytes constitute 20-30% of white blood cells in a normal, healthy human. White blood cells function in the defense against invaders that enter the body. Once the viral enzyme enters that particular lymphocyte, known as a T-lymphocyte, the virus, in a sense, takes a piggy back ride on a T cell and works its way inside the DNA enzyme where it uses the viral RNA to replicate itself again and again.

Once infected, the body's immune system goes into overload trying to fight off the virus. Certain types of cells within the immune system, 'B cells', produce massive amounts of antibodies to combat the invading HIV proteins. Other cells known as helper and cytotoxic T cells arrive on the field of battle to help. Unfortunately, the virus infects billions of these cells, even though their numbers are replenished every day. Eventually, the battle against the invading virus is lost and the body is no longer able to produce the warrior cells to fight against it. This may take years, but the end result is that cells of the body's immune system are no longer effective against invaders.

HIV becomes full-blown AIDS (Acquired Immunodeficiency Syndrome) when the body is no longer able to produce defenses against infections. AIDS is a secondary immune deficiency caused by exposure to the HIV virus.

After infection, many people develop signs and symptoms of the common flu, but symptoms disappear after a few days. Eventually, however, the infected person will grow sick and suffer from weight loss, recurring fevers, swollen lymph nodes, infections that don't heal and chronic weariness. Because the body's defense system is so compromised, successfully fighting any kind of an infection becomes increasingly difficult. Nearly every body system can be affected by the virus, which eventually shut down and lead to death.

Drugs on the market today can't cure AIDS. It is currently impossible to reverse the mutation of HIV genes after they've combined with a person's DNA, mainly due to the fact that HIV genes have a high mutation rate. One drug currently being used to attempt to combat the disease is called AZT. This drug, (azidothymidine) is capable of blocking reverse transcription and replaces normal nucleotide phosphates in DNA, which are the essential building blocks of DNA. The only problem with AZT however, is that in time, the drug also incorporates itself into the DNA of body cells and kills them.

When HIV genes replicate, (the process of forming a protein molecule at a particular site during protein development, from information contained in mRNA) they create polypeptide strands that certain enzymes 'cut up' into proteins. Certain drugs can prevent this 'cutting' from occurring and so disarm the assembly of additional HIV genes, but these drugs have horrible side effects. In addition, the cost of many of these medications is way beyond the budget of most people suffering from the disease.

At the present time, the best way to prevent the spread of HIV/AIDS is to practice safe sex and learn about the disease and how it is transmitted. Education has been successful in somewhat slowing down the advance of the disease in some countries, but the cost of that education costs billions of dollars every year.

Research and development of a low cost vaccine is currently under way. Some vaccines have already been tested, but with poor results. One vaccine, AIDSVAX, did reach final stages of development, but failed to yield much encouragement. It did produce mild degrees of protection among mainly African and Asian males, which might indicate that certain ethnicities are more resistant to the process or infection. Test results combining AIDSVAX with another vaccine are due in 2008.