The past couple of days I have watched a four-hour Frontline special on AIDS (see “currently watching”). Much of the special, which aired last summer, marked the history of the virus, our knowledge and understanding of it and our response to it. Fascinating stuff, I’d have to say–I shared some of the most amazing details with Brooke over dinner last night, and she too marveled. Here are a few of the things which have most struck me…I cannot claim to be thoroughly knowledgeable about this material, so don’t quote my explanations as Bible truth (smile)…this is the best I can do to figure out how this virus works at present. And I’m still learning…
Science as a Mimic
In my reading today, I began to realise just how much of our health science revolves around mimicry. Our methods for treatment or avoidance of most diseases are not stand-alone but are instead dependent on the “natural” efforts of the body to fight infection or disease. In fact, in most cases scientists will study how the bodies of some people overcome viruses and bacteria, and then build their remedies around this. Unfortunately, in the case of HIV, no person has ever been able to entirely remove the virus from their system, and so this intelligent observation cannot come about.
But I am so struck with how God has formed the body’s defenses, how detailed and minute and impressive all of its immunising capabailities are as He has fashioned it! Corrupted are these bodies, yes, and yet such a marvelous machine! And how much goes on within us each day of which we are entirely unaware. The body itself is a weapon against disease, and most of our scientific helps and heal-alls do nothing more than unsheath the built-in weaponry of our cleverly designed bodies. Marvelous.
Sadly, HIV disarms the body altogether.
The HIV virus actually contains within it genetic information which corrupts certain cells (T-cells) in the human immune system, genetically rewriting these T-cells to become HIV manufacturers. The T-cells then multiply HIV in an infected person’s blood until at last the T-cell is destroyed. HIV reproduces billions of times everyday within an infected individual in just this way.
Why does our marvelous immune system not attack this foreign threat? Primarily because all of the dangerous material possessed by HIV–the RNA code, the genetic material which corrupts the T-cells–is on the inside, while the outer shell of HIV is a near-solid capsule of natural sugars. These sugars are common and natural within the human body, and so the immune system doesn’t recognise that HIV is a threat. HIV then sidles up to a T-cell and bonds not once but twice (almost like a kind of security measure for itself), and when it has twice bonded to the T-cell, it begins to enter the cell and corrupt it.
Interestingly, there are gaps in the sugar-coating which camouflages the virus, but these gaps (in molecular terms) are so profound, so deep that they are practically impenetrable to our immune system.
HIV is considered a retrovirus because it contains RNA which, in operation with a living T-cell, then translates to DNA (the work orders of the cell, if you will). RNA usually does not create anything permanent but is manufactured by DNA to perform certain tasks–it typically follows this model:
DNA ——–> RNA ———–> proteins
But in the case of this virus, the RNA converts back to DNA, instructing the T-cell to do something very different from its normal operation. The same thing occurs when viruses cause cancers–they corrupt the DNA within the host’s normal living cells, converting them into cancerous or precancerous cells. The body can fight many kinds of cancerous cells thanks to the immune system; but again, sadly, as HIV attacks the immune system itself, there is no natural defense to it. This is also why many persons who become infected with HIV eventually develop cancers of varying kinds on their bodies–the immune system is no longer able to counteract the effects of other viruses or diseases.
When the HIV virus transmutes RNA into DNA, it’s a pretty complex process and one fraught with corruption. The example given in the material here was that of a child at a keyboard trying to type the same thing again and again really quickly–a young child will hit wrong keys and the message will come out a little different again and again. This is the situation with HIV–as it makes copies of itself, the copies are altered just a little bit–mutated. This happens all the time within individuals who are infected: every person with HIV has, in fact, many slightly modified HIV cells moving about inside them.
Thus any vaccine for HIV will have to prove effective against not one simple virus but, in fact, many varying and slightly altered forms of the virus. There are now two main strains of the virus, with many subtypes from each strain–a vaccine will have to stop them all.
It took several years of AIDS research before doctors realised that the only way to fight a virus which multiplies and mutates itself so rapidly with a single human system was, in a sense, to corner it. Dr. David Ho was one of the men instrumental in this–I actually emailed him a few questions this morning, and he emailed me back some information to help me along in my understanding, which I’m fairly excited about. He and several others developed a means of using multiple medications to sort of keep HIV on its heels, attacking it on several fronts at once. (Interestingly, doctors may need to use the same method in creating a vaccine–an HIV vaccine may require several different vaccinations together to really guard against the virus.) These groups of drugs or “cocktails” must be changed regularly, as the virus can become resistant to them over time.
There’s much more, but all in all I’m fascinated…almost a shame I have to change tasks to something else for the rest of the day, but I’ve miles to go before I sleep and promises to keep…