Why it's so hard to cure HIV/AIDs

The difference


A lot of people actually don't know the difference between HIV and AIDs.

HIV is Human Immunodeficiency Virus


AIDs is Acquired Immune Deficiency syndrome


The difference is that if you imagine the virus like a battle. Having HIV is like fighting a losing battle, having AIDs is the after effect, being controlled by the enemy.


First we need to understand how we become immune to normal viruses


Let's use Influenza as an example

1. Influenza virus enters body cells or are engulfed by phagocytes (your white blood cells)

2. After engulfing the pathogen (influenza), the phagocyte puts the virus' antigens on it's surface.

Antigens are sort of like names for micro-organisms. It's a protein which tells other things it's them.

3. T helper cells have a receptor which fits perfectly onto the antigen being presented.

It's important to know that only certain T helper cells have the right receptor which will fit. There are tens of millions of T helper cells in your body. They all fit different random things.

Kind of like finding a person for a job, only certain people fit the criteria!

4. This activates T cells to divide rapidly by mitosis.

5. These genetically identical cloned T cells

The cancer cell is leaking!

a) divide into memory cells
b) stimulate phagocytosis
c) stimulate B cells to divide
d) kill infected cells

a) Memory cells are cells which drift about in your body and await for future infection so that it can enable a rapid response and kill the pathogen quickly. (often you don't even notice!)

b) Phagocytosis is the process where white blood cells engulf the pathogen (and again present the antigens)

c) B cells are involved in long term immunity, it involves antibodies which break down pathogens. And it involves memory cells again for long term immunity.

d) T cells brutally kill infected cells by releasing a protein that makes holes in the cells membrane. Because the cell has loads of holes, it's completely permeable and hence dies. Because viruses need to hide in cells, they die as well.

The problem with HIV


What HIV does is attack T helper cells. This means that T cells cannot clone and hence no memory cells.

Instead what HIV does is use the T helper cells as a factory to make tons of copies of HIV. Evil right?

The problem with a vaccine


The problem with a vaccine is that HIV mutates so often.

Mutations of a virus involve a change in the antigen. Increasing the virus' antigenetic variability.


Because of this there's no point giving someone a vaccine for HIV for them to be infected by one of the hundreds of other strains.

(also why the common cold has no vaccine)

It would also have severe side effects as the weak pathogen in the vaccine itself would damage our immune system.

AIDs


Once you have AIDs it's game over, goodbye immune system.

During this final phase even the common cold is a dangerous infection as you have no immune system to fight off infections.