There is an exciting new research line of enquiry in the battle against the HIV-Aids virus. It involves genetic engineering of so-called â€˜killerâ€™ T-cells. The aim is to develop ways to contain HIV by energizing cellular CD8 cytotoxic T lymphocyte (CTL) responses so that it seeks out and destroys HIV in a body.
HIV suppresses the immune system of sufferers by blocking CTLs. To overcome this, CTLs must carry a specific molecule of a receptor that is the guidance system for targeting the HIV infected proteins, in the cells where they live and replicate. Scientists at the university of California have managed to do this for the first time, in mice.
The latest study shows for the first time that genetic engineering can build immune cells that work on cutting out HIV effectively in living tissue, albeit in mice, in these early stages. All research is an iterative, step by step, process, and the researchers need to move on to a critical sixth step; namely transferring the process to human HIV patients.
Step 1 was done in a previous experiment. Where HIV was grown inside human-like cells in laboratory animal hosts.
Step 2 was also part of an earlier experiment than this latest one, but it was a vital part of the anti HIV development process. Here the scientists took the CTLs of a HIV patient and tagged the T-cell receptor responsible for hitting the HIV target. This step proved the existence of such immune system T-cells that may be used to reduce HIV. However, they were insufficient to remove all HIV cells.
Step 3 in this new research was to clone the HIV-removing T-cell receptor and genetically engineer the stem cells that form the desired blood cells. These are called hematopoietic stem cells or HSCs that will develop into working CTLs, that then remove the damaged HIV cells later.
Step 4 involves placing the new stem cells into the human thymus tissue implanted in laboratory mice and watch the impact of the growing population of anti HIV stem T-cells. They recorded how they attacked the damaging HIV proteins within the mice. Exhaustive tests on the miceâ€™s blood, plasma and organs showed the T-cells to be doing the job they were intended for 14 days and 42 days after implantation. Good CD4 helper T-cells increased while levels of HIV in the mice went down. The usual situation with HIV infections is to see CD4s slump. These are white blood cells that aid the body in fighting infections.
The research conclusion is a big step forward in that the engineered cells do grow and spread and help to reduce the spread of HIV infection. The hope is that these steps will lead to the eradication of HIV.
Step 5 will be to replicate and prove these results a number of times and then move on to clinical trials with human patients as step 6. If this proves successful, the procedure will be formalized and shared throughout the medical establishment.