The HIV – Tobacco Connection

SciWorks Radio is a production of 88.5 WFDD and SciWorks, the Science Center and Environmental Park of Forsyth County, located in Winston-Salem.  

Much medical research is done to find cures for diseases, however some, like HIV, remain incurable. In the mean time, research is done on many aspects of the disease to better understand how it functions in the human body.

HIV is a retrovirus. Whenever HIV infects a cell, essentially what's happening is that virus is taking over the cell as a whole and causing that cell to make more virus particles. They can go out and infect other cells.

That's Dr. Travis Russell. In his dissertation research at UNCG, he took a look at an interesting correlation of instances of HIV infection among tobacco users.

Our research was looking at these epidemiological studies from the late 80s and early 90s that demonstrate there's a link between tobacco smoking and HIV infectivity. We decided to look at this from more of a genetic level to determine if there is in fact something changing at the cellular or the genetic level that's causing HIV to be able to infect easier.

Smoking and HIV infection can be traits of people who live riskier lifestyles. Could this be the reason for a connection?

You could make that argument with some of the studies, the earlier studies that were made. But what we wanted to do was look at genetic studies and determine if there is in fact a link between the genes that are altered as a result of the tobacco smoke and the infectivity of the HIV virus in human T cells, that have been incubated with tobacco smoke.

Dr. Russell found something interesting about the effects of tobacco smoke on these human T-Cells.

So whenever we incubated these cells with tobacco smoke we looked at levels of gene expression, or the amounts of protein that are produced from these genes and you have a normal basal level of expression. And whenever the cells are in the presence of tobacco smoke, certain genes are expressed more, or more of that protein is produced whenever they're in the presence of tobacco smoke, and those of the over-expressed genes. On the other hand you have certain genes or certain proteins that are expressed at a lower level in the presence of tobacco smoke versus normal cells. One would think that there is some ingredient in tobacco smoke that is causing this HIV increase or this infectivity increase.

Through further research, it was concluded that a percentage of the genes with altered expressions were linked to the rate of HIV infectivity. So, what in tobacco smoke is causing this change?

One thing that we wanted to focus on as well is, is it just nicotine that's causing this increasing infectivity of the HIV virus? And what we found is that it's not. Whenever we take these human T cells and they're in the presence of nicotine alone we see no increase in HIV infectivity, whereas on the other hand whenever we can make them with the tobacco smoke as a whole that's when we see the increase in infectivity.

Dr. Russell has established that a link between tobacco smoke and HIV infection exists, and that the link has to do with the effects of the tobacco smoke on human DNA. He has also established that nicotine is not the ingredient, at least by itself, which is causing the increase in viral infectivity that we see with tobacco smoke.

So, if the research doesn't cure HIV or establish the ingredient that causes a genetic change, why is it important?

This research is aimed at giving us a better understanding of this HIV virus. Being a retrovirus it can also give us an understanding of other retroviruses. But it's really aimed at allowing us to see how this virus works within ourselves. This information could possibly be used in the future as a new target for researchers in drug discovery to help decrease or lower infectivity rate of the virus.

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