Lactobacillus: The Soldier of the Vaginal Tract

The Human Immunodeficiency Virus (“HIV”) is one of the most commonly known microbes in American history. HIV is also one of the most devastating because it diminishes the immune system, leaving the victims susceptible to diseases that others who are immuno-competent would not be susceptible to. Some how, the virus has evolved to infect the very cells that are responsible for “killing” the virus.

Simplified Background on HIV infection:

Essentially, HIV infects the T-helper cells of the immune system. T-helper cells help elicit an immune response against foreign invaders with the help of antibodies. Antibodies are basically proteins that recognize the foreign invader, bind to it, and mark it for destruction. Most antibodies can only bind to foreign invaders they have previously been exposed to. The T-helper cell is distinguished from its cousin, Cytotoxic T cells by the CD4+ receptor found on the T-helper’s cell surface.

HIV enters T-helper cells by binding to the CD4+ receptor. After HIV binds to the CD4+ receptor, a co-receptor is revealed which facilitates its further entrance into the cell. Once inside the cell HIV may remain latent for years, or become active and acutely cause the manifestations of the disease, “AIDS” (Acquired Immune Deficiency Syndrome). 

Lactobacillus and the “Cure”: 

Although it very difficult to find a cure for HIV because the virus constantly evolves, creating a quasi species that antibodies cannot recognize, advancements in HIV research are being made everyday. One of the most interesting articles that I’ve come across in Nature discussed the use of the bacterium, lactobacillus, found in the female vaginal tract. According to the article, “Prevention of vaginal SHIV transmission in macaques by a live recombinant Lactobacillus” by Lagenaur et. al., lactobacilli are being used to prevent HIV infiltration and subsequent infection.

Basically, scientists are genetically altering the lactobacilli to recognize HIV, bind it and quench the virus (like an antibody). The idea is, if HIV is bound to lactobacilli, it can’t bind to the CD4+ receptor on the surface of the T-helper cells. According to the article, the experiment was conducted in monkeys (like the polio vaccine) using Simian HIV (SHIV). The experiment showed that the re-engineered lactobacilli reduced SHIV infection by sixty-three percent. If the lactobacilli become just as effective in human females then the implications are of course astronomical! Maybe we can stop HIV with a simple bacterium already found in the female vaginal microflora. Certainly, as mentioned by the article, this method is far less expensive than manufacturing a drug.

The question is whether the genetically modified lactobacilli would be patentable if it was also effective in humans?

There was a really good seminar that may answer this, posted by PatentBaristas:
http://www.patentbaristas.com/archives/2013/09/12/section-101-patent-eligibility-issues-in-the-life-sciences/

The Science Article:
http://www.nature.com/mi/journal/v4/n6/full/mi201130a.html#aff1

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