Nov 08, 2013
Honor Whiteman. “Cats may be key to HIV vaccine.” Medical News Today. MediLexicon, Intl., 4 Oct. 2013. Web. 9 Oct. 2013. http://www.medicalnewstoday.com/articles/266911.php
Evolutionarily Conserved Epitopes on Human Immunodeficiency Virus Type 1 (HIV-1) and Feline Immunodeficiency Virus Reverse Transcriptases Detected by HIV-1-Infected Subjects, Miss P. Sanou, Shannon R. Roff, Anthony Mennella, John W. Sleasman, Mobeen H. Rathore, Janet K. Yamamoto, Jay A. Levy, doi: 10.1128/JVI.00359-13, published online in the Journal of Virology, 3 July 2013
News Release: http://news.ufl.edu/2013/10/01/aids-vaccine/
The cat, scientifically classified as Felis catus, is a remarkable creature. In addition their ability to invoke severe rhinitis, conjunctivitis, sneezing, pruritus and congestion when I am around them, they may also be an indispensable tool in the development of a potential HIV vaccine.
Cats have been considered a human companion as far back as the Neolithic era, around 7500BC. Evolutionarily they have remarkable senses, likely attributed to their role as hunters prior to their domestication. Their eye sight is unimpaired at a level of light 6 times darker than what is needed for human vision. Their vibrissae (whiskers) are highly sensitive structures that are all over their bodies and usually serve to provide depth information to the brain while maneuvering in the dark. A cat’s hearing is so fine-tuned that it can detect a broad range of frequencies, covering almost 11 octaves. Finally, cats have a much attuned sense of smell. Their ability to sense the material known as catnip is so sensitive it can sense it at a concentration of one part per billion (1/1,000,000,000). The cat’s brain is said to always be in an alpha-wave state. This brain state is reproduced in mammals during phases of extreme relaxation and has been hypothesized to be linked to extra-sensory perception. Fascinating right? What may be even more fascinating is that cats may be the next big research area to help create a vaccine to HIV.
A recent study done from researchers from the University of Florida and the University of California, San Francisco has shown that blood from subjects infected with HIV created an immune response against a feline immunodeficiency
virus (FIV) protein.
The feline immunodeficiency virus (FIV) is closely related to the human immunodeficiency virus (HIV) as well as other species variations of the virus like simian immunodeficiency virus (SIV). They are all considered evolutionary cousins in a way that is said to have come from a common genetic ancestor. For more information on this phenomenon, I encourage you to visit/revisit my article from March 2013 titled ‘Turning Back the Clock: Origins of HIV’.
One shortcoming that previous attempts at creating an HIV vaccine showed was that immunogenicity (ability to invoke an immune response) was never sufficient enough to create a commercially available, widely used vaccine. One of the reasons for this lack of immune response was the difficulty in finding ways to select regions of the HIV-1 genome as a target for the vaccine. The researchers have potentially identified a method to target specific regions based on viruses that share genetic homology or similarity. By looking at both the FIV virus in cats and the HIV virus in humans, they were able to find select regions of the genome that are called ‘evolutionarily conserved’ which means that over long periods of time, these regions do not mutate and change. In genetics, regions of genetic material that are highly conserved usually points to these areas being highly important for the survival of the organism. Without the comparison the best that researchers could hope for was a ‘best guess’ type of approach based on currently proven and accepted knowledge. The use of the FIV virus to better point researchers in the right direction is the first time an attempt like this has been utilized to make a vaccine.
So… how did they achieve this miraculous feat? Because we know that T-cells are responsible both for fighting infection and are also the targets of HIV, the researchers used T-cells from HIV-infected patients and incubated them with various proteins that are considered essential for the survival of both HIV and FIV. From the responses of these experiments, the researchers were able to measure the immune response and they found that there was one particular region on the FIV that triggered patients’ T-cells to kill HIV. Of significant note, one researcher stresses that it is important to realize that this data does not mean that FIV can infect humans, but rather that the similarity in the viruses is close enough that they can observe the cross-reaction.
So, your next question might be ‘What does this all mean for vaccination efforts?’ The Food and Drug Administration (FDA) requires testing in two different animal species before testing in humans is allowed to commence. This means that we will likely see results in monkeys and cats before we see a human trial, but as we have seen this year with other therapeutic modalities, this testing could happen very quickly.
I know I’ve said this before, but I am truly excited and inspired by all of the fantastic research that has been done recently. Researchers are trying exhaustively to find a way to end this global epidemic. With over 20 medications that can be used in various combinations to keep viral replication at bay, many efforts are now being made to create vaccinations and cures for those not yet infected and those already infected.