Can the tonsils influence oral HIV transmission?

Jul 26, 2007

Current research demonstrates that the tonsils may possess the necessary factors to act as a transmission site for the spread of HIV. The related report by Moutsopoulos et al, “Tonsil Epithelial Factors May Influence Oropharyngeal Human Immunodeficiency Virus Transmission,” appears in the August issue of The American Journal of Pathology.

Human immunodeficiency virus (HIV) spreads mainly through sexual contact of mucosal surfaces, which the virus must cross to come in contact with underlying immune cells for infection to occur. While the oral mucosal surfaces are largely protected by their thickened exterior and the defensive proteins present in saliva, it is speculated that a low number of infections may occur via oral sexual contact. Researchers have questioned whether such transmission is facilitated by the tonsils, which contain high numbers of immune cells that may be easily accessible to HIV.

Researchers led by Dr. Sharon M. Wahl, of the National Institute of Dental and Craniofacial Research, NIH, examined this question by comparing the gene expression profiles of tonsils and oral gingiva. Although many of the genes examined showed similar expression patterns between the two oral sites, differences were observed. Notably, several genes related to immune functions, including HIV co-receptor CXCR4, displayed significantly higher expression in the tonsils while gingiva more strongly expressed keratin genes, which “thicken” the tissue and provide barrier protection.

Further, Dr. Wahl’s group found that CXCR4 protein was expressed on gingiva, oral mucosa and tonsils, but the expression was strongest in tonsils, particularly in regions where immune surveillance is known to occur. Levels of additional molecules that may bind and entrap HIV, such as complement receptors and FcR, were also higher in the tonsils. However, when antiviral proteins were examined, lower levels of SLPI (secretory leukocyte protease inhibitor), defensins, and thrombospondin were found in the tonsils.

Altogether, Moutsopoulos et al’s data “suggest that increased expression of molecules associated with HIV binding and entry coupled with decreased innate antiviral factors may render the tonsil a potential site for oral transmission.” The decreased amount of keratin and antiviral proteins in the tonsils renders this tissue more permeable to foreign invaders, thus allowing tonsils to function in immune surveillance. However, it also renders the site more accessible to pathogens that infect immune cells. Future studies will elucidate how host vulnerability is influenced by tonsils during exposure to HIV.

Source: American Journal of Pathology

Explore further: Condoms 'too small' for Uganda men

add to favorites email to friend print save as pdf

Related Stories

World greenhouse emissions threaten warming goal

1 hour ago

Emissions of greenhouse gases are rising so fast that within one generation the world will have used up its margin of safety for limiting global warming to 2°C (3.6°F), an international team of scientists ...

Uncovering the forbidden side of molecules

1 hour ago

Researchers at the University of Basel in Switzerland have succeeded in observing the "forbidden" infrared spectrum of a charged molecule for the first time. These extremely weak spectra offer perspectives ...

Engineered proteins stick like glue—even in water

1 hour ago

Shellfish such as mussels and barnacles secrete very sticky proteins that help them cling to rocks or ship hulls, even underwater. Inspired by these natural adhesives, a team of MIT engineers has designed new materials that ...

Recommended for you

Obese British man in court fight for surgery

Jul 11, 2011

A British man weighing 22 stone (139 kilograms, 306 pounds) launched a court appeal Monday against a decision to refuse him state-funded obesity surgery because he is not fat enough.

2008 crisis spurred rise in suicides in Europe

Jul 08, 2011

The financial crisis that began to hit Europe in mid-2008 reversed a steady, years-long fall in suicides among people of working age, according to a letter published on Friday by The Lancet.

New food labels dished up to keep Europe healthy

Jul 06, 2011

A groundbreaking deal on compulsory new food labels Wednesday is set to give Europeans clear information on the nutritional and energy content of products, as well as country of origin.

Overweight men have poorer sperm count

Jul 04, 2011

Overweight or obese men, like their female counterparts, have a lower chance of becoming a parent, according to a comparison of sperm quality presented at a European fertility meeting Monday.

User comments : 0