Irish and NY scientists claim discovery to potentially pave way for HIV and E. Coli vaccines

28 Aug 2013

Images from the transatlantic study carried out by scientists in Ireland and New York. Image via 'The Journal of Experimental Medicine'

A transatlantic group of scientists from Trinity College Dublin (TCD) in Ireland, the Icahn School of Medicine at Mount Sinai (MSSM) and The Rockefeller University, both in New York, believe they have come up with a novel discovery that may one day help with the design of new vaccines against infections such as HIV and E. Coli.

The international collaboration has apparently spawned discoveries involving new routes of cellular traffic to the gastrointestinal (GI) tract.

Broken down into layman’s terms, the scientists believe their discovery may have a potential impact on the design of new vaccines against infections.

The results of the research study, which was led by Dr Ed Lavelle at TCD and Dr Saurabh Mehandru at MSSM, was recently published in the medical journal The Journal of Experimental Medicine.

According to the research group, their analysis shows – for the first time – direct evidence of cellular movement between the lung and GI tract.

The intestinal gut in human beings

The scientists at TCD and in New York have been studying the mechanisms by which immune cells are directed to the GI tract. They say that such analysis is key to developing what they are calling “novel vaccines” against mucosal infections, such as HIV.

As a result of their research, they believe this could broaden the potential vaccination routes available to tackle such infections.

In traditional medicine, vaccines have been usually administered via injection but opening up needle-free vaccinations could be valuable, the scientists claim.

Why? They believe such vaccinations without having to use a needle could help with patient compliance and – interestingly – help with induce stronger immune responses at the site of an infection.

Icahn School of Medicine at Mount Sinai

A poster in Icahn School of Medicine at Mount Sinai (MSSM) welcomes the latest cohort of students to the bio-medical school in New York. Image via MSSM Facebook page

Dendritic cells

The human immune system has a type of cell called the dendritic cell (DC), which is responsible for triggering immune responses during infections.

These cells orchestrate the movement of lymphocytes to various compartments in the body, a “key” event in the immune response, the scientists said.

Apparently, current theories suggested that only intestinal DCs have the capacity to bestow lymphocytes (types of white blood cells that are responsible for protecting the body against bacterial and viral infections) with the ability to travel to the small and large intestine to fight infection.

However, the research teams believe that they have uncovered, for the first time, that DCs in the lung can strongly help with the movement of lymphocytes to the intestine.

So, how did they come up with their findings?

The Dublin and New York research groups targeted dendritic cells in the lung via a nasally administered immunisation.

They said this resulted in a “successful” immune response being activated against a “highly infectious” strain of Salmonella.

The results also appeared to show that, as a result of using this pathway, the immunisation was significantly more potent at triggering the immune response to Salmonella than an orally administered vaccine.

This, they believe, would have selectively targeted DCs in the gut.

‘Exciting findings’ – says TCD biochemist

Lavelle, who is associate professor in immunology in the School of Biochemistry and Immunology at TCD, said that these are very “exciting findings”.

He said that the results may provide opportunities to develop novel vaccine strategies for GI infections.

“While oral vaccination can be effective the option of vaccination in the respiratory tract could be invaluable in cases where the oral route is not optimal,” explained Lavelle.

Meanwhile, the lead author of the paper is Dr Darren Ruane. A recently graduated PhD student from TCD, he is currently Stateside at MSSM. He conducted the research between MSSM, TCD and The Rockefeller University New York.

Ruane said that this study reveals that pathways of “cellular recruitment to the gut” are much more diverse than previously appreciated by those in the medical research space.

“This theory predicts that the immune system at the various mucosal surfaces including the lung, digestive and reproductive tracts are connected, offering the potential to vaccinate at one site yet induce immunity at other mucosal sites.

“This mucosal cross talk has the potential to open up the possibilities for developing new types of vaccines for infections affecting the gut.”

Further studies need to be done to better understand the physiological relevance of this pathway in the GI, said Dr Mehandru, assistant professor of gastroenterology at the Icahn School of Medicine at Mount Sinai (MSSM).

Carmel Doyle was a long-time reporter with Silicon Republic