Trudeau Institute makes discovery in vaccine development
Researchers find lipids could provide benefits as new vaccine adjuvants
New research from the US laboratory of Dr Elizabeth Leadbetter at the Trudeau Institute, Saranac Lake, New York, may lead to a whole new class of vaccines. Dr Leadbetter's lab has discovered new properties of a potential vaccine adjuvant that suggest it could be useful for enhancing protection against a number of different infections. This new data has been published in the January 2012 issue of Nature Immunology (Vol. 13, pp. 44-50).
Effective vaccines train our bodies to recognise harmful microbes and typically contain disabled microbes, or even just components of microbes called antigens. Most human vaccines also contain adjuvants -- substances added to the vaccine to improve immune response to the antigens. Adjuvants increase the strength of the immune response and also allow for smaller amounts of antigens to be used in vaccine production.
Immune response to antigens results in the production of antibodies that are a secreted product of B cells. Antibodies attach to antigens and help our bodies eliminate harmful microbes. Some T cells can help B cells make antibodies.
Dr Leadbetter previously discovered that natural killer T (NKT) cells, a special population of T cells, help B cells to make antibodies. NKT cells are special because they recognise lipid antigens. In contrast, most helper T cells recognise protein antigens. Because many harmful microbes produce unique lipids, Dr Leadbetter hypothesised that directing NKT cells to help B cells could provide a new way to induce antibodies against harmful microbes, which would complement existing vaccine technologies.
Dr Leadbetter's latest studies have advanced her hypothesis that lipid molecules may serve as promising vaccine components. The studies demonstrate that NKT cells can help B cells produce antibodies that recognise lipids, but this does not result in long-lived memory immune responses to the lipid antigens.
The studies also demonstrate that the lipids, when used as adjuvants to enhance immune responses to more conventional protein antigens, induce memory immune responses against the protein target without inducing a memory response to the lipid itself.
Together, these findings suggest a single lipid adjuvant could be used multiple times without losing its effect. The new research also characterises how NKT cells help B cells produce antibodies when lipids are used as a vaccine adjuvant.
Lipids may become an important new class of adjuvants not only because of their intrinsic properties but also because of their capacity to activate NKT cells.
According to Dr Leadbetter: ‘These cells are really fascinating because they have both innate and adaptive immune cell properties. In other words, they act rapidly, but also specifically. NKT cell activation by certain lipids enhances the activation of other immune cells, thus acting as the body's natural adjuvant.’
The research, which is funded by the Trudeau Institute, was performed with current and former Trudeau faculty members, including Dr Irah King, Michael Tighe, John Dibble, Dr Anne Fortier, and Dr Markus Mohrs. Dr Michael Brenner, of Brigham & Women's Hospital, and Dr Gurdyal Besra and Dr Natacha Verapeen from University of Birmingham (UK) were also important contributors to these studies.
For more information visit: http://www.nature.com/ni/journal/vaop/ncurrent/full/ni.2172.html.