Mon June 10, 2013
Dr. Stephen Trent, University of Texas at Austin – Bacteria and Vaccines
In today’s Academic Minute, Dr. Stephen Trent of the University of Texas at Austin reveals how bacteria could be used to create better vaccines.
Stephen Trent is an associate professor of molecular genetics and microbiology at the University of Texas at Austin. His lab explores how diverse environmental stimuli promote changes in conserved microbial structures found on the surface of pathogenic bacteria. His current research project is exploring the use of bacteria to improve the efficacy of vaccines for diseases such as flu, pertussis, cholera, and HPV.
Dr. Stephen Trent – Bacteria and Vaccines
To be effective, a vaccine must accomplish two major feats: one, it must activate the immune, and two, it should be specific to an infection. Serious diseases that were once a common horror - like polio and smallpox - have been eradicated thanks to vaccines.
Historically, bacterial vaccines contained whole bacteria that were killed or deactivated. These vaccines were great for general stimulation of the immune system because bacteria have lots of common immune triggers that our bodies recognize. However, it’s now popular for vaccines to contain only pieces of bacteria instead of the whole thing. Although these bacterial pieces are specific to the infection they come from, usually they don’t activate your immune system strongly enough. This makes it necessary to add something called an adjuvant – an extra, amplifying component that can rev up the immune system.
For about 80 years, only one adjuvant – which was called alum - was available, but it has some limitations. Finally in 2009, the FDA approved a vaccine with a new adjuvant, MPL, which comes from a molecule on the surface of bacteria. This molecule is called lipid A. In high quantities of its natural form, lipid A causes a severely strong immune response. However, MPL is a mixture of lipid A molecules that have been chemically altered to be safe in vaccines yet still activate the immune system just right.
In my lab, my graduate student Brittany Needham explored the potential to modify lipids for use as adjuvants and engineered 61 bacterial strains that make customized versions of lipid A. These lipids could serve as a toolkit to pair designer adjuvants with specific parts of bacteria, viruses, or other infections and ultimately generate better vaccines.
Production support for the Academic Minute comes from Newman’s Own, giving all profits to charity and pursuing the common good for over 30 years, and from Mount Holyoke College.