Researchers discover faster vaccine testing method

by David Hyland

For University microbiologists, the motto “seeing is believing” guided them in their development of a new technique to test the effectiveness of experimental vaccines.
University researchers, with assistance from colleagues at the University of Glasgow and Dartmouth Medical College, created the new approach that will allow them to visualize the performance of vaccines more quickly than ever before.
“This is huge for us,” said Marc Jenkins, the project’s lead researcher and microbiology professor.
So huge, in fact, that the project had a research report published in the latest addition of Science magazine.
When vaccinating an organism, the purpose is to elicit a certain type of response from the immune system that aids in protection. This new technique allows researchers to discover quickly whether the immune response has been turned on.
Previously, most of the tools researchers used to study the immune system involved very indirect measures of immune responses.
Researchers would use the vaccine on experimental animals. Scientists would then draw blood from the animal to determine if antibodies had formed around the vaccine’s proteins which meant the vaccine was working. The resulting experiment would often take weeks to conclude.
The new method allows researchers to physically follow the two types of lymphocytes that help create those antibodies. Immune responses begin in the lymph nodes of an organism, where B lymphocytes and T lymphocytes find each other and bind together. Then, T lymphocytes send a chemical message to the B lymphocytes, which begin to make the antibodies.
Researchers can examine the early phases of antibody production, with the new procedure. Using specific experimental mice who have been injected with a vaccine, the scientists later remove and examine the mouse’s lymph nodes.
The vaccine is tagged with enzymes that produce color so when antibodies are produced in the lymph nodes, it is visible. By staining specific lymphocytes, they can determine the location and number of responses, and how the vaccine is working. As a result, researchers are able to observe effectiveness as quickly as two days after immunizing the mice.
Jason Cuyster, associate professor of microbiology and immunology at the University of California at San Francisco, said the new method is important because it is the first demonstration in which scientists can see the events happening in the lymph nodes.
“It will crystallize some of the thoughts that are out there,” Cuyster said. “It will certainly clarify where things are.”
For Jenkins, the new technique is getting to the heart of the matter.
“They can learn much more than they can by superficial methods because they can follow the two critical cell types that are involved in the response,” Jenkins said.
Jenkins said the method will aid basic scientists who are interested in how the immune system functions. Numerous companies involved with vaccines have also expressed interest in learning about the method, he said.
“You don’t know how to fix the car if you don’t know how it works,” he said.
The project began three years ago when a professor from the University of Glasgow came to the United States and began working at the project with researchers at the University. Later, researchers from Dartmouth College contributed a critical antibody to the project.
During that time, researchers were honing their skills with the technique as well as running breeding studies to produce specific mice that were genetically identical.
Matthew Mescher, director of the University’s Center for Immunology, said Jenkins has pioneered a unique way of looking at immune responses. As a result, numerous other laboratories have begun using his techniques, Mescher said.
“It does allow predictions of the kind of immune response that are going to be generated at a very early time,” Mescher said.
Jenkins said the next step in the project is to understand the chemical messages and molecules that influence cell behavior in regards to the lymphocytes.