At the ARS Foreign Animal Disease Research Unit, located at the Plum Island Animal Disease Center in Orient Point, NY, scientists are using a new tool that tracks the adaptive immune response of cattle to foot-and-mouth disease virus (FMDV) vaccines.

The new technique, based on what are called major histocompatibility complex (MHC) tetramers (molecules), has only recently been applied to livestock, says ARS microbiologist William Golde. The method was first developed in mice and humans.

"The technology allows scientists to follow more complicated T cell immune responses, in addition to B cells," Mr Golde says. "It is based on typing cattle, just like you type a human for an organ transplant and know exactly which molecules you're working with."

T cells have different jobs. Some send instructions to the rest of the immune system so the body can produce the most effective weapons against invaders—bacteria, viruses or parasites. Other types of T cells recognize and kill virus-infected cells directly. T cells also help B cells to make special Y-shaped proteins called antibodies that stop invaders in their tracks and alert the body, which then makes toxic substances to fight and destroy intruders.

The objective is to show that MHC tetramers can be applied to vaccine development in cattle and create tools for working with livestock diseases, says Golde, who has used the technique in pigs.

In the study, pigs were vaccinated either with a vaccine targeting T cells or another vaccine targeting B cells and then compared. The research showed that a different kind of immune response to FMDV could be induced by redesigning vaccines to target T cells.

Mr Golde is partnering with ILRI researchers to apply these tools to other cattle diseases such as East Coast fever.

Rift Valley fever, East Coast fever, and foot-and-mouth disease studies are just a few of the many research projects under way between ARS and international scientists. Such collaborative research continues to help nations deal with global threats to livestock. It also promotes food security worldwide.