A protein found in the saliva of ticks helps protect mice from developing Lyme disease, Yale researchers have discovered. The findings, published in the November 19 issue of Cell Host & Microbe, may spur development of a new vaccine against infection from Lyme disease, which is spread through tick bites.

Traditionally, vaccines have directly targeted specific pathogens. This is the first time that antibodies against a protein in the saliva of a pathogen's transmitting agent (in this case, the tick) has been shown to confer immunity when administered protectively as a vaccine.

The Lyme bacterium known as Borrelia burgdorferi is transmitted by ticks. When it moves through the tick, it is coated with a tick salivary protein known as Salp15. The Yale team injected Salp15 into healthy mice and found that it significantly protected them from getting Lyme disease…