VACCINES IN DEVELOPMENT

The rOspA vaccines were an interesting approach and potentially very helpful in endemic areas of the USA , however, there were many complications. Essentially, the cross reactivity and autoimmune arthritis risk was known and published as the vaccine was being produced. The vaccine was made before the specific cross reactive epitope was found, thus there was no effort made to eliminate it before vaccine trials and mass production.

A non self-reactive version of OspA may be the basis of the next Lyme disease vaccine.

Since the time of LYMErix, the specific epitopes involved in T cell cross reactivity have been found on the C-terminal end of OspA and the human leukocyte function-associated antigen 1 alpha (hLFA-1a) [6]. This epitope, OspA 165-173 , has since been mutated in such a way to reduce similarity to hLFA-1a but keep overall 3D structure of OspA, resulting in the protein FTK-OspA.

The T cell response to OspA 165-173 is mainly a TH1 response, so the modifications in FTK-OspA eliminate the cross reactivity and a harmful inflammatory response while keeping other TH2 T cell responses to OspA to produce protective immunity. The authors of this study furthermore suggest a multivalent vaccine in order to increase vaccine disease-prevention effectiveness.