THE OUTER SURFACE PROTEIN-A (OSPA) VACCINE AGAINST LYME-DISEASE - EFFICACY IN THE RHESUS-MONKEY

The efficacy of an outer surface protein A (OspA) vaccine in three dif ferent formulations was investigated in the rhesus monkey. The challen ge infection was administered using Ixodes scapularis ticks that were infected with the B31 strain of Borrelia burgdorferi. Protection was a ssessed against both infection and disease, by a variety of procedures . Some of the animals were radically immune suppressed, as an attempt to reveal any putative low level infection in the vaccinated animals. The significant difference found between the spirochaetal infection ra tes of ticks that had fed on vaccinated vs. control monkeys, lack of s eroconversion in the vaccinated animals, and the absence of spirochaet al DNA in the skin of vaccinated monkeys were protected against tick c hallenge. The post-mortem immunohistochemical and polymerase chain rea ction analyses, however, suggest that these monkeys may have undergone a low-level infection that was transient. (C) 1997 Elsevier Science L td.