Identification of TROSPA homologue in Ixodes persulcatus Schulze, the specific vector for human Lyme borreliosis in Japan.

The tick receptor for outer surface protein A (TROSPA) is an Ixodes scapularis (I. scapularis) receptor for Borrelia burgdorferi (B. burgdorferi), the causative agent of Lyme disease in North America. The blockade of TROSPA has been shown to reduce B. burgdorferi adherence to the I. scapularis gut in vivo. Thus, TROSPA is one of the potential targets for the development of vector-antigen-based vaccines to prevent the transmission of B. burgdorferi. The aim of this study is to identify the TROSPA gene in I. persulcatus Schulze, the specific vector for human Lyme borreliosis in Japan. The cDNA clone encoding the TROSPA-like sequence with 483 nucleotides was obtained from whole-body homogenates of fed nymphs of I. persulcatus. The putative amino acid sequence of I. persulcatus TROSPA was 88.2% and 87.8% identical to that of I. scapularis and I. ricinus, respectively. This finding will facilitate investigations on the role of I. persulcatus TROSPA and its interaction with Borrelia spp. and will have important implications on endeavors to develop a tick vaccine.