title: Identification of the Babesia-responsive leucine-rich repeat domain-containing protein from the hard tick Haemaphysalis longicornis.
abstract: Haemaphysalis longicornis is a tick known for transmitting Babesia parasites, including Babesia gibsoni, in East Asian countries. The vector tick must have strategies to control Babesia parasites, while Babesia parasites are also considered to establish an evasive mechanism from the tick's innate immunity. Due to this mutual tolerance, H. longicornis is considered to be a vector of Babesia parasites. Recent studies have shown the important roles of leucine-rich repeat (LRR) domain-containing proteins in innate immunity in many living organisms. Some LRR domain-containing proteins were identified in ticks; however, their functions are still unknown. In this study, a novel LRR domain-containing protein was identified from H. longicornis (HlLRR). HlLRR contains two LRR domains, and the expression levels of mRNA and proteins were upregulated during blood feeding, particularly in the salivary glands and midgut. In addition, recombinant HlLRR (rHlLRR) demonstrated growth inhibition activity against B. gibsoni in vitro without a hemolytic effect at any concentration used. Moreover, the diameters of Babesia merozoites treated with rHlLRR were significantly larger than those of the control group. These results strongly indicate the key roles of HlLRR in the tick's innate immunity against Babesia parasites. Furthermore, HlLRR might be a potential alternative drug to treat babesiosis.
authors.affiliation: Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, Korimoto, Kagoshima, 890-0065, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Maeda
authors.forename: Koshi
authors.initials: K
authors.lastname: Kurisu
authors.forename: Takeshi
authors.initials: T
authors.lastname: Miyata
authors.forename: Kodai
authors.initials: K
authors.lastname: Kusakisako
authors.forename: Remil Linggatong
authors.initials: RL
authors.lastname: Galay
authors.forename: Talactac Melbourne
authors.initials: TM
authors.lastname: Rio
authors.forename: Masami
authors.initials: M
authors.lastname: Mochizuki
authors.forename: Kozo
authors.initials: K
authors.lastname: Fujisaki
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D001403:Babesia / Q000235:genetics / Q000502:physiology*; D004064:Digestive System; D005786:Gene Expression Regulation / Q000502:physiology; D006790:Host-Parasite Interactions; D026863:Ixodidae / Q000469:parasitology*; D000090263:Leucine-Rich Repeat Proteins; D052940:Merozoites; D011506:Proteins / Q000378:metabolism*; D012469:Salivary Glands
chemical_list: D000090263:Leucine-Rich Repeat Proteins; D011506:Proteins