Primary embryonic cells of Rhipicephalus microplus and Amblyomma cajennense ticks as a substrate for the development of Borrelia burgdorferi (strain G39/40)

Abstract

Borrelia burgdorferi, the agent of Lyme borreliosis, is a spirochetes transmitted by ticks to humans and animals. Its cultivation in vitro in tick cells allows studies of its biology and provides methodology for future research in Brazil, and for the isolation of Borrelia spp. We examined in vitro the characteristics of embryonic cells of Rhipicephalus microplus and Amblyomma cajennense in cell culture and investigated the suitability of embryonic cells as a substrate for cultivation of B. burgdorferi. Subcultures were prepared from primary cultures of embrionary cells of R. microplus and A. cajennense maintained in Leibovitz's (L-15) complete medium at 28 °C and 31 °C, respectively. When a monolayer had formed, the L-15 was replaced with Barbour-Stoener-Kelly medium for experiments to infect cell cultures with B. burgdorferi. After 72 hours of cultivation, the spirochetes were counted using an inverted phase contrast microscope and dark-field illumination (400×). Survival, multiplication and the adherence of B. burgdorferi for embryonic cells of R. microplus and A. cajennense were observed. B. burgdorferi cultured with embryonic cells of R. microplus grew on average to a density (final count) of 2.4 × 10 7 spirochetes/mL, whereas in cell-free culture, an average of 2.5 × 10 7 spirochetes/mL were counted. When cultivated with A. cajennense cells, the final count of spirochetes was on average 1.7 × 10 7 spirochetes/mL, while spirochetes cultured under cell-free conditions replicated on average of 2.

Fluorescent membrane markers elucidate the association of Borrelia burgdorferi with tick cell lines

“…Furthermore, they have supported the identification of cellular receptors for spirochete adherence in addition to various strategies for inducing an adaptive immune response against spirochetes in vitro ( 5 ). Similar studies using tick cells have elucidated the phenomenon of spirochete tropism within tick tissues and cells, as well as spirochete transmission mechanisms ( 6 – 8 ).…”

Seroprevalence for Rickettsia spp. and Borrelia spp. in horses from non-endemic areas at the Southeastern Brazil

“…Vector aptitude of ticks from both Amblyomma and Rhipicephalus genus on the transmission of the B. burgdorferi was not defined yet. However, Rezende et al 37 reported embryonic cells from Rhipicephalus microplus and A. cajennense s.l as possible substrates for the growth of B. burgdorferi sensu stricto strain G39 / 40. Recently, Higa et al 9 described the first molecular evidence of Borrelia spp.…”

Reptile vector-borne diseases of zoonotic concern

“…Mites parasitizing reptiles belong to the orders Trombidiformes (Acariformes) and Mesostigmata. With seven families and more than 30 genera infesting reptiles and amphibians ( Zhang et al, 2011 ; Rezende et al, 2012 ), the Trombidiformes is the most represented order of mites parasitizing herpetofauna, whereas Mesostigmata includes five families and 18 genera ( Lizaso, 1979 , 1982 ). The role of mites as vectors of zoonotic pathogens has not been fully investigated although data suggest their implication as vectors for some of them, such as Rickettsia spp.…”