Inhibition of <i>Ehrlichia canis</i>and <i>Babesia canis</i> transmission among ticks fed together on dogs vaccinated with Bm86 antigen

Abstract

GAVAC (Heber Biotec S.A, Havana, Cuba) is a commercially available vaccine developed withthe Rhipicephalus (Boophilus) microplus Bm86 recombinant antigen. Bm86 is a "concealed" antigen that is present in the plasmatic membrane of tick gut epithelial cells with unknown function so far. It is well known that after vaccination in the last fifteen years in Cuba, there was a significant decrease of babesiosis (Babesia bovis and Babesia bigemina) and anaplasmosis (Anaplasma marginale) in cattle. A reduced transmission capacity of ticks fed on tick-immune animals and humans has been reported for several tick-borne pathogens. Recent experiments have demonstrated that an anti-tick vaccine may contribute to the control of tick-borne pathogens not only by decreasing the exposure of susceptible hosts to ticks, but also by reducing the vector capacity of ticks. In this study, the potential of Bm86 vaccination to interfere with pathogen transmission among ticks was evaluated by using as experimental model the brown dog tick Rhipicephalus sanguineus and the tickborne Babesia canis and Ehrlichia canis pathogens. Dogs, vaccinated and not vaccinated, were infested with pathogen-infected ticks and noninfected nymphs of R. sanguineus. After feeding, the pathogen transmission to newly molted adults from co-feeding uninfected nymphs was studied by conventional PCR and qPCR. Results suggest that the anti-Bm86 antibodies could be able to block the transmission of B. canis and/or E. canis from infected to non-infected ticks.Engorged dropped-off naive nymphs were collected and kept in a BOD incubator having a 12 h light: 12 h dark photoperiod, 28˚C and 80% relative humidity, until molt. Ten newly molted naive ticks from each group were analyzed by conventional PCR, as described above,

Comparison of Montanide GEL 01 and oily MontanideTM ISA 50 in presenting a peptide to the immune system of dogs

“…On the other hand, oil-based adjuvants as emulsions of water-in-oil, or vice versa are among the most efficient adjuvants known and they are in wide use for veterinary vaccines (Aucouturier et al, 2001). In our experience, water-in-oil (W/O) emulsions induce strong, long-term immunity but can sometimes induce local reactions which could be severe in some cases (Rodríguez-Mallon et al, 2013, 2020. Generally, water-in-oil emulsions (W/O) are recommended for bovines, small ruminants, poultry and fish when long-term immunity is required.…”

“…These anti-tick effects were demonstrated to be positively correlated with the specific immune response against the pP0. However, the oily formulation of this effective antigen produced some side undesired effects on the inoculation site of immunized dogs (Rodríguez-Mallon et al, 2013, 2020. The objective of this study was to assess the immunogenicity of the pP0-Bm86 chemical conjugate formulated with the polymeric adjuvant Montanide™ GEL 01 (SEPPIC, France) in dogs and compare the specific antibody response obtained with that of the same antigen in oily formulation using Montanide TM ISA 50 (SEPPIC, France).…”

10. Public-private partnership enabled use of anti-tick vaccine for integrated cattle fever tick eradication in the USA

“…Bm86-based products represent the first generation of anti-tick vaccines to be commercialized (Rodriguez et al 1995b;Willadsen et al 1995). The opportunity to research existing and emerging anti-tick vaccine technology according to the One Health perspective to deal with ticks and tick-borne diseases of public health and veterinary importance was a factor that facilitated the public-private partnership delivering a new Bm86-based vaccine formulation for experimental use in cattle in the USA and Puerto Rico (Évora et al 2017;Rodríguez-Mallon et al 2013). This is another example of how the One Health approach has expanded to try to overcome barriers for the development and commercialization of novel global health vaccines, and public-private partnerships have been identified as a mechanism to achieve that goal (Benfield 2016;King et al 2004;Monath 2013).…”

Deciphering Babesia-Vector Interactions

“…Bm86 is a glycoprotein, recognized for the first time in R. microplus , and present in midgut cells, that is likely to be involved in the endocytosis of the blood ingested by ticks (Gough and Kemp, 1993 ; Bastos et al, 2010 ; Rodríguez-Mallon, 2016 ). Regardless of the efficiency of Bm86 against tick infestation, some studies aimed to evaluate the role of Bm86 in Babesia infection (Bastos et al, 2010 ; Rodríguez-Mallon et al, 2013 ). RNA interference (RNAi) studies carried out in R. microplus females showed that Bm86 silencing significantly reduced the number of ticks; by contrast, silencing did not affect the efficiency of transovarial transmission of B. bovis (Bastos et al, 2010 ).…”

“…RNA interference (RNAi) studies carried out in R. microplus females showed that Bm86 silencing significantly reduced the number of ticks; by contrast, silencing did not affect the efficiency of transovarial transmission of B. bovis (Bastos et al, 2010 ). In a different study using Gavac®, a vaccine based on the Bm86 antigen, naïve nymphs that co-fed on immunized dogs presented lower levels of B. canis , (Rodríguez-Mallon et al, 2013 ). It is conceivable that the lysis of midgut cells inhibited the entry of zygotes and/or their posterior differentiation into motile ookinetes, compromising B. canis acquisition by the nymphs.…”