Immune responses against recombinant tick antigen, Bm95, for the control of Rhipicephalus (Boophilus) microplus ticks in cattle Amit Kumar a , Rajat Garg a, *, C.L. Yadav a , Stuti Vatsya a , R.R. Kumar a , Parthasarthy Sugumar b , Dev Chandran b , Lakshmi Narasu Mangamoorib c , S.N. Bedarkar a a Department of Veterinary Parasitology, College of Veterinary and Animal Sciences, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand 263145, India b R&D, Indian Immunologicals limited, Hyderabad, India c School of Biotechnology, Jawaharlal Nehru Technological University, Hyderabad, India 1. Introduction Ticks, including Rhipicephalus (Boophilus) microplus, cause significant economic losses to the livestock industry in terms of decreased milk yield, meat production, death of affected animals, damaged hides and cost of acaricides. The traditional control methods for these ectoparasites are mainly based on the use of chemical acaricides, which however, has produced a never-ending array of acaricide- resistant ticks (Graf et al., 2004). Further keeping in view of the increasing concern about environmental safety and human health, alternative tick control measures have become necessary. In this context, development of host immunity through administration of tick antigens is being attempted globally (De La Fuente and Kocan, 2006). In progress of development of cattle tick vaccines, various concealed gut antigens from R. microplus have been identified viz. Bm86, Bm91, Bm95, BmPRM, etc., which have been used alone or in combination (De La Fuente and Kocan, 2006; Nuttall et al., 2006). Of these, Bm95 has Veterinary Parasitology 165 (2009) 119–124 ARTICLE INFO Article history: Received 21 January 2009 Received in revised form 20 June 2009 Accepted 23 June 2009 Keywords: Bm95 Cattle Immune response Rhipicephalus (Boophilus) microplus ABSTRACT Immune responses against Bm95 recombinant cattle tick antigen and its protective efficacy for control of Rhipicephalus (Boophilus) microplus ticks were determined in experimental crossbred cow calves. Anti-Bm95 antibody titers, as assessed by indirect ELISA, in immunized calves ranged from 196.1  13.7 on day 0 to 7979.9  312.5 on day 110 post-primary immunization. The rise in antibody titer was statistically significant (p < 0.01) throughout the study period. Besides this, constantly higher lymphoproliferative response (LPR), as assessed by lymphocyte stimulation test, was observed from 10 days post- immunization, but a positive LPR of antigen stimulated cells in immunized animals was recorded only on day 50 and day 70 post-immunization. Following challenge of immunized calves with larvae of R. microplus, significant increase (p < 0.01) in rejection percentage, mean number of damaged ticks, mean percentage of dead ticks, and decrease in engorgement weight were recorded in immunized animals. Also, there were significant differences (p < 0.01) in preoviposition period, oviposition period, egg mass weight and percent hatchability between the immunized and control calves. The percent reduction in number of adult females in vaccinated calves, reduction in mean weight of egg masses, percent reduction in mean weight and reduction in fertility of engorged females collected from vaccinated calves were determined and the efficacy of Bm95 recombinant cattle tick antigen was 81.27%. ß 2009 Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +91 9412439281. E-mail address: rajatgarg_2000@yahoo.com (R. Garg). Contents lists available at ScienceDirect Veterinary Parasitology journal homepage: www.elsevier.com/locate/vetpar 0304-4017/$ – see front matter ß 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.vetpar.2009.06.030