Immunopotentiation of outer membrane protein through anti-idiotype Pasteurella multocida vaccine in rabbits Javid Arif a, * , Sajjad-Ur Rahman a , Muhammad Arshad a , Pervez Akhtar b a Institute of Microbiology, University of Agriculture, Faisalabad 38000 Pakistan b Department of Animal Breeding and Genetics University of Agriculture, Faisalabad, Pakistan article info Article history: Received 24 July 2012 Received in revised form 21 March 2013 Accepted 22 May 2013 Keywords: Outer membrane proteins Pasteurella multocida Anti-idiotype vaccine Indirect haemagglutination test abstract Pasteurella multocida was isolated from cattle affected with haemorrhagic septicaemia and characterized on the basis of morphological, cultural and biochemical tests. Bacterial outer membrane proteins (OMPs) were extracted with 1% Sarkosyl method. P. multocida anti-idiotype vaccine prepared from OMPs (21.3 mg per 100 ml), was evaluated and compared with bacterin supplemented with 10% OMPs and plain alum-adsorbed bacterin in rabbit models. It was observed that OMPs-anti-idiotype vaccine induced high levels of antibody titres (geomean titres -GMT) detected using indirect haemagglutination (IHA) test. The OMPs anti-idiotype antibody titres of 168.9 GMT were obtained to 42.2 GMT in OMPs sup- plemented bacterin on 21 days post vaccination, while the plain bacterin had the least titre of 27.9 GMT. The OMPs-anti-idiotype vaccine provoked better immunogenic response in terms of highest GMT titres and long lasting effect in rabbits and 100% protection against the challenge with homologous strain of P. multocida,while 88% protection was obtained in rabbits, given OMPs supplemented bacterin. Ó 2013 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved. 1. Introduction Haemorrhagic septicaemia (HS) is endemic in most parts of tropical Asia and Africa, and causes high mortality in livestock [5]. Pasteurella multocida is the etiological agent and can be separated in to serogroups A, B, D, E and F based on the antigenicity of their capsule [9,42] and serotypes 1-16 based on lipopolysaccharide (LPS) antigens. The capsular serogroup is generally related to disease predilection, with the HS strain belonging to serogroups B and E [50]. In the recent past (1987), the Asian serotype B:2 and the African E:2 serotype (Carter & Heddleston system) were mainly responsible for the disease [21]. Previously, Penn & Nagy separated a nontoxic polysaccharide capsular antigen, which was non-immunogenic in rabbits but produced mouse protective antibodies in cattle [39]. Limited information is available on antigens of P. multocida that stimulate immunity in cattle. In HS, capsular antigen, LPS or LPS protein complex, and outer membrane proteins (OMPs), including iron-regulated outer proteins, are effective immunogens of serotypes B and E [13]. P. multocid a capsular strains type A and type F were compared for outer membrane protein (OMP) profiles and sequence analysis. On the basis of molecular heterogeneity, the heat modifiable ompA and porin ompH were identified, which play important roles in host pathogen interactions [18]. Although HS may be controlled through vaccination, most of the vaccine efficacy response was restricted to homologous species [36]. Live attenuated strains of P. multocida currently in use as vaccines are undefined and outbreaks of pasteurellosis have been attributed to the vaccine strains [20,34]. Alum precipitated vaccine provides reliable immunity for only 3e4 months and anaphylactic shock reaction may also occur [23]. Reports also indicated that the bacterin provided limited protection against heterologous sero- types and the vaccinated animals suffered from disease outbreaks [20,41]. The anti-idiotype network hypothesis was proposed by Niels Jerne [26]. Further studies have elaborated that different antigenic determinants within variable domains of immunoglobulin, not only recognize but also elicit an immune response in the same indi- vidual [8,26] and these antigenic determinants are collectively recognized as idiotypes (Ids). Many groups of researchers [7,27,51] have intensively investigated the potential immune regulatory role of Ids e anti-Ids interaction. Anti-idiotypic antibodies were demonstrated in prion-biology, which was based on the recognition of a specific antigen com- bining site of an antibody, mimicking the structure of prion antigens. Anti-idiotype vaccine is useful to improve the conventional experi- mental vaccines, and it is especially recommended when the mole- cule is infectious, toxic or difficult to isolate and purify [49]. In spite of regular vaccination with conventional vaccines, HS continues to be a major problem. The aim of the present study was * Corresponding author. Tel.: þ92 302 3440154. E-mail address: javidarif@yahoo.com (J. Arif). Contents lists available at SciVerse ScienceDirect Biologicals journal homepage: www.elsevier.com/locate/biologicals 1045-1056/$36.00 Ó 2013 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.biologicals.2013.05.003 Biologicals xxx (2013) 1e6 Please cite this article in press as: Arif J, et al., Immunopotentiation of outer membrane protein through anti-idiotype Pasteurella multocida vaccine in rabbits, Biologicals (2013), http://dx.doi.org/10.1016/j.biologicals.2013.05.003