At 150 dpv, specific antibodies to Sterne were detected only in 13% of cattle

At 150 dpv, specific antibodies to Sterne were detected only in 13% of cattle. Discussion The protective activity of anthrax vaccines mainly depends on their ability to elicit antibodies directed to toxin components (Little et al., 1997; Beedham et al., 2001; Reuveny et al., 2001; Kobiler et al., 2002); however, little is known on the effective duration of immunity, many studies demonstrating the decline of the specific antibody response and the need of different vaccination schedules to ensure protection. proved to be a very sensitive and specific test. Moreover, the Sterne-based CFT offers many benefits with regard to costs, standardization and reproducibility of the assay procedure. has two principal virulence factors, the toxin complex, and the poly–D-glutamic acid capsule, coded by plasmids pXO1 and pXO2, respectively. The capsule protects the bacterium from phagocytosis while the toxin complex consists of three synergistically acting proteins, Protective Antigen (PA), Lethal Factor (LF), and Edema Factor (EF), produced during the log phase of growth. The interaction of these proteins forms the lethal and edema toxins, responsible for cytotoxic effects (Collier and Young, 2003; World Health Organization [WHO], 2008). The protection against anthrax mainly depends on the hosts humoral response to the toxin components (Turnbull et al., 1988; Pitt et al., 2001; Friedlander et al., 2002). The PA is a key element: the anti-PA antibodies are not, in themselves, a guarantee of protected status, but they must be in the blood of animal SB-568849 or human for the subject to be protected SB-568849 (Ivins and Welkos, 1988; Ivins et al., 1990; Little et al., 1997). Since anthrax is primarily a disease of animals, its control in animals and humans depends on the prevention in livestock, principally cattle, sheep, and goats. Most anthrax vaccines for animals utilize the strain 34F2, developed by Max Sterne in 1937 (Sterne, 1939) which lacks genes for capsule formation but still produces the toxin (pXO1+/pXO2C), responsible for the induction of protective antibodies. The protective effect of a single dose of this vaccine is said to last for 9 to 12 months so annual boosters are recommended in endemic areas (Sterne, 1939). Also, a single dose of Sterne vaccine may not be sufficient to ensure protective immunity in the animal to last for a year, and more than one initial dose of the Sterne SB-568849 vaccine may be necessary (Turnbull et al., 2004; Mongoh et al., 2008; World Health Organization [WHO], 2008). However, very few SB-568849 studies focusing on immunological characterization have been conducted with cattle and goats (Dipti et al., 2013; Roy et al., 2013). Serological methods, which have not a prominent role in diagnosis, are very useful epidemiological and research tools (Turnbull et al., 1992; Quinn et al., 2004) since they enable to monitor the humoral response following vaccination or naturally acquired infection. The titration of specific antibodies in sera of vaccinated animals is crucial to evaluate the efficacy of the vaccination and to obtain epidemiological information in areas where the disease is endemic. Currently, the ELISA is considered the most effective serological method; however, it utilizes purified toxin antigens PA and LF whose preparation is expensive and lacks of a good standardization in regard to purity, composition of antigens and preparation procedure. Moreover, reference SB-568849 standard serum is not available. The Complement Fixation Test (CFT) is a serological method prescribed as individual confirmatory test in many infectious diseases. It is able Rabbit Polyclonal to CROT to detect specific antibodies in animal and human serum samples and may detect incomplete antibodies. The antigen preparation, mainly consisting in an inactivated bacterial suspension, is not expensive and can be easily standardized. The purpose of this study was to develop a Sterne-based CFT able to detect anti-anthrax antibodies induced in animals vaccinated with the Sterne 34F2 vaccine. We assessed the efficacy of our method in laboratory animals and under field conditions by monitoring the humoral response induced in cattle by vaccination with Sterne 34F2. Materials and Methods Bacterial Strains and Growth Conditions The strain 34F2, used for the preparation of the veterinary vaccine, and the virulent strain A0843 (Fasanella et al., 2001) were supplied by the National Reference Centre for Anthrax (Ce.R.N.A.) of the Istituto Zooprofilattico Sperimentale of Puglia and.