Isolation of B. anthraces in culture and preparation of antigens: Isolation and identification of field isolates of B. anthracis was carried out from a total of 13 suspected animal cases in Bangladesh during the period between May 2013 to April 2015. The samples was collected from two infected areas of Tangail sadar, Tangail, Shahjadpur Upazila, Sirajganj and Srimongal Upazila, Moulvibazar. Samples were collected from an infected area of Madhupur Upazila, Tangail, Gopalpur Upazila, Tangail, Ghatail Upazila, Tangail, Dhanbari Upazila, Tangail, Belkuchi Upazila, Sirajganj, Barisal sadar, Barisal and Moulvibazar sadar, Moulvibazar. Cattle suddenly died and discharging tarry colored blood through the natural opening constituted the study materials. The turbinate bone and discharges through rectal opening was collected in sterile vials and transported to the laboratory, Department of Pathology, Bangladesh Agricultural University, Mymensingh. About 1.0gm of turbinate bone or discharges from the dead cattle was crushed on sterile pestle and mortar with 5ml sterile distilled water under a biosafety cabinet level 2 (BSL-2). The suspension was heated in a thermal block at 90? for 05mins to kill contaminating bacteria and other vegetative pathogens. 100μl suspension in 10ml nutrient broth containing 0.05mg/ml Fungizone (amphotericin B, Thermo Fisher Scientific INC, NY) was incubated at 37°C for 12hrs with shaking (160rpm). About 1ml of bacterial growth in nutrient broth in eppendorf tube was centrifuged at 10000 x g for 5 minutes and sediment was smeared on glass slides, stained with Gram’s iodine to visualize the growth of bacteria. In positive cases the bacterial growth in nutrient broth was, therefore, used to isolate B. anthraces on polymyxin-lysozyme-EDTA-thallous acetate (PLET) agar and sheep blood agar media. To isolate vaccine strain of B. anthracis (Sterne strain F-34), a vaccine vial (100ml) was collected from the Livestock Research Institute (LRI), Mohakhali, Dhaka, Bangladesh on July 2013. About 1.0ml of vaccine formulation was taken into an eppendorf tube and centrifuged at 10000 x g for 5mins. The supernatant was discarded and the pellet was washed twice with sterile distilled water by centrifugation at 10000 x g for 5mins. The supernatant was discarded and 100μl sterile distilled water was added to the tube. Using a bacteriological loop the broth was used to grow on sheep blood agar plate at 37°C for 12 hrs. Once the bacterial growth was seen on culture, the bacterial colony was stained with Gram’s iodine (Luna, 1968) and examined under microscope to observe the morphology of the bacteria. PX01 and PX02 plasmid specific PCR was carried out to identify species of B. anthraces. The field bacterial isolates of B. anthraces was used in antigen preparation and to evaluate protective efficacy of the vaccine against challenge infection in mice model. The name of the isolates designated as BD_Vac_2014 (vaccine bacteria, F-34 Stern strain) and FI SPUR_2014 (virulent field isolate of B. anthracis) with the Genbank accession number of KT995458 and KT893481 respectively. The virulent field isolate used in this study was collected and characterize from Shahjadpur Upazila, Sirajganj district, Bangladesh.