The present study was an attempt to raise specific hyper-immune polyclonal antibodies against IBD virus in Pakistan. 4 did not drop AMG 837 calcium hydrate their activity till the end of experiment. IBD virus infected birds were injected with purified antibodies which induced 92% recovery as compared to control birds. The study implicates that this purified antibodies may be useful as a therapeutic agent to remedy IBD infected birds. Keywords:immunoglobulin Y, immunoglobulin therapy, passive antibody transfer, passive immunotherapy == Introduction == Infectious bursal disease (IBD) is an acute highly contagious, viral disease of growing chickens with worldwide occurrence. IBD was observed in chickens in 1957 in Gumboro district of Delaware, USA. Birds that survive the AMG 837 calcium hydrate disease are permanently immunosuppressed, therefore more susceptible to other disease causing brokers and do not respond properly to vaccinations. The bursa of Fabricius (BF) is the main target organ of IBD computer virus (IBDV) where it replicates in immature bursa-derived lymphocytes (B-lymphocytes) of chickens. IBD can be characterized by sudden onset, short course, and considerable destruction of lymphocytes in BF and profuse watery diarrhea followed by death or quick recovery [3]. There is no specific treatment available for this disease but palliative treatment may be undertaken for its control. Passive hyperimmune therapy (PHT) is usually another alternative to standard vaccination. Passive immunization with antibodies derived from blood is usually widely used to prevent or treat infections like measles, hepatitis A, hepatitis B, tetanus, varicella, rabies, and vaccinia etc. [5]. Rabbits and other animals are normally utilized for production of polyclonal antibodies; however, by 1962 it was found that immunoglobulin concentration in the yolk was equal to or greater than that found in hen serum [9]. According to an increasing number of publications, the antibodies produced in hens are useful in many applications, including immunotherapy and immunodiagnostics [11,1,2]. In some cases, hens being distant relatives of mammals; offer a good AMG 837 calcium hydrate alternative to rabbits in generating antibodies against mammalian antigens [12]. Fischer et al. [4] investigated extraction of immunogloblin Y (IgY) from egg yolk using polyacrylamide gel electrophoresis (PAGE) and densitometric analysis and concluded that dextran sulfate was very effective, quick and simple method to extract antibodies. The present study was designed to raise and isolate specific hyper immune polyclonal antibodies against IBD. Quantification of antibodies was carried out through enzyme linked immunosorbant assay (ELISA) and AGPT and different antibody titers were prepared. Furthermore the antibody titers were applied to infected birds for evaluation as effective therapeutic agent. == Materials and Methods == == Immunization of hens == Hundred commercial layers (Bab-Cock breed) of 72 weeks of age were obtained from suppliers and were housed in individual cages to avoid mixing of the eggs. ELISA titer of IBD antibodies before vaccination was 3,083. Oil based vaccine against IBD AMG 837 calcium hydrate computer virus (Bursine-K; Forte Dodge, USA) was injected subcutaneously into chickens according to four treatment regimens. In the first treatment program (T1), birds were vaccinated twice with 0.5 ml vaccine seven days parted. In the second treatment program (T2), birds were vaccinated daily starting from 0.1~1 ml for 10 days. In the third treatment program (T3), birds were vaccinated daily starting from 0.1~1 ml in ten days and 0.5 ml afterwards weekly for two times. In the fourth treatment program (T4), birds were vaccinated twice; at start of experiment and then after two weeks with dose rate of 0. 5 ml each time. The eggs were collected daily, labeled accordingly and were stored in a refrigerator at BMP8A 4 until isolation of the immunoglobulin [6]. All experimental procedures were conducted according to ethical guideline lines provided by the Ministry of AMG 837 calcium hydrate Food, Agriculture and Livestock, Government of Pakistan. == Purification of immunoglobulins by dextran sulphate == The procedure was essentially as explained in Koko et al. [6]. Reagents were obtained from Sigma and Pharmacia USA. Briefly, egg yolks were separated from your white. Phosphate buffered saline (PBS) was added in the yolk to bring the volume to 50ml and mixed. Diluted yolk suspension was centrifuged for 10 min at 2,000g. Pellet was discarded and supernatant was saved. Supernatant was mixed with.