Experimental oil- emulsion vaccine was formulated with a ration of one part of 0.05% β- propiolactone Inactivated antigen and four parts oil adjuvant ISA -70. Four hundred white. HY - Line (W-36) chicks were reared in four groups. Group 1 and 2 were vaccinated by live attenuated H 120 at day 10 and reared experimental oil -emulsion and commercial oil - emulsion vaccines respectively. At this time group 3 was received single dose of experimental oil -emulsion vaccine and group 4 was unvaccinated control. At week 29 all of groups were challenged by 0.25.107 EID50 bird of infected allantoic fluid when they were on peak of production. All groups were bled frequently and the sera were assayed by ELISA and AGLD tests. Clinical signs and high percentage drop in egg production in groups 3 and 4 were noted moreover. On virus and or viral antigen in the trachea of groups 1 and 2 were detected at days 5 and 10 postchallenge. The results of clinical observation egg production virus isolation and detection in the trachea and levels of antibody suggested that layers vaccinated with a combination of live attenuated and the experimental Inactivated vaccines had the highest protection.

Avian influenza (AI) H9N2 is a low pathogenic virus subtype belonging to Orthomyxoviridae family. Given the prevalence of this subtype as an infectious agent in poultry industry, special attention has been always directed toward the development of vaccine production against this infection. The vaccine of this infection is produced by killing the virus and using a mixture of Inactivated antigen and oil phase. Egg-based viral antigens have high levels of unwanted proteins that may adversely affect the vaccine formulation. In addition, it is required to raise the antigen concentration for the production of combination vaccines, especially in low doses. This underscores the need to the improvement of the downstream purification process and concentration of antigens. The optimization of downstream processing would decrease the cost of vaccine procurement and maintenance. Regarding this, the present study was conducted to evaluate a downstream procedure for the concentration and purification of avian influenza virus (H9N2) and investigate the immunogenicity of the vaccine containing these antigens. To this end, after harvesting and clarifying virus-containing allantoic fluid, it was concentrated and purified using ultrafiltration and chromatography, respectively. The concentrated and purified samples were checked for their ovalbumin level and emulsified with oil adjuvant to access their immunogenicity. The results showed that one dose of both formulated antigens (i. e., concentrated and purified) was effective in raising the immune response in the vaccinated chicks for a long time. The applied formulation had a one-year stability in the refrigerator. Furthermore, the concentrated antigen showed a high hemagglutination activity through a year when storing in the refrigerator. Based on the findings, the optimization of downstream process of influenza (H9N2) vaccine production and use of new technologies could be considered in the large-scale preparation of a sustainable vaccine without any unwanted risk factors.

An experimental Inactivated oil-emulsion H9N2 avian influenza vaccine was formulated with 3 parts of Inactivated avian influenza antigen A/Chicken/Iran/101/1998 (H9N2) emulsified in 7 parts of oil adjuvant. Twelve week-old specific pathogen-free (SPF) chickens were divided into seven groups of 10 birds. Six groups were vaccinated with 1, 1/10th, 1/50th, 1/100th, 1/200th and 1/400th field dose of the experimental avian influenza vaccine (EAIV). The last group, was injected with saline and served as the control group. The mean titer in haemagglutination inhibition (HI) test (log 2) on the vaccinated groups, 21 days post-vaccination were 6.0, 4.4, 3.83, 3.3, 3.0 and 2, respectively. Prevention of virus shedding through cloaca was used as the potency test which revealed that the protective doses 50% PD50) of full, 1/10th and 1/50th of the field dose of the experimental vaccine were 100, 100 and 96.25%, respectively. Those groups that received <1/50th dose could not prevent virus shedding. So it can be concluded that EAI vaccine could even be entirely protective and efficient in 1/10th dose and got a desirable immunity in experimental SPF chickens.  

Background and Aims: Influenza vaccination is one of the best way to prevent and control influenza worldwide. It is manufactured by WHO-licensed companies based on the WHO expertise committee annually. The aim of this study was partial quality control of the commercial human influenza vaccine 2008-9 and its matching with the circulating strains.Materials and Methods: The trivalent imported vaccine was cultured in bacterial and fungal media, injected to the mice and inoculated into the allantoic cavity of Embryonated Chicken Eggs (ECEs). Hemagglutination-Inhibition (HI) assay was carried out on pre and post vaccination serum samples. The bacterial endotoxin was assessed by LAL assay. The Hemagglutinin (HA) content of the vaccine was measured using SRID. Heterogenecity of the circulating influenza strains during 2008-9 seasons in Tehran in comparison to the vaccine strains was determined.Results: No bacterial contamination and no occurrence of mortality and morbidity in animal was observed. The mean fold increase of HI antibody titer in subjects without previous vaccination for H1N1, H3N2 and B strains were 6.7, 3.3 and 1.8 respectively, while in subjects with previous vaccination were 4, 1.6 and 1.1 for same strains. Amino acid variation was found in Tehran H1N1 isolates but the H3N2 isolates showed higher genetic resemblance to the 2008-9 vaccine strain.Conclusion: The sterility, safety, and efficacy of the vaccine were approved and there was some variation in A/H1N1 but not in A/H3N2 isolates in comparison with the vaccine strain.