RESUMO
Three imported strains of low pathogenic H5N2 avian influenza [AI] from the United State Department of Agriculture [USDA] of the United States [A/Ty/CA/209092/02, A/Chicken/ PA/13609/93 and A/Ty/MN/3689-1551/81] were used to prepare 3 experimental batches of oil emulsion vaccine against AI designated as [1, 2 and 3] in order. Evaluation of the prepared vaccines was carried out using standardized hemagglutination inhibition test [HI]. Evaluation was based on using the same antigen used for preparation of vaccine as HI antigen [homologous strain]. Cross reactivity test was carried out between the three different strains and the prepared vaccines. Moreover, the H5N1 locally isolated highly pathogenic avian influenza [HPAI] A/Ch/Eg/2009 H5N1 was used as a heterologous antigen for HI test against the prepared vaccines. Obtained results revealed that a protective titer was obtained by vaccine 1 and 2. Using homologous virus as an antigen produce high titer rather than using other viruses, the vaccines failed to produce HI antibodies against locally isolated H5N1 AI virus