This study used a DNA vaccine plasmid expressing the NP from A/Goose/Gong Dong/1/96 (H5N1). A DNA vaccine expressing HA from A/Goose/Gong Dong/1/96 (H5N1) has been found to elicit antibody responses and protect chickens against challenge with HPAI virus [25] . Methods used for producing the HA-expression DNA vaccine were adopted when preparing the DNA expression plasmid pCAGG-NP. NP antibody responses were detected in immunized chickens, suggesting that this vaccine elicits successful immune responses to the NP antigen in chickens. The T cell responses were not detected directly in this study, but it was inferred that a successful antibody response would have been accompanied by a successful T cell response based on our knowledge of the DNA vaccine. Nine of the peptides were synthesized and used to stimulate sensitized splenic lymphocytes to verify that they were epitopes. Increases in the proliferation of CD8 + T lymphocytes and the secretion of chicken IFN-c demonstrated the antigenicity of these peptides. NP 89-97 (PKKTGGPIY) and NP 198-206 (KRGINDRNF) induced significant T cell responses in splenic lymphocytes. An analysis of the prediction results showed that NP 89-97 was predicted to be a T cell epitope for both B15 and B19, while NP 198-206 also belonged to the B19 haplotype. Thus, it is suggested that the major haplotype of the experimental SPF chickens might be B19. NP 89-97 also overlapped with a previously identified HLA-A68 restriction T cell epitope NP 91-99 (KTGGPIYKR) of the H3N2 AIV [7] . This further verifies the significance of this epitope, which could be used in human and chicken vaccines to provide protection against different influenza virus subtypes.