Monoclonal antibodies were used to study antigenic variation in the nucleoprotein of influenza A viruses. We found that the nucleoprotein molecule of the WSN/33 strain possesses at least five different determinants. Viruses of other influenza A virus subtypes showed antigenic variation in these nucleoprotein determinants, although changes in only one determinant were detected in H0N1 and animal...

Background and Aims: Avian Influenza (AI) H9N2 subtype was first reported to infect turkeys in the United States in 1966 and has been panzootic in Eurasia. In Iran, the H9N2 virus was first isolated from broiler chickens in 1998 in Ghazvin province and it is the most prevalent subtype of influenza virus in poultry industry in Iran at the present time. Materials and Methods: In this study, we se...

Using genetically typed recombinant influenza A viruses that differ only in their genes for nucleoprotein, we have demonstrated that repeated stimulation in vitro of C57BL/6 spleen cells primed in vivo with E61-13-H17 (H3N2) virus results in the selection of a population of cytotoxic T lymphocytes (CTL) whose recognition of infected target cells maps to the gene for nucleoprotein of the 1968 vi...

We have rescued influenza A virus by transfection of 12 plasmids into Vero cells. The eight individual negative-sense genomic viral RNAs were transcribed from plasmids containing human RNA polymerase I promoter and hepatitis delta virus ribozyme sequences. The three influenza virus polymerase proteins and the nucleoprotein were expressed from protein expression plasmids. This plasmid-based reve...

An ammonium deoxycholate fraction from bromelain-treated influenza A virus was highly enriched for virus nucleoprotein and contained residual haemagglutinin (NP/HA). The preparation did not contain detectable levels of matrix or neuraminidase proteins and was free of infectious virus. NP/HA effectively primed mice for cytotoxic T cells which lysed syngeneic cells infected with any type A influe...

Nucleoprotein (NP), the structural component of ribonucleoprotein complex of avian influenza virus, performs multiple essential functions in the regulation of viral RNA synthesis and in the control of nuclear traffic of viral proteins. Mutations have often been found in NP, some of which are relevant to viral survival strategies. In this study, we used nanospray-MS/MS to analyze tryptic digesti...

Subcutaneous administration in mice of recombinant Sindbis viruses expressing a class I major histocompatibility complex-restricted 9-mer epitope of the Plasmodium yoelii circumsporozoite protein or the nucleoprotein of influenza virus induces a large epitope-specific CD8(+) T-cell response. This immunization also elicits a high degree of protection against infection with malaria or influenza A...

UNLABELLED Numerous experimental studies have demonstrated that CD8(+) T cells contribute to immunity against influenza by limiting viral replication. It is therefore surprising that rigorous statistical tests have failed to find evidence of positive selection in the epitopes targeted by CD8(+) T cells. Here we use a novel computational approach to test for selection in CD8(+) T-cell epitopes. ...

BACKGROUND MHC class I-restricted CD8+ cytotoxic T lymphocytes (CTL) are thought to play a major role in clearing virus and promoting recovery from influenza infection and disease. This has been demonstrated for clearance of influenza virus from the lungs of infected mice. However, human influenza infection is primarily a respiratory mucosal infection involving the nasopharynx and tracheobronch...