Human CD4+ T-cell repertoire of responses to influenza A virus hemagglutinin after recent natural infection.

The HA 20-40 sequence corresponds to amino acids 36-56 of Genbank ID 49339231 for HA of Influenza A virus (A/Beijing/32/92). Human CD4+ T cell lines from recently infected (within the prior 3-6 months) donors were generated against the hemagglutinin protein (HA) of influenza A virus (A/Beijing/32/93). Two donors were screened for reactivity against the HA 20-40 region by pooling two overlapping peptides (HA 20-35 and HA 25-40). The response in both donors was shown to be HLA-DR-restricted by using anti-DR antibodies.