Limiting dilution analysis of memory cytotoxic T lymphocytes specific for individual influenza virus gene products.

The frequency of memory T cells specific for individual influenza virus gene products in the spleens of BALB/c mice primed with A/Puerto Rico/8/34/1(H1N1) (PR8) influenza A virus was determined by using limiting dilution protocols. The results confirm that the influenza virus nucleoprotein (NP) is the predominant protein recognized by BALB/c cytotoxic T lymphocyte (CTL). This was true whether the responder splenocytes were restimulated with homologous PR8 virus or heterologous A/Japan/305/57 (H2N2) (JAP). The frequency hierarchy for BALB/c splenocytes restimulated with PR8 was NP greater than PB2 greater than or equal to H1 greater than NS1 greater than H2. The frequency of CTL specific for all other influenza gene products was too low to calculate. The CTL hierarchy for BALB/c splenocytes restimulated with JAP was NP greater than NS1, with all others lower than 1 in 96,000.