Extrinsically derived TNF is primarily responsible for limiting antiviral CD8+ T cell response magnitude.

TNF is a pro-inflammatory cytokine produced by both lymphoid and non-lymphoid cells. As a consequence of the widespread expression of its receptors (TNFR1 and 2), TNF plays a role in many important biological processes. In the context of influenza A virus (IAV) infection, TNF has variably been implicated in mediating immunopathology as well as suppression of the immune response.

Consequences of suboptimal priming are apparent for low-avidity T-cell responses.

The emergence of the novel reassortant A(H1N1)-2009 influenza virus highlighted the threat to the global population posed by an influenza pandemic. Pre-existing CD8(+) T-cell immunity targeting conserved epitopes provides immune protection against newly emerging strains of influenza virus, when minimal antibody immunity exists. However, the occurrence of mutations within T-cell antigenic peptides that enable the virus to evade T-cell recognition constitutes a substantial issue for virus control and vaccine design.

Memory precursor phenotype of CD8+ T cells reflects early antigenic experience rather than memory numbers in a model of localized acute influenza infection.

The mechanistic basis of memory T-cell development is poorly defined. Phenotypic markers that define precursors at effector stages have been characterized for acute systemic infections with high antigen load. We asked whether such markers can identify memory precursors from early effectors (d6) to late memory (>d500) for two immunodominant CD8(+) responses during the course of a localized low-load influenza infection in mice.

Fixing an irrelevant TCR alpha chain reveals the importance of TCR beta diversity for optimal TCR alpha beta pairing and function of virus-specific CD8+ T cells.

TCR repertoire diversity can influence the efficacy of CD8(+) T-cell populations, with greater breadth eliciting better protection. We analyzed TCR beta diversity and functional capacity for influenza-specific CD8(+) T cells expressing a single TCR alpha chain. Mice (A7) transgenic for the H2K(b)OVA(257-264)-specific V alpha 2.

Primary CTL response magnitude in mice is determined by the extent of naive T cell recruitment and subsequent clonal expansion.

CD8+ T cell responses to viral infection are characterized by the emergence of dominant and subdominant CTL populations. The immunodominance hierarchies of these populations are highly reproducible for any given spectrum of virus-induced peptide-MHCI complexes and are likely determined by multiple factors. Recent studies demonstrate a direct correlation between naive epitope-specific CD8+ T cell precursor (CTLp) frequency and the magnitude of the response after antigen challenge.