T cell unresponsiveness in vitro can be due to activation in vivo

Abstract

During investigations into the behaviour and fate of ovalbumin (OVA)-specific CD8+ T cells in a TCR transgenic system, cytotoxic T lymphocyte (CTL) activity (as measured by classical in vitro stimulation followed by 51Cr-release assay) was found to be reduced after OVA peptide administration. This paradoxically occurred even during the peak of activation and expansion of these T cells. The reduced responsiveness occurred for both classical CTL assays and in vitro proliferation assays, and would apparently be consistent with induction of anergic or suppressor T cells. Instead, we provide evidence that in vivo peptide treatment generated activated killers which consequently killed the stimulat..