Development of a direct in situ RT-PCR method using labeled primers to detect cytokine mRNA inside cells

Clinical validation of IFNγ/IL-10 and IFNγ/IL-2 FluoroSpot assays for the detection of Tr1 T cells and influenza vaccine monitoring in humans

The type of T cell polarization and simultaneous production of multiple cytokines have been correlated with vaccine efficacy. ELISpot is a T cell detection technique optimized for the measurement of a secreted cytokine at the single cell level. The FluoroSpot assay differs from ELISpot by the use of multiple fluorescent-labeled anticytokine detection antibodies, allowing optimal measurement of multiple cytokines. In the present study, we show that an IFNγ/IL-10 FluoroSpot assay is more sensitive than flow cytometry to detect Tr1 regulatory T cells, an immunosuppressive T cell population characterized by the production of IL-10 and IFNγ. As many tolerogenic vaccines are designed to induce these Tr1 cells, this FluoroSpot test could represent a standard method for the detection of these cells in the future. The use of an IFNγ/IL-2 FluoroSpot assay during influenza vaccine monitoring showed that the influenza-specific IL-2-producing T-cell response was the dominant response both before and after vaccine administration. This study therefore questions the rationale of using the single-color IFNγ ELISpot as the standard technique to monitor vaccine-specific T-cell response. Using this same test, a trend was also observed between baseline levels of IFNγ T cell response and T cell vaccine response. In addition, a lower IFNγ+IL-2+ T-cell response after vaccine was observed in the group of patients treated with TNFα inhibitors (P=0.08). This study therefore supports the use of the FluoroSpot assay due to its robustness, versatility and the complementary information that it provides compared with ELISpot or flow cytometry to monitor vaccine-specific T-cell responses.

In situ amplification of oestrogen receptor alpha mRNA in breast cancer cell lines and tumours

The aim of this work was to develop a direct in situ reverse transcription polymerase chain reaction (in situ RT-PCR) assay for the detection of oestrogen receptor alpha (ERalpha) mRNA on in vitro cell lines and breast tumour cell smears. ERalpha mRNA amplification was performed on MCF-7 (ERalpha positive) and MDA-MB-231 (ERalpha negative) cell lines as well as on 51 cytological smears of breast tumour samples from patients. The in situ amplification of mRNA in cell lines and ex vivo breast tumours was successful. However, finding an equilibrium between optimal cell morphology and PCR performance varied with each tumour, leading to difficulty in standardisation for daily practice. Nonetheless, in situ RT-PCR is a useful tool for the detection of ERalpha mRNA in selected cases, both in vitro and ex vivo. J Clin PATHOL: Mol Pathol