Fig. 1.

Model for selection and evaluation of specimens for antigen-specific T-cell immune responses. This figure illustrates the screening for T-cell responses using the Interferon gamma (IFN-γ) ELISpot assay, and subsequent use of flow cytometry to evaluate co-expressing responses. Arm A denotes stimulation of PBMCs from HIV-1 infected individuals with consensus group M peptides. After flow cytometry, T-cells in Arm A were stratified into IFN-γ secreting (IFN-γ positive) and non-secreting (IFN-γ negative) populations. Secretion of other T-cell functions (Perforin, TNF-α and IL-2) was then compared across the two groups. Arm B comprised healthy HIV-1 uninfected individuals, serologically reactive to Adenovirus by antibody testing, but IFN-γ ELISpot negative to Adenovirus peptide stimulation. The IFN-γ negative T-cells were assessed for expression of Adenovirus-specific Perforin, TNF-α,and IL-2 using flow cytometry.