zyme-linked immuno-spot; NGS, next generation sequencing; RT-PCR, real-time quantitative polymerase chain reaction; further abbreviations are listed in Table 1.Seventeen studies (53 ) measured secretion of inflammatory and/or TH -subsetspecific cytokines (e.g., IL-4, IL-5, IL-17A, IFN-) by enzyme-linked immuno-sorbent assay (ELISA) (11/32 research, 34 ), ELISpot (5/32 studies, 16 ) or other methods (e.g., intracellular staining, 3/32 studies, 9.4 ) following a number of days of cellular expansion. In 9 out of these 17 research, proliferation was measured in parallel (marked with in Table 3). We observed a trend for a preferential differentiation towards the TH two lineage within the cytokine production (5/17 studies, 29 ) for PPD (3/17 research, 18 ) (Coulter, 2010; Jenkinson, 2010; Sieben, 2002) [79,80,93] and MCI/MI (1/17 studies, 6 ) (Masjedi, 2003) [107]. Two research defined a TH 1 cytokine profile of chemical-specific T cells, i.e., for DNCB (note: TH two shift in atopic patients) (Newell, 2013) [103] and fragrances (Sieben, 2001) [105]. In 3 studies (18 ), chemical-stimulated cells secreted a mix of TH 1 (e.g., IFN-) and TH 2 (e.g., IL-4, IL-5 and/or IL-13) cytokines. Chemical EP Activator site substances utilized in these 3 research partially overlapped with all the ones mentioned above as inducing a TH 2 profile, i.e., PPD, BB, MCI, fragrance mix and parthenolide (Gibson, 2015; Moed, 2005; Wahlkvist, 2008) [94,95,117]. The remaining eight studies (47 ) did not measure a conclusive, within this regard, panel of cytokines (e.g., IL-1/IL-1 or IFN-/TNF-/IL-2 or IFN- alone).Cells 2022, 11,12 ofGene expression by real-time quantitative polymerase chain reaction (RT-PCR), microarray or RNA sequencing (4/32 studies, 13 ) and cellular phenotype/activation adjustments (e.g., CD69 expression by flow cytometry, 5/32 studies, 16 ) have been frequent added read-outs, especially amongst more current publications (Table three, Supplementary Material Table S2). None of the studies produced conclusive observations on major variations inside the activation or function of CD4+ and CD8+ T cell subsets in chemical-associated allergies. Sieben and colleagues (2001) [105] observed that 83 of established eugenol-specific T cell clones had been CD4+HLA-DR+, plus the remaining 17 have been CD8+. Wicks, 2019 [102] and Oakes, 2017 [100] each observed a shift in the central memory (CM) to the effector memory (EM) compartment in PPD and HIV-1 Antagonist Purity & Documentation PPD-HSA stimulated CD4+ and CD8+ T cells of allergic patients. Additionally, within the former study, an expansion of na e T cells was detected inside the blood compartment. A simultaneous contraction with the memory T cell population (in all probability as a consequence of recruitment to the web site of patch test application) was also observed [102]. 4 studies (13 ) nailed antigen-specific T cell involvement by producing T cell clones confirming their proliferative capability upon re-stimulation with all the original antigens, PPD and BB (Gibson, 2015; Jenkinson, 2010; Sieben, 2002; Skazik, 2008) [79,80,94,101]. Two research performed HLA-blocking through T cell clone re-stimulation to confirm MHCrestricted T cell activation (Kim, 2020; Sieben, 2002) [80,108]. TCR capabilities were addressed in two PPD-related studies (Oakes, 2017; Skazik, 2008) [100,101]. Oakes, 2017 [100] performed an unbiased high-throughput sequencing from the TCR – and -chains of PBMC derived from one PPD-allergic patient in ex vivo circumstances immediately after 6 days of culture with PPD-HSA. Around 800 TCR – and – chain sequences (0.eight of all detected TCR) were thought of PPD