Anti-TNFRSF4 monoclonal antibody, clone OX-40

Background: There is an unmet need for reliable minimally invasive diagnostic biomarkers for immunological allograft monitoring and for the detection of acute kidney transplant rejection. Here, targeted proteomic analysis was applied to compare 92 proteins in sera of belatacept-treated patients who had biopsy-proven, acute T-cell-mediated rejection (aTCMR) with patients without aTCMR. Methods: Proximity extension immunoassay was used to measure 92 inflammation-related protein concentrations in the prerejection and rejection sera of 11 patients with aTCMR and 9 patients without aTCMR. This assay uses 2 matched oligonucleotide-labeled antibody probes for each protein and polymerase chain reaction to measure normalized protein expression values. Results: Five proteins (CD5, CD8A, NCR1, TNFRSF4, and TNFRSF9) were expressed significantly higher in samples with aTCMR compared with samples without aTCMR (adjusted P-value < 0.014) and had a good predictive capacity for aTCMR [area under the curve in a receiver-operator curve ranged from 0.83 to 0.91 (P < 0.014)]. These proteins are associated with CD8(+) cytotoxic T-cell and NK cell functions. Nonhierarchical clustering analysis showed distinct clustering of samples with aTCMR and samples without aTCMR. This clustering was not found in prerejection samples (1 month after transplantation). In prerejection samples, IFN-gamma was expressed at a significantly lower level (normalized protein expression value median -0.15, interquartile range: -0.27 to 0.04) than in samples of patients without rejection (median 0.13, interquartile range: -0.07 to 0.15, adjusted P-value = 0.00367). Conclusions: Targeted proteomic analysis with proximity extension immunoassay is a promising minimally invasive technique to diagnose aTCMR in kidney transplant recipients.

TNFR superfamily (TNFRSF)4 (OX40, CD134) and TNFRSF25 are costimulatory receptors that influence CD4(+) and CD8(+) T cell responses to cognate Ag. Independently, these receptors have been described to stimulate overlapping functions, including enhanced proliferation and activation for both regulatory T cells (CD4(+)Foxp3(+); Tregs) and conventional T cells (CD4(+)Foxp3(-) or CD8(+)Foxp3(-); Tconvs). To determine the relative functionality of TNFRSF4 and TNFRSF25 in T cell immunity, the activity of TNFRSF4 and TNFRS25 agonistic Abs was compared in the context of both traditional protein/adjuvant (OVA/aluminum hydroxide) and CD8(+)-specific heat shock protein-based (gp96-Ig) vaccine approaches. These studies demonstrate that both TNFRSF4 and TNFRSF25 independently and additively costimulate vaccine-induced CD8(+) T cell proliferation following both primary and secondary Ag challenge. In contrast, the activities of TNFRSF4 and TNFRSF25 were observed to be divergent in the costimulation of CD4(+) T cell immunity. TNFRSF4 agonists were potent costimulators of OVA/aluminum hydroxide-induced CD4(+) Tconv proliferation, but they only weakly costimulated Treg proliferation and IgG2a production, whereas TNFRSF25 agonists were strong costimulators of Treg proliferation, producers of IgG1, IgG2a, and IgG2b, and weak costimulators of CD4(+) Tconv proliferation. Interestingly, Ag-specific cellular and humoral responses were uncoupled upon secondary immunization, which was dramatically affected by the presence of TNFRSF4 or TNFRSF25 costimulation. These studies highlight the overlapping but nonredundant activities of TNFRSF4 and TNFRSF25 in T cell immunity, which may guide the application of receptor agonistic agents as vaccine adjuvants for infectious disease and tumor immunity. The Journal of Immunology, 2012, 189: 3311-3318.