Figure 1: A schematic diagram showing possible cysteinylation of PSMA protein and reductive cleavage of PSMA by GILT in prostate cancer cells. The prostate specific membrane protein PSMA or its peptides can be oxidized in the presence of cystine in bodily fluid and that Ags/peptides remain non-functional in the absence of reductive processing by GILT. The results of which could be a differential selection and display of HLA class II-peptide complexes on the surface of prostate cancer cells, lowering CD4+ T cell recognition. The introduction of GILT in prostate cancer cells may lead to reduction and processing of the cysteinylated Ags/peptides, restoring functional PSMA presentation and improved CD4+ T cell recognition of prostate tumors.