Project description:Several HLA allelic variants have been associated with protection from, or susceptibility to infectious and autoimmune diseases. Here, we examined whether specific HLA alleles would be associated with different Mtb infection outcomes. We found that DQA1*03:01, DPB1*04:02, and DRB4*01:01 were signficantly more frequent in inividuals with active TB (susceptibility alleles). Furthermore, individuals who express any of the three susceptibility alleles were associated with lower magnitude of responses against Mtb antigens. We investigated the gene expression changes induced in PBMCs by Mtb lysate and a peptide pool (MTB300) in individuals with or without expression of the susceptibility alleles.
Project description:Abnormalities at any stage of trophoblast development may result in pregnancy-related com-plications. Many of these adverse outcomes are discovered later in pregnancy, but the underly-ing pathomechanisms constitute during the first trimester. Acquiring developmentally relevant material to elucidate the disease mechanisms is difficult. Human pluripotent stem cell (hPSC) technology can provide a renewable source of relevant cells. BMP4, A83-01, and PD173074 (BAP) treatment drives trophoblast commitment of hPSCs towards syncytiotrophoblast (STB) but lacks extravillous trophoblast (EVT) cells. EVTs mediate key functions during placentation, remodel-ing of uterine spiral arteries, and maintenance of immunological tolerance. We optimized the protocol for more efficient generation of HLA-Gpos EVT-like trophoblasts from primed hiPSCs. Increasing the concentrations of A83-01 and PD173074, while decreasing bulk cell density re-sulted in the increase of HLA-G of up to 71%. Gene expression profiling support the advance-ments of our treatment regarding the generation of trophoblast cells. The reported differentia-tion protocol will allow the on-demand access to human trophoblast cells enriched for HLA-Gpos EVT-like cells, allowing the elucidation of placenta-related disorders and to investigate the im-munological tolerance towards the fetus, overcoming the difficulties in obtaining primary EVTs without the need for a complex differentiation pathway via naïve pluripotent or trophoblast stem cells.
Project description:Human leukocyte antigen (HLA) - B*51:01 and endoplasmic reticulum aminopeptidase 1 (ERAP1) are two strong predisposing genetic factors to Behçet's disease (BD). Previous studies have focused on two subgroups of HLA-B*51 peptidome containing Proline (Pro) or Alanine (Ala) at position 2 (P2). Little is known about the unconventional non-Pro/Ala2 HLA-B*51-bound peptides. We aimed to study the features of this novel sub-peptidome, and investigate its regulation by ERAP1. CRISPR-Cas9 was used to generate an HLA-ABC-knockout HeLa cell line (HeLa.ABC-KO), which was subsequently transduced to express HLA-B*51:01 (HeLa.ABC-KO.B51). ERAP1 was silenced using lentiviral shRNA. Peptides bound to HLA-B*51:01 were eluted and analyzed by Mass Spectrometry. The characteristics of non-Pro/Ala2, Pro2 and Ala2 peptides, and their alteration by ERAP1 silencing were investigated. Effects of ERAP1 silencing on cell surface expression of HLA-B*51:01 were studied using flow cytometry. More than 20% of peptides eluted from HLA-B*51:01 lacked Proline or Alanine at P2. This unconventional group of HLA-B*51:01-bound peptides was enriched for 8-mers (with fewer 9-mers) compared to Pro2 and Ala2 sub-peptidomes, and had similar N-terminal and C-terminal residue usages to Ala2 peptides with the exception of the less abundant Leucine at position Ω. Knockdown of ERAP1 increased the percentage of non-Pro/Ala2 to approximately 40%, increased the percentage of longer (10-mer and 11-mer) peptides eluted from HLA-B*51:01 complexes, and abrogated the predominance of Leucine at P1. Interestingly knockdown of ERAP1 altered the length and N-terminal residue usage of non-Ala2&Pro2 and Ala2 but not the Pro2 peptides. Finally, ERAP1 silencing regulated the expression levels of cell surface HLA-B*51 in a cell type - dependent manner. The HLA-B*51:01 peptidome includes a surprisingly high proportion of unconventional non-Pro/Ala2 peptides which are increased by ERAP1 silencing, mimicking the loss-of-function BD risk variant.
Project description:Abacavir, a nucleoside reverse-transcriptase inhibitor used for the treatment of human immunodeficiency virus (HIV) infection, develops hypersensitivity in patients carrying HLA-B*57:01 allele through drug antigen presentation. We found that abacavir exposure induced HLA allotype-specific innate immune response in keratinocyte derived from HLA-B*57:01 transgenic mice. Therefore, the mechanism of the novel response was analyzed comprehensively.
Project description:The majority of peptides presented by MHC class I results from proteasomal protein turnover. The specialized immunoproteasome, which is induced during inflammation, plays a major role in antigenic peptide generation. However, other cellular proteases can, either alone or together with the proteasome, contribute peptides for MHC class I loading non-canonically. We used an im-munopeptidomics workflow combined with a prediction software for proteasomal cleavage probabilities to analyze how inflammatory conditions affect proteasomal processing of immune epitopes presented by A549 cells. Treatment of A549 cells with IFNγ enhanced proteasomal cleavage probability of MHC class I ligands for both, the constitutive proteasome and the im-munoproteasome. Furthermore, IFNγ alters the contribution of the different HLA allotypes to the immunopeptidome. When we calculated HLA allotype-specific proteasomal cleavage probabili-ties for MHC class I ligands, peptides presented by HLA-A*30:01 showed characteristics hinting at a reduced C-terminal proteasomal cleavage probability independently of the type of proteasome. This was confirmed by HLA-A*30:01 ligands from the immune epitope database, which also showed this effect. Furthermore, two additional HLA allotypes, namely HLA-A*03:01 and HLA-A*11:01, presented peptides with a markedly reduced C-terminal proteasomal cleavage probability. Peptides eluted from all three HLA allotypes shared a peptide binding motif with a C-terminal lysine residue suggesting that this lysine residue impairs proteasome-dependent HLA ligand production and might, in turn, favor peptide generation by other cellular proteases. The mass spectrometry raw files used in this study were originally produced for a previous publication, where they were utilized to address the influence of cigarette smoke on the antiviral T-cell immune response. Here, we have reanalyzed the data to investigate processing of MHC class I ligands by c20S or i20S, respectively. Original publication: Chen, J.; Wang, X.; Schmalen, A.; Haines, S.; Wolff, M.; Ma, H.; Zhang, H.; Stoleriu, M.G.; Nowak, J.; Nakayama, M.; et al. Antiviral CD8(+) T cell immune responses are impaired by cigarette smoke and in COPD. Eur Respir J 2023, doi:10.1183/13993003.01374-2022.
Project description:HLA DRB1*15:01 is overrepresentated in Parkinson's disease patients and binds with high affinity to the ⍺-synuclein peptide, 32-46. Immunization of humanized mice expressing HLA DRB1*15:01 with ⍺-syn32-46 induces enteric phenotypes similar to those of prodromal Parkinson's disease. We collected the small intestines from HLA mice immunized with either Complete Freund's Adjuvant (CFA) with ⍺-syn32-46 or CFA alone, sorted the CD45+ immune cells, then performed single-cell RNA sequencing to evaluate gene expression at single cell resolution.