Project description:Celiac disease (CeD) is a common autoimmune disorder caused by an abnormal immune response to dietary gluten proteins. The disease has high heritability. HLA is the major susceptibility factor, and the HLA effect is mediated via presentation of deamidated gluten peptides by disease-associated HLA-DQ variants to CD4+ T cells. In addition to gluten-specific CD4+ T cells the patients have antibodies to transglutaminase 2 (autoantigen) and deamidated gluten peptides. These disease-specific antibodies recognize defined epitopes and they display common usage of specific heavy and light chains across patients. Interactions between T cells and B cells are likely central in the pathogenesis, but how the repertoires of naïve T and B cells relate to the pathogenic effector cells is unexplored. To this end, we applied machine learning classification models to naïve B cell receptor (BCR) repertoires from CeD patients and healthy controls. Strikingly, we obtained a promising classification performance with an F1 score of 85%. Clusters of heavy and light chain sequences were inferred and used as features for the model, and signatures associated with the disease were then characterized. These signatures included amino acid (AA) 3-mers with distinct bio-physiochemical characteristics and enriched V and J genes. We found that CeD-associated clusters can be identified and that common motifs can be characterized from naïve BCR repertoires. The results may indicate a genetic influence by BCR encoding genes in CeD. Analysis of naïve BCRs as presented here may become an important part of assessing the risk of individuals to develop CeD. Our model demonstrates the potential of using BCR repertoires and in particular, naïve BCR repertoires, as disease susceptibility markers.
Project description:Determination of expression levels of light chain V genes in peripheral blood B cells after FACS sorting for two populations of B cells (CD20+CD138-IgKappa+IgLambda- and CD20+CD138-IgKappa-IgLambda+). Analysis was performed on healthy individuals and SLE patients with analysis performed using several models. Dual channel hybridization with experimental samples detected on red channel and reference sample detected on green channel. Two replicate hybridizations.
Project description:Determination of expression levels of light chain V genes in peripheral blood B cells after FACS sorting for two populations of B cells (CD20+CD138-IgKappa+IgLambda- and CD20+CD138-IgKappa-IgLambda+). Analysis was performed on healthy individuals and SLE patients with analysis performed using several models.
Project description:Human aging is associated with a profound loss of thymus productivity, yet naïve T lymphocytes still maintain their numbers by division in the periphery for many years. The extent of such proliferation may depend on the cytokine environment, including IL-7 and T-cell receptor (TCR) "tonic" signaling mediated by self pMHCs recognition. Additionally, intrinsic properties of distinct subpopulations of naïve T cells could influence the overall dynamics of aging-related changes within the naïve T cell compartment. Here, we investigated the differences in the architecture of TCR beta repertoires for naïve CD4, naïve CD8, naïve CD4+CD25-CD31+ (enriched with recent thymic emigrants, RTE), and mature naïve CD4+CD25-CD31- peripheral blood subsets between young and middle-age/old healthy individuals. In addition to observing the accumulation of clonal expansions (as was shown previously), we reveal several notable changes in the characteristics of T cell repertoire. We observed significant decrease of CDR3 length, NDN insert, and number of non-template added N nucleotides within TCR beta CDR3 with aging, together with a prominent change of physicochemical properties of the central part of CDR3 loop. These changes were similar across CD4, CD8, RTE-enriched, and mature CD4 subsets of naïve T cells, with minimal or no difference observed between the latter two subsets for individuals of the same age group. We also observed an increase in "publicity" (fraction of shared clonotypes) of CD4, but not CD8 naïve T cell repertoires. We propose several explanations for these phenomena built upon previous studies of naïve T-cell homeostasis, and call for further studies of the mechanisms causing the observed changes and of consequences of these changes in respect of the possible holes formed in the landscape of naïve T cell TCR repertoire.
Project description:Aim: To compare the overall transcriptional profile in healthy controls and celiac disease patients. This dataset, was used to evaluate if our in vitro model (intestinal intraepithelial lymphocytes, desccribed in doi:10.1016/j.jaut.2020.10242 ) is representative of the transcriptional profile in the intestine under healthy or inflammatory conditions. Samples: Upper colonoscopy biopsies from 5 control and 11 celiac disease patients were taken, total RNA was extracted and RNA-sequencing was performed (without replicates)
Project description:Prolactin is a peptide hormone produced by the anterior pituitary gland that is critical in lactation. Prolactin can also be produced by lymphocytes, and both B and T cells express prolactin receptors. These findings have suggested that prolactin has immunomodulatory functions. Studies in spontaneously autoimmune hosts have demonstrated a role for prolactin in augmenting autoreactivity. We chose to analyze prolactin effects on anti-DNA B cells in nonspontaneously autoimmune female BALB/c mice transgenic for the heavy chain of an anti-DNA antibody. Treatment with prolactin for 4 weeks induced a lupus-like phenotype with an increased number of transgene-expressing B cells, elevated serum anti-DNA antibody titers, and glomerular immunoglobulin deposits. Prolactin caused a decrease in the population of transitional B cells and an increase in mature follicular and marginal zone B cells. The DNA-reactive B cells had a follicular cell phenotype. Anti-DNA hybridomas demonstrated that prolactin alters selection of the naive B cell repertoire. The expansion and activation of anti-DNA B cells in prolactin-treated R4A-gamma2b BALB/c mice was dependent on the presence of CD4(+) T cells. Finally, treatment with prolactin was unable to break tolerance in R4A-gamma2b transgenic C57Bl/6 mice, suggesting that responsiveness of the immune system to prolactin is genetically determined.
Project description:The clone size distribution of the human naive T-cell receptor (TCR) repertoire is an important determinant of adaptive immunity. We estimated the abundance of TCR sequences in samples of naive T cells from blood using an accurate quantitative sequencing protocol. We observe most TCR sequences only once, consistent with the enormous diversity of the repertoire. However, a substantial number of sequences were observed multiple times. We detect abundant TCR sequences even after exclusion of methodological confounders such as sort contamination, and multiple mRNA sampling from the same cell. By combining experimental data with predictions from models we describe two mechanisms contributing to TCR sequence abundance. TCR? abundant sequences can be primarily attributed to many identical recombination events in different cells, while abundant TCR? sequences are primarily derived from large clones, which make up a small percentage of the naive repertoire, and could be established early in the development of the T-cell repertoire.
Project description:T-cell receptor (TCR) genomic loci undergo somatic V(D)J recombination, plus the addition/subtraction of nontemplated bases at recombination junctions, in order to generate the repertoire of structurally diverse T cells necessary for antigen recognition. TCR beta subunits can be unambiguously identified by their hypervariable CDR3 (Complement Determining Region 3) sequence. This is the site of V(D)J recombination encoding the principal site of antigen contact. The complexity and dynamics of the T-cell repertoire remain unknown because the potential repertoire size has made conventional sequence analysis intractable. Here, we use 5'-RACE, Illumina sequencing, and a novel short read assembly strategy to sample CDR3(beta) diversity in human T lymphocytes from peripheral blood. Assembly of 40.5 million short reads identified 33,664 distinct TCR(beta) clonotypes and provides precise measurements of CDR3(beta) length diversity, usage of nontemplated bases, sequence convergence, and preferences for TRBV (T-cell receptor beta variable gene) and TRBJ (T-cell receptor beta joining gene) gene usage and pairing. CDR3 length between conserved residues of TRBV and TRBJ ranged from 21 to 81 nucleotides (nt). TRBV gene usage ranged from 0.01% for TRBV17 to 24.6% for TRBV20-1. TRBJ gene usage ranged from 1.6% for TRBJ2-6 to 17.2% for TRBJ2-1. We identified 1573 examples of convergence where the same amino acid translation was specified by distinct CDR3(beta) nucleotide sequences. Direct sequence-based immunoprofiling will likely prove to be a useful tool for understanding repertoire dynamics in response to immune challenge, without a priori knowledge of antigen.