High-throughput quantitative assessments of the chemical complementarity of celiac disease-related IGH CDR3s and a gliadin epitope.

The long-term value of efficient antigen discovery includes gaining insights into the variety of potential cancer neoantigens, effective vaccines lacking adverse effects, and adaptive immune receptor (IR) targets for blocking adaptive IR-antigen interactions in autoimmunity. While the preceding goals have been partially addressed via big data approaches to HLA (human leukocyte antigen)-epitope binding, there has been little such progress in the big data setting for adaptive IR-epitope binding. This delay in progress for the latter is likely due to, among other things, the much more complicated adaptive IR repertoire in an individual compared to individual HLA alleles. Thus, results described here represent the application of an algorithm for efficient assessment of immunoglobulin heavy chain complementarity determining region-3 (IGH CDR3)-gliadin epitope interactions, with a focus on epitopes known to be associated with an immune response in celiac disease. The hydrophobic, chemical complementarity between celiac case IGH CDR3s and known celiac epitopes was found to be greater in comparison to the hydrophobic, chemical complementarity between the same celiac case IGH CDR3s and a series of control epitopes. Thus, the approaches indicated here likely offer guidance for the development of conveniently applied algorithms for antigen verification and discovery.

Jain R ，Bressler M ，Chobrutskiy A ，Chobrutskiy BI ，Blanck G ... -  《-》

IGH Complementarity Determining Region-3-Cytomegalovirus Protein Chemical Complementarity Linked to Better Overall Survival Probabilities for Glioblastoma.

Hudock TR ，Song JJ ，Chobrutskiy A ，Chobrutskiy BI ，Blanck G ... -  《-》

Chemical Complementarity of Tumor Resident, Adaptive Immune Receptor CDR3s and Previously Defined Hepatitis C Virus Epitopes Correlates with Improved Outcomes in Hepatocellular Carcinoma.

Song JJ ，Chobrutskiy A ，Chobrutskiy BI ，Cios KJ ，Huda TI ，Eakins RA ，Diaz MJ ，Blanck G ... -  《-》

Human genome search in celiac disease: mutated gliadin T-cell-like epitope in two human proteins promotes T-cell activation.

Discovery of a number of novel and known human genes whose protein products bear striking similarity to two or more wheat gliadin domains raised the possibility that human intestinal non-HLA peptides homologous to celiac T-cell epitopes could play a role in non-HLA gene specification in celiac disease. Database searching of the entire human genome identified only 11 gut-expressed proteins with high T-cell epitope homology, particularly to the DQ2-gamma-I-gliadin epitope (i.e. TFIIA, FOXJ2 and IgD; mean BestFit quality score=40 versus random value of 24). Others were similar to DQ2-alpha-I-gliadin (i.e. PAX9; BestFit quality 46 versus 20 for random), or DQ2-alpha-II-gliadin (PHLDA1, known in mice as the T-cell death-associated gene; BestFit quality 43 versus 30 for random) epitopes. Among proteins previously screened for gliadin homology, noteworthy was achaete scute homologous protein (DQ2-alpha-I-gliadin; BestFit quality 41 versus 22 for random). With the exception of IgD, all are nuclear factors. Paying particular attention to the position of potential major histocompatibility complex (MHC) anchor residues, several were selected for testing in a DQ2-gamma-I-gliadin-restricted T-cell system. All native 10-mer peptides were inactive, even when deamidated, but V96F substitution of deamidated TFIIA amino acid residues 91-100 stimulated IL-2 release at levels exceeding the wheat gliadin positive control. Also active, but only slightly, was L1009F substitution of AIB3 amino acid residues 1004-1013. PlotSimilarity alignment of TFIIAs from eight species revealed subthreshold similarity score in the peptide region, in contrast to the highly conserved amino and carboxy termini. Molecular modeling of TFIIA[V96F] peptide points to an important juxtaposition of an upwardly projecting phenylalanine residue at peptide position 6 that likely contacts a receptor complementarity-determining region, and a downwardly projecting glutamic acid residue that fits into the shallow MHC P7 pocket. These observations tentatively point to a new multi-gene hypothesis for the initiation of celiac disease in which deamidated free human peptides with T-cell epitope homology (particularly those made more homologous by mutation) escape negative selection, as per deamidation of the HEL(48-62) peptide in the hen egg lysozyme model of autoimmunity. Deamidation following peptide release due to injury triggers inflammation, thereafter repeatedly provoked by dietary gliadin immunodominant peptides concentrated in the proximal small intestine.

Kumar R ，Eastwood AL ，Brown ML ，Laurie GW ... -  《JOURNAL OF MOLECULAR BIOLOGY》

High-throughput, sliding-window algorithm for assessing chemical complementarity between immune receptor CDR3 domains and cancer mutant peptides: TRG-PIK3CA interactions and breast cancer.

Physicochemical assessments of a vast accumulation of adaptive immune receptor (IR) recombinations have led to correlations of those properties with sub-divisions of various diseases. In the cancer setting, such assessments, particularly for the complementarity determining region-3 (CDR3) immune receptor domain, have been used to establish chemical complementarity matches to mutant amino acids (AA). These matches, in some cases, over very large numbers of tumor samples, have correlated with survival and gene expression distinctions. For example, in melanoma, electrostatic charge based, T-cell receptor CDR3-DNAH9 mutant AA complementarity represents better survival over multiple datasets that represent tumor tissue, T-cell receptor CDR3s. In this report, the complementarity approach has been expanded to include a more comprehensive representation of the interaction of T-cell receptor CDR3s and mutant AAs by incorporating the impact of the wild-type AAs surrounding the mutant AA. This "sliding window" approach was benchmarked against two large datasets of empirically determined CDR3-epitope pairs; showed more significant patient subdivisions; revealed a novel, TRG CDR3-mutant PIK3CA linkage in breast cancer; and was particularly suited to use with big data collections using only modest and widely-available processors. Thus, the algorithm should support more rapid and convenient indications (or prescreens) of CDR3-mutant peptide interactions for more focused studies and more efficient development of patient immunology-related prognostic tools and therapies.

Chobrutskiy BI ，Chobrutskiy A ，Zaman S ，Yeagley M ，Huda TI ，Blanck G ... -  《-》