Project description:Seeking to identify HLA class I peptides that originate from vaccinia virus proteins to understand the mechanism of immune protection. Note that vaccinia-infected B cells will still continue to present (primarily) a wide variety of peptides originating from endogenous proteins; this data set contains evidence for more than 5000 such peptides. The objective and challenge is to detect and identify the peptides that originate from the pathogen (vaccinia virus) in the presence (background) of this large number of endogensous 'self' peptides. Keywords: Peptide search results from multiple injections of multiple strong cation exchange fractions combined into one set of results.
Project description:Dengue and Zika are two mosquito-borne diseases of great concern, affecting mainly the tropical and subtropical regions worldwide. The arrival of Zika virus (ZIKV) in dengue virus (DENV) endemic areas imposed challenges for differential diagnosis and the development of candidate vaccines. The use of peptides has shown great potential to achieve these goals. We aimed to identify the linear epitope profile recognized by the serum samples of dengue and Zika patients in the E and NS1 proteins of DENV and ZIKV to select peptides with the potential for the development of diagnostic tests and vaccines. Analysis of a peptide microarray platform with serum samples of dengue and Zika patients demonstrated that the epitopes were evenly distributed across the entire viral proteins, showing no preference for particular regions. However, several epitopes were within epitope hot spots constituted by clusters of peptides recognized in more than 30% of the sub-arrays analyzed with individual or pools of serum samples. The serum samples of dengue and Zika patients showed a high level of cross-reaction for epitopes in the DENV and ZIKV proteins. Analysis of an additional peptide microarray platform containing selected peptides based on the results of the first screening showed that three peptides (DENV: TQGEPSLNEEQDKRF and TQTVGPWHLGKLEID; ZIKV: LELDPPFGDSYIVIG), highly specific for their cognate viruses (p<0.05), were within the epitope hot spots; however, these peptides showed low detection rates (32.5, 35.0, and 28.6%, respectively). We also found two peptides (DENV: WEVEDYGFGVFTTNI and LELDFDLCEGTTVVV) in the epitope hot spots detected by both dengue and Zika patients with similarly high rates (arbitrary detection rate cut-off threshold of ≥40%). The epitope hot spots harbor several immunodominant epitopes recognized by a higher number of individuals when compared to the 15 aa sequence peptides. Therefore, the entire epitope hot spots, spanning up to ~30 aa, would have more potential than peptides of only 15 aa to serve as antigens in diagnostic tests and vaccine developments.
Project description:Dengue and Zika are two mosquito-borne diseases of great concern, affecting mainly the tropical and subtropical regions worldwide. The arrival of Zika virus (ZIKV) in dengue virus (DENV) endemic areas imposed challenges for differential diagnosis and the development of candidate vaccines. The use of peptides has shown great potential to achieve these goals. We aimed to identify the linear epitope profile recognized by the serum samples of dengue and Zika patients in the E and NS1 proteins of DENV and ZIKV to select peptides with the potential for the development of diagnostic tests and vaccines. Analysis of a peptide microarray platform with serum samples of dengue and Zika patients demonstrated that the epitopes were evenly distributed across the entire viral proteins, showing no preference for particular regions. However, several epitopes were within epitope hot spots constituted by clusters of peptides recognized in more than 30% of the sub-arrays analyzed with individual or pools of serum samples. The serum samples of dengue and Zika patients showed a high level of cross-reaction for epitopes in the DENV and ZIKV proteins. Analysis of an additional peptide microarray platform containing selected peptides based on the results of the first screening showed that three peptides (DENV: TQGEPSLNEEQDKRF and TQTVGPWHLGKLEID; ZIKV: LELDPPFGDSYIVIG), highly specific for their cognate viruses (p<0.05), were within the epitope hot spots; however, these peptides showed low detection rates (32.5, 35.0, and 28.6%, respectively). We also found two peptides (DENV: WEVEDYGFGVFTTNI and LELDFDLCEGTTVVV) in the epitope hot spots detected by both dengue and Zika patients with similarly high rates (arbitrary detection rate cut-off threshold of ≥40%). The epitope hot spots harbor several immunodominant epitopes recognized by a higher number of individuals when compared to the 15 aa sequence peptides. Therefore, the entire epitope hot spots, spanning up to ~30 aa, would have more potential than peptides of only 15 aa to serve as antigens in diagnostic tests and vaccine developments.
Project description:T cell-mediated immunity seems to play a critical role against SARS-CoV-2 infection and establishing protective memory. Yet the repertoire of viral epitopes responsible for activation of T cell responses remains mostly unknown. Identification and characterization of viral peptides presented on class I human leukocyte antigen (HLA-I) will reveal the viral signatures as seen by cytotoxic T cells that can then be harnessed for the development of effective vaccines. Here, we report the first HLA-I immunopeptidome of SARS-CoV-2 in two human cell lines at different times post-infection using mass spectrometry. We found HLA-I peptides derived not only from canonical ORFs, but also from internal out-of-frame ORFs in Spike and Nucleoprotein not currently captured by vaccine approaches. Whole proteome analysis revealed that expression of ubiquitination pathway proteins, and the proteasome maturation protein, POMP, were significantly altered in infected cells. Retrospective analysis of computational predictions highlighted shortcomings of in silico-only approaches in recovering the observed viral epitopes. Finally, given the experimental evidence for endogenous processing and presentation of the viral peptides we detected, we estimated that at least one HLA-A, -B, or -C allele is covered by at least one peptide for 99% of the population. These biological insights and the list of naturally presented SARS-CoV-2 peptides will facilitate data-driven selection of peptides for immune monitoring and vaccine development.
Project description:These assays represent antibody-binding assays to analyze seroprevalence of antigens and epitopes at the individual level and also to perform fine epitope mapping characterizations. In this screening 392,299 peptides derived from reactive (antigenic) regions of Trypanosoma cruzi proteins were displayed in the form of short peptides (tiling array, overlapped) and assayed with individual serum samples (antibodies) from Chagas Disease patients across the Americas. Sectorized peptide arrays (QX12-plex slides, Roche Nimblegen) were incubated with serum samples (primary antibodies), washed, and then incubated with a fluorescently-labeled anti-human IgG commercial antibody (secondary antibodies). Raw readouts of fluoresence (signal), as well as normalized signal values are provided in this submission for all samples analyzed. All samples were analyzed in duplicate (r1 = replicate 1; r2 = replicate 2).
Project description:Citrullinated and unmodified peptides (>95% purity, ProImmune AB) were immobilized onto a chemically modified glass slide, sera from RA patients and healthy controls were applied into the reactions sites and fluorescence intensity after incubation with anti-human IgG antibody was acquired in a laser scanner. Final results for each citrullinated peptide were calculated by subtracting the intensity values of corresponding arginine containing control peptide from citrullinated peptide for all RA patients and controls.
Project description:The novel neuroproteasome is localized to the neuronal plasma membrane to degrade intracellular proteins into peptides that are released to the extracellular space. Selective inhibition of this neuronal membrane proteasome (NMP) complex ceased the release of peptides and rapidly attenuated neuronal transmission. Based on these findings, we hypothesize that these neuron-specific peptides mediate a novel form of communication through unique peptide-receptor interactions to promote intracellular signaling cascades relevant to neuronal development and function. Our work indicates that NMP peptides can rapidly induce N-methyl-D-aspartate receptor (NMDAR)-dependent calcium influx from dendrites to the soma, leading to rapid and sustained phosphorylation of the well-defined activity-dependent transcription factor cAMP response element-binding protein (CREB). We also determined that the gene expression program drastically changes upon NMP peptide treatment of neurons with an increase in expression of immediate early genes (e.g., Fos, Npas4, Egr4) known to have critical neuroregulatory roles. These data support our current thinking that NMP peptides are endogenous and selective activators of synaptic NMDA receptors and are critical for promoting activity-dependent gene expression. This pathway is orthogonal to the classic neurotransmitters previously described to activate NMDARs and points to NMP and its resulting peptides as key contributors to the development and function of the nervous system. However, the unique peptide sequences leading to neuronal activation are still poorly understood. Here, we show that the NMP peptides have tremendous sequence diversity through an unbiased peptidomic approach, and the current ongoing effort is to identify unique active peptide sequences with distinct receptor specificity. Elucidating the mechanism of the NMP and its active peptide products is crucial to understanding the role of this novel signaling process in the nervous system.
Project description:Total RNAs were extracted from internodes and roots of 18 day-after-germination soybean plants, and the expression levels of the genes that encode xylem sap associated peptides or proteins were analyzed.