T-Cell Memory Responses Elicited by Yellow Fever Vaccine are Targeted to Overlapping Epitopes Containing Multiple HLA-I and -II Binding Motifs

The yellow fever vaccines (YF-17D-204 and 17DD) are considered to be among the safest vaccines and the presence of neutralizing antibodies is correlated with protection, although other immune effector mechanisms are known to be involved. T-cell responses are known to play an important role modulating antibody production and the killing of infected cells. However, little is known about the repertoire of T-cell responses elicited by the YF-17DD vaccine in humans. In this report, a library of 653 partially overlapping 15-mer peptides covering the envelope (Env) and nonstructural (NS) proteins 1 to 5 of the vaccine was utilized to perform a comprehensive analysis of the virus-specific CD4+ and CD8+ T-cell responses. The T-cell responses were screened ex-vivo by IFN-γ ELISPOT assays using blood samples from 220 YF-17DD vaccinees collected two months to four years after immunization. Each peptide was tested in 75 to 208 separate individuals of the cohort. The screening identified sixteen immunodominant antigens that elicited activation of circulating memory T-cells in 10% to 33% of the individuals. Biochemical in-vitro binding assays and immunogenetic and immunogenicity studies indicated that each of the sixteen immunogenic 15-mer peptides contained two or more partially overlapping epitopes that could bind with high affinity to molecules of different HLAs. The prevalence of the immunogenicity of a peptide in the cohort was correlated with the diversity of HLA-II alleles that they could bind. These findings suggest that overlapping of HLA binding motifs within a peptide enhances its T-cell immunogenicity and the prevalence of the response in the population. In summary, the results suggests that in addition to factors of the innate immunity, "promiscuous" T-cell antigens might contribute to the high efficacy of the yellow fever vaccines. © 2013 de Melo et al

Position of the mandibular foramen in different facial shapes assessed by cone-beam computed tomography: a cross-sectional retrospective study

Purpose: The mandibular foramen, located on the internal surface of the mandibular ramus, is an important anatomical landmark for the success during the inferior alveolar nerve block. This cross-sectional retrospective study aimed to evaluate the location of the mandibular foramen through ConeBeam Computed Tomography (CBCT) in different facial shapes. Materials and Methods: The determination of the location of the mandibular foramen was performed using CBCT of mesocephalic, dolichocephalic and brachycephalic patients (n=40 each). The ramus width (W), the distance from the mandibular foramen to the deepest point of the anterior border of the mandibular ramus (D), the distance from the mandibular foramen to the lowest point of the mandibular notch (V) and the distance from the inferior border of the mandible to the lowest point in of the mandibular border (R), as well as the ratios W/D and V/R, were measured. ANCOVA, two-way ANOVA and Chi-square tests were used to analyze the variation among the facial shapes. Results.: The ramus width (W) was greater (p 0.0001) in the brachycephalic (28.4 +/- 0.5 mm) than in both mesocephalic (26.8 +/- 0.36 mm) and dolichocephalic (25.5 +/- 0.39 mm) patients. D (p=0.0433) and R (p=0.0072) were also greater in the brachycephalic (17.7 +/- 0.36 mm; 43.4 +/- 0.75 mm, respectively) than dolichocephalic (16.5 +/- 03 mm; 40.3 +/- 0.63 mm, respectively), but both did not differ from mesocephalic (17.34.36 mm; 41.8 +/- 0.66 mm, respectively) patients. The other measurements (V, W/J and R/V) did not significantly differ among facial shapes. Conclusion: The localization of the mandibular foramen was. in the horizontal direction, more posterior in the brachycephalic patients and, in the vertical direction, higher in the dolichocephalic patients, when compared to the other groups analyzed. Thus, the anatomic data found in this study may help dentists to increase the success of the inferior alveolar nerve block and prevent surgical complications.1354455

Urinary peptides as a novel source of T Cell allergen epitopes

Mouse allergy in both laboratory workers and in inner-city children is associated with allergic rhinitis and asthma, posing a serious public health concern. Urine is a major source of mouse allergens, as mice spray urine onto their surroundings, where the proteins dry up and become airborne on dust particles. Here, we tested whether oligopeptides that are abundant in mouse urine may contribute to mouse allergic T cell response. Over 1,300 distinct oligopeptides were detected by mass spectrometry analysis of the low molecular weight filtrate fraction of mouse urine (LoMo). Posttranslationally modified peptides were common, accounting for almost half of total peptides. A pool consisting of 225 unique oligopeptides of 13 residues or more in size identified within was tested for its capacity to elicit T cell reactivity in mouse allergic donors. Following 14-day in vitro stimulation of PBMCs, we detected responses in about 95% of donors tested, directed against 116 distinct peptides, predominantly associated with Th2 cytokines (IL-5). Peptides from non-urine related proteins such as epidermal growth factor, collagen, and Beta-globin accounted for the highest response (15.9, 9.1, and 8.1% of the total response, respectively). Peptides derived from major urinary proteins (MUPs), kidney androgen-regulated protein (KAP), and uromodulin were the main T cell targets from kidney or urine related sources. Further ex vivo analysis of enrichment of 4-1BB expressing cells demonstrated that LoMo pool-specific T cell reactivity can be detected directly ex vivo in mouse allergic but not in non-allergic donors. Further cytometric analysis of responding cells revealed a bone fide memory T cell phenotype and confirmed their Th2 polarization. Overall, these data suggest that mouse urine-derived oligopeptides are a novel target for mouse allergy-associated T cell responses, which may contribute to immunopathological mechanisms in mouse allergy

Acute Auditory Stimulation with Different Styles of Music Influences Cardiac Autonomic Regulation in Men

Background: No clear evidence is available in the literature regarding the acute effect of different styles of music on cardiac autonomic control. Objectives: The present study aimed to evaluate the acute effects of classical baroque and heavy metal musical auditory stimulation on Heart Rate Variability (HRV) in healthy men. Patients and Methods: In this study, HRV was analyzed regarding time (SDNN, RMSSD, NN50, and pNN50) and frequency domain (LF, HF, and LF / HF) in 12 healthy men. HRV was recorded at seated rest for 10 minutes. Subsequently, the participants were exposed to classical baroque or heavy metal music for five minutes through an earphone at seated rest. After exposure to the first song, they remained at rest for five minutes and they were again exposed to classical baroque or heavy metal music. The music sequence was random for each individual. Standard statistical methods were used for calculation of means and standard deviations. Besides, ANOVA and Friedman test were used for parametric and non-parametric distributions, respectively. Results: While listening to heavy metal music, SDNN was reduced compared to the baseline (P = 0.023). In addition, the LF index (ms2 and nu) was reduced during exposure to both heavy metal and classical baroque musical auditory stimulation compared to the control condition (P = 0.010 and P = 0.048, respectively). However, the HF index (ms2) was reduced only during auditory stimulation with music heavy metal (P = 0.01). The LF/HF ratio on the other hand decreased during auditory stimulation with classical baroque music (P = 0.019). Conclusions: Acute auditory stimulation with the selected heavy metal musical auditory stimulation decreased the sympathetic and parasympathetic modulation on the heart, while exposure to a selected classical baroque music reduced sympathetic regulation on the heart

Dengue virus infection elicits highly polarized CX3CR1+ cytotoxic CD4+ T cells associated with protective immunity

Dengue virus (DENV) is a rapidly spreading pathogen with unusual pathogenesis, and correlates of protection from severe dengue disease and vaccine efficacy have not yet been established. Although DENV-specific CD8+ T-cell responses have been extensively studied, the breadth and specificity of CD4+ T-cell responses remains to be defined. Here we define HLA-restricted CD4+ T-cell epitopes resulting from natural infection with dengue virus in a hyperepidemic setting. Ex vivo flow-cytometric analysis of DENV-specific CD4+ T cells revealed that the virus-specific cells were highly polarized, with a strong bias toward a CX3CR1+ Eomesodermin+ perforin+ granzyme B+ CD45RA+ CD4 CTL phenotype. Importantly, these cells correlated with a protective HLA DR allele, and we demonstrate that these cells have direct ex vivo DENV-specific cytolytic activity. We speculate that cytotoxic dengue-specific CD4+ T cells may play a role in the control of dengue infection in vivo, and this immune correlate may be a key target for dengue virus vaccine development

SAMARAS OF AUSTROPLENCKIA POPULNEA (CELASTRACEAE): NEW CONSTITUENTS AND EFFECT OF EXTRACTS AND FRIEDELIN ON GERMINATION OF BIDENS PILOSA (ASTERACEAE)

Objective: Evaluation of the impact of extracts and constituents from samaras of Austroplenckia populnea on percentage of seed germination (%SG), germination speed index (GSI), length of rootlets (LR), seedling length (SL), and on dry mass (DM) of Bidens pilosa L weed.Methods: The  powder  of  samaras  was  extracted  with  organic  solvents  providing  the  hexane  (SAPEH),  chloroform  (SAPEC),  ethyl  acetate  (SAPEAE) and ethanol  (SAPEE)  extracts. The terpene 1 was isolated from SAPEH by means of column and thin layer chromatography and identified through NMR spectroscopy. Each extract and 1 were subjected to growth inhibition assays evaluating the following parameters: %SG, GSI, LR, SL and DM, with five repetitions.Results: The compounds Friedelin (1), 7-hydroxy-clerodan-3-en-16,15:18,20-diolide (2), 3,5,7,4'-tetrahydroxy-6-methoxy-8-prenylflavanone (3), tetradecanamide (4), and 4-hydroxy-1,6,15-acetyloxy-8,9-benzoyloxy-agarofurane (5) were isolated from hexane extract of samaras of A. populnea and identified by spectroscopic data. The compounds 2, 3 and 5 were not previously described as being chemical constituents from Celastraceae family. In addition, the novel compounds 3 and 5 were described here for the first time. Substantial effect on the germination of B. pilosa L. (picão-preto) was observed after treatment of seeds with nonpolar extracts from Samaras of A. populnea. Friedelin inhibited the seed germination in the tested concentrations showing toxic properties against picão-preto.Conclusion: The germination inhibition of seeds was higher using nonpolar extracts than polar extract. Friedelin inhibited the seed germination in the tested concentrations showing toxic properties against B. pilosa.Â

Characterization of magnitude and antigen specificity of HLA-DP, DQ, and DRB3/4/5 restricted DENV-specific CD4+ T cell responses

Background: Dengue Virus (DENV) associated disease is a major public health problem. Assessment of HLA class II restricted DENV-specific responses is relevant for immunopathology and definition of correlates of protection. While previous studies characterized responses restricted by the HLA-DRB1 locus, the responses associated with other class II loci have not been characterized to date. Accordingly, we mapped HLA-DP, DQ, and DRB3/4/5 restricted DENV-specific CD4 T cell epitopes in PBMCs derived from the DENV endemic region Sri Lanka. Methods: We studied 12 DP, DQ, and DRB3/4/5 alleles that are commonly expressed and provide worldwide coverage >82% for each of the loci analyzed and >99% when combined. CD4+ T cells purified by negative selection were stimulated with pools of HLA-predicted binders for 2 weeks with autologous APC. Epitope reactive T cells were enumerated using IFNγ ELISPOT assay. This strategy was previously applied to identify DRB1 restricted epitopes. In parallel, membrane expression levels of HLA-DR, DP, and DQ proteins was assessed using flow cytometry. Results: Epitopes were identified for all DP, DQ, and DRB3/4/5 allelic variants albeit with magnitudes significantly lower than the ones previously observed for the DRB1 locus. This was in line with lower membrane expression of HLA-DP and DQ molecules on the PBMCs tested, as compared to HLA-DR. Significant differences between loci were observed in antigen immunodominance. Capsid responses were dominant for DRB1/3/4/5 and DP alleles but negligible for the DQ alleles. NS3 responses were dominant in the case of DRB1/3/4/5 and DQ but absent in the case of DP. NS1 responses were prominent in the case of the DP alleles, but negligible in the case of DR and DQ. In terms of epitope specificity, repertoire was largely overlapping between DRB1 and DRB3/4/5, while DP and DQ loci recognized largely distinct epitope sets. Conclusion: The HLA-DP, DQ, and DRB3/4/5 loci mediate DENV-CD4 specific immune responses of lower magnitude as compared to HLA-DRB1, consistent with their lower levels of expression. The responses are associated with distinct and characteristic patterns of immunodominance, and variable epitope overlap across loci

SARS-CoV-2 vaccination induces immunological T cell memory able to cross-recognize variants from Alpha to Omicron

We address whether T cell responses induced by different vaccine platforms (mRNA-1273, BNT162b2, Ad26.COV2.S, and NVX-CoV2373) cross-recognize early SARS-CoV-2 variants. T cell responses to early variants were preserved across vaccine platforms. By contrast, significant overall decreases were observed for memory B cells and neutralizing antibodies. In subjects 3c6 months post-vaccination, 90% (CD4+) and 87% (CD8+) of memory T cell responses were preserved against variants on average by AIM assay, and 84% (CD4+) and 85% (CD8+) preserved against Omicron. Omicron RBD memory B cell recognition was substantially reduced to 42% compared with other variants. T cell epitope repertoire analysis revealed a median of 11 and 10 spike epitopes recognized by CD4+ and CD8+ T cells, with average preservation > 80% for Omicron. Functional preservation of the majority of T cell responses may play an important role as a second-level defense against diverse variants