Role of the afferent lymph as an immunological conduit to analyze tissue antigenic and inflammatory load.

The lymphatic fluid is the conduit by which part of the tissue "omics" is transported to the draining lymph node for immunosurveillance. Following cannulation of the pre-nodal cervical and mesenteric afferent lymphatics, herein we investigate the lymph proteomic composition, uncovering that its composition varies according to the tissue of origin. Tissue specificity is also reflected in the dendritic cell-major histocompatibility complex class II-eluted immunopeptidome harvested from the cervical and mesenteric nodes. Following inflammatory disruption of the gut barrier, the lymph antigenic and inflammatory loads are analyzed in both mice and subjects with inflammatory bowel diseases. Gastrointestinal tissue damage reflects the lymph inflammatory and damage-associated molecular pattern signatures, microbiome-derived by-products, and immunomodulatory molecules, including metabolites of the gut-brain axis, mapped in the afferent mesenteric lymph. Our data point to the relevance of the lymphatic fluid to probe the tissue-specific antigenic and inflammatory load transported to the draining lymph node for immunosurveillance.

Necrotizing Enterocolitis-Associated Acute Kidney Injury-Transforming the Paradigm.

Necrotizing enterocolitis (NEC) is one of the most common conditions requiring emergency surgery in the neonatal intensive care unit and is associated with a septic shock-like state contributing to multiorgan dysfunction. NEC affects 6 to 10% of very low-birth-weight infants and remains a leading cause of death. The occurrence of severe acute kidney injury (AKI) following surgical NEC is a harbinger of multiple morbidities. This review presents current evidence about the clinical impact of NEC-associated AKI on the clinical outcomes. Studies evaluating nephroprotective strategies to prevent AKI and its consequences are greatly needed to improve the postoperative recovery and clinical outcomes in neonates with NEC. Future observational studies and clinical trials in preterm infants with NEC prioritize measuring short-term (AKI) and longer term (chronic kidney disease) kidney outcomes. KEY POINTS: · Severe AKI is common following surgical NEC.. · Severe AKI following NEC is associated with poor clinical outcomes.. · Studies evaluating nephroprotective strategies to prevent AKI and its consequences are needed.. IMPACT: · Severe AKI (stage 2 and 3) occurs in 32.6% of neonates after NEC diagnosis and in 58.7% following surgical NEC diagnosis.. · NEC-associated AKI is associated with severe postoperative course, moderate-to-severe bronchopulmonary dysplasia, surgical complications, brain injury, and longer hospital stay in preterm infants.. · Severity of NEC-associated AKI can be utilized by bedside providers for the prognostication of clinical outcomes in preterm infants..

Is Necrotizing Enterocolitis and Spontaneous Intestinal Perforation Part of Same Disease Spectrum - New Insights?

The diagnosis of NEC is based on the presence of pneumatosis, dilated bowel loops, portal venous gas, or pneumoperitoneum on the abdominal x-ray. Published studies suggest that the appearance of pneumatosis most likely depends on the gestational age, with a shift occurring between 27-28 weeks. For infants of gestational age under 27 weeks, pneumoperitoneum is the most likely presentation of bowel injury due to the thin bowel wall and the colonization of the gut with the non-gas-producing bacteria. Assessment of postoperative morbidity and white matter injury on the brain MRI at term equivalent age in a cohort of preterm infants failed to identify differences between SIP and NEC groups when confirmed by histology. These findings illustrate the difficulty in conclusively identifying cases as SIP or NEC, particularly when gestational age is considered and raise speculation that both conditions lie on the same spectrum of intestinal injury.

Clinical and Growth Correlates of Retinopathy of Prematurity in Preterm Infants with Surgical Necrotizing Enterocolitis and Intestinal Perforation.

OBJECTIVE: This study aimed to identify the clinical and growth parameters associated with retinopathy of prematurity (ROP) in infants with necrotizing enterocolitis (NEC) and spontaneous ileal perforation (SIP). STUDY DESIGN: We conducted a retrospective cohort study that compared clinical data before and after NEC/SIP onset in neonates, categorizing by any ROP and severe ROP (type 1/2) status. RESULTS: The analysis included 109 infants with surgical NEC/SIP. Sixty infants (60/109, 55%) were diagnosed with any ROP, 32/109 (29.3%) infants (22% type 1 and 7.3% type 2) with severe ROP. On univariate analysis, those with severe ROP (32/109, 39.5%) were of lower median gestational age (GA, 23.8 weeks [23.4, 24.6] vs. 27.3 [26.3, 29.0], p < 0.001), lower median birth weight (625 g [512, 710] vs. 935 [700, 1,180], p < 0.001) and experienced higher exposure to clinical chorioamnionitis (22.6 vs. 2.13%, p < 0.006), and later median onset of ROP diagnosis (63.0 days [47.0, 77.2] vs. 29.0 [19.0, 41.0], p < 0.001), received Penrose drain placement more commonly (19 [59.4%] vs. 16 [34.0%], p = 0.04), retained less residual small bowel (70.0 cm [63.1, 90.8] vs. 90.8 [72.0, 101], p = 0.007) following surgery, were exposed to higher FiO2 7 days after birth (p = 0.001), received ventilation longer and exposed to higher FiO2 at 2 weeks (p < 0.05) following NEC and developed acute kidney injury (AKI) more often (25 [86.2%] vs. 20 [46.5%], p = 0.002) than those without ROP. Those with severe ROP had lower length, weight for length, and head circumference z scores. In an adjusted Firth's logistic regression, GA (adjusted odds ratio [aOR] = 0.51, 95% confidence interval [CI]: [0.35, 0.76]) and diagnosis at later age (aOR = 1.08, 95% CI: [1.03, 1.13]) was shown to be significantly associated with any ROP. CONCLUSION: Infants who develop severe ROP following surgical NEC/SIP are likely to be younger, smaller, have been exposed to more O2, develop AKI, and grow poorly compared with those did not develop severe ROP. KEY POINTS: · Thirty percent of infants with NEC/SIP had severe ROP.. · Those with severe ROP had poor growth parameters before and after NEC/SIP.. · Risk factors based ROP prevention strategies are needed to have improved ophthalmic outcomes..

Clinical Correlates of Cholestasis in Preterm Infants with Surgical Necrotizing Enterocolitis.

Background: We sought to investigate the clinical determinants and outcomes of cholestasis in preterm infants with surgical necrotizing enterocolitis (sNEC). Methods: Retrospective comparison of clinical information in preterm infants who developed cholestasis vs those who did not. Results: Sixty-two (62/91, 68.1%) infants with NEC developed cholestasis at any time following the onset of illness. Cholestasis was seen more frequently in those who had received ionotropic support at 24 hours following sNEC diagnosis (87.1% vs 58.6%; p = 0.002), had higher mean C-reactive protein levels 2 weeks after NEC diagnosis (p = 0.009), had blood culture-positive sepsis [25 (40.3%) vs 4 (13.8%); p = 0.011], received parenteral nutrition (PN) for longer durations (108.4 ± 56.63 days vs 97.56 ± 56.05 days; p = 0.007), had higher weight-for-length z scores at 36 weeks' postmenstrual age [-1.0 (-1.73, -0.12) vs -1.32 (-1.76, -0.76); p = 0.025], had a longer length of hospital stay (153.7 ± 77.57 days vs 112.51 ± 85.22 days; p = 0.024), had intestinal failure more often (61% vs 25.0%, p = 0.003), had more surgical complications (50% vs 27.6%; p = 0.044), and had >1 complication (21% vs 3.4%; p = 0.031). Using linear regression, the number of days after surgery when feeds could be started [OR 15.4; confidence interval (CI) 3.71, 27.13; p = 0.009] and the postoperative ileus duration (OR 11.9, CI 1.1, 22.8; p = 0.03) were independently associated with direct bilirubin between 2 and 5 mg/dL (mild-moderate cholestasis) at 2 months of age. The duration of PN was independently associated with direct bilirubin >5 mg/dL (severe cholestasis) at 2 months of age in these patients. Conclusion: Cholestasis was seen in 68% of infants following surgical NEC. The most likely contributive factors are intestinal failure and subsequent PN dependence for longer periods. Our data suggest that identification and prevention of risk factors such as sepsis and surgical complications and early feeds following NEC surgery may improve outcomes.

Silent Airway Mucus Plugs in COPD and Clinical Implications.

BACKGROUND: Airway mucus plugs are frequently identified on CT scans of patients with COPD with a smoking history without mucus-related symptoms (ie, cough, phlegm [silent mucus plugs]). RESEARCH QUESTION: In patients with COPD, what are the risk and protective factors associated with silent airway mucus plugs? Are silent mucus plugs associated with functional, structural, and clinical measures of disease? STUDY DESIGN AND METHODS: We identified mucus plugs on chest CT scans of participants with COPD from the COPDGene study. The mucus plug score was defined as the number of pulmonary segments with mucus plugs, ranging from 0 to 18, and categorized into three groups (0, 1-2, and ≥ 3). We determined risk and protective factors for silent mucus plugs and the associations of silent mucus plugs with measures of disease severity using multivariable linear and logistic regression models. RESULTS: Of 4,363 participants with COPD, 1,739 had no cough or phlegm. Among the 1,739 participants, 627 (36%) had airway mucus plugs identified on CT scan. Risk factors of silent mucus plugs (compared with symptomatic mucus plugs) were older age (OR, 1.02), female sex (OR, 1.40), and Black race (OR, 1.93) (all P values < .01). Among those without cough or phlegm, silent mucus plugs (vs absence of mucus plugs) were associated with worse 6-min walk distance, worse resting arterial oxygen saturation, worse FEV1 % predicted, greater emphysema, thicker airway walls, and higher odds of severe exacerbation in the past year in adjusted models. INTERPRETATION: Mucus plugs are common in patients with COPD without mucus-related symptoms. Silent mucus plugs are associated with worse functional, structural, and clinical measures of disease. CT scan-identified mucus plugs can complement the evaluation of patients with COPD.

Immunopeptidome profiling of human coronavirus OC43-infected cells identifies CD4 T-cell epitopes specific to seasonal coronaviruses or cross-reactive with SARS-CoV-2.

Seasonal "common-cold" human coronaviruses are widely spread throughout the world and are mainly associated with mild upper respiratory tract infections. The emergence of highly pathogenic coronaviruses MERS-CoV, SARS-CoV, and most recently SARS-CoV-2 has prompted increased attention to coronavirus biology and immunopathology, but the T-cell response to seasonal coronaviruses remains largely uncharacterized. Here we report the repertoire of viral peptides that are naturally processed and presented upon infection of a model cell line with seasonal coronavirus OC43. We identified MHC-bound peptides derived from each of the viral structural proteins (spike, nucleoprotein, hemagglutinin-esterase, membrane, and envelope) as well as non-structural proteins nsp3, nsp5, nsp6, and nsp12. Eighty MHC-II bound peptides corresponding to 14 distinct OC43-derived epitopes were identified, including many at very high abundance within the overall MHC-II peptidome. Fewer and less abundant MHC-I bound OC43-derived peptides were observed, possibly due to MHC-I downregulation induced by OC43 infection. The MHC-II peptides elicited low-abundance recall T-cell responses in most donors tested. In vitro assays confirmed that the peptides were recognized by CD4+ T cells and identified the presenting HLA alleles. T-cell responses cross-reactive between OC43, SARS-CoV-2, and the other seasonal coronaviruses were confirmed in samples of peripheral blood and peptide-expanded T-cell lines. Among the validated epitopes, spike protein S903-917 presented by DPA1*01:03/DPB1*04:01 and S1085-1099 presented by DRB1*15:01 shared substantial homology to other human coronaviruses, including SARS-CoV-2, and were targeted by cross-reactive CD4 T cells. Nucleoprotein N54-68 and hemagglutinin-esterase HE128-142 presented by DRB1*15:01 and HE259-273 presented by DPA1*01:03/DPB1*04:01 are immunodominant epitopes with low coronavirus homology that are not cross-reactive with SARS-CoV-2. Overall, the set of naturally processed and presented OC43 epitopes comprise both OC43-specific and human coronavirus cross-reactive epitopes, which can be used to follow CD4 T-cell cross-reactivity after infection or vaccination, and to guide selection of epitopes for inclusion in pan-coronavirus vaccines.

Airway-Occluding Mucus Plugs and Mortality in Patients With Chronic Obstructive Pulmonary Disease.

Importance: Airway mucus plugs are common in patients with chronic obstructive pulmonary disease (COPD); however, the association of airway mucus plugging and mortality in patients with COPD is unknown. Objective: To determine whether airway mucus plugs identified on chest computed tomography (CT) were associated with increased all-cause mortality. Design, Setting, and Participants: Observational retrospective analysis of prospectively collected data of patients with a diagnosis of COPD in the Genetic Epidemiology of COPD cohort. Participants were non-Hispanic Black or White individuals, aged 45 to 80 years, who smoked at least 10 pack-years. Participants were enrolled at 21 centers across the US between November 2007 and April 2011 and were followed up through August 31, 2022. Exposures: Mucus plugs that completely occluded airways on chest CT scans, identified in medium- to large-sized airways (ie, approximately 2- to 10-mm lumen diameter) and categorized as affecting 0, 1 to 2, or 3 or more lung segments. Main Outcomes and Measures: The primary outcome was all-cause mortality, assessed with proportional hazard regression analysis. Models were adjusted for age, sex, race and ethnicity, body mass index, pack-years smoked, current smoking status, forced expiratory volume in the first second of expiration, and CT measures of emphysema and airway disease. Results: Among the 4483 participants with COPD, 4363 were included in the primary analysis (median age, 63 years [IQR, 57-70 years]; 44% were women). A total of 2585 (59.3%), 953 (21.8%), and 825 (18.9%) participants had mucus plugs in 0, 1 to 2, and 3 or more lung segments, respectively. During a median 9.5-year follow-up, 1769 participants (40.6%) died. The mortality rates were 34.0% (95% CI, 32.2%-35.8%), 46.7% (95% CI, 43.5%-49.9%), and 54.1% (95% CI, 50.7%-57.4%) in participants who had mucus plugs in 0, 1 to 2, and 3 or more lung segments, respectively. The presence of mucus plugs in 1 to 2 vs 0 and 3 or more vs 0 lung segments was associated with an adjusted hazard ratio of death of 1.15 (95% CI, 1.02-1.29) and 1.24 (95% CI, 1.10-1.41), respectively. Conclusions and Relevance: In participants with COPD, the presence of mucus plugs that obstructed medium- to large-sized airways was associated with higher all-cause mortality compared with patients without mucus plugging on chest CT scans.

CD4 Effector TCR Avidity for Peptide on APC Determines the Level of Memory Generated.

Initial TCR affinity for peptide Ag is known to impact the generation of memory; however, its contributions later, when effectors must again recognize Ag at 5-8 d postinfection to become memory, is unclear. We examined whether the effector TCR affinity for peptide at this "effector checkpoint" dictates the extent of memory and degree of protection against rechallenge. We made an influenza A virus nucleoprotein (NP)-specific TCR transgenic mouse strain, FluNP, and generated NP-peptide variants that are presented by MHC class II to bind to the FluNP TCR over a broad range of avidity. To evaluate the impact of avidity in vivo, we primed naive donor FluNP in influenza A virus-infected host mice, purified donor effectors at the checkpoint, and cotransferred them with the range of peptides pulsed on activated APCs into second uninfected hosts. Higher-avidity peptides yielded higher numbers of FluNP memory cells in spleen and most dramatically in lung and draining lymph nodes and induced better protection against lethal influenza infection. Avidity determined memory cell number, not cytokine profile, and already impacted donor cell number within several days of transfer. We previously found that autocrine IL-2 production at the checkpoint prevents default effector apoptosis and supports memory formation. Here, we find that peptide avidity determines the level of IL-2 produced by these effectors and that IL-2Rα expression by the APCs enhances memory formation, suggesting that transpresentation of IL-2 by APCs further amplifies IL-2 availability. Secondary memory generation was also avidity dependent. We propose that this regulatory pathway selects CD4 effectors of highest affinity to progress to memory.

Immunopeptidome profiling of human coronavirus OC43-infected cells identifies CD4 T cell epitopes specific to seasonal coronaviruses or cross-reactive with SARS-CoV-2.

Seasonal "common-cold" human coronaviruses are widely spread throughout the world and are mainly associated with mild upper respiratory tract infections. The emergence of highly pathogenic coronaviruses MERS-CoV, SARS-CoV, and most recently SARS-CoV-2 has prompted increased attention to coronavirus biology and immunopathology, but identification and characterization of the T cell response to seasonal human coronaviruses remain largely uncharacterized. Here we report the repertoire of viral peptides that are naturally processed and presented upon infection of a model cell line with seasonal human coronavirus OC43. We identified MHC-I and MHC-II bound peptides derived from the viral spike, nucleocapsid, hemagglutinin-esterase, 3C-like proteinase, and envelope proteins. Only three MHC-I bound OC43-derived peptides were observed, possibly due to the potent MHC-I downregulation induced by OC43 infection. By contrast, 80 MHC-II bound peptides corresponding to 14 distinct OC43-derived epitopes were identified, including many at very high abundance within the overall MHC-II peptidome. These peptides elicited low-abundance recall T cell responses in most donors tested. In vitro assays confirmed that the peptides were recognized by CD4+ T cells and identified the presenting HLA alleles. T cell responses cross-reactive between OC43, SARS-CoV-2, and the other seasonal coronaviruses were confirmed in samples of peripheral blood and peptide-expanded T cell lines. Among the validated epitopes, S 903-917 presented by DPA1*01:03/DPB1*04:01 and S 1085-1099 presented by DRB1*15:01 shared substantial homology to other human coronaviruses, including SARS-CoV-2, and were targeted by cross-reactive CD4 T cells. N 54-68 and HE 128-142 presented by DRB1*15:01 and HE 259-273 presented by DPA1*01:03/DPB1*04:01 are immunodominant epitopes with low coronavirus homology that are not cross-reactive with SARS-CoV-2. Overall, the set of naturally processed and presented OC43 epitopes comprise both OC43-specific and human coronavirus cross-reactive epitopes, which can be used to follow T cell cross-reactivity after infection or vaccination and could aid in the selection of epitopes for inclusion in pan-coronavirus vaccines. Author Summary: There is much current interest in cellular immune responses to seasonal common-cold coronaviruses because of their possible role in mediating protection against SARS-CoV-2 infection or pathology. However, identification of relevant T cell epitopes and systematic studies of the T cell responses responding to these viruses are scarce. We conducted a study to identify naturally processed and presented MHC-I and MHC-II epitopes from human cells infected with the seasonal coronavirus HCoV-OC43, and to characterize the T cell responses associated with these epitopes. We found epitopes specific to the seasonal coronaviruses, as well as epitopes cross-reactive between HCoV-OC43 and SARS-CoV-2. These epitopes should be useful in following immune responses to seasonal coronaviruses and identifying their roles in COVID-19 vaccination, infection, and pathogenesis.

Immunopeptidome profiling of human coronavirus OC43-infected cells identifies CD4 T cell epitopes specific to seasonal coronaviruses or cross-reactive with SARS-CoV-2

Seasonal "common-cold" human coronaviruses are widely spread throughout the world and are mainly associated with mild upper respiratory tract infections. The emergence of highly pathogenic coronaviruses MERS-CoV, SARS-CoV, and most recently SARS-CoV-2 has prompted increased attention to coronavirus biology and immunopathology, but identification and characterization of the T cell response to seasonal human coronaviruses remain largely uncharacterized. Here we report the repertoire of viral peptides that are naturally processed and presented upon infection of a model cell line with seasonal human coronavirus OC43. We identified MHC-I and MHC-II bound peptides derived from the viral spike, nucleocapsid, hemagglutinin-esterase, 3C-like proteinase, and envelope proteins. Only three MHC-I bound OC43-derived peptides were observed, possibly due to the potent MHC-I downregulation induced by OC43 infection. By contrast, 80 MHC-II bound peptides corresponding to 14 distinct OC43-derived epitopes were identified, including many at very high abundance within the overall MHC-II peptidome. These peptides elicited low-abundance recall T cell responses in most donors tested. In vitro assays confirmed that the peptides were recognized by CD4+ T cells and identified the presenting HLA alleles. T cell responses cross-reactive between OC43, SARS-CoV-2, and the other seasonal coronaviruses were confirmed in samples of peripheral blood and peptide-expanded T cell lines. Among the validated epitopes, S903-917 presented by DPA1*01:03/DPB1*04:01 and S1085-1099 presented by DRB1*15:01 shared substantial homology to other human coronaviruses, including SARS-CoV-2, and were targeted by cross-reactive CD4 T cells. N54-68 and HE128-142 presented by DRB1*15:01 and HE259-273 presented by DPA1*01:03/DPB1*04:01 are immunodominant epitopes with low coronavirus homology that are not cross-reactive with SARS-CoV-2. Overall, the set of naturally processed and presented OC43 epitopes comprise both OC43-specific and human coronavirus cross-reactive epitopes, which can be used to follow T cell cross-reactivity after infection or vaccination and could aid in the selection of epitopes for inclusion in pan-coronavirus vaccines. Author SummaryThere is much current interest in cellular immune responses to seasonal common-cold coronaviruses because of their possible role in mediating protection against SARS-CoV-2 infection or pathology. However, identification of relevant T cell epitopes and systematic studies of the T cell responses responding to these viruses are scarce. We conducted a study to identify naturally processed and presented MHC-I and MHC-II epitopes from human cells infected with the seasonal coronavirus HCoV-OC43, and to characterize the T cell responses associated with these epitopes. We found epitopes specific to the seasonal coronaviruses, as well as epitopes cross-reactive between HCoV-OC43 and SARS-CoV-2. These epitopes should be useful in following immune responses to seasonal coronaviruses and identifying their roles in COVID-19 vaccination, infection, and pathogenesis.

Adult Partial Anomalous Pulmonary Venous Return Repair and Superior Vena Cava Syndrome: A Delayed Complication of the Warden Procedure.

The Warden procedure is one of the most common techniques for surgical correction of partial anomalous pulmonary venous return (PAPVR), involving transection and reanastomosis of the superior vena cava (SVC) to the right atrial appendage and baffling of the anomalous pulmonary veins through the atrial septal defect. While the procedure is typically well-tolerated in pediatric patients, adult patients requiring surgical correction of PAPVR are uncommon. The authors report a case of a 33-year-old woman who developed SVC syndrome as a delayed complication of the Warden procedure. Keywords: Cardiac, Congenital, Complications © RSNA, 2022.

PDIA3 epitope-driven immune autoreactivity contributes to hepatic damage in type 2 diabetes.

A diet rich in saturated fat and carbohydrates causes low-grade chronic inflammation in several organs, including the liver, ultimately driving nonalcoholic steatohepatitis. In this setting, environment-driven lipotoxicity and glucotoxicity induce liver damage, which promotes dendritic cell activation and generates a major histocompatibility complex class II (MHC-II) immunopeptidome enriched with peptides derived from proteins involved in cellular metabolism, oxidative phosphorylation, and the stress responses. Here, we demonstrated that lipotoxicity and glucotoxicity, as driven by a high-fat and high-fructose (HFHF) diet, promoted MHC-II presentation of nested T and B cell epitopes from protein disulfide isomerase family A member 3 (PDIA3), which is involved in immunogenic cell death. Increased MHC-II presentation of PDIA3 peptides was associated with antigen-specific proliferation of hepatic CD4+ immune infiltrates and isotype switch of anti-PDIA3 antibodies from IgM to IgG3, indicative of cellular and humoral PDIA3 autoreactivity. Passive transfer of PDIA3-specific T cells or PDIA3-specific antibodies also exacerbated hepatocyte death, as determined by increased hepatic transaminases detected in the sera of mice subjected to an HFHF but not control diet. Increased humoral responses to PDIA3 were also observed in patients with chronic inflammatory liver conditions, including autoimmune hepatitis, primary biliary cholangitis, and type 2 diabetes. Together, our data indicated that metabolic insults caused by an HFHF diet elicited liver damage and promoted pathogenic immune autoreactivity driven by T and B cell PDIA3 epitopes.

Broadly recognized, cross-reactive SARS-CoV-2 CD4 T cell epitopes are highly conserved across human coronaviruses and presented by common HLA alleles.

Sequence homology between SARS-CoV-2 and common-cold human coronaviruses (HCoVs) raises the possibility that memory responses to prior HCoV infection can affect T cell response in COVID-19. We studied T cell responses to SARS-CoV-2 and HCoVs in convalescent COVID-19 donors and identified a highly conserved SARS-CoV-2 sequence, S811-831, with overlapping epitopes presented by common MHC class II proteins HLA-DQ5 and HLA-DP4. These epitopes are recognized by low-abundance CD4 T cells from convalescent COVID-19 donors, mRNA vaccine recipients, and uninfected donors. TCR sequencing revealed a diverse repertoire with public TCRs. T cell cross-reactivity is driven by the high conservation across human and animal coronaviruses of T cell contact residues in both HLA-DQ5 and HLA-DP4 binding frames, with distinct patterns of HCoV cross-reactivity explained by MHC class II binding preferences and substitutions at secondary TCR contact sites. These data highlight S811-831 as a highly conserved CD4 T cell epitope broadly recognized across human populations.

Regulation of the BCR signalosome by the class II peptide editor, H2-M, affects the development and repertoire of innate-like B cells.

The non-classical Major Histocompatibility Complex class II (MHCII) protein, H2-M, edits peptides bound to conventional MHCII in favor of stable peptide/MHCII (p/MHCII) complexes. Here, we show that H2-M deficiency affects B-1 cell survival, reduces cell renewal capacity, and alters immunoglobulin repertoire, allowing for the selection of cells specific for highly abundant epitopes, but not low-frequency epitopes. H2-M-deficient B-1 cells have shorter CDR3 length, higher content of positively charged amino acids, shorter junctional regions, less mutation frequency, and a skewed clonal distribution. Mechanistically, H2-M loss reduces plasma membrane p/MHCII association with B cell receptors (BCR) on B-1 cells and diminishes integrated BCR signal strength, a key determinant of B-1 cell selection, maturation, and maintenance. Thus, H2-M:MHCII interaction serves as a cell-intrinsic regulator of BCR signaling and influences the selection of the B-1 cell clonal repertoire.

A druggable pocket on PSMD10Gankyrin that can accommodate an interface peptide and doxorubicin.

BACKGROUND: PSMD10Gankyrin, a proteasomal chaperone is also an oncoprotein. Overexpression of PSMD10Gankyrin is associated with poor prognosis and survival in many cancers. Therefore, PSMD10Gankyrin is a sought-after drug target in many hard-to-treat cancers. However, its surface appears flat and undruggable. Here, we build on our earlier discovery of a common hot spot region that defined the interface of multiple interacting partners of PSMD10Gankyrin to expose vulnerable spots for a peptide and a small molecule inhibitor. METHODS: High throughput virtual screening was used to screen compounds against PSMD10Gankyrin. Interaction of PSMD10Gankyrin with the drug or protein (CLIC1) or peptide was studied using any one or more of these techniques; Microscale Thermophoresis, limited trypsinolysis, SPR and ITC. Cytotoxic effect of doxorubicin was evaluated using MTT assay. RESULTS: We identified doxorubicin as the first-generation small molecule inhibitor of PSMD10Gankyrin. K116 and to a lesser extent R41 on PSMD10Gankyrin contribute to the bulk of binding energy for the peptide EEVD, CLIC1 and doxorubicin. We further demonstrate that PSMD10Gankyrin is an intended target for doxorubicin in cells. GENERAL SIGNIFICANCE: Drug design against protein interactions in general and PSMD10Gankyrin in particular, remains a challenge. We provide consolidated biophysical evidence for the use of a shared interface motif EEVD as a possible inhibitor of interaction network in cancers driven by PSMD10Gankyrin. We identify a chemical scaffold for designing novel inhibitors of PSMD10Gankyrin. These findings will impact the field of protein interactions in the context of disease biology/drug discovery.