An HLA-E-targeted TCR bispecific molecule redirects T cell immunity against Mycobacterium tuberculosis.

Peptides presented by HLA-E, a molecule with very limited polymorphism, represent attractive targets for T cell receptor (TCR)-based immunotherapies to circumvent the limitations imposed by the high polymorphism of classical HLA genes in the human population. Here, we describe a TCR-based bispecific molecule that potently and selectively binds HLA-E in complex with a peptide encoded by the inhA gene of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis in humans. We reveal the biophysical and structural bases underpinning the potency and specificity of this molecule and demonstrate its ability to redirect polyclonal T cells to target HLA-E-expressing cells transduced with mycobacterial inhA as well as primary cells infected with virulent Mtb. Additionally, we demonstrate elimination of Mtb-infected cells and reduction of intracellular Mtb growth. Our study suggests an approach to enhance host T cell immunity against Mtb and provides proof of principle for an innovative TCR-based therapeutic strategy overcoming HLA polymorphism and therefore applicable to a broader patient population.

Instability of the HLA-E peptidome of HIV presents a major barrier to therapeutic targeting.

Naturally occurring T cells that recognize microbial peptides via HLA-E, a nonpolymorphic HLA class Ib molecule, could provide the foundation for new universal immunotherapeutics. However, confidence in the biological relevance of putative ligands is crucial, given that the mechanisms by which pathogen-derived peptides can access the HLA-E presentation pathway are poorly understood. We systematically interrogated the HIV proteome using immunopeptidomic and bioinformatic approaches, coupled with biochemical and cellular assays. No HIV HLA-E peptides were identified by tandem mass spectrometry analysis of HIV-infected cells. In addition, all bioinformatically predicted HIV peptide ligands (>80) were characterized by poor complex stability. Furthermore, infected cell elimination assays using an affinity-enhanced T cell receptor bispecific targeted to a previously reported HIV Gag HLA-E epitope demonstrated inconsistent presentation of the peptide, despite normal HLA-E expression on HIV-infected cells. This work highlights the instability of the HIV HLA-E peptidome as a major challenge for drug development.

Disordered Eating in Early Adolescence: Disparities Among Minoritised Youth.

BACKGROUND: Disordered eating in early adolescence impacts development, with long-term health implications. Minoritised adolescents might be at higher risk of disordered eating due to minority stress, but most research has focused on White, heterosexual, cisgender individuals; less is known about disordered eating among minoritised adolescents. We examined sexual, gender, racial, and ethnic identities in relation to disordered eating in early adolescence. METHOD: Using 2-year follow-up data from adolescents ages 10-14 in the Adolescent Brain Cognitive Development Study (N = 9385), we examined associations between sexual, gender, racial, and ethnic identities and past-2 week disordered eating (preoccupation with weight, weight control behaviors, and binge eating). RESULTS: Compared to heterosexual peers, gay/bisexual adolescents had higher odds of all three outcomes (AOR 1.90-3.32); those "questioning" their sexual identity had higher odds of preoccupation with weight (AOR 1.82) and binge eating (AOR 2.53). Compared to cisgender adolescents, transgender adolescents had higher odds of binge eating (AOR 2.62); those "questioning" their gender identity had higher odds of preoccupation with weight (AOR 2.45). Adolescents whose racial identity was categorised as "Another" had higher odds of preoccupation with weight (AOR 1.46) and weight control behaviors (AOR 1.58) compared to White adolescents. Finally, Hispanic adolescents had higher odds of all disordered eating outcomes than non-Hispanic adolescents (AOR 1.25-1.59). DISCUSSION: This study is among the first to reveal disparities in disordered eating among minoritised early adolescents. Further examination of these disparities can inform future interventions. Healthcare providers are encouraged to screen for disordered eating, recognising that minoritised early adolescents may be at risk.

Structure-guided stabilization of pathogen-derived peptide-HLA-E complexes using non-natural amino acids conserves native TCR recognition.

The nonpolymorphic class Ib molecule, HLA-E, primarily presents peptides from HLA class Ia leader peptides, providing an inhibitory signal to NK cells via CD94/NKG2 interactions. Although peptides of pathogenic origin can also be presented by HLA-E to T cells, the molecular basis underpinning their role in antigen surveillance is largely unknown. Here, we solved a co-complex crystal structure of a TCR with an HLA-E presented peptide (pHLA-E) from bacterial (Mycobacterium tuberculosis) origin, and the first TCR-pHLA-E complex with a noncanonically presented peptide from viral (HIV) origin. The structures provided a molecular foundation to develop a novel method to introduce cysteine traps using non-natural amino acid chemistry that stabilized pHLA-E complexes while maintaining native interface contacts between the TCRs and different pHLA-E complexes. These pHLA-E monomers could be used to isolate pHLA-E-specific T cells, with obvious utility for studying pHLA-E restricted T cells, and for the identification of putative therapeutic TCRs.

Evaluation of a complex intervention for prisoners with common mental health problems, near to and after release: the Engager randomised controlled trial.

BACKGROUND: Many male prisoners have significant mental health problems, including anxiety and depression. High proportions struggle with homelessness and substance misuse. AIMS: This study aims to evaluate whether the Engager intervention improves mental health outcomes following release. METHOD: The design is a parallel randomised superiority trial that was conducted in the North West and South West of England (ISRCTN11707331). Men serving a prison sentence of 2 years or less were individually allocated 1:1 to either the intervention (Engager plus usual care) or usual care alone. Engager included psychological and practical support in prison, on release and for 3-5 months in the community. The primary outcome was the Clinical Outcomes in Routine Evaluation Outcome Measure (CORE-OM), 6 months after release. Primary analysis compared groups based on intention-to-treat (ITT). RESULTS: In total, 280 men were randomised out of the 396 who were potentially eligible and agreed to participate; 105 did not meet the mental health inclusion criteria. There was no mean difference in the ITT complete case analysis between groups (92 in each arm) for change in the CORE-OM score (1.1, 95% CI -1.1 to 3.2, P = 0.325) or secondary analyses. There were no consistent clinically significant between-group differences for secondary outcomes. Full delivery was not achieved, with 77% (108/140) receiving community-based contact. CONCLUSIONS: Engager is the first trial of a collaborative care intervention adapted for prison leavers. The intervention was not shown to be effective using standard outcome measures. Further testing of different support strategies for prison with mental health problems is needed.

Group-Based Medical Mistrust in Adolescents With Poorly Controlled Asthma Living in Rural Areas.

Black youth and rural adolescents are two groups who experience asthma disparities. Racism and discrimination in health care likely lead to group-based (systems-level) medical mistrust for some adolescents. Group-based medical mistrust, one pathway by which racism drives health inequities, is associated with poorer outcomes for patients with chronic conditions. Despite its potential importance in adolescent asthma, previous research has not considered group-based medical mistrust in this population. To fill this gap, we characterize group-based medical mistrust among rural adolescents with poorly controlled asthma, examining demographic differences. We analyzed baseline data from a school-based clinical trial in which 164 adolescents (mean age = 16.3; 76.2% Black) completed the Group-Based Medical Mistrust Scale (GBMMS). Using linear regression, we tested associations with race, gender, and age, controlling for recent medical visits and insurance status. The total GBMMS mean score was 2.3 (SD = 1.22); subscale scores ranged from 2.3 to 2.4. Black adolescents reported significantly higher total GBMMS scores (ß = .45, p = .003) and significantly higher scores on two GBMMS subscales: suspicion of health care providers (ß = .56, p = .007) and lack of support from health care providers (ß = .36, p = .007). Gender and age were not associated with GBMMS scores. Health care providers need to consider medical mistrust and its role in their clinical care. Together with their institutions, health care providers and researchers should work toward changing systems that perpetuate racism to build trust as a means of reducing asthma disparities among adolescents.

Asthma Knowledge, Self-Efficacy, and Self-Management Among Rural Adolescents with Poorly Controlled Asthma.

Rural adolescents with asthma are a disparate group. Self-management is essential to asthma control. We describe asthma knowledge, self-efficacy, and self-management behaviors among 198 rural adolescents with poorly controlled asthma, exploring demographic differences; we also test the application of Social Cognitive Theory to asthma self-management examining if self-efficacy mediates associations between knowledge and self-management. Asthma knowledge and self-management were relatively poor in our sample, particularly among male and White adolescents; greater knowledge was significantly associated with better symptom prevention and management. Self-efficacy partially mediated the association between knowledge and symptom prevention, but not acute symptom management, suggesting that knowledge may not improve symptom prevention behaviors without confidence to implement such behaviors and that factors beyond knowledge and self-efficacy likely play a role in asthma self-management in this population. Addressing asthma knowledge and self-efficacy could improve self-management and, ultimately, enhance asthma control among rural adolescents with poorly controlled asthma.

Immune-Mobilizing Monoclonal T Cell Receptors Mediate Specific and Rapid Elimination of Hepatitis B-Infected Cells.

BACKGROUND AND AIMS: Therapies for chronic hepatitis B virus (HBV) infection are urgently needed because of viral integration, persistence of viral antigen expression, inadequate HBV-specific immune responses, and treatment regimens that require lifelong adherence to suppress the virus. Immune mobilizing monoclonal T Cell receptors against virus (ImmTAV) molecules represent a therapeutic strategy combining an affinity-enhanced T Cell receptor with an anti-CD3 T Cell-activating moiety. This bispecific fusion protein redirects T cells to specifically lyse infected cells expressing the target virus-derived peptides presented by human leukocyte antigen (HLA). APPROACH AND RESULTS: ImmTAV molecules specific for HLA-A*02:01-restricted epitopes from HBV envelope, polymerase, and core antigens were engineered. The ability of ImmTAV-Env to activate and redirect polyclonal T cells toward cells containing integrated HBV and cells infected with HBV was assessed using cytokine secretion assays and imaging-based killing assays. Elimination of infected cells was further quantified using a modified fluorescent hybridization of viral RNA assay. Here, we demonstrate that picomolar concentrations of ImmTAV-Env can redirect T cells from healthy and HBV-infected donors toward hepatocellular carcinoma (HCC) cells containing integrated HBV DNA resulting in cytokine release, which could be suppressed by the addition of a corticosteroid in vitro. Importantly, ImmTAV-Env redirection of T cells induced cytolysis of antigen-positive HCC cells and cells infected with HBV in vitro, causing a reduction of hepatitis B e antigen and specific loss of cells expressing viral RNA. CONCLUSIONS: The ImmTAV platform has the potential to enable the elimination of infected cells by redirecting endogenous non-HBV-specific T cells, bypassing exhausted HBV-specific T cells. This represents a promising therapeutic option in the treatment of chronic hepatitis B, with our lead candidate now entering trials.

Associations among anxiety, self-efficacy, and self-care in rural adolescents with poorly controlled asthma.

BACKGROUND: Rural adolescents are vulnerable to asthma; good self-care can reduce morbidity. The subtypes of anxiety (eg, asthma-related, generalized) may have differential associations with asthma self-care. Low self-efficacy, a determinant of behavior, is associated with increased anxiety. Little is known regarding these relationships in rural adolescents. OBJECTIVE: To evaluate whether anxiety symptoms are associated with asthma symptom prevention and management among rural adolescents and whether self-efficacy mediates these relationships. METHODS: We used baseline data from 197 rural adolescents (mean age = 16 years; 69% girls; 62% Black) who were part of a trial that tested the effectiveness of a school-based asthma intervention. Adolescents completed the Youth Asthma-Related Anxiety Scale, Screen for Child Anxiety and Emotional Disorders, Asthma Management Self-efficacy Index, and Asthma Prevention and Management Indices. Linear regression was performed to test whether: (1) asthma-related and generalized anxiety had curvilinear relationships with self-care; (2) social and separation anxiety had linear relationships with self-care; and (3) self-efficacy mediated relationships. RESULTS: Asthma-related anxiety had a significant curvilinear relationship with prevention (P = 0.001) and a linear association with management (P = .01). Generalized anxiety had a significant curvilinear association with management (P = .03), whereas social anxiety had a significant linear relationship with prevention (P = .04). Self-efficacy partially or fully mediated these relationships. CONCLUSION: Anxiety symptoms were associated with asthma self-care among this sample of rural adolescents, with differing roles for prevention and management. Self-efficacy may be a mechanism to improve asthma self-care among rural adolescents with anxiety. With a lack of self-efficacy, asthma-related, generalized, or social anxiety may motivate adolescents to take steps to care for their asthma.

Social Determinants of Health and Emergency Department Use Among Children With Sickle Cell Disease.

Sickle cell disease (SCD) is associated with disproportionate emergency department (ED) use. This study described the social determinants of health associated with ED visits and hospital admission from the ED among children with SCD using a nationally representative dataset. We analyzed data from 126 children 0 to 17 years of age with SCD included in the 2011 to 2017 rounds of the National Health Interview Survey (mean age, 8 y; 50% female individuals; 74% African American). Study variables were summarized using weighted means and proportions and compared according to ED use and admission by Wald tests. Fifty-two identified children had visited the ED within the last 12 months and 21 were admitted to the hospital after their most recent ED visit. Children living in a single-mother household were more likely to visit the ED (P=0.040), as were younger children (mean age, 6 vs. 9 y; P=0.034), with no evaluated social determinants of health significantly impacting hospital admission from the ED. The lack of association between ED use and either poverty or insurance type may be related to the overall high level of social disadvantage among children with SCD. Our findings demonstrate the need to better characterize specific social factors impacting acute care use among children with SCD.

Mobile health intervention for youth with sickle cell disease: Impact on adherence, disease knowledge, and quality of life.

BACKGROUND: Adherence to illness self-management among youth with sickle cell disease (SCD) positively impacts health outcomes and decreases overall healthcare costs. Despite this, children with SCD face several barriers to adherence, with adherence rates that remain moderate to low. The current feasibility study examined the Intensive Training Program (ITP), a mobile health (mHealth) intervention for youth with SCD designed to promote disease knowledge, adherence, and patient-provider communication. PROCEDURE: Youth with SCD prescribed hydroxyurea between ages 7-18 completed baseline disease knowledge and psychosocial assessments and then were provided with the ITP app. Youth participated in the 90-day ITP, during which they completed three education modules, tracked adherence through daily self-recorded videos on the app, and received video messages from providers. Participants completed poststudy knowledge, psychosocial, and feasibility questionnaires. Medication possession ratio (MPR) was obtained via pharmacy-refill rates. RESULTS: Thirty-two youths (mean age = 13.0 years) participated, with an average adherence tracking rate of 0.6 (standard deviation = 0.34). All participants demonstrated increased MPR (0.57-0.74, P < 0.001, d = 0.75) and disease knowledge (59.6-88.6%, P < 0.001). There was variable engagement in the ITP; completers demonstrated significantly better SCD-related functioning (P < 0.05), higher parent-reported treatment functioning (P < 0.05), and lower pain impact than noncompleters of the ITP (P < 0.05). CONCLUSIONS: Results support the ITP can feasibly be implemented to promote adherence among youth with SCD. All participants demonstrated increased adherence and disease knowledge. However, there was variable engagement and only intervention completers showed improvements in psychosocial outcomes. Further research is needed to evaluate long-term outcomes and ways to promote engagement in mHealth interventions among the youth.

Utilizing a Novel Mobile Health "Selfie" Application to Improve Compliance to Iron Chelation in Pediatric Patients Receiving Chronic Transfusions.

Iron chelation therapy can prevent iron overload for pediatric patients with sickle cell disease and ß-thalassemia major; however, adherence is suboptimal. Therefore, we developed an intensive training program (ITP), to improve medication management and disease knowledge. The objectives were to determine feasibility of the ITP and its preliminary impact on adherence, disease knowledge, and health outcomes. Pediatric patients were recruited to participate in the ITP over a 90-day period and were followed for 6 months. The ITP consisted of 3 components: (1) provider-led education modules; (2) patient recording daily videos of at-home medication administration; and (3) provider feedback through video messages through the ITP app. Eleven patients participated (mean=12.4 y). Initially, patients endorsed high satisfaction and ease of use and tracked their medication usage 81% (24 out of 30) of days. At 90 days, adherence rates remained consistent (80%) and disease knowledge retention was high (96%). At 6 months, participants exhibited a clinically relevant decrease in serum ferritin, which trended toward statistical significance (P=0.068). Medication possession ratio did not significantly increase (0.65 to 0.72; not significant). The mobile ITP was feasibly implemented in a clinical setting; in addition, high levels of compliance, disease knowledge retention, and acceptance encourage larger studies evaluating mobile health technology to improve child health parameters.

Over-expression of DNMT3A predicts the risk of recurrent vulvar squamous cell carcinomas.

OBJECTIVE: Cancer initiation and progression has been linked to aberrant expression of the DNA methyltransferases (DNMT), the enzymes which establish and maintain DNA methylation patterns throughout the genome. In this study, we investigated if DNMT expression in vulvar squamous cell carcinomas (VSCC) was related to clinical outcome. METHODS: DNMT1, DNMT3A and DNMT3B expression was measured in a subset of cases drawn from a cohort of consecutive women treated for primary VSCC at the Pan Birmingham Gynaecological Cancer Centre between 2001 and 2008. Univariable and multivariable competing risk modelling was performed to identify whether DNMT expression was associated with local disease recurrence or disease morbidity. RESULTS: Over-expression of DNMT3A in the invasive component of the tumour was seen in 44% of tumours and was associated with an increased risk of local vulvar recurrence (LVR) (HR=4.51, p=0.012). This risk was found to increase further after adjustment for disease stage (HR=6.00, p=0.003) and groin node metastasis (HR=4.81, p=0.008). Over-expression of DNMT3B was associated with an increased risk of LVR (HR=5.69 p=0.03), however this ceased to be significant after adjustment for groin node metastasis. In a subset analysis, over-expression of DNMT3A was found to be significantly more common in VSCCs that stained negative for CDKN2A. CONCLUSIONS: These observations are consistent with the possibility that epigenetic changes contribute to vulvar neoplasia and DNMT3A over-expression may be useful in predicting local disease recurrence.

Clinical outcomes of splenectomy in children: report of the splenectomy in congenital hemolytic anemia registry.

The outcomes of children with congenital hemolytic anemia (CHA) undergoing total splenectomy (TS) or partial splenectomy (PS) remain unclear. In this study, we collected data from 100 children with CHA who underwent TS or PS from 2005 to 2013 at 16 sites in the Splenectomy in Congenital Hemolytic Anemia (SICHA) consortium using a patient registry. We analyzed demographics and baseline clinical status, operative details, and outcomes at 4, 24, and 52 weeks after surgery. Results were summarized as hematologic outcomes, short-term adverse events (AEs) (≤30 days after surgery), and long-term AEs (31-365 days after surgery). For children with hereditary spherocytosis, after surgery there was an increase in hemoglobin (baseline 10.1 ± 1.8 g/dl, 52 week 12.8 ± 1.6 g/dl; mean ± SD), decrease in reticulocyte and bilirubin as well as control of symptoms. Children with sickle cell disease had control of clinical symptoms after surgery, but had no change in hematologic parameters. There was an 11% rate of short-term AEs and 11% rate of long-term AEs. As we accumulate more subjects and longer follow-up, use of a patient registry should enhance our capacity for clinical trials and engage all stakeholders in the decision-making process.

U.S. responses to Japanese wartime inhuman experimentation after World War II.

In 1945-46, representatives of the U.S. government made similar discoveries in both Germany and Japan, unearthing evidence of unethical experiments on human beings that could be viewed as war crimes. The outcomes in the two defeated nations, however, were strikingly different. In Germany, the United States, influenced by the Canadian physician John Thompson, played a key role in bringing Nazi physicians to trial and publicizing their misdeeds. In Japan, the United States played an equally key role in concealing information about the biological warfare experiments and in securing immunity from prosecution for the perpetrators. The greater force of appeals to national security and wartime exigency help to explain these different outcomes.

Sexual and Gender Minority Sleep Health Disparities and Minority Stress in Early Adolescence.

PURPOSE: Sleep is essential to adolescent development. Sexual and gender minority (SGM; e.g., lesbian, gay, bisexual, transgender) adults are at high risk for poor sleep, partially due to minority stress (e.g., discrimination). However, sleep has rarely been studied among SGM adolescents. In a national sample of early adolescents, we analyzed sexual minority (SM) and gender minority (GM) identity, gender incongruence, and gender nonconformity in association with sleep and tested minority and general stressors as mediators. METHODS: We cross-sectionally analyzed data from 10,070 adolescents aged 10-14 in the Adolescent Brain Cognitive Development℠ Study. Using logistic regression models, we analyzed associations between identity (SM and GM), sexual identity discrimination, minority and general stressors (sexual identity discrimination, teasing, and conflict with parents) and sleep health (duration, latency, and disturbance). We used Baron and Kenny's method to test for mediation. RESULTS: Participants reported sexual identity (4% SM, 4% questioning) and gender identity (0.4% GM, 0.6% questioning); 65% were White, 20% were Hispanic, and 52% were assigned male at birth. Compared to heterosexual, SM participants had higher odds of short sleep duration, long sleep latency, and sleep disturbance. GM participants and those reporting gender incongruence and nonconformity had higher odds of long sleep latency and sleep disturbance. Sexual identity discrimination and general social stressors partially mediated some associations. DISCUSSION: SGM participants reported poorer sleep. Minority and general social stressors partially accounted for some disparities. Policies need to address SGM identity-based discrimination and challenge social norms that produce minority stress for SGM early adolescents.

The impact of the COVID-19 pandemic for children in custody: An analysis of inspection reports.

BACKGROUND: Children in custodial settings are a vulnerable group. Prior to the COVID-19 pandemic there were concerns about the safety of children in these settings. COVID-19 has had an impact on everyone but given the vulnerability of children in custody, there were concerns about the impact of COVID-19 restrictions. All custody settings for children are independently inspected and this research aimed to analyse data from inspection reports. Twenty-six inspection reports undertaken between March 2020 and October 2021 were analysed to understand the impact of COVID-19 on delivery of usual care/regime. RESULTS: Data showed that across all site's children spent considerable amounts of time isolated and in some cases, this was deemed to amount to solitary confinement. There was evidence of some positive experiences, in the smaller sites, around COVID-19 slowing the pace of life allowing staff and children could foster relationships. However, in the larger sites, isolation was extreme and COVID-19 policies such as 'bubbles' appear to have created unintended consequences as sites have moved into recovery, leading to increased violence and stress. COVID-19 directly impacted staffing levels. This and the COVID-19 policies to reduce mixing also had an impact on how children's behaviour, welfare and safeguarding was managed. In some larger sites, being COVID-19 secure was prioritised over the needs of the children. CONCLUSIONS: This research highlights the importance of multi-site longitudinal research to understand how children, staff and institution's function. The experiences of children in custody during COVID-19 differed by site type. The research suggests that the larger sites are struggling to keep children safe and there should be a shift towards smaller, more therapeutic environments. More research is needed to understand the longer-term unintended consequences of COVID-19 policy in custody, for these vulnerable children.

Clinicians' use of the structured professional judgement approach for adult secure psychiatric service admission assessments: A systematic review.

The structured professional judgement (SPJ) approach was initially developed to support risk assessment and management decisions. The approach is now being adapted and applied to admission assessments for adult secure services. This systematic review aims to summarise the evidence for the effectiveness and acceptability of the SPJ approach in admission assessments of this kind. A comprehensive electronic search strategy was used to identify studies indexed in PubMed, PsycInfo, Medline and Cochrane Library (January 2007 -January 2024). Two search strategies included terms (and synonyms) for psychiatric patients (quantitative) or clinicians and clinicians' experiences (qualitative), structured professional judgement, admission, and secure services. Twelve quantitative articles (published 2007-2020) were identified. SPJ-informed guidance included were the DUNDRUM-1, DUNDRUM-2, DUNDRUM-3, DUNDRUM-4, and the HCR-20. While findings were variable, the overall pattern indicated that ratings suggestive of more problems were associated with increased likelihood of admission or movement to higher security levels. There is emerging evidence for the use of SPJ guidance to support admission decision-making. Specifically, it should be used as an adjunct to existing decision-making processes rather than as a replacement for those processes. Further research, both quantitative and qualitative, across a wider range of settings and populations is recommended.

Solid-state NMR evidence for ß-hairpin structure within MAX8 designer peptide nanofibers.

MAX8, a designer peptide known to undergo self-assembly following changes in temperature, pH, and ionic strength, has demonstrated usefulness for tissue engineering and drug delivery. It is hypothesized that the self-assembled MAX8 nanofiber structure consists of closed ß-hairpins aligned into antiparallel ß-sheets. Here, we report evidence from solid-state NMR spectroscopy that supports the presence of the hypothesized ß-hairpin conformation within the nanofiber structure. Specifically, our (13)C-(13)C two-dimensional exchange data indicate spatial proximity between V3 and K17, and (13)C-(13)C dipolar coupling measurements reveal proximity between the V3 and V18 backbone carbonyls. Moreover, isotopic dilution of labeled MAX8 nanofibers did not result in a loss of the (13)C-(13)C dipolar couplings, showing that these couplings are primarily intramolecular. NMR spectra also indicate the existence of a minor conformation, which is discussed in terms of previously hypothesized nanofiber physical cross-linking and possible nanofiber polymorphism.