Two human antibodies to a meningococcal serogroup B vaccine antigen enhance binding of complement Factor H by stabilizing the Factor H binding site.

Microbial pathogens bind host complement regulatory proteins to evade the immune system. The bacterial pathogen Neisseria meningitidis, or meningococcus, binds several complement regulators, including human Factor H (FH). FH binding protein (FHbp) is a component of two licensed meningococcal vaccines and in mice FHbp elicits antibodies that inhibit binding of FH to FHbp, which defeat the bacterial evasion mechanism. However, humans vaccinated with FHbp develop antibodies that enhance binding of FH to the bacteria, which could limit the effectiveness of the vaccines. In the present study, we show that two vaccine-elicited antibody fragments (Fabs) isolated from different human subjects increase binding of complement FH to meningococcal FHbp by ELISA. The two Fabs have different effects on the kinetics of FH binding to immobilized FHbp as measured by surface plasmon resonance. The 1.7- and 2.0-Å resolution X-ray crystal structures of the Fabs in complexes with FHbp illustrate that the two Fabs bind to similar epitopes on the amino-terminal domain of FHbp, adjacent to the FH binding site. Superposition models of ternary complexes of each Fab with FHbp and FH show that there is likely minimal contact between the Fabs and FH. Collectively, the structures reveal that the Fabs enhance binding of FH to FHbp by altering the conformations and mobilities of two loops adjacent to the FH binding site of FHbp. In addition, the 1.5 Å-resolution structure of one of the isolated Fabs defines the structural rearrangements associated with binding to FHbp. The FH-enhancing human Fabs, which are mirrored in the human polyclonal antibody responses, have important implications for tuning the effectiveness of FHbp-based vaccines.

Defining Physiological Decompensation: An Expert Consensus and Retrospective Outcome Validation.

OBJECTIVES: Physiological decompensation of hospitalized patients is common and is associated with substantial morbidity and mortality. Research surrounding patient decompensation has been hampered by the absence of a robust definition of decompensation and lack of standardized clinical criteria with which to identify patients who have decompensated. We aimed to: 1) develop a consensus definition of physiological decompensation and 2) to develop clinical criteria to identify patients who have decompensated. DESIGN: We utilized a three-phase, modified electronic Delphi (eDelphi) process, followed by a discussion round to generate consensus on the definition of physiological decompensation and on criteria to identify decompensation. We then validated the criteria using a retrospective cohort study of adult patients admitted to the Hospital of the University of Pennsylvania. SETTING: Quaternary academic medical center. PATIENTS: Adult patients admitted to the Hospital of the University of Pennsylvania who had triggered a rapid response team (RRT) response between January 1, 2019, and December 31, 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Sixty-nine experts participated in the eDelphi. Participation was high across the three survey rounds (first round: 93%, second round: 94%, and third round: 98%). The expert panel arrived at a consensus definition of physiological decompensation, "An acute worsening of a patient's clinical status that poses a substantial increase to an individual's short-term risk of death or serious harm." Consensus was also reached on criteria for physiological decompensation. Invasive mechanical ventilation, severe hypoxemia, and use of vasopressor or inotrope medication were bundled as criteria for our novel decompensation metric: the adult inpatient decompensation event (AIDE). Patients who met greater than one AIDE criteria within 24 hours of an RRT call had increased adjusted odds of 7-day mortality (adjusted odds ratio [aOR], 4.1 [95% CI, 2.5-6.7]) and intensive care unit transfer (aOR, 20.6 [95% CI, 14.2-30.0]). CONCLUSIONS: Through the eDelphi process, we have reached a consensus definition of physiological decompensation and proposed clinical criteria with which to identify patients who have decompensated using data easily available from the electronic medical record, the AIDE criteria.

COVID-19 vaccine hesitancy among patients in two urban emergency departments.

BACKGROUND: Widespread vaccination is an essential component of the public health response to the COVID-19 pandemic, yet vaccine hesitancy remains pervasive. This prospective survey investigation aimed to measure the prevalence of vaccine hesitancy in a patient cohort at two urban emergency departments (EDs) and characterize underlying factors contributing to hesitancy. METHODS: Adult ED patients with stable clinical status (Emergency Severity Index 3-5) and without active COVID-19 disease or altered mental status were considered for participation. Demographic elements were collected as well as reported barriers/concerns related to vaccination and trusted sources of health information. Data were collected in person via a survey instrument proctored by trained research assistants. RESULTS: A total of 1,555 patients were approached, and 1,068 patients completed surveys (completion rate = 68.7%). Mean (±SD) age was 44.1 (±15.5) years (range = 18-93 years), 61% were female, and 70% were Black. A total of 31.6% of ED patients reported vaccine hesitancy. Of note, 19.7% of the hesitant cohort were health care workers. In multivariable regression analysis, Black race (odds ratio [OR] = 4.24, 95% confidence interval [CI] = 2.62 to 6.85) and younger age (age 18-24 years-OR = 4.57, 95% CI = 2.66 to 7.86; age 25-35 years-OR = 5.71, 95% CI = 3.71 to 8.81) were independently associated with hesitancy, to a greater degree than level of education (high school education or less-OR = 2.27, 95% CI = 1.23 to 4.19). Hesitant patients were significantly less likely to trust governmental sources of vaccine information than nonhesitant patients (39.6% vs. 78.9%, p < 0.001); less difference was noted in the domain of trust toward friends/family (51.1% vs. 61.0%, p = 0.004). Hesitant patients also reported perceived vaccine safety concerns and perceived insufficient research. CONCLUSIONS: Vaccine hesitancy is common among ED patients and more common among Black and younger patients, independent of education level. Hesitant patients report perceived safety concerns and low trust in government information sources but less so friends or family. This suggests that strategies to combat hesitancy may need tailoring to specific populations.

Transcriptional regulation of autophagy-lysosomal function in BRAF-driven melanoma progression and chemoresistance.

Autophagy maintains homeostasis and is induced upon stress. Yet, its mechanistic interaction with oncogenic signaling remains elusive. Here, we show that in BRAFV600E-melanoma, autophagy is induced by BRAF inhibitor (BRAFi), as part of a transcriptional program coordinating lysosome biogenesis/function, mediated by the TFEB transcription factor. TFEB is phosphorylated and thus inactivated by BRAFV600E via its downstream ERK independently of mTORC1. BRAFi disrupts TFEB phosphorylation, allowing its nuclear translocation, which is synergized by increased phosphorylation/inactivation of the ZKSCAN3 transcriptional repressor by JNK2/p38-MAPK. Blockade of BRAFi-induced transcriptional activation of autophagy-lysosomal function in melanoma xenografts causes enhanced tumor progression, EMT-transdifferentiation, metastatic dissemination, and chemoresistance, which is associated with elevated TGF-ß levels and enhanced TGF-ß signaling. Inhibition of TGF-ß signaling restores tumor differentiation and drug responsiveness in melanoma cells. Thus, the "BRAF-TFEB-autophagy-lysosome" axis represents an intrinsic regulatory pathway in BRAF-mutant melanoma, coupling BRAF signaling with TGF-ß signaling to drive tumor progression and chemoresistance.