SARS-CoV-2 variant of concern fitness and adaptation in primary human airway epithelia.

The severe acute respiratory syndrome coronavirus 2 pandemic is characterized by the emergence of novel variants of concern (VOCs) that replace ancestral strains. Here, we dissect the complex selective pressures by evaluating variant fitness and adaptation in human respiratory tissues. We evaluate viral properties and host responses to reconstruct forces behind D614G through Omicron (BA.1) emergence. We observe differential replication in airway epithelia, differences in cellular tropism, and virus-induced cytotoxicity. D614G accumulates the most mutations after infection, supporting zoonosis and adaptation to the human airway. We perform head-to-head competitions and observe the highest fitness for Gamma and Delta. Under these conditions, RNA recombination favors variants encoding the B.1.617.1 lineage 3' end. Based on viral growth kinetics, Alpha, Gamma, and Delta exhibit increased fitness compared to D614G. In contrast, the global success of Omicron likely derives from increased transmission and antigenic variation. Our data provide molecular evidence to support epidemiological observations of VOC emergence.

Homotypic antibodies target novel E glycoprotein domains after natural DENV 3 infection/vaccination.

The envelope (E) glycoprotein is the primary target of type-specific (TS) neutralizing antibodies (nAbs) after infection with any of the four distinct dengue virus serotypes (DENV1-4). nAbs can be elicited to distinct structural E domains (EDs) I, II, or III. However, the relative contribution of these domain-specific antibodies is unclear. To identify the primary DENV3 nAb targets in sera after natural infection or vaccination, chimeric DENV1 recombinant encoding DENV3 EDI, EDII, or EDIII were generated. DENV3 EDII is the principal target of TS polyclonal nAb responses and encodes two or more neutralizing epitopes. In contrast, some were individuals vaccinated with a DENV3 monovalent vaccine-elicited serum TS nAbs targeting each ED in a subject-dependent fashion, with an emphasis on EDI and EDIII. Vaccine responses were also sensitive to DENV3 genotypic variation. This DENV1/3 panel allows the measurement of serum ED TS nAbs, revealing differences in TS nAb immunity after natural infection or vaccination.

Dengue virus 4/2 envelope domain chimeric virus panel maps type-specific responses against dengue serotype 2.

IMPORTANCE: The four dengue virus (DENV) serotypes infect several hundred million people each year. Although primary infection is generally mild, subsequent infection by differing serotypes increases the risk for symptomatic disease ranging from fever to life-threatening shock. Despite the availability of licensed vaccines, a comprehensive understanding of antibodies that target the viral envelope protein and protect from infection remains incomplete. In this manuscript, we develop a panel of recombinant viruses that graft each envelope domain of DENV2 onto the DENV4 envelope glycoprotein, revealing protein interactions important for virus viability. Furthermore, we map neutralizing antibody responses after primary DENV2 natural infection and a human challenge model to distinct domains on the viral envelope protein. The panel of recombinant viruses provides a new tool for dissecting the E domain-specific targeting of protective antibody responses, informing future DENV vaccine design.

A live dengue virus vaccine carrying a chimeric envelope glycoprotein elicits dual DENV2-DENV4 serotype-specific immunity.

The four dengue virus serotypes co-circulate globally and cause significant human disease. Dengue vaccine development is challenging because some virus-specific antibodies are protective, while others are implicated in enhanced viral replication and more severe disease. Current dengue tetravalent vaccines contain four live attenuated serotypes formulated to theoretically induce balanced protective immunity. Among the number of vaccine candidates in clinical trials, only Dengvaxia is licensed for use in DENV seropositive individuals. To simplify live-virus vaccine design, we identify co-evolutionary constraints inherent in flavivirus virion assembly and design chimeric viruses to replace domain II (EDII) of the DENV2 envelope (E) glycoprotein with EDII from DENV4. The chimeric DENV2/4EDII virus replicates efficiently in vitro and in vivo. In male macaques, a single inoculation of DENV2/4EDII induces type-specific neutralizing antibodies to both DENV2 and DENV4, thereby providing a strategy to simplify DENV vaccine design by utilizing a single bivalent E glycoprotein immunogen for two DENV serotypes.

Identification of Dengue Virus Serotype 3 Specific Antigenic Sites Targeted by Neutralizing Human Antibodies.

The rational design of dengue virus (DENV) vaccines requires a detailed understanding of the molecular basis for antibody-mediated immunity. The durably protective antibody response to DENV after primary infection is serotype specific. However, there is an incomplete understanding of the antigenic determinants for DENV type-specific (TS) antibodies, especially for DENV serotype 3, which has only one well-studied, strongly neutralizing human monoclonal antibody (mAb). Here, we investigated the human B cell response in children after natural DENV infection in the endemic area of Nicaragua and isolated 15 DENV3 TS mAbs recognizing the envelope (E) glycoprotein. Functional epitope mapping of these mAbs and small animal prophylaxis studies revealed a complex landscape with protective epitopes clustering in at least 6-7 antigenic sites. Potently neutralizing TS mAbs recognized sites principally in E glycoprotein domains I and II, and patterns suggest frequent recognition of quaternary structures on the surface of viral particles.

Patterns of peritraumatic threat perceptions in patients evaluated for suspected acute coronary syndrome according to prior and current posttraumatic stress symptoms.

OBJECTIVE: Prior posttraumatic stress disorder (PTSD) and elevated threat perceptions predict posttraumatic psychopathology after evaluation for acute coronary syndrome (ACS), but most research has measured threat retrospectively. We investigated how threat perceptions during ACS evaluation in the emergency department (ED) and upon recall were associated with posttraumatic psychopathology burden due to prior trauma and the suspected ACS. METHODS: Perceived threat was assessed in the ED, and ED threat recall was assessed upon inpatient transfer/discharge, along with acute stress disorder (ASD) symptoms due to suspected ACS and PTSD symptoms due to prior trauma. The sample comprised 894 participants (mean age = 60.7 ±â€¯13.1 years; 46.8% female; 56.3% Hispanic; 20.5% Black). One-way ANOVAs examined how those with consistent posttraumatic psychopathology (prior PTSD/ASD; 14.8%), prior posttraumatic psychopathology (prior PTSD/no ASD; 6.8%), new-onset posttraumatic psychopathology (no PTSD/ASD; 15.7%), or no posttraumatic psychopathology (no PTSD/no ASD; 62.8%) differed in threat perception, threat recall, and their discrepancy. RESULTS: Threat perception scores ranged from 6 to 24. Participants with consistent posttraumatic psychopathology had higher threat perceptions (M = 14.01) than those with prior posttraumatic psychopathology (M = 12.02) and new-onset posttraumatic psychopathology (M = 12.21) (ps ≤ 0.001); the latter two did not differ significantly but had higher threat perceptions than those with no posttraumatic psychopathology (M = 9.84) (p < .001). Similar results were observed for threat recall (p < .001). The new-onset posttraumatic psychopathology group also had a greater increase in perceived threat versus the no posttraumatic psychopathology group (p = .06). Results were similar adjusting for potential confounders. CONCLUSIONS: Assessing threat perceptions during ACS evaluation and hospitalization may help identify those at risk for emotional difficulties post-ACS.

Outcomes of cleft lip repair for internationally adopted children.

BACKGROUND: Large numbers of international children with cleft lip-cleft palate are adopted in the United States; many underwent their first operation before arrival. METHODS: The authors reviewed records of internationally adopted children with cleft lip-cleft palate treated by one surgeon over 25 years. This study focused on anatomical types, frequency/methods of repair, correction of unrepaired deformities, and secondary procedures in this country. RESULTS: Of 105 internationally adopted children with cleft lip-cleft palate, 91 percent were Asian; 75 percent had labial or labiopalatal closure in their native country. Of repaired unilateral cleft lips, 43 percent required complete revision, 49 percent required minor revisions, and 8 percent required no revision. All repaired bilateral cleft lips were revised; 90 percent were complete and 10 percent were minor. "Delayed" primary nasal correction was always necessary in both unilateral and bilateral forms. Labial closure was scheduled first in young infants with an unrepaired unilateral defect, whereas palatal closure took precedence in older children. Premaxillary setback and palatoplasty were scheduled first in older children with unrepaired bilateral cleft lip-cleft palate. Of children arriving with repaired palate, 43 percent required a pharyngeal flap. CONCLUSIONS: Whenever cleft lip-cleft palate is repaired in another country, revision rates are high for both unilateral and bilateral types. Nevertheless, primary closure in the native country may increase the likelihood for adoption. Traditional surgical protocols often are altered for an adoptee with an unrepaired cleft lip-cleft palate, particularly the sequence of labial and palatal closure, depending on the child's age and type of defect.