Targeting Viral Proteostasis Limits Influenza Virus, HIV, and Dengue Virus Infection.

Viruses are obligate parasites and thus require the machinery of the host cell to replicate. Inhibition of host factors co-opted during active infection is a strategy hosts use to suppress viral replication and a potential pan-antiviral therapy. To define the cellular proteins and processes required for a virus during infection is thus crucial to understanding the mechanisms of virally induced disease. In this report, we generated fully infectious tagged influenza viruses and used infection-based proteomics to identify pivotal arms of cellular signaling required for influenza virus growth and infectivity. Using mathematical modeling and genetic and pharmacologic approaches, we revealed that modulation of Sec61-mediated cotranslational translocation selectively impaired glycoprotein proteostasis of influenza as well as HIV and dengue viruses and led to inhibition of viral growth and infectivity. Thus, by studying virus-human protein-protein interactions in the context of active replication, we have identified targetable host factors for broad-spectrum antiviral therapies.

High-complexity extracellular barcoding using a viral hemagglutinin.

While single-cell sequencing technologies have revealed tissue heterogeneity, resolving mixed cellular libraries into cellular clones is essential for many pooled screens and clonal lineage tracing. Fluorescent proteins are limited in number, while DNA barcodes can only be read after cell lysis. To overcome these limitations, we used influenza virus hemagglutinins to engineer a genetically encoded cell-surface protein barcoding system. Using antibodies paired to hemagglutinins carrying combinations of escape mutations, we developed an exponential protein barcoding system which can label 128 clones using seven antibodies. This study provides a proof of principle for a strategy to create protein-level cell barcodes that can be used in vivo in mice to track clonal populations.

Optimal activation of Fc-mediated effector functions by influenza virus hemagglutinin antibodies requires two points of contact.

Influenza virus strain-specific monoclonal antibodies (mAbs) provide protection independent of Fc gamma receptor (FcγR) engagement. In contrast, optimal in vivo protection achieved by broadly reactive mAbs requires Fc-FcγR engagement. Most strain-specific mAbs target the head domain of the viral hemagglutinin (HA), whereas broadly reactive mAbs typically recognize epitopes within the HA stalk. This observation has led to questions regarding the mechanism regulating the activation of Fc-dependent effector functions by broadly reactive antibodies. To dissect the molecular mechanism responsible for this dichotomy, we inserted the FLAG epitope into discrete locations on HAs. By characterizing the interactions of several FLAG-tagged HAs with a FLAG-specific antibody, we show that in addition to Fc-FcγR engagement mediated by the FLAG-specific antibody, a second intermolecular bridge between the receptor-binding region of the HA and sialic acid on effector cells is required for optimal activation. Inhibition of this second molecular bridge, through the use of an F(ab')2 or the mutation of the sialic acid-binding site, renders the Fc-FcγR interaction unable to optimally activate effector cells. Our findings indicate that broadly reactive mAbs require two molecular contacts to possibly stabilize the immunologic synapse and potently induce antibody-dependent cell-mediated antiviral responses: (i) the interaction between the Fc of a mAb bound to HA with the FcγR of the effector cell and (ii) the interaction between the HA and its sialic acid receptor on the effector cell. This concept might be broadly applicable for protective antibody responses to viral pathogens that have suitable receptors on effector cells.

Dose-Dependent Effect of Enzyme Replacement Therapy on Neutralizing Antidrug Antibody Titers and Clinical Outcome in Patients with Fabry Disease.

BACKGROUND: Use of enzyme replacement therapy (ERT) to treat Fabry disease, caused by deficient lysosomal α-galactosidase A activity, can lead to formation of neutralizing antidrug antibodies (ADAs). These antibodies are associated with increased accumulation of plasma globotriaosylceramide (Gb3) and disease progression. Because agalsidase ERT can saturate ADA-binding sites during infusions (achieving agalsidase/antibody equilibrium), we investigated in this open cohort study whether saturated patients (who have excess agalsidase after infusions) experience better clinical outcomes compared with not saturated patients (who have excess ADAs after infusions). METHODS: We isolated ADAs from sera of 26 men with Fabry disease receiving ERT (for a median of 94 months) and determined the amount of agalsidase necessary for antibody saturation. Clinical and biochemical outcomes included measurements of eGFR, interventricular septum thickness, and lyso-Gb3. RESULTS: ADA titers decreased significantly in all patients during infusion. Agalsidase-α and agalsidase-ß had similar ADA-binding capacity and comparable ADA saturation frequency. Fourteen patients with saturated ADAs presented with mild (but significant) loss of eGFR, stable septum thickness, and significantly decreased lyso-Gb3 levels. The 12 not saturated patients had a more pronounced and significant loss of eGFR, increased septum thickness, and a smaller, nonsignificant reduction in lyso-Gb3, over time. In three patients, dose escalation resulted in partially elevated ADA titers, but importantly, also in reduced lyso-Gb3 levels. CONCLUSIONS: A not saturated ADA status during infusion is associated with progressive loss of eGFR and ongoing cardiac hypertrophy. Dose escalation can result in saturation of ADAs and decreasing lyso-Gb3 levels, but may lead to increased ADA titers.

First national iodine survey in Madagascar demonstrates iodine deficiency.

Universal salt iodization (USI) was adopted in Madagascar in 1995 within the framework of a worldwide policy to eliminate iodine deficiency disorders. Despite early USI adoption, there are no representative data on the iodine status of the Malagasy population. The aims of this study were to determine the iodine status of the Malagasy population and to assess the use of adequately iodized salt among households. We randomly sampled women of reproductive age (WRA) using a national, two-stage, stratified cross-sectional survey in 2014. Casual urine from WRA and salt samples from the household containing WRA were collected to measure urinary iodine concentration (UIC) and to assess household salt iodine content. Data from 1,721 WRA in 1,128 households were collected and analysed. The national median UIC was 46 µg L-1 (interquartile range [IQR]: 13-98 µg L-1 ), indicating a moderate iodine deficiency. The median UIC was 53 µg L-1 (IQR: 9-89 µg L-1 ) in pregnant women and 46 µg L-1 (IQR: 13-98 µg L-1 ) in non-pregnant women. The national median iodine concentration of household salt was 10 mg kg-1 (IQR: 6.3-15.8 mg kg-1 ) and 26.2% (95% CI [22.1, 31.0]) of households containing WRA used adequately iodized salt (≥15 mg kg-1 ). Women living in households with adequately iodized salt had higher median UIC (72 vs. 50 µg L-1 ). Iodine status was significantly lower among women from low socio-economic households. Madagascar's USI program needs to be revitalized. Implementing strategies to provide adequately iodized salt and enhancing iodized salt legislation to prevent severe complications resulting from iodine deficiency in the Malagasy population are essential.

Broadly-Reactive Neutralizing and Non-neutralizing Antibodies Directed against the H7 Influenza Virus Hemagglutinin Reveal Divergent Mechanisms of Protection.

In the early spring of 2013, Chinese health authorities reported several cases of H7N9 influenza virus infections in humans. Since then the virus has established itself at the human-animal interface in Eastern China and continues to cause several hundred infections annually. In order to characterize the antibody response to the H7N9 virus we generated several mouse monoclonal antibodies against the hemagglutinin of the A/Shanghai/1/13 (H7N9) virus. Of particular note are two monoclonal antibodies, 1B2 and 1H5, that show broad reactivity to divergent H7 hemagglutinins. Monoclonal antibody 1B2 binds to viruses of the Eurasian and North American H7 lineages and monoclonal antibody 1H5 reacts broadly to virus isolates of the Eurasian lineage. Interestingly, 1B2 shows broad hemagglutination inhibiting and neutralizing activity, while 1H5 fails to inhibit hemagglutination and demonstrates no neutralizing activity in vitro. However, both monoclonal antibodies were highly protective in an in vivo passive transfer challenge model in mice, even at low doses. Experiments using mutant antibodies that lack the ability for Fc/Fc-receptor and Fc/complement interactions suggest that the protection provided by mAb 1H5 is, at least in part, mediated by the Fc-fragment of the mAb. These findings highlight that a protective response to a pathogen may not only be due to neutralizing antibodies, but can also be the result of highly efficacious non-neutralizing antibodies not readily detected by classical in vitro neutralization or hemagglutination inhibition assays. This is of interest because H7 influenza virus vaccines induce only low hemagglutination inhibiting antibody titers while eliciting robust antibody titers as measured by ELISA. Our data suggest that these binding but non-neutralizing antibodies contribute to protection in vivo.

Direct administration in the respiratory tract improves efficacy of broadly neutralizing anti-influenza virus monoclonal antibodies.

The emergence of influenza virus strains resistant to approved neuraminidase inhibitors and the time constrains after infection when these drugs can be effective constitute major drawbacks for this class of drugs. This highlights a critical need to discover new therapeutic agents that can be used for the treatment of influenza virus-infected patients. The use of broadly neutralizing anti-influenza monoclonal antibodies (MAbs) has been sought as an alternative immunotherapy against influenza infection. Here, we tested in mice previously characterized broadly neutralizing anti-hemagglutinin (HA) stalk MAbs prophylactically and therapeutically using different routes of administration. The efficacy of treatment against an influenza H1N1 pandemic virus challenge was compared between two systemic routes of administration, intraperitoneal (i.p.) and intravenous (i.v.), and two local routes, intranasal (i.n.) and aerosol (a.e.). The dose of MAb required for prophylactic protection was reduced by 10-fold in animals treated locally (i.n. or a.e.) compared with those treated systemically (i.p. or i.v.). Improved therapeutic protection was observed in animals treated i.n. on day 5 postinfection (60% survival) compared with those treated via the i.p. route (20% survival). An increase in therapeutic efficacy against other influenza virus subtypes (H5N1) was also observed when a local route of administration was used. Our findings demonstrate that local administration significantly decreases the amount of broadly neutralizing monoclonal antibody required for protection against influenza, which highlights the potential use of MAbs as a therapeutic agent for influenza-associated disease.

Characterization of a broadly neutralizing monoclonal antibody that targets the fusion domain of group 2 influenza A virus hemagglutinin.

UNLABELLED: Due to continuous changes to its antigenic regions, influenza viruses can evade immune detection and cause a significant amount of morbidity and mortality around the world. Influenza vaccinations can protect against disease but must be annually reformulated to match the current circulating strains. In the development of a broad-spectrum influenza vaccine, the elucidation of conserved epitopes is paramount. To this end, we designed an immunization strategy in mice to boost the humoral response against conserved regions of the hemagglutinin (HA) glycoprotein. Of note, generation and identification of broadly neutralizing antibodies that target group 2 HAs are rare and thus far have yielded only a few monoclonal antibodies (MAbs). Here, we demonstrate that mouse MAb 9H10 has broad and potent in vitro neutralizing activity against H3 and H10 group 2 influenza A subtypes. In the mouse model, MAb 9H10 protects mice against two divergent mouse-adapted H3N2 strains, in both pre- and postexposure administration regimens. In vitro and cell-free assays suggest that MAb 9H10 inhibits viral replication by blocking HA-dependent fusion of the viral and endosomal membranes early in the replication cycle and by disrupting viral particle egress in the late stage of infection. Interestingly, electron microscopy reconstructions of MAb 9H10 bound to the HA reveal that it binds a similar binding footprint to MAbs CR8020 and CR8043. IMPORTANCE: The influenza hemagglutinin is the major antigenic target of the humoral immune response. However, due to continuous antigenic changes that occur on the surface of this glycoprotein, influenza viruses can escape the immune system and cause significant disease to the host. Toward the development of broad-spectrum therapeutics and vaccines against influenza virus, elucidation of conserved regions of influenza viruses is crucial. Thus, defining these types of epitopes through the generation and characterization of broadly neutralizing monoclonal antibodies (MAbs) can greatly assist others in highlighting conserved regions of hemagglutinin. Here, we demonstrate that MAb 9H10 that targets the hemagglutinin stalk has broadly neutralizing activity against group 2 influenza A viruses in vitro and in vivo.

TTN novel splice variant in familial dilated cardiomyopathy and splice variants review: a case report.

This case report details the identification of a novel likely pathogenic splicing variant in the TTN gene, associated with dilated cardiomyopathy (DCM), in a 42-year-old male patient presenting with early-onset heart failure and reduced ejection fraction. DCM is a nonischemic heart condition characterized by left biventricular dilation and systolic dysfunction, with approximately one-third of cases being familial and often linked to genetic mutations. The TTN gene, encoding the largest human protein essential for muscle contraction and sarcomere structure, is implicated in about 25% of DCM cases through mutations, especially truncating variants. Our investigation revealed a previously unreported G > C mutation at the splice acceptor site in intron 356 of TTN, confirmed by Sanger sequencing and not found in population databases, suggesting a novel contribution to the understanding of DCM etiology. The case emphasizes the critical role of the TTN gene in cardiac function and the genetic complexity underlying DCM. A comprehensive literature review highlighted the prevalence and significance of splice variants in the TTN gene, particularly those affecting the titin A-band, which is known for its role in muscle contraction and stability. This variant's identification underscores the importance of genetic screening in patients with DCM, offering insights into the disease's familial transmission and potential therapeutic targets. Our findings contribute to the expanding knowledge of genetic factors in DCM, demonstrating the necessity of integrating genetic diagnostics in cardiovascular medicine. This case supports the growing evidence linking splicing mutations in specific regions of the TTN gene to DCM development and underscores the importance of genetic counseling and testing in managing heart disease.

Long-wavelength traveling waves of vasomotion modulate the perfusion of cortex.

Brain arterioles are active, multicellular complexes whose diameters oscillate at ∼ 0.1 Hz. We assess the physiological impact and spatiotemporal dynamics of vaso-oscillations in the awake mouse. First, vaso-oscillations in penetrating arterioles, which source blood from pial arterioles to the capillary bed, profoundly impact perfusion throughout neocortex. The modulation in flux during resting-state activity exceeds that of stimulus-induced activity. Second, the change in perfusion through arterioles relative to the change in their diameter is weak. This implies that the capillary bed dominates the hydrodynamic resistance of brain vasculature. Lastly, the phase of vaso-oscillations evolves slowly along arterioles, with a wavelength that exceeds the span of the cortical mantle and sufficient variability to establish functional cortical areas as parcels of uniform phase. The phase-gradient supports traveling waves in either direction along both pial and penetrating arterioles. This implies that waves along penetrating arterioles can mix, but not directionally transport, interstitial fluids.

Pharmacovigilance of malaria intermittent preventive treatment in infants coupled with routine immunizations in 6 African countries.

BACKGROUND: Intermittent preventive treatment in infants (IPTi) is a new malaria control strategy coupled with the delivery of routine immunizations recommended by the World Health Organization since 2009 for countries with moderate to high endemicity. To evaluate its safety profile and identify potential new adverse events (AEs) following simultaneous administration of sulfadoxine-pyrimethamine (SP-IPTi) with immunizations, we measured AE incidence and evaluated spontaneous AE reporting. METHODS: A cohort event monitoring study was conducted on 24 000 infants in 2 countries after administration of SP-IPTi during routine immunizations. Additional pharmacovigilance training and supervision were conducted to stimulate AE passive reporting in 6 African countries. RESULTS: No serious AEs were found by active follow-up, representing 95% probability that the rate does not exceed 1 per 8000. No serious AEs were found by retrospective review of hospital registers. The rate of moderate AEs probably linked to immunization and/or SP-IPTi was 1.8 per 1000 doses (95% confidence interval, 1.50-2.00). Spontaneous reporting of AEs remained <1% of cases collected by active follow-up. CONCLUSIONS: Simultaneous administration of SP-IPTi and immunizations is a safe strategy for implementation with a low risk of serious AEs to infants. Strategies toward strengthening spontaneous reporting in Africa should include not only the provider but also beneficiaries or their caregivers.

Plasmodium falciparum drug resistance in Madagascar: facing the spread of unusual pfdhfr and pfmdr-1 haplotypes and the decrease of dihydroartemisinin susceptibility.

The aim of this study was to provide the first comprehensive spatiotemporal picture of Plasmodium falciparum resistance in various geographic areas in Madagascar. Additional data about the antimalarial resistance in the neighboring islands of the Comoros archipelago were also collected. We assessed the prevalence of pfcrt, pfmdr-1, pfdhfr, and pfdhps mutations and the pfmdr-1 gene copy number in 1,596 P. falciparum isolates collected in 26 health centers (20 in Madagascar and 6 in the Comoros Islands) from 2006 to 2008. The in vitro responses to a panel of drugs by 373 of the parasite isolates were determined. The results showed (i) unusual profiles of chloroquine susceptibility in Madagascar, (ii) a rapid rise in the frequency of parasites with both the pfdhfr and the pfdhps mutations, (iii) the alarming emergence of the single pfdhfr 164L genotype, and (iv) the progressive loss of the most susceptible isolates to artemisinin derivatives. In the context of the implementation of the new national policy for the fight against malaria, continued surveillance for the detection of P. falciparum resistance in the future is required.

The spontaneous resolution of primary congenital glaucoma.

PURPOSE: To describe the ocular findings in a series of children with spontaneous resolution of primary congenital glaucoma (PCG). METHODS: The medical records of 356 patients with PCG were reviewed. Nine patients with spontaneous resolution of PCG were studied. Fourteen of 18 eyes possessed evidence of early glaucoma, were found to have normal intraocular pressures, and were clinically classified as having spontaneous resolution of PCG. None of the eyes with spontaneous resolution received surgery or any glaucoma medication. RESULTS: Spontaneous resolution of PCG in all nine patients was recognized after 4 months of age. At the time of diagnosis, large corneas were observed in all affected eyes and Haab's striae in 10 of 14 eyes. Intraocular pressures were normal in 14 eyes. In all 14 eyes, the anterior chambers were deep, the lenses were clear, and the angles were abnormal with the typical appearance of PCG. The eyes with spontaneous resolution of PCG possessed angle abnormalities that were less severe compared to three fellow eyes that required glaucoma treatments. CONCLUSION: The occurrence of spontaneous resolution of PCG in these patients is supported by objective clinical evidence. The explanation for this spontaneous resolution is unknown. Its mechanism could be related to continued postnatal development of the angle structures in eyes possessing milder angle abnormalities. The anterior segment findings in patients with spontaneous resolution of PCG are similar to those of patients with treated PCG, the intraocular pressures are normal, the optic nerve damage is stable, and the filtration angles possess mild or moderate abnormalities.

Assessment of the efficacy of antimalarial drugs recommended by the National Malaria Control Programme in Madagascar: up-dated baseline data from randomized and multi-site clinical trials.

BACKGROUND: In order to improve the monitoring of the antimalarial drug resistance in Madagascar, a new national network based on eight sentinel sites was set up. In 2006/2007, a multi-site randomized clinical trial was designed to assess the therapeutic efficacy of chloroquine (CQ), sulphadoxine-pyrimethamine (SP), amodiaquine (AQ) and artesunate plus amodiaquine combination (ASAQ), the antimalarial therapies recommended by the National Malaria Control Programme (NMCP). METHODS: Children between six months and 15 years of age, with uncomplicated falciparum malaria, were enrolled. Primary endpoints were the day-14 and day-28 risks of parasitological failure, either unadjusted or adjusted by genotyping. Risks of clinical and parasitological treatment failure after adjustment by genotyping were estimated using Kaplan-Meier survival analysis. Secondary outcomes included fever clearance, parasite clearance, change in haemoglobin levels between Day 0 and the last day of follow-up, and the incidence of adverse events. RESULTS: A total of 1,347 of 1,434 patients (93.9%) completed treatment and follow-up to day 28. All treatment regimens, except for the chloroquine (CQ) treatment group, resulted in clinical cure rates above 97.6% by day-14 and 96.7% by day-28 (adjusted by genotyping). Parasite and fever clearance was more rapid with artesunate plus amodiaquine, but the extent of haematological recovery on day-28 did not differ significantly between the four groups. No severe side-effects were observed during the follow-up period. CONCLUSION: These findings (i) constitute an up-dated baseline data on the efficacy of antimalarial drugs recommended by the NMCP, (ii) show that antimalarial drug resistance remains low in Madagascar, except for CQ, compared to the bordering countries in the Indian Ocean region such as the Comoros Archipelago and (iii) support the current policy of ASAQ as the first-line treatment in uncomplicated falciparum malaria.

A Method to Assess Fc-mediated Effector Functions Induced by Influenza Hemagglutinin Specific Antibodies.

Antibodies play a crucial role in coupling the innate and adaptive immune responses against viral pathogens through their antigen binding domains and Fc-regions. Here, we describe how to measure the activation of Fc effector functions by monoclonal antibodies targeting the influenza virus hemagglutinin with the use of a genetically engineered Jurkat cell line expressing an activating type 1 Fc-FcγR. Using this method, the contribution of specific Fc-FcγR interactions conferred by immunoglobulins can be determined using an in vitro assay.

Generation of Escape Variants of Neutralizing Influenza Virus Monoclonal Antibodies.

Influenza viruses exhibit a remarkable ability to adapt and evade the host immune response. One way is through antigenic changes that occur on the surface glycoproteins of the virus. The generation of escape variants is a powerful method in elucidating how viruses escape immune detection and in identifying critical residues required for antibody binding. Here, we describe a protocol on how to generate influenza A virus escape variants by utilizing human or murine monoclonal antibodies (mAbs) directed against the viral hemagglutinin (HA). With the use of our technique, we previously characterized critical residues required for the binding of antibodies targeting either the head or stalk of the novel avian H7N9 HA. The protocol can be easily adapted for other virus systems. Analyses of escape variants are important for modeling antigenic drift, determining single nucleotide polymorphisms (SNPs) conferring resistance and virus fitness, and in the designing of vaccines and/or therapeutics.

Alveolar macrophages are critical for broadly-reactive antibody-mediated protection against influenza A virus in mice.

The aim of candidate universal influenza vaccines is to provide broad protection against influenza A and B viruses. Studies have demonstrated that broadly reactive antibodies require Fc-Fc gamma receptor interactions for optimal protection; however, the innate effector cells responsible for mediating this protection remain largely unknown. Here, we examine the roles of alveolar macrophages, natural killer cells, and neutrophils in antibody-mediated protection. We demonstrate that alveolar macrophages play a dominant role in conferring protection provided by both broadly neutralizing and non-neutralizing antibodies in mice. Our data also reveal the potential mechanisms by which alveolar macrophages mediate protection in vivo, namely antibody-induced inflammation and antibody-dependent cellular phagocytosis. This study highlights the importance of innate effector cells in establishing a broad-spectrum antiviral state, as well as providing a better understanding of how multiple arms of the immune system cooperate to achieve an optimal antiviral response following influenza virus infection or immunization.Broadly reactive antibodies that recognize influenza A virus HA can be protective, but the mechanism is not completely understood. Here, He et al. show that the inflammatory response and phagocytosis mediated by the interaction between protective antibodies and macrophages are essential for protection.

Low autochtonous urban malaria in Antananarivo (Madagascar).

BACKGROUND: The study of urban malaria is an area undergoing rapid expansion, after many years of neglect. The problem of over-diagnosis of malaria, especially in low transmission settings including urban areas, is also receiving deserved attention. The primary objective of the present study was to assess the frequency of malaria among febrile outpatients seen in private and public primary care facilities of Antananarivo. The second aim was to determine, among the diagnosed malaria cases, the contribution of autochthonous urban malaria. METHODS: Two cross-sectional surveys in 43 health centres in Antananarivo in February 2003 (rainy season) and in July 2003 (dry season) were conducted. Consenting clinically suspected malaria patients with fever or history of fever in the past 48 hours were included. Malaria rapid diagnostic tests and microscopy were used to diagnose malaria. Basic information was collected from patients to try to identify the origin of the infection: autochthonous or introduced. RESULTS: In February, among 771 patients, 15 (1.9%) positive cases were detected. Three malaria parasites were implicated: Plasmodium. falciparum (n = 12), Plasmodium vivax (n = 2) and Plasmodium. ovale (n = 1). Only two cases, both P. falciparum, were likely to have been autochthonous (0.26%). In July, among 739 blood smears examined, 11 (1.5%) were positive: P. falciparum (n = 9) and P. vivax (n = 2). Three cases of P. falciparum malaria were considered to be of local origin (0.4%). CONCLUSION: This study demonstrates that malaria cases among febrile episodes are low in Antananarivo and autochthonous malaria cases exist but are rare.

Both Neutralizing and Non-Neutralizing Human H7N9 Influenza Vaccine-Induced Monoclonal Antibodies Confer Protection.

Pathogenic H7N9 avian influenza viruses continue to represent a public health concern, and several candidate vaccines are currently being developed. It is vital to assess if protective antibodies are induced following vaccination and to characterize the diversity of epitopes targeted. Here we characterized the binding and functional properties of twelve H7-reactive human antibodies induced by a candidate A/Anhui/1/2013 (H7N9) vaccine. Both neutralizing and non-neutralizing antibodies protected mice in vivo during passive transfer challenge experiments. Mapping the H7 hemagglutinin antigenic sites by generating escape mutant variants against the neutralizing antibodies identified unique epitopes on the head and stalk domains. Further, the broadly cross-reactive non-neutralizing antibodies generated in this study were protective through Fc-mediated effector cell recruitment. These findings reveal important properties of vaccine-induced antibodies and provide a better understanding of the human monoclonal antibody response to influenza in the context of vaccines.

Isolated subconjunctival hemorrhages in nonaccidental trauma.

PURPOSE: To establish child abuse as part of the differential diagnosis of isolated bilateral subconjunctival hemorrhages in infants. METHODS: To review three cases of nonaccident trauma initially presenting with isolated bilateral subconjunctival hemorrhages as the only significant clinical finding. RESULTS: Ophthalmic examination in cases 1 and 2 were entirely normal except for the large bilateral subconjunctival hemorrhages. Hematological parameters were normal in all three infants. Initial radiological findings were normal in case 1 but multiple healing rib fractures were identified when the chest X-ray was repeated 3 weeks later. Case 2 had skin and skeletal X-ray findings compatible with abuse at time of presentation to the ophthalmologist. Case 3 was admitted to hospital for multiple unexplained limb fractures but had been seen 2 weeks prior for poorly explained bilateral isolated subconjunctival hemorrhages and facial petechiae. CONCLUSION: Nonaccidental trauma should be considered in the differential diagnosis of bilateral isolated subconjunctival hemorrhages in infants especially if associated with facial petechiae. These isolated subconjunctival hemorrhages may be part of the traumatic asphyxia syndrome caused by severe, prolonged compression of the child's chest and upper abdomen. Appropriate assessment includes a complete ophthalmic and pediatric examination as well as hematological testing and imaging studies. If the coagulation profile and initial imaging studies are normal yet there remains a high suspicion of abuse, an immediate nuclear scan or a repeat skeletal survey or chest film 2 weeks later is indicated.