NANOBODY® Molecule, a Giga Medical Tool in Nanodimensions

Although antibodies remain the most widely used tool for biomedical research, antibody technology is not flawless. Innovative alternatives, such as Nanobody® molecules, were developed to address the shortcomings of conventional antibodies. Nanobody® molecules are antigen-binding variable-domain fragments derived from the heavy-chain-only antibodies of camelids (VHH) and combine the advantageous properties of small molecules and monoclonal antibodies. Nanobody® molecules present a small size (~15 kDa, 4 nm long and 2.5 nm wide), high solubility, stability, specificity, and affinity, ease of cloning, and thermal and chemical resistance. Recombinant production in microorganisms is cost-effective, and VHH are also building blocks for multidomain constructs. These unique features led to numerous applications in fundamental research, diagnostics, and therapy. Nanobody® molecules are employed as biomarker probes and, when fused to radioisotopes or fluorophores, represent ideal non-invasive in vivo imaging agents. They can be used as neutralizing agents, receptor-ligand antagonists, or in targeted vehicle-based drug therapy. As early as 2018, the first Nanobody®, Cablivi (caplacizumab), a single-domain antibody (sdAb) drug developed by French pharmaceutical giant Sanofi for the treatment of adult patients with acquired thrombocytopenic purpura (aTTP), was launched. Nanobody® compounds are ideal tools for further development in clinics for diagnostic and therapeutic purposes.

Transferring With TACT: A Novel Tool to Standardize Transfer Decisions From a Level IV NICU

BACKGROUND

Neonatal patients who no longer require level IV neonatal intensive care unit care are transferred to less acute levels of care. Standardized assessment tools have been shown to be beneficial in the transfer of patient care. However, no standardized tools were available to assist neonatal providers in the assessment and communication of the infants needs at transfer.

PURPOSE

The purpose was to develop a Transfer Assessment and Communication Tool (TACT) that guides provider decision making in the transfer of infants from a level IV neonatal intensive care unit to a less acute level of care within a regionalized healthcare system.

METHODS

Phase 1 included developing the first draft of the TACT using retrospective data, known variables from published literature, and study team expertise. In phase 2, the final draft of the TACT was created through feedback from expert neonatal providers in the regionalized care system using e-Delphi methodology.

RESULTS

The first draft of the TACT, developed in phase 1, included 36 characteristics. In phase 2, nurses, nurse practitioners, and physician experts representing all levels of newborn care participated in 4 e-Delphi surveys to develop the final draft of the TACT, which included 74 weighted characteristics.

IMPLICATIONS FOR PRACTICE AND RESEARCH

Potential benefits of the TACT include improved communication across healthcare teams, reduced risk for readmission, and increased caregiver visitation. The next steps are to validate the TACT for use either retrospectively or in real time, including characteristic weights, before implementation of this tool in the clinical setting.

Ethnographies of the super-rich

Rosita Armytage. 2020. Big capital in an unequal world: The micropolitics of wealth in Pakistan. London: Berghahn Books.

Ashley Mears. 2020. Very important people: Status and beauty in the global party circuit. New York: Princeton University Press.

Trigeminal endonasal perception - an outcome predictor for septoplasty

BACKGROUND

No adequate test exists to predict outcome after septoplasty. Despite adequate surgery, patients still might experience nasal breathing impairment. The aim of this study was to determine if pre-operative trigeminal sensitivity can predict satisfaction after septoplasty.

METHODS

Single centre prospective cohort study in tertiary referral centre with follow-up time of 6 weeks postoperatively. Patients scheduled for septoplasty or septorhinoplasty with turbinoplasty were consecutively selected the day before surgery. Standard preoperative examinations (acoustic rhinometry and Sniffin’ Sticks 12 test), the evaluation of nasal obstruction on a visual analogue scale (VAS) and the trigeminal lateralisation task were performed before and 6 weeks after surgery. Biopsies were taken during surgery and TRPV1 mRNA expression was measured by PCR.

RESULTS

Thirty patients were included with a median age of 29 years and equal gender distribution. Trigeminal perception and sensation of nasal obstruction showed a significant correlation: preoperative lateralisation test scores, representing endonasal trigeminal sensitivity, correlated significantly with the mean VAS change scores, which demonstrate subjective improvement. A lateralisation test score of 31.5 and more had a sensitivity of 88% to predict an improvement of more than 3 VAS points. Additionally, high TRPV1 mRNA expression was linked with good postoperative VAS scores.

CONCLUSION

The preoperative evaluation of the trigeminal sensitivity could improve patients’ selection for septoplasty with a higher rate of satisfaction. Endonasal trigeminal sensitivity is directly linked with subjective outcome. Therefore, patients with low trigeminal sensitivity should undergo septoplasty only after thorough counselling.

Open rhinoplasty using a columellar strut: effects of the graft on nasal tip projection and rotation

BACKGROUND

Despite the discordance in the literature concerning the effect of columellar strut grafts on nasal tip rotation, this method is often used when an increase in nasolabial angle or nasal tip projection is desired.

OBJECTIVES

We aimed to elucidate the change in nasolabial angles and nasal tip projections after exclusive columellar strut graft implantations and in addition to other surgical steps. Furthermore, differences in these parameters between patients with conchal and septal columellar strut grafts were investigated.

METHODS

A monocentric retrospective cohort study of 173 open septorhinoplasties with columellar strut graft technique, between 2006 and 2016, was conducted. The pre- and postoperative nasal tip projection, nasolabial and nasofrontal angle and interalar distance were determined and the Goode-ratio was calculated.

RESULTS

In cases where uprotation was not specifically desired, neither nasolabial angles nor tip projections changed significantly, irrespective of whether a columellar strut graft was used alone or with additional surgical steps. If an uprotation through surgery was desired, a significant mean increase in nasolabial angle of 4.4° was achieved. Furthermore, conchal instead of septal columellar strut grafts showed significantly better results.

CONCLUSION

In our study, a columellar strut graft-without any additional surgical step-does only have an improving impact on nasal tip rotations and projections, if specifically intended to by the surgeon. In other words, if the strut graft was not chosen for an uprotational intention, it did not relevantly impact on the nasolabial angle or nasal tip projection. However, in patients where an uprotation is desired, the columellar strut graft still represents a meaningful tool. Since conchal instead of septal columellar strut grafts showed better results, we suggest using them for these patients.

LEVEL OF EVIDENCE

2b.

Lymphocytic choriomeningitis virus infection induced by percutaneous exposure

We report a case of acquired lymphocytic choriomeningitis virus (LCMV) infection due to an accidental percutaneous inoculation of LCMV at work. The injured worker developed a flu-like syndrome, followed by pericarditis and meningoencephalitis. Seroconversion was confirmed by ELISA. The patient made a complete recovery. We review measures undertaken to prevent a similar event and propose a follow-up protocol in the event of accidental LCMV exposure.

Precision Measurement of the (e^{+}+e^{-}) Flux in Primary Cosmic Rays from 0.5 GeV to 1 TeV with the Alpha Magnetic Spectrometer on the International Space Station

We present a measurement of the cosmic ray (e^{+}+e^{-}) flux in the range 0.5 GeV to 1 TeV based on the analysis of 10.6 million (e^{+}+e^{-}) events collected by AMS. The statistics and the resolution of AMS provide a precision measurement of the flux. The flux is smooth and reveals new and distinct information. Above 30.2 GeV, the flux can be described by a single power law with a spectral index γ=-3.170±0.008(stat+syst)±0.008(energy scale).

Electron and positron fluxes in primary cosmic rays measured with the alpha magnetic spectrometer on the international space station

Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at ∼30  GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index. The determination of the differing behavior of the spectral indices versus energy is a new observation and provides important information on the origins of cosmic-ray electrons and positrons.

High statistics measurement of the positron fraction in primary cosmic rays of 0.5-500 GeV with the alpha magnetic spectrometer on the international space station

A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200  GeV the positron fraction no longer exhibits an increase with energy.

Nuclear magnetization in gallium arsenide quantum dots at zero magnetic field

Optical and electrical control of the nuclear spin system allows enhancing the sensitivity of NMR applications and spin-based information storage and processing. Dynamic nuclear polarization in semiconductors is commonly achieved in the presence of a stabilizing external magnetic field. Here we report efficient optical pumping of nuclear spins at zero magnetic field in strain-free GaAs quantum dots. The strong interaction of a single, optically injected electron spin with the nuclear spins acts as a stabilizing, effective magnetic field (Knight field) on the nuclei. We optically tune the Knight field amplitude and direction. In combination with a small transverse magnetic field, we are able to control the longitudinal and transverse components of the nuclear spin polarization in the absence of lattice strain--that is, in dots with strongly reduced static nuclear quadrupole effects, as reproduced by our model calculations.

P2-14-05: Racial Differences in the Use of Adjuvant Chemotherapy for Breast Cancer in a Large Urban Integrated Health System

Background: Despite improvements in breast cancer treatment, there continues to be a gap in survival between African American (AA) and White women with breast cancer, which may be due at least in part to racial differences in the patterns of care. In order to better understand breast cancer survival disparities, we evaluated racial differences in the receipt of adjuvant chemotherapy among women treated at a large integrated health care system in Southeastern Michigan. Materials and Methods: The study population included 2,234 women (33 % AA) with stage I through III breast cancer treated at the Henry Ford Health System (HFHS) from 1996 through 2005. Linked datasets from the HFHS, the Metropolitan Detroit Cancer Surveillance System (MDCSS) and the U.S. Census Bureau were used to obtain sociodemographic and clinical information. Co-morbidity was assessed by the Charlson co-morbidity index (CCI), and economic deprivation was categorized using a neighborhood deprivation index (DI). Results: AA women were significantly more likely than Whites to have larger tumors (40% vs. 31% > 2 cm), as well as more aggressive tumors (29% vs 19% estrogen and progesterone negative). AA women were also significantly more likely than Whites to have other co-morbid conditions (15 % vs. 8% with a CCI of 2+) and to reside in a more economically deprived area (45% vs. 5% reside in the most deprived area). While AA women were more likely to receive adjuvant chemotherapy (47% vs. 43%, p=0.0278), they were also more likely to have a delay in initiation of treatment (57% vs 45% delayed beyond 60 days from diagnosis, p=0.0004). After multivariable adjustment for age, DI, CCI, insurance and surgery, there were no racial differences in treatment delay (Odds Ratio 1.20, 95% confidence interval, 0.82−1.77). Discussion: In a large urban integrated health care system, racial differences in the delay in receipt of adjuvant chemotherapy for breast cancer can be explained by clinical and socioeconomic characteristics.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-14-05.

Dark-bright mixing of interband transitions in symmetric semiconductor quantum dots

In photoluminescence spectra of symmetric [111] grown GaAs/AlGaAs quantum dots in longitudinal magnetic fields applied along the growth axis, we observe in addition to the expected bright states also nominally dark transitions for both charged and neutral excitons. We uncover a strongly nonmonotonic, sign-changing field dependence of the bright neutral exciton splitting resulting from the interplay between exchange and Zeeman effects. Our theory shows quantitatively that these surprising experimental results are due to magnetic-field-induced ±3/2 heavy-hole mixing, an inherent property of systems with C(3v) point-group symmetry.

Difficidin and bacilysin produced by plant-associated Bacillus amyloliquefaciens are efficient in controlling fire blight disease

Representatives of Bacillus amyloliquefaciens were shown to possess biocontrol activity against fire blight, a serious disease of orchard trees caused by Erwinia amylovora. Genome analysis of B. amyloliquefaciens FZB42 identified gene clusters responsible for synthesis of several polyketide compounds with antibacterial action. We show here that the antibacterial polyketides difficidin and to a minor extent bacillaene act efficiently against E. amylovora. Surprisingly, a mutant strain blocked in the production of difficidin (CH8 Deltadfn) inhibited growth of E. amylovora and suppressed fire blight disease nearly in the same range as the wild type. In addition, a sfp mutant (CH3 Deltasfp) unable to synthesize non-ribosomally lipopeptides and polyketides did still suppress growth of E. amylovora, suggesting that besides action of polyketides another antagonistic principle exist. A double mutant (RS06 Deltasfp Deltabac) devoid in polyketide and bacilysin synthesis was unable to suppress growth of E. amylovora indicating that the additional inhibitory effect is due to production of bacilysin, a dipeptide whose synthesis does not depend on Sfp. We propose to use B. amyloliquefaciens strains with enhanced synthesis of difficidin and/or bacilysin for development of biocontrol agents efficient against fire blight disease.

Prospective multicenter study of bronchiolitis: predicting safe discharges from the emergency department

OBJECTIVE

Bronchiolitis is the leading cause of hospitalization for infants. Our objective was to identify factors associated with safe discharge to home from the emergency department.

METHODS

We conducted a prospective cohort study during 2 consecutive bronchiolitis seasons, from 2004 to 2006. Thirty US emergency departments contributed data. All patients were < 2 years of age and had a final emergency department attending physician diagnosis of bronchiolitis. Using multivariate logistic regression, a low-risk model was developed with a random half of the data and then validated with the other half.

RESULTS

Of 1456 enrolled patients, 837 (57%) were discharged home from the emergency department. The following factors predicted safe discharge to home: age of > or = 2 months, no history of intubation, a history of eczema, age-specific respiratory rates (< 45 breaths per minute for 0-1.9 months, < 43 breaths per minute for 2-5.9 months, and < 40 breaths per minute for 6-23.9 months), no/mild retractions, initial oxygen saturation of > or = 94%, fewer albuterol or epinephrine treatments in the first hour, and adequate oral intake. The importance of each factor varied slightly according to age, but the comprehensive model (developed and validated for all children < 2 years of age) yielded an area under the receiver operating characteristic curve of 0.81, with a good fit of the data.

CONCLUSIONS

This large multicenter study of children presenting to the emergency department with bronchiolitis identified several factors associated with safe discharge, including cut points for respiratory rate and oxygen saturation. Although the low-risk model requires further study, we believe that it will assist clinicians evaluating children with bronchiolitis and may help reduce some unnecessary hospitalizations.

Evaluation of compliance with palivizumab recommendations in a multicenter study of young children presenting to the emergency department with bronchiolitis

OBJECTIVE

Monthly palivizumab injections from November to March decrease risk of respiratory syncytial virus (RSV)-related hospitalization during RSV season in high-risk infants born less than 35 weeks of gestation. Our objective was to investigate compliance with the American Academy of Pediatrics (AAP) recommendations for palivizumab prophylaxis among children who present to the emergency department (ED) with bronchiolitis.

METHODS

Seventeen centers, from 9 US states, performed a prospective, observational study of ED patients less than 2 years with an attending physician diagnosis of bronchiolitis. Researchers conducted a structured interview, followed by a chart review, and a 2-week follow-up phone call.

RESULTS

Of 825 eligible children, 624 (73%) were enrolled. According to AAP recommendations, 35 children (6%) should have received palivizumab, but only 17 (49%; 95% confidence interval, 31%-66%) did. Prophylaxis with palivizumab did not differ by US region (P > 0.50). The ED clinical presentations were similar when comparing those children that did and did not receive prophylaxis (all P > 0.27). Those receiving palivizumab were more likely to come to the ED using systemic corticosteroids (22% vs 7%; P = 0.003) and to be treated with corticosteroids in the ED (31% vs 15%; P = 0.02). The 2 groups were at similar risk of hospitalization (52% vs 39%; P = 0.11).

CONCLUSIONS

According to parental report, only half of children presenting to the ED with bronchiolitis who met AAP criteria for palivizumab prophylaxis received this monoclonal antibody. Emergency department visits provide an untapped opportunity for staff to educate families and communicate with PCPs about RSV prophylaxis.

Regulated expression of microinjected DNA in adult Aedes aegypti mosquitoes

We have developed a novel molecular genetic approach to investigating gene regulation in adult mosquitoes called whole body transfection (WBT). This DNA microinjection method allows for both constitutive and regulated expression of plasmid vectors in the fat body and midgut of adult mosquitoes within 24 h of injection. Using a luciferase reporter gene containing the Aedes aegypti heat shock protein 70 (Hsp70) promoter, we optimized the WBT protocol at various times post-injection and used these parameters to measure the expression of a vitellogenin-luciferase reporter gene in response to blood meal feeding. These studies showed that a 843 bp fragment of the Ae. aegypti vitellogenin-C (VgC) promoter caused a greater than 200-fold induction of luciferase activity in a strict tissue-specific manner, and only in response to feeding. Functional mapping of the VgC promoter by WBT identified essential upstream regulatory elements in the region spanning -780 to -182 bp from the transcriptional start site. We also constructed a lipopolysaccharide-regulated expression vector using a 1096 bp genomic fragment of the Ae. aegypti cecropin B (CecB) promoter. Our data show that four days after WBT injection, the CecB-luciferase reporter gene could be induced more than 100-fold in the fat body following lipopolysaccharide injection. Moreover, we found that lipopolysaccharide-induction of the CecB reporter gene occurred up to 28 days post-WBT injection. These data suggest that WBT could provide a novel strategy to express recombinant proteins and RNAi constructs in adult mosquitoes using conventional microinjection methods.

Association between Method of Delivery and Puerperal Infectious Complications in the Perinatal Database of Baden-Württemberg 1998–2001

The strongest argument against caesarean delivery relates to maternal complications. Evidence supporting this for elective operations is controversial. The perinatal database 1998-2001 of the German state of Baden-Württemberg was studied to assess the maternal obstetrical risk associated with caesarean delivery with regard to puerperal infectious complications. For statistical analysis the chi2 test, Fisher's exact test, Mantel-Haenszel statistics and relative risks were used to describe the risk of exposure. Surgical delivery was associated with a significantly higher risk of infectious disorders (p < 0.0001). There was a significantly higher risk of septicaemia in the group undergoing caesarean compared to vaginal delivery (p < 0.0001), for pregnancies with and without risk factors of infection, and also for caesarean delivery prior to labour and rupture of membranes (ROM) and singleton gestations (RR 8.56; 95% CI 4.4-16.65, stratum without risks). The rate of wound disorders was found to be significantly increased in the case of surgical delivery (p < 0.0001). After exclusion of pregnancies with risk factors for infectious complications and multi-fetal gestation, a significantly higher risk was also found for caesarean delivery prior to labour and ROM versus vaginal delivery (RR 16.97; 95% CI 14.16-20.34). Caesarean delivery significantly increased the likelihood that a woman would experience fever in puerperium (p < 0.0001), for pregnancies with and without ante- or perinatal risk factors for infectious complications, and also when caesarean delivery prior to labour and ROM and singletons in the cephalic presentation were considered separately (RR 11.03; 95% CI 9.39-12.96; stratum without risks). Considering the obstetrical challenge of how more women can deliver with fewer complications, reducing unnecessary caesarean delivery still seems to be an appropriate approach.

Mütterliche Anämie post partum - Entwicklungstendenzen und Variabilität unter Berücksichtigung unterschiedlicher Klinikkategorien

BACKGROUND

Postpartum anaemia continues to be the most common puerperal complication in Germany. Interest, however, increases in maternal quality of life after delivery and with regard to scarce resources in the costs associated with anaemia.

MATERIAL AND METHODS

With this background, perinatal survey data of Baden-Wurttemberg 1998 - 2003 (566,920 pregnancies) were studied regarding development and variability of anaemia in pregnancy and puerperium.

RESULTS

The anaemia rate post-partum increased from 1998 to 2003 (1998 12.2 %, 2003 15.6 %). This is a significant trend. The category of small hospital departments, however, had lower rates in 2003 than in 1998. Significant differences exist between the rates of the hospital categories. High-volume departments show the highest rate (e. g., 2003: hospital departments > 1000 deliveries per year 23.2 %, consultant departments < 500 deliveries per year 9.4 %). The differences existed throughout the observed period and remained significant when all pregnancies with risk factors associated with higher blood loss were not taken into account and methods of delivery were considered separately. In 2003, anaemia during pregnancy, up to then documented for less then 2 % of the pregnancies, showed a much higher rate (e. g., high-volume departments: 6-fold higher than in 2002).

DISCUSSION

Many factors may contribute to these differences, including aspects of obstetrical management, volume-outcome associations, and documentation.

CONCLUSIONS

Reducing interhospital variability includes the option of reducing anaemia rates post-partum. Analysis and reflection of these results within the departments may suggest strategic changes concerning prevention, therapy, obstetric management, and workload as well as documentation habits.

Infection of dendritic cells by lymphocytic choriomeningitis virus

Dendritic cells (DCs) comprise the major antigen-presenting cells (APCs) of the host, uniquely programmed to stimulate immunologically naïve T lymphocytes. Viruses that can target and disorder the function of these cells enjoy a selective advantage. The cellular receptor for lymphocytic choriomeningitis virus (LCMV), Lassa fever virus (LFV), and several other arenaviruses is alpha-dystroglycan (alpha-DG). Among cells of the immune system, CD11c+ and DEC-205+ DCs primarily and preferentially express alpha-DG. By selection, strains and variants of LCMV generated as quasi-species that bind alpha-DG with high affinity replicate in the majority of CD11c+ and DEC-205+ (>75%) DCs, causing a generalized immunosuppression, and establish a persistent infection. In contrast, viral strains and variants that bind with low affinity to alpha-DG display minimal replication in CD11c+ and DEC-205+ DCs (<10%), rarely replicate in the white pulp, and generate a robust anti-LCMV CTL response that clears the virus infection. Hence, receptor-virus interaction on DCs in vivo is an essential step in the initiation of virus-induced immunosuppression and viral persistence. Investigation into the mechanism of how virus-infected DCs cause immunosuppression reveals loss of MHC class II surface expression and costimulatory molecules on surface of such DCs. As a consequence DCs are unable to act as APCs, initiate immune responses, and have a defect in migration into the T cell area. These data indicate that LCMV infection influences DC maturation and migration, leading to decreased T cell stimulatory capacity of DCs, events essential for the initiation of immune responses. Because several other viruses known to cause immunosuppression (HIV, measles) interact with DCs, the observations noted here are likely a common selective mechanism by which viruses also are able to evade the host's immune system.

Stress responsivity and socioeconomic status: a mechanism for increased cardiovascular disease risk?

AIMS

Low socioeconomic status is associated with increased cardiovascular disease risk. We hypothesized that psychobiological pathways, specifically slow recovery in blood pressure and heart rate variability following mental stress, partly mediate social inequalities in risk.

METHODS AND RESULTS

Participants were 123 men and 105 women in good health aged 47-58 years drawn from the Whitehall II cohort of British civil servants. Grade of employment was the indicator of socioeconomic status. Cardiovascular measures were monitored during performance of two behavioural tasks, and for 45 min following stress. Post-stress return of blood pressure and heart rate variability to resting levels was less complete after 45 min in the medium and low than in the high grade of employment groups. The odds of failure to return to baseline by 45 min in the low relative to the high grade of employment groups were 2.60 (95% CI 1.20-5.65) and 3.85 (1.48-10.0) for systolic and diastolic pressure, respectively, and 5.19 (1.88-18.6) for heart rate variability, adjusted for sex, age, baseline levels and reactions to tasks. Subjective ratings of task difficulty, involvement and stress did not differ by socioeconomic status.

CONCLUSIONS

Lower socioeconomic status is associated with delayed recovery in cardiovascular function after mental stress. Impaired recovery may reflect heightened allostatic load, and constitute a mechanism through which low socioeconomic status enhances cardiovascular disease risk.

Molecular analysis of the interaction of LCMV with its cellular receptor [alpha]-dystroglycan

alpha-Dystroglycan (DG) has been identified as the cellular receptor for lymphocytic choriomeningitis virus (LCMV) and Lassa fever virus (LFV). This subunit of DG is a highly versatile cell surface molecule that provides a molecular link between the extracellular matrix (ECM) and a beta-DG transmembrane component, which interacts with the actin-based cytoskeleton. In addition, DG exhibits a complex pattern of interaction with a wide variety of ECM and cellular proteins. In the present study, we characterized the binding of LCMV to alpha-DG and addressed the role of alpha-DG-associated host-derived proteins in virus infection. We found that the COOH-terminal region of alpha-DG's first globular domain and the NH2-terminal region of the mucin-related structures of alpha-DG together form the binding site for LCMV. The virus-alpha-DG binding unlike ECM alpha-DG interactions was not dependent on divalent cations. Despite such differences in binding, LCMV and laminin-1 use, in part, an overlapping binding site on alpha-DG, and the ability of an LCMV isolate to compete with laminin-1 for receptor binding is determined by its binding affinity to alpha-DG. This competition of the virus with ECM molecules for receptor binding likely explains the recently found correlation between the affinity of LCMV binding to alpha-DG, tissue tropism, and pathological potential. LCMV strains and variants with high binding affinity to alpha-DG but not low affinity binders are able to infect CD11c+ dendritic cells, which express alpha-DG at their surface. Infection followed by dysfunction of these antigen-presenting cells contributes to immunosuppression and persistent viral infection in vivo.