Cytomegalovirus infection and antibody protection of the developing placenta

Long-term outcomes of congenital cytomegalovirus infection in children early identified by extended hearing-targeted screening

OBJECTIVES

Congenital Cytomegalovirus (cCMV) has been associated with hearing, vision, and neurodevelopmental long-term sequelae. Despite the social burden associated with the disease, a universally accepted consensus on screening, diagnostic, therapeutic and follow-up approaches has not been reached. The present observational retrospective study aims at describing long-term sequelae and radiological abnormalities associated with cCMV in children early identified by extended hearing-targeted screening and evaluated by audiological follow-up in a single III Level Audiological Referral Center for at least 2 years.

METHODS

Audiological neonatal and follow-up data were available for all subjects. Data collection included clinical neonatal and virological assessment at birth. Ophthalmological, neurodevelopmental and neuroradiological follow-up abnormalities compatible with cCMV sequelae were collected by clinical reports. Spearman's rank correlation coefficient (rho-ρ) was used to evaluate possible correlations among the considered parameters.

RESULTS

61 newborns were identified by extended hearing-targeted cCMV screening and diagnosed mostly (83.6 %) by PCR viral DNA extraction in urine collected within the 15° day of life. Seventeen babies were born preterm, with a mean gestational age of 33.5 weeks. Sixteen patients (26.2 %) were admitted to an Intensive or sub-Intensive Neonatal Care Unit. At birth, 35 newborns were symptomatic (57.3 %), and 19 of them received antiviral treatment by valganciclovir or ganciclovir. Overall, 20 children (32.7 %) were diagnosed with sensorineural hearing loss (SNHL), among them 17 (85 %) were refer at the newborn hearing screening while 3 (15 %) were Pass. 5/20 children (25 %) presented isolated SNHL, while in 15/20 (75 %) children SNHL was associated to other long-term sequelae. In 5 patients (25 %) a progression of the hearing threshold was observed, with a mean age of progression of 26 months of age. Risk factors for progression were a worse final hearing threshold (Spearman's ρ = 0.434; p = 0.0001) and a worse hearing threshold at birth (Spearman's ρ = 0.298; p = 0.020). Thirteen children were fitted with hearing aids, 8 of whom subsequently underwent cochlear implantation. Concerning long term impairments, 10/61 children (17 %) presented a variety of ophthalmological sequelae, while 16/40 cCMV patients (40 %) were diagnosed with neurodevelopmental abnormalities. Language delays were significantly associated with a worse hearing threshold (ρ = 0.582; p = 0.0001) and with other neurocognitive abnormalities (ρ = 0.677, p = 0.0001). 30 children underwent radiological brain evaluation by Magnetic Resonance Imaging, and 63.3 % of them presented abnormalities compatible with cCMV. Mean viral load at birth did not show significant associations with long-term sequelae.

CONCLUSIONS

The study highlights the diverse and significant long-term sequelae of cCMV infection detected through early screening. With a significant proportion of cCMV children developing sensorineural hearing loss, ophthalmological and neurodevelopmental issues, the results emphasize the importance of continuous, multidisciplinary follow-up. Early identification and tailored interventions are crucial for improving the long-term health and quality of life of children affected by cCMV.

Safety and Efficacy of Antiviral Drugs and Vaccines in Pregnant Women: Insights from Physiologically Based Pharmacokinetic Modeling and Integration of Viral Infection Dynamics

Addressing the complexities of managing viral infections during pregnancy is essential for informed medical decision-making. This comprehensive review delves into the management of key viral infections impacting pregnant women, namely Human Immunodeficiency Virus (HIV), Hepatitis B Virus/Hepatitis C Virus (HBV/HCV), Influenza, Cytomegalovirus (CMV), and SARS-CoV-2 (COVID-19). We evaluate the safety and efficacy profiles of antiviral treatments for each infection, while also exploring innovative avenues such as gene vaccines and their potential in mitigating viral threats during pregnancy. Additionally, the review examines strategies to overcome challenges, encompassing prophylactic and therapeutic vaccine research, regulatory considerations, and safety protocols. Utilizing advanced methodologies, including PBPK modeling, machine learning, artificial intelligence, and causal inference, we can amplify our comprehension and decision-making capabilities in this intricate domain. This narrative review aims to shed light on diverse approaches and ongoing advancements, this review aims to foster progress in antiviral therapy for pregnant women, improving maternal and fetal health outcomes.

Molecular Mechanisms of ZIKV-Induced Teratogenesis: A Systematic Review of Studies in Animal Models

Zika virus (ZIKV) is a teratogen that causes congenital anomalies, being linked to microcephaly in children exposed during pregnancy. Animal studies have been conducted to investigate the molecular mechanisms related to ZIKV teratogenesis. Although animal models can mimic the effects of ZIKV in human embryo development, few in vivo studies have addressed molecular changes following ZIKV infection in embryos. Moreover, few literature reviews have been conducted with these studies. The aim of this systematic review is to evaluate the molecular mechanisms of ZIKV teratogenesis determined from studies in animal models. PubMed/MEDLINE, EMBASE, Web of Science, and Scopus as well as grey literature were searched for studies that evaluated molecular alterations related to ZIKV teratogenesis which occurred during embryonic development. Nine studies were included: six with mice, one with mice and guinea pigs, one with pigs and one with chickens. In general, studies presented an unclear or high risk of bias for methodological criteria. Most of studies reported embryos exposed to ZIKV presenting microcephaly, reduced cortex thickness, and growth restriction. Different techniques were used to evaluated molecular changes in the animals following ZIKV infection: RNA sequencing, RT-qPCR, and in situ hybridization. It was found that common pathways are changed in most studies, being pathways related to immune response upregulated and those involved to neurodevelopment downregulated.

Pregnancy and viral infections: Mechanisms of fetal damage, diagnosis and prevention of neonatal adverse outcomes from cytomegalovirus to SARS-CoV-2 and Zika virus

Some maternal infections, contracted before or during pregnancy, can be transmitted to the fetus, during gestation (congenital infection), during labor and childbirth (perinatal infection) and through breastfeeding (postnatal infection). The agents responsible for these infections can be viruses, bacteria, protozoa, fungi. Among the viruses most frequently responsible for congenital infections are Cytomegalovirus (CMV), Herpes simplex 1–2, Herpes virus 6, Varicella zoster. Moreover Hepatitis B and C virus, HIV, Parvovirus B19 and non-polio Enteroviruses when contracted during pregnancy may involve the fetus or newborn at birth. Recently, new viruses have emerged, SARS-Cov-2 and Zika virus, of which we do not yet fully know the characteristics and pathogenic power when contracted during pregnancy.

Viral infections in pregnancy can damage the fetus (spontaneous abortion, fetal death, intrauterine growth retardation) or the newborn (congenital anomalies, organ diseases with sequelae of different severity). Some risk factors specifically influence the incidence of transmission to the fetus: the timing of the infection in pregnancy, the order of the infection, primary or reinfection or chronic, the duration of membrane rupture, type of delivery, socio-economic conditions and breastfeeding. Frequently infected neonates, symptomatic at birth, have worse outcomes than asymptomatic. Many asymptomatic babies develop long term neurosensory outcomes.

The way in which the virus interacts with the maternal immune system, the maternal-fetal interface and the placenta explain these results and also the differences that are observed from time to time in the fetal‑neonatal outcomes of maternal infections. The maternal immune system undergoes functional adaptation during pregnancy, once thought as physiological immunosuppression. This adaptation, crucial for generating a balance between maternal immunity and fetus, is necessary to promote and support the pregnancy itself and the growth of the fetus. When this adaptation is upset by the viral infection, the balance is broken, and the infection can spread and lead to the adverse outcomes previously described. In this review we will describe the main viral harmful infections in pregnancy and the potential mechanisms of the damages on the fetus and newborn.

Receptors in host pathogen interactions between human cytomegalovirus and the placenta during congenital infection

Cellular receptors in human cytomegalovirus (HCMV) mother to child transmission play an important role in congenital infection. Placental trophoblast cells are a significant cell type in placental development, placental functional processes, and in HCMV transmission. Different cells within the placental floating and chorionic villi present alternate receptors for HCMV cell entry. Syncytiotrophoblasts present neonatal Fc receptors that bind and transport circulating maternal immunoglobulin G across the placental interface which can also be bound to HCMV virions, facilitating viral entry into the placenta and foetal circulation. Cytotrophoblast express HCMV receptors including integrin-α1β1, integrin-αVβ3, epidermal growth factor receptor and platelet-derived growth factor receptor alpha. The latter interacts with HCMV glycoprotein-H, glycoprotein-L and glycoprotein-O (gH/gL/gO) trimers (predominantly in placental fibroblasts) and the gH/gL/pUL128, UL130-UL131A pentameric complex in other placental cell types. The pentameric complex allows viral tropism of placental trophoblasts, endothelial cells, epithelial cells, leukocytes and monocytes. This review outlines HCMV ligands and target receptor proteins in congenital HCMV infection.

Association of human cytomegalovirus (HCMV) neutralizing antibodies with antibodies to the HCMV glycoprotein complexes

Background

Human cytomegalovirus (HCMV) causes asymptomatic infections, but also causes congenital infections when women were infected with HCMV during pregnancy, and life-threatening diseases in immunocompromised patients. To better understand the mechanism of the neutralization activity against HCMV, the association of HCMV NT antibody titers was assessed with the antibody titers against each glycoprotein complex (gc) of HCMV.

Methods

Sera collected from 78 healthy adult volunteers were used. HCMV Merlin strain and HCMV clinical isolate strain 1612 were used in the NT assay with the plaque reduction assay, in which both the MRC-5 fibroblasts cells and the RPE-1 epithelial cells were used. Glycoprotein complex of gB, gH/gL complexes (gH/gL/gO and gH/gL/UL128–131A [PC]) and gM/gN were selected as target glycoproteins. 293FT cells expressed with gB, gM/gN, gH/gL/gO, or PC, were prepared and used for the measurement of the antibody titers against each gc in an indirect immunofluorescence assay (IIFA). The correlation between the IIFA titers to each gc and the HCMV-NT titers was evaluated.

Results

There were no significant correlations between gB-specific IIFA titers and the HCMV-NT titers in epithelial cells or between gM/gN complex-specific IIFA titers and the HCMV-NT titers. On the other hand, there was a statistically significant positive correlation between the IIFA titers to gH/gL complexes and HCMV-NT titers.

Conclusions

The data suggest that the gH/gL complexes might be the major target to induce NT activity against HCMV.

Seroprevalence of Human Cytomegalovirus in Pregnant Women in the Asir Region, Kingdom of Saudi Arabia

BACKGROUND

Human cytomegalovirus (HCMV) infection spreads easily by interpersonal contact.

OBJECTIVE

This study determined the prevalence of seropositivity of cytomegalovirus immunoglobulin G (IgG) in the Asir Region, Kingdom of Saudi Arabia.

METHODS

The study evaluated the seropositivity for cytomegalovirus-specific IgG in 460 females. Collected samples were processed and tested using enzyme-linked immunosorbent assay and specific HCMV IgG.

RESULTS

The study showed that all the respondents aged 15-20 years were seropositive for the HCMV. HCMV seropositive status was recorded in 99.2% of the older patients (>40 years of age). In the remaining age groups, the rate of seropositivity ranged from 95.7 (age range 20-25 years) to 98.9% (age range 30 years).

CONCLUSIONS

In all age groups of females tested, the prevalence of seropositive for HCMV was high, i.e., in the range of 95.7-100%.

Immune Correlates of Protection Against Human Cytomegalovirus Acquisition, Replication, and Disease

Human cytomegalovirus (HCMV) is the most common infectious cause of infant birth defects and an etiology of significant morbidity and mortality in solid organ and hematopoietic stem cell transplant recipients. There is tremendous interest in developing a vaccine or immunotherapeutic to reduce the burden of HCMV-associated disease, yet after nearly a half-century of research and development in this field we remain without such an intervention. Defining immune correlates of protection is a process that enables targeted vaccine/immunotherapeutic discovery and informed evaluation of clinical performance. Outcomes in the HCMV field have previously been measured against a variety of clinical end points, including virus acquisition, systemic replication, and progression to disease. Herein we review immune correlates of protection against each of these end points in turn, showing that control of HCMV likely depends on a combination of innate immune factors, antibodies, and T-cell responses. Furthermore, protective immune responses are heterogeneous, with no single immune parameter predicting protection against all clinical outcomes and stages of HCMV infection. A detailed understanding of protective immune responses for a given clinical end point will inform immunogen selection and guide preclinical and clinical evaluation of vaccines or immunotherapeutics to prevent HCMV-mediated congenital and transplant disease.

A new era in cytomegalovirus vaccinology: considerations for rational design of next-generation vaccines to prevent congenital cytomegalovirus infection

Human cytomegalovirus (HCMV), a member of the beta-herpesvirus family, is the most common cause of congenital infection worldwide as well as an important cause of morbidity in transplant recipients and immunosuppressed individuals. An estimated 1 in 150 infants are infected with HCMV at birth, which can result in lifelong, debilitating neurologic sequelae including microcephaly, sensorineural hearing loss, and cognitive impairment. Natural maternal immunity to HCMV decreases the frequency of reinfection and reduces risk of congenital transmission but does not completely protect against neonatal disease. Thus, a vaccine to reduce the incidence and severity of infant infection is a public health priority. A variety of candidate HCMV vaccine approaches have been tried previously, including live-attenuated viruses, glycoprotein subunit formulations, viral vectors, and single/bivalent DNA plasmids, but all have failed to reach target endpoints in clinical trials. Nevertheless, there is a great deal to be learned from the successes and failures of the HCMV vaccine field (both congenital and transplant-associated), as well as from vaccine development efforts for other herpesvirus pathogens including herpes simplex virus 1 and 2, varicella zoster virus, and Epstein-Barr virus. Here, we review those successes and failures, evaluating recent cutting-edge discoveries that have shaped the HCMV vaccine field and identifying topics of critical importance for future investigation. These considerations will inform rational design and evaluation of next-generation vaccines to prevent HCMV-associated congenital infection and disease.

Prevention and treatment of fetal cytomegalovirus infection with cytomegalovirus hyperimmune globulin: a multicenter study in Madrid

INTRODUCTION

Cytomegalovirus (CMV) is the leading cause of congenital infection worldwide. Data about the management of CMV infection in pregnant women are scarce, and treatment options are very limited. The aim of the study is to investigate the effectiveness of cytomegalovirus hyperimmune globulin (CMV-HIG) for the prevention and treatment of congenital CMV (cCMV) infection.

MATERIALS AND METHODS

A retrospective observational study was conducted in three tertiary hospitals in Madrid. In the period 2009-2015, CMV-HIG (Cytotect^® CP Biotest, Biotest) treatment was offered to all pregnant women with primary CMV infection and/or detection of CMV-DNA in amniotic fluid in participating centers. Women were divided into prevention and treatment groups (PG and TG, respectively). Those with primary CMV infection who had not undergone amniocentesis comprised the PG and received monthly CMV-HIG (100 UI/kg). If CMV-DNA was subsequently detected in amniotic fluid, one extra dose of CMV-HIG (200 UI/kg) was given 4 weeks after the last dose. Those women were considered to be part of the PG group despite detection of CMV-DNA in amniotic fluid. In the case of a negative result in CMV-DNA detection in amniotic fluid or if amniocentesis was not performed, monthly HIG was given up to the end of the pregnancy.

RESULTS

Thirty-six pregnant women were included. Median gestational age at birth was 39 weeks (interquartile range: 38-40) and two children (5.5%) were premature (born at 28 and 34 weeks' gestation). Amniocentesis was performed in 30/36 (83.4%) pregnancies and CMV PCR was positive in 21 of them (70%). One fetus with a positive PCR in amniotic fluid that received one dose of HIG after amniocentesis presented a negative CMV-PCR in urine at birth, and was asymptomatic at 12 months of age. Twenty-four children were infected at birth, and 16/21 (76.2%) presented no sequelae at 12 months, while two (9.5%) had a mild unilateral hearing loss and three (14.3%) severe hearing loss or neurological sequelae. Seventeen women were included in the PG and 19 in the TG. In the PG 7/17 (41%) fetuses were infected, one pregnancy was terminated due to abnormalities in cordocentesis and one showed a mild hearing loss at 12 months of age. In the TG, 18/19 children (95%) were diagnosed with cCMV, while the remaining neonate had negative urine CMV at birth. Eight out of the 19 fetuses (42.1%) showed CMV related abnormalities in the fetal US before HIG treatment. Complete clinical assessment in the neonatal period and at 12 months of age was available in 16 and 15 children, respectively. At birth 50% were symptomatic and at 12 months of age, 4/15 (26.7%) showed a hearing loss and 3/15 (20%) neurologic impairment. Fetuses with abnormalities in ultrasonography before HIG presented a high risk of sequelae (odds ratios: 60; 95%CI: 3-1185; p = .007).

DISCUSSION

Prophylactic HIG administration in pregnant women after CMV primary infection seems not to reduce significantly the rate of congenital infection, but is safe and it could have a favorable effect on the symptoms and sequelae of infected fetuses. The risk of long-term sequelae in fetuses without US abnormalities before HIG is low, so it could be an option in infected fetuses with normal imaging. On the other hand, the risk of sequelae among infected fetuses with abnormalities in fetal ultrasonography before HIG despite treatment is high.

Replication-defective lymphocytic choriomeningitis virus vectors expressing guinea pig cytomegalovirus gB and pp65 homologs are protective against congenital guinea pig cytomegalovirus infection

BACKGROUND

Congenital cytomegalovirus infection can be life-threatening and often results in significant developmental deficits and/or hearing loss. Thus, there is a critical need for an effective anti-CMV vaccine.

OBJECTIVE

To determine the efficacy of replication-defective lymphocytic choriomeningitis virus (rLCMV) vectors expressing the guinea pig CMV (GPCMV) antigens, gB and pp65, in the guinea pig model of congenital CMV infection.

METHODS

Female Hartley strain guinea pigs were divided into three groups: Buffer control group (n = 9), rLCMV-gB group (n = 11), and rLCMV-pp65 (n = 11). The vaccines were administered three times IM at 1.54 × 10(6)FFU per dose at 21-day intervals. At two weeks after vaccination, the female guinea pigs underwent breeding. Pregnant guinea pigs were challenged SQ at ∼ 45-55 days of gestation with 1 × 10(5)PFU of GPCMV. Viremia in the dams, pup survival, weights of pups at delivery, and viral load in both dam and pup tissues were determined.

RESULTS

Pup survival was significantly increased in the LCMV-gB vaccine group. There was 23% pup mortality in the gB vaccine group (p = 0.044) and 26% pup mortality in the pp65 vaccine group (p = 0.054) compared to 49% control pup mortality. The gB vaccine induced high levels of gB binding and detectable neutralizing antibodies, reduced dam viremia, and significantly reduced viral load in dam tissues compared to control dams (p < 0.03). Reduced viral load and transmission in pups born to gB-vaccinated dams was observed compared to pups from pp65-vaccinated or control dams.

CONCLUSIONS

The rLCMV-gB vaccine significantly improved pup survival and also increased pup weights and gestation time. The gB vaccine was also more effective at decreasing viral load in dams and pups and limiting congenital transmission. Thus, rLCMV vectors that express CMV antigens may be an effective vaccine strategy for congenital CMV infection.

Low Interferon Relative-Response to Cytomegalovirus Is Associated with Low Likelihood of Intrauterine Transmission of the Virus

Background

Congenital Cytomegalovirus (CMV) is a very common intrauterine infection which can cause severe mental and hearing impairments. Notably, only 40% of primarily infected women transmit CMV to the fetus. CMV-specific T-cell response has a role in CMV disease but individual immune heterogeneity precludes reliable correlation between measurable T-cells response and intrauterine transmission.

Study Aim

To establish a correlation between maternal T-cells response and fetal CMV transmission using an individual normalized immune response.

Methods

We analyzed IFN-γ secretion upon whole blood stimulation from primary CMV-infected pregnant women, with either CMV-peptides or PHA-mitogen.

Results

We established a new normalization method of individual IFN-γ response to CMV by defining the ratio between specific-CMV response and non-specific mitogen response (defined as IFN-γ relative response, RR), aiming to overcome high person-to-person immune variability. We found a unique subpopulation of women with low IFN-γ RR strongly correlated with absence of transmission. IFN-γ RR lower than 1.8% (threshold determined by ROC analysis) reduces the pre-test probability of transmission from 40% to 8%, revealing an unexpected link between low IFN-γ RR and non-transmission.

Conclusion

In pregnant women with primary CMV infection, low IFN-γ RR is associated with low risk of transmission.

Placenta-on-a-chip: a novel platform to study the biology of the human placenta

OBJECTIVE

Studying the biology of the human placenta represents a major experimental challenge. Although conventional cell culture techniques have been used to study different types of placenta-derived cells, current in vitro models have limitations in recapitulating organ-specific structure and key physiological functions of the placenta. Here we demonstrate that it is possible to leverage microfluidic and microfabrication technologies to develop a microengineered biomimetic model that replicates the architecture and function of the placenta.

MATERIALS AND METHODS

A "Placenta-on-a-Chip" microdevice was created by using a set of soft elastomer-based microfabrication techniques known as soft lithography. This microsystem consisted of two polydimethylsiloxane (PDMS) microfluidic channels separated by a thin extracellular matrix (ECM) membrane. To reproduce the placental barrier in this model, human trophoblasts (JEG-3) and human umbilical vein endothelial cells (HUVECs) were seeded onto the opposite sides of the ECM membrane and cultured under dynamic flow conditions to form confluent epithelial and endothelial layers in close apposition. We tested the physiological function of the microengineered placental barrier by measuring glucose transport across the trophoblast-endothelial interface over time. The permeability of the barrier study was analyzed and compared to that obtained from acellular devices and additional control groups that contained epithelial or endothelial layers alone.

RESULTS

Our microfluidic cell culture system provided a tightly controlled fluidic environment conducive to the proliferation and maintenance of JEG-3 trophoblasts and HUVECs on the ECM scaffold. Prolonged culture in this model produced confluent cellular monolayers on the intervening membrane that together formed the placental barrier. This in vivo-like microarchitecture was also critical for creating a physiologically relevant effective barrier to glucose transport. Quantitative investigation of barrier function was conducted by calculating permeability coefficients and metabolic rates in varying conditions of barrier structure. The rates of glucose transport and metabolism were consistent with previously reported in vivo observations.

CONCLUSION

The "Placenta-on-a-Chip" microdevice described herein provides new opportunities to simulate and analyze critical physiological responses of the placental barrier. This system may be used to address the major limitations of existing placenta model systems and serve to enable research platforms for reproductive biology and medicine.

The immunological underpinnings of vaccinations to prevent cytomegalovirus disease

A universal cytomegalovirus (CMV) vaccination promises to reduce the burden of the developmental damage that afflicts up to 0.5% of live births worldwide. An effective vaccination that prevents transplacental transmission would reduce CMV congenital disease and CMV-associated still births and leave populations less susceptible to opportunistic CMV disease. Thus, a vaccination against this virus has long been recognized for the potential of enormous health-care savings because congenital damage is life-long and existing anti-viral options are limited. Vaccine researchers, industry leaders, and regulatory representatives have discussed the challenges posed by clinical efficacy trials that would lead to a universal CMV vaccine, reviewing the links between infection and disease, and identifying settings where disrupting viral transmission might provide a surrogate endpoint for disease prevention. Reducing the complexity of such trials would facilitate vaccine development. Children and adolescents are the targets for universal vaccination, with the expectation of protecting the offspring of immunized women. Given that a majority of females worldwide experience CMV infection during childhood, a universal vaccine must boost natural immunity and reduce transmission due to reactivation and re-infection as well as primary infection during pregnancy. Although current vaccine strategies recognize the value of humoral and cellular immunity, the precise mechanisms that act at the placental interface remain elusive. Immunity resulting from natural infection appears to limit rather than prevent reactivation of latent viruses and susceptibility to re-infection, leaving a challenge for universal vaccination to improve upon natural immunity levels. Despite these hurdles, early phase clinical trials have achieved primary end points in CMV seronegative subjects. Efficacy studies must be expanded to mixed populations of CMV-naive and naturally infected subjects to understand the overall efficacy and potential. Together with CMV vaccine candidates currently in clinical development, additional promising preclinical strategies continue to come forward; however, these face limitations due to the insufficient understanding of host defense mechanisms that prevent transmission, as well as the age-old challenges of reaching the appropriate threshold of immunogenicity, efficacy, durability and potency. This review focuses on the current understanding of natural and CMV vaccine-induced protective immunity.

GWAS, cytomegalovirus infection, and schizophrenia

In recent years good progress has been made in uncovering the genetic underpinnings of schizophrenia. Even so, as a polygenic disorder, schizophrenia has a complex etiology that is far from understood. Meanwhile data are being collected enabling the study of interactions between genes and the environment. A confluence of data from genetic and environmental exposure studies points to the role of infections and immunity in the pathophysiology of schizophrenia. In a recent study by Børglum et al., a single nucleotide polymorphism (SNP) in the gene CTNNA3 was identified that may provide clues to gene-environment interactions. The carriers of the minor allele for the SNP had a 5 fold risk of later developing schizophrenia if their mothers were CMV positive, while the children not carrying the allele had no excess risk from maternal CMV. In the current paper we summarize recent advances to clarify possible mechanism of such interactions between the host genotype and infection in schizophrenia risk.

Models of vertical cytomegalovirus (CMV) transmission and pathogenesis

Despite the considerable clinical impact of congenital human cytomegalovirus (HCMV) infection, the mechanisms of maternal-fetal transmission and the resultant placental and fetal damage are largely unknown. Here, we discuss animal models for the evaluation of CMV vaccines and virus-induced pathology and particularly explore surrogate human models for HCMV transmission and pathogenesis in the maternal-fetal interface. Studies in floating and anchoring placental villi and more recently, ex vivo modeling of HCMV infection in integral human decidual tissues, provide unique insights into patterns of viral tropism, spread, and injury, defining the outcome of congenital infection, and the effect of potential antiviral interventions.