Six-month safety follow-up of an adjuvanted SARS-CoV-2 trimeric S-protein subunit vaccine (SCB-2019) in adults: A phase 2/3, double-blind, randomized study.

BACKGROUND: We evaluated the safety of SCB-2019, a protein subunit vaccine candidate containing a recombinant SARS-CoV-2 spike (S) trimer fusion protein, combined with CpG-1018/alum adjuvants. METHODS: This ongoing phase 2/3, double-blind, placebo-controlled, randomized trial is being conducted in Belgium, Brazil, Colombia, the Philippines, and South Africa in participants ≥ 12 years of age. Participants were randomly assigned to receive 2 doses of SCB-2019 or placebo administered intramuscularly 21 days apart. Here, we present the safety results of SCB-2019 over the 6-month period following 2-dose primary vaccination series in all adult participants (≥18 years of age). RESULTS: A total of 30,137 adult participants received at least one dose of study vaccine (n = 15,070) or placebo (n = 15,067) between 24 March 2021 and 01 December 2021. Unsolicited adverse events, medically-attended adverse events, adverse events of special interest, and serious adverse events were reported in similar frequencies in both study arms over the 6-month follow-up period. Vaccine-related SAEs were reported by 4 of 15,070 SCB-2019 recipients (hypersensitivity reactions in two participants, Bell's palsy, and spontaneous abortion) and 2 of 15,067 placebo recipients (COVID-19, pneumonia, and acute respiratory distress syndrome in one participant and spontaneous abortion in the other one). No signs of vaccine-associated enhanced disease were observed. CONCLUSIONS: SCB-2019 administered as a 2-dose series has an acceptable safety profile. No safety concerns were identified during the 6-month follow-up after the primary vaccination. CLINICAL TRIALS REGISTRATION: NCT04672395; EudraCT: 2020-004272-17.

Selective deficits in attentional set-shifting in mice induced by maternal immune activation with poly(I:C).

Maternal immune activation has been identified as a significant risk factor for schizophrenia. Using rodent models, past work has demonstrated various behavioral and brain impairments in offspring after immune-activating events. We applied 5 mg/kg of poly(I:C) on gestation day 9 to pregnant mouse dams, whose offspring were then stressed during puberty. We show impairments in attentional set-shifting in a T-maze, and a decreased number of parvalbumin-positive interneurons in the hippocampus as a result of peripubertal stress specifically in females.

Maternal Immune Activation during Pregnancy Alters Postnatal Brain Growth and Cognitive Development in Nonhuman Primate Offspring.

Human epidemiological studies implicate exposure to infection during gestation in the etiology of neurodevelopmental disorders. Animal models of maternal immune activation (MIA) have identified the maternal immune response as the critical link between maternal infection and aberrant offspring brain and behavior development. Here we evaluate neurodevelopment of male rhesus monkeys (Macaca mulatta) born to MIA-treated dams (n = 14) injected with a modified form of the viral mimic polyinosinic:polycytidylic acid at the end of the first trimester. Control dams received saline injections at the same gestational time points (n = 10) or were untreated (n = 4). MIA-treated dams exhibited a strong immune response as indexed by transient increases in sickness behavior, temperature, and inflammatory cytokines. Although offspring born to control or MIA-treated dams did not differ on measures of physical growth and early developmental milestones, the MIA-treated animals exhibited subtle changes in cognitive development and deviated from species-typical brain growth trajectories. Longitudinal MRI revealed significant gray matter volume reductions in the prefrontal and frontal cortices of MIA-treated offspring at 6 months that persisted through the final time point at 45 months along with smaller frontal white matter volumes in MIA-treated animals at 36 and 45 months. These findings provide the first evidence of early postnatal changes in brain development in MIA-exposed nonhuman primates and establish a translationally relevant model system to explore the neurodevelopmental trajectory of risk associated with prenatal immune challenge from birth through late adolescence.SIGNIFICANCE STATEMENT Women exposed to infection during pregnancy have an increased risk of giving birth to a child who will later be diagnosed with a neurodevelopmental disorder. Preclinical maternal immune activation (MIA) models have demonstrated that the effects of maternal infection on fetal brain development are mediated by maternal immune response. Since the majority of MIA models are conducted in rodents, the nonhuman primate provides a unique system to evaluate the MIA hypothesis in a species closely related to humans. Here we report the first longitudinal study conducted in a nonhuman primate MIA model. MIA-exposed offspring demonstrate subtle changes in cognitive development paired with marked reductions in frontal gray and white matter, further supporting the association between prenatal immune challenge and alterations in offspring neurodevelopment.

Enhancement of placental inflammation by Dibutyl Phthalate.

Recent studies suggest that women with high exposures to dibutyl phthalate (DBP) are at increased risk for preterm birth, a condition associated with aberrant inflammation in the placenta often caused by subclinical infections. Placental inflammation is also a risk factor for neurodevelopmental disorders whose risk may also be enhanced by DBP. It is unclear, however, if DBP enhances placental inflammation. Therefore, we studied the effects of DBP on the production of biomarkers of placental inflammation and neurodevelopment under basal conditions and a setting of mild infection. Placental explant cultures established from women undergoing elective caesarean delivery were treated with DBP with and without co-stimulation by 107 CFU/mL heat-killed E. coli for 24 h at 37 °C. Conditioned medium was harvested and concentrations of IL-1ß, TNF-α, IL-10, HO-1 and BDNF, a biomarker for neurodevelopment, were quantified. DBP significantly enhanced IL-6 production in basal cultures but had no significant on the other biomarkers quantified. Both TNF-α and IL-1ß production was enhanced by DBP for cultures co-stimulated with E. coli. Although marginal enhancement of IL-6, and IL-10 were observed for bacteria co-treated cultures, results were either non-monotonic or only approached statistical significance. HO-1 production tended to be reduced at the highest concentration of DBP tested and BDNF production was reduced by DBP in a dose-dependent manner for bacteria-stimulated cultures. These results suggest that DBP enhances basal IL-6 production but has little or no effect on other biomarkers studied. However, DBP enhances IL-1ß and TNF-α production but reduces BDNF production by bacteria-stimulated cultures.

Resveratrol ameliorates the effect of maternal immune activation associated with schizophrenia in adulthood offspring.

Maternal exposure to infectious agents such as arboviruses, bacteria, or other protozoans has been associated with an elevated risk of schizophrenia (SZ). Evidence suggests that immunological processes occurring during infection may disturb the neural progenitor, impacting the central nervous system (CNS) functions. Moreover, growing evidence suggests that resveratrol (RSV) has neuroprotective activity through anti-oxidant and anti-inflammatory mechanisms. Therefore, we investigated if the treatment with RSV during pregnancy would prevent the abnormalities associated with a SZ-like phenotype induced by maternal immune activation (MIA). Pregnant dams stimulated with a subcutaneous (s.c.) injection of polyriboinosinic-polyribocytidylic acid (poly I:C; 50 mg/kg), a viral nucleic acid mimetic or vehicle, on gestational day (GD) 12.5, were treated with RSV (40 mg/kg, s.c.) or saline, from GD 9.5 to GD 14.5. On day 45 after birth, the offspring was evaluated using a three-compartment social interaction test, elevated plus maze, and hyperlocomotion test induced by amphetamine. After the behavioral tests, the relative expression of mRNA to synapsin 1 (Syn1), oligodendrocyte transcription factor 1 (Olig1), and SRY (sex-determining region Y)-box 2 (Sox2) was determined in the hippocampus and cortex. Treatment with RSV restored the social behavior and attenuated the hyperlocomotion of the offspring bred by dams submitted to MIA. RSV prevented the effects of MIA on Syn1 and Olig1 expression in the hippocampus and Syn1 in the cortex. The present study showed that maternal treatment with RSV attenuates some of the negative behavioral impacts caused by MIA, with modulation of synaptic and oligodendrogenesis processes.

[Consensus of infectious complications in patients treated with selected biological therapies.Screening of hepatitis B in high risk Chilean and immigrant pregnant women: Management of mother to child transmission Second part: Chilean Guidelines for Prevention of Infections associated to use of Biological Therapies (PREVITEB)]. / Consenso sobre riesgo de complicaciones infecciosas en pacientes usuarios de medicamentos biológicos seleccionados.Parte II: Guía clínica chilena de Prevención de Infecciones Asociadas al Uso de Terapias Biológicas (PREVITEB).

The use of biological therapies has meant a great improvement in the management of several conditions like autoimmune, neoplastic or others diseases. Although its use has implied significant improvements in the prognosis of these diseases, it is not exempt from complications: infectious diseases as one of them. The objective of this consensus was to evaluate, from an infectious viewpoint, the safeness of the most frequently used biological therapies and give recommendations for the prevention of infections in patients treated with these drugs. These recommendations were based on the highest quality evidence available for the selected biologics. The consensus counts of 2 manuscripts. This second part is a guideline that details these recommendations through screening strategies, prophylactic therapies and vaccines indications for bacterial, mycobacterial, viral, fungal and parasitic infections, both for adults and children.

Consenso sobre riesgo de complicaciones infecciosas en pacientes usuarios de medicamentos biológicos seleccionados. Parte II: Guía clínica chilena de Prevención de Infecciones Asociadas al Uso de Terapias Biológicas (PREVITEB) / Consensus of infectious complications in patients treated with selected biological therapies. Screening of hepatitis B in high risk Chilean and immigrant pregnant women: Management of mother to child transmission Second part: Chilean Guidelines for Prevention of Infections associated to use of Biological Therapies (PREVITEB)

Resumen La incorporación de terapias biológicas ha significado un gran avance en el manejo de diversas patologías de origen autoinmune, neoplásico u otros. Si bien su uso ha implicado mejoras significativas en el pronóstico de estas enfermedades, no está exento de complicaciones, entre éstas, las infecciosas. El objetivo de este consenso fue evaluar el perfil de seguridad, desde la mirada infectológica, de las terapias biológicas de uso más frecuente y dar recomendaciones para la prevención de infecciones en pacientes tratados con ellas, basándose en la evidencia de mayor calidad disponible para los biológicos seleccionados. El consenso cuenta de dos manuscritos. Esta segunda parte corresponde a la guía clínica que detalla estas recomendaciones mediante estrategias de cribado, terapias profilácticas e indicación de vacunas, según corresponde, para infecciones bacterianas, y por micobacterias en particular, virus, hongos y parásitos, tanto para adultos como para niños.

The use of biological therapies has meant a great improvement in the management of several conditions like autoimmune, neoplastic or others diseases. Although its use has implied significant improvements in the prognosis of these diseases, it is not exempt from complications: infectious diseases as one of them. The objective of this consensus was to evaluate, from an infectious viewpoint, the safeness of the most frequently used biological therapies and give recommendations for the prevention of infections in patients treated with these drugs. These recommendations were based on the highest quality evidence available for the selected biologics. The consensus counts of 2 manuscripts. This second part is a guideline that details these recommendations through screening strategies, prophylactic therapies and vaccines indications for bacterial, mycobacterial, viral, fungal and parasitic infections, both for adults and children.

Value of an in-depth analysis of unpublished data on the safety of influenza vaccines in pregnant women.

BACKGROUND: Unpublished data can sometimes provide valuable information on the safety of biologic products. METHODS: We assessed information potentially available from regulatory authorities, manufacturers, and public health agencies. We explored 4 recently established vaccine registries, reviewed package inserts from 99 influenza vaccines, and contacted vaccine manufacturers and regulatory agencies for data on influenza vaccine safety in pregnant women. RESULTS: The vaccine registries did not have sufficient data to analyze and there are problems with the quality of the information. The majority of package inserts provided no product-specific safety information for pregnant women, especially in less developed countries. The majority of available data come from reports gathered from passive adverse event reporting systems in the general population and reports of women enrolled in clinical trials of influenza vaccines who became pregnant at various times before or after receiving influenza vaccine. The information was not collected in a systematic manner, there are inconsistencies in the follow up of pregnant women and the available information about pregnancy outcomes. Considerable resources would be needed to systematically identify all of the information, try to obtain missing follow up information, and conduct analyses. There would be substantial limitations to any attempt to conduct a systematic analysis. CONCLUSIONS: The value of trying to analyze unpublished data on the safety of influenza vaccine in pregnancy is limited and would require considerable resources to thoroughly investigate. Expanding efforts to identify and review unpublished data regarding the safety of influenza vaccines in pregnancy is not likely to produce information of high scientific value or information that could not be identified from publications and other publically available data.

Zidovudine use in pregnancy and congenital malformations.

OBJECTIVE: There is inconsistent evidence that zidovudine use during pregnancy increases overall, cardiac, and male genital malformations. DESIGN: We conducted a systematic review and meta-analysis of zidovudine use and malformations and, using Bayesian methods, combined it with data from a cohort study of mother-infant pairs in the nationwide Medicaid Analytic eXtract (MAX). METHODS: Using MAX data (2000-2010), we identified pregnant women with HIV treated with antiretroviral therapy (ART). Women with at least one zidovudine dispensing during the first trimester were compared to women receiving ART without zidovudine in the first trimester. Malformation outcomes were defined using diagnosis/procedure codes. To adjust for confounding, we performed 1 : 1 propensity score matching. Bayesian methods require specification of a prior, which we developed in the meta-analysis. Logistic regression models combined MAX data with the prior, estimating odds ratios (ORs) and 95% credible intervals. RESULTS: Fourteen articles contributed information on overall malformations, seven on cardiac malformations, and five on male genital malformations. In MAX, matching led to a sample of 735 women each in the zidovudine and comparator groups. When comparing first trimester zidovudine use to other ART, the Bayesian procedure yielded OR estimates slightly above the null for overall [OR = 1.11, 95% credible interval (0.80-1.55)] and cardiac [OR = 1.30 (0.63-2.71)] malformations. There were no zidovudine-exposed cases of male genital malformations in MAX, but the meta-analysis yielded elevated OR estimates [OR = 2.57 (1.26-5.24)]. CONCLUSION: For most malformations, first-trimester zidovudine was not associated with increased risk. The potential increase in male genital malformations was small in absolute terms, and should be evaluated further.

Mitochondrial toxicity and caspase activation in HIV pregnant women.

To assess the impact of HIV-infection and highly active anti-retroviral treatment in mitochondria and apoptotic activation of caspases during pregnancy and their association with adverse perinatal outcome. Changes of mitochondrial parameters and apoptotic caspase activation in maternal peripheral blood mononuclear cells were compared at first trimester of pregnancy and delivery in 27 HIV-infected and -treated pregnant women versus 24 uninfected pregnant controls. We correlated immunovirological, therapeutic and perinatal outcome with experimental findings: mitochondrial DNA (mtDNA) content, mitochondrial protein synthesis, mitochondrial function and apoptotic caspase activation. The HIV pregnancies showed increased adverse perinatal outcome (OR: 4.81 [1.14-20.16]; P < 0.05) and decreased mtDNA content (42.66 ± 5.94%, P < 0.01) compared to controls, even higher in naïve participants. This depletion caused a correlated decrease in mitochondrial protein synthesis (12.82 ± 5.73%, P < 0.01) and function (20.50 ± 10.14%, P < 0.001), not observed in controls. Along pregnancy, apoptotic caspase-3 activation increased 63.64 ± 45.45% in controls (P < 0.001) and 100.00 ± 47.37% in HIV-pregnancies (P < 0.001), in correlation with longer exposure to nucleoside analogues. HIV-infected women showed increased obstetric problems and declined genetic and functional mitochondrial parameters during pregnancy, especially those firstly exposed to anti-retrovirals. The apoptotic activation of caspases along pregnancy is emphasized in HIV pregnancies promoted by nucleoside analogues. However, we could not demonstrate direct mitochondrial or apoptotic implication in adverse obstetric outcome probably because of the reduced sample size.

Certolizumab treatment during late pregnancy in patients with rheumatic diseases: Low drug levels in cord blood but possible risk for maternal infections. A case series of 13 patients.

OBJECTIVE: Due to reduction of immune-suppressive drugs, patients with rheumatic diseases can experience an increase in disease activity during pregnancy. In such cases, TNF-inhibitors may be prescribed. However, monoclonal antibodies with the Fc moiety are actively transported across the placenta, resulting in therapeutic drug levels in the newborn. As certolizumab (CZP) lacks the Fc moiety, it may bear a lower risk for the child. METHOD: We report a case series of thirteen patients (5 with rheumatoid arthritis and 8 with spondyloarthritis) treated with CZP during late pregnancy to control disease activity. RESULT: CZP measured in cord blood of eleven infants ranged between undetectable levels and 1µg/mL whereas the median CZP level of maternal plasma was 32.97µg/mL. Three women developed an infection during the third trimester, of whom one had a severe infection and one had an infection that resulted in a pre-term delivery. During the postpartum period, 6 patients remained on CZP while breastfeeding. CZP levels in the breast milk of two breastfeeding patients were undetectable. CONCLUSION: The lack of the active transplacental transfer of CZP gives the possibility to treat inflammatory arthritis during late gestation without potential harm to the newborn. However, in pregnant women treated with TNF-inhibitors and prednisone, attention should be given to the increased susceptibility to infections, which might cause prematurity. CZP treatment can be continued while breastfeeding.

[The endothelium of the vessels and proxidative-antioxidative balans in pregnancy rats with endothoxinaemia].

Actual problem of modern obstetrics is the infection in pregnancy which leads the deadborn, early children's death rate ind disease. In Belarus disease of newborns at specific infections for postnatal the period has made 14.1 per thousand, and death rate of 0.38 per thousand. The purpose of researches--to study a condition endothelium and activity of lipid peroxidation products at pregnant rats with endothoxinaemia. In experiments on 49 pregnancy rats with intramuscular injection of endotoxine (Lipopolysaccharide E. coli Serotype O127:B8 "Sigma") during the period placentation dysfunction development endohelium is established, that was shown more expressed in 2,3 times (p < 0.05) constriction by reaction on noradrenalin, increase in 18,3 times (p < 0.001) quantities circulating endothelium cages and decrease in 14 times (p < 0.001) the deendent endothelium vasodilatation under influence acetilcholine, to the dress increase of level of lipid peroxidation products: concentration of diene conjugates on 91% (p < 0.001), malone dialdegide--on 56% (p < 0.001), Shiff bases--on 7.9% (p < 0.05); and decrease in indicators of antioxidant protection: maintenances retinol on 29% (p < 0.05), α-tocopherol--on 6% (p < 0.001).

Ultrasound-guided intrauterine injection of lipopolysaccharide as a novel model of preterm birth in the mouse.

Mouse models are used to study mechanisms that link intrauterine infection and preterm birth (PTB). To mimic intrauterine infection, lipopolysaccharide (LPS) is commonly injected into the uterus via minilaparotomy, which is invasive, and can cause PTB in control animals. We hypothesized that less-invasive ultrasound-guided intrauterine LPS injection or intravaginal LPS administration could induce PTB by stimulating an inflammatory response of the uteroplacental tissues, while minimizing PTB in control animals. On day 17 of gestation mice received LPS intravaginally (10 to 240 µg; n = 3 to 8) or into the uterus (20 µg) under ultrasound guidance (n = 7) or via laparotomy (n = 7). Control animals received phosphate-buffered saline (PBS; n = 5 to 7). Intrauterine administration of LPS, both under ultrasound guidance and via laparotomy, induced delivery earlier than in PBS control groups (P < 0.01). Intravaginal LPS administration did not stimulate PTB. Quantitative real-time PCR and immunohistochemistry of tissues harvested 6 hours after treatment confirmed that ultrasound-guided LPS administration induced a localized inflammatory response. Ultrasound-guided intrauterine LPS injection reliably induces PTB in the mouse and mimics the local inflammatory and immune responses observed in the more-invasive laparotomy model of inflammation-induced PTB. Ultrasound-guided intrauterine LPS injection is a useful novel model of PTB for future studies and concords with the principles of reduction, replacement, and refinement.

15-epi-lipoxin A4 reduces the mortality of prematurely born pups in a mouse model of infection-induced preterm birth.

Preterm birth remains the leading cause of neonatal mortality and morbidity worldwide. There are currently few effective therapies and therefore an urgent need for novel treatments. Although there is much focus on trying to alter gestation of delivery, the primary aim of preterm birth prevention therapies should be to reduce prematurity related mortality and morbidity. Given the link between intrauterine infection and inflammation and preterm labour (PTL), we hypothesized that administration of lipoxins, key anti-inflammatory and pro-resolution mediators, could be a useful novel treatment for PTL. Using a mouse model of infection-induced PTL, we investigated whether 15-epi-lipoxin A4 could delay lipopolysaccharide (LPS)-induced PTL and reduce pup mortality. On D17 of gestation mice (n = 9-12) were pretreated with vehicle or 15-epi-lipoxin A4 prior to intrauterine administration of LPS or PBS. Although pretreatment with 15-epi-lipoxin A4 did not delay LPS-induced PTL, there was a significant reduction in the mortality amongst prematurely delivered pups (defined as delivery within 36 h of surgery) in mice treated with 15-epi-lipoxin A4 prior to LPS treatment, compared with those receiving LPS alone (P < 0.05). Quantitative real-time (QRT)-PCR analysis of utero-placental tissues harvested 6 h post-treatment demonstrated that 15-epi-lipoxin A4 treatment increased Ptgs2 expression in the uterus, placenta and fetal membranes (P < 0.05) and decreased 15-Hpgd expression (P < 0.05) in the placenta and uterus, suggesting that 15-epi-lipoxin A4 may regulate the local production and activity of prostaglandins. These data suggest that augmenting lipoxin levels could be a useful novel therapeutic option in the treatment of PTL, protecting the fetus from the adverse effects of infection-induced preterm birth.

Asymptomatic bacteriuria & obstetric outcome following treatment in early versus late pregnancy in north Indian women.

BACKGROUND & OBJECTIVES: Asymptomatic bacteriuria during pregnancy if left untreated, may lead to acute pyelonephritis, preterm labour, low birth weight foetus, etc. Adequate and early treatment reduces the incidence of these obstetric complications. The present study was done to determine presence of asymptomatic bacteriuria (ASB) and obstetric outcome following treatment in early versus late pregnancy. METHODS: A prospective cohort study was conducted at a tertiary care teaching hospital of north India. Pregnant women till 20 wk (n=371) and between 32 to 34 wk gestation (n=274) having no urinary complaints were included. Their mid stream urine sample was sent for culture and sensitivity. Women having > 10 [5] colony forming units/ml of single organism were diagnosed positive for ASB and treated. They were followed till delivery for obstetric outcome. Relative risk with 95% confidence interval was used to describe association between ASB and outcome of interest. RESULTS: ASB was found in 17 per cent pregnant women till 20 wk and in 16 per cent between 32 to 34 wk gestation. Increased incidence of preeclamptic toxaemia (PET) [RR 3.79, 95% CI 1.80-7.97], preterm premature rupture of membrane (PPROM)[RR 3.63, 45% CI 1.63-8.07], preterm labour (PTL) [RR 3.27, 95% CI 1.38-7.72], intrauterine growth restriction (IUGR)[RR 3.79, 95% CI 1.80-79], low birth weight (LBW) [RR1.37, 95% CI 0.71-2.61] was seen in late detected women (32-34 wk) as compared to ASB negative women, whereas no significant difference was seen in early detected women (till 20 wk) as compared to ASB negative women. INTERPRETATION & CONCLUSIONS: Early detection and treatment of ASB during pregnancy prevents complications like PET, IUGR, PTL, PPROM and LBW. Therefore, screening and treatment of ASB may be incorporated as routine antenatal care for safe motherhood and healthy newborn.

Improving participant understanding of informed consent in an HIV-prevention clinical trial: a comparison of methods.

Empirical research on informed consent has shown that study participants often do not fully understand consent information. This study assessed participant understanding of three mock consent approaches describing an HIV-prevention clinical trial in Lilongwe, Malawi prior to trial implementation. Pregnant women (n = 297) were systematically selected from antenatal-care waiting lines and sequentially allocated to receive an enhanced standard consent form (group 1), a context-specific consent form (group 2), or context-specific counseling cards (group 3). Understanding of research concepts and study procedures was assessed immediately postintervention and at 1-week follow-up. At postintervention, participants in groups 2 and 3 understood more about research concepts and study procedures compared with group 1. Group 3 participants also understood more about study procedures compared with group 2. At follow-up, participants in groups 2 and 3 continued to understand more about research concepts and study procedures. Context-specific approaches improved understanding of consent information in this study.

Maternal/fetal mortality and fetal growth restriction: role of nitric oxide and virulence factors in intrauterine infection in rats.

OBJECTIVE: The mechanism of infection-related deaths of pregnant rats and intrauterine growth restriction are not understood. We assessed whether nitric oxide (NO) has differential effects on infection with Escherichia coli Dr/Afa mutants that lack either AfaE or AfaD invasins. STUDY DESIGN: Sprague-Dawley rats were infected intrauterinally with the clinical strain of E coli AfaE(+)D(+) or 1 of its isogenic mutants in the presence or absence of the NO synthesis inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME). Maternal/fetal mortality rates, fetoplacental weight, and infection rates were evaluated. RESULTS: Maternal and/or fetal death was associated with the presence of at least 1 virulence factor (AfaE(+)D(+)>AfaE(+)D(-)>AfaE(-)D(+)) and was increased by L-NAME treatment. The fetal and placental weights were lower than controls and were further reduced by L-NAME treatment. CONCLUSION: These results demonstrate that NO enhanced AfaE- and AfaD-mediated virulence and plays an important role in Dr/Afa(+)E coli gestational tropism.