Control of maternal Zika virus infection during pregnancy is associated with lower antibody titers in a macaque model

IntroductionZika virus (ZIKV) infection during pregnancy results in a spectrum of birth defects and neurodevelopmental deficits in prenatally exposed infants, with no clear understanding of why some pregnancies are more severely affected. Differential control of maternal ZIKV infection may explain the spectrum of adverse outcomes.MethodsHere, we investigated whether the magnitude and breadth of the maternal ZIKV-specific antibody response is associated with better virologic control using a rhesus macaque model of prenatal ZIKV infection. We inoculated 18 dams with an Asian-lineage ZIKV isolate (PRVABC59) at 30-45 gestational days. Plasma vRNA and infectious virus kinetics were determined over the course of pregnancy, as well as vRNA burden in the maternal-fetal interface (MFI) at delivery. Binding and neutralizing antibody assays were performed to determine the magnitude of the ZIKV-specific IgM and IgG antibody responses throughout pregnancy, along with peptide microarray assays to define the breadth of linear ZIKV epitopes recognized.ResultsDams with better virologic control (n= 9) cleared detectable infectious virus and vRNA from the plasma by 7 days post-infection (DPI) and had a lower vRNA burden in the MFI at delivery. In comparison, dams with worse virologic control (n= 9) still cleared detectable infectious virus from the plasma by 7 DPI but had vRNA that persisted longer, and had higher vRNA burden in the MFI at delivery. The magnitudes of the ZIKV-specific antibody responses were significantly lower in the dams with better virologic control, suggesting that higher antibody titers are not associated with better control of ZIKV infection. Additionally, the breadth of the ZIKV linear epitopes recognized did not differ between the dams with better and worse control of ZIKV infection.DiscussionThus, the magnitude and breadth of the maternal antibody responses do not seem to impact maternal virologic control. This may be because control of maternal infection is determined in the first 7 DPI, when detectable infectious virus is present and before robust antibody responses are generated. However, the presence of higher ZIKV-specific antibody titers in dams with worse virologic control suggests that these could be used as a biomarker of poor maternal control of infection and should be explored further

20: Modeling Zika virus tissue tropism in rhesus macaques to define the risk of donor derived transmission

Abstract Background Almost 115,000 people in the United States are currently on a transplant waitlist, which vastly exceeds the number of organ donors every year. This discrepancy emphasizes the need for retention of all possible donors. Those who have recently traveled to an area with an active outbreak of Zika virus (ZIKV) are often disqualified as a donor because immunosuppressed recipients would be at risk of a donor-derived ZIKV infection. Therefore, we define ZIKV tissue tropism and the risk of donor derived transmission. Methods We subcutaneously inoculated 15 Indian-origin rhesus macaques (RM) with a Puerto Rican isolate of ZIKV (PRVABC59). All RMs were inoculated in mid to early gestation.We inoculated during pregnancy because plasma viremia is typically prolonged in pregnancy and we wanted to model tissue tropism for donor derived transmission in the worst scenario of prolonged viremia. At 30, 65, and 105 days post-infection (dpi), the animals were euthanized and comprehensive necropsies were performed, which evaluated a minimum of 60 tissues per animal. ZIKV RNA was quantified in tissues via qRT-PCR. Results Plasma viremia duration was >10 days in 13 of 15 RMs. ZIKV RNA was most commonly detected in lymph nodes, with 19/45 lymph nodes that were vRNA positive in 5 RMs at 30 dpi. There were 15/45 vRNA positive lymph nodes at 60 dpi and 8/38 at 105 dpi. Reproductive and maternal fetal-interface (MFI) tissues were the second most commonly positive tissues. Twenty-five MFI tissues, including the amniotic/chorionic membrane, decidua, placenta, uterus, and placental bed, were positive, with 10/53 positive at 30 dpi, 14/24 positive at 60 dpi and 1/47 positive at 105 dpi. Other vRNA positive tissues included the primary bronchus, femoral vein, kidney, thyroid, lung, colon, mammary gland, pericardium, hand nerve, and sciatic nerve in 1–2 RMs at one of the three timepoints. Conclusions We found ZIKV RNA most frequently within lymph nodes. Lymph nodes are included in lung and small bowel transplants, indicating that these transplants could pose a risk of donor-derived ZIKV transmission. Virus detection within other commonly transplanted tissues, such as the kidney and blood vessels was much less common. We did not determine what fraction of vRNA comes from replication-competent virus in each tissue; some tissues with vRNA might not contain virions that could initiate new infections. Donor-derived Zika virus transmission from other commonly transplanted organs, such as liver, seems unlikely since no viral RNA was detected in this organ

79: Modeling Zika Virus Tissue Tropism in Rhesus Macaques to Define the Risk of Donor-derived Transmission

Abstract Background Almost 115,000 people in the United States are currently on a transplant waitlist, which vastly exceeds the number of organ donors every year. This discrepancy emphasizes the need for retention of all possible donors. Those who have recently traveled to an area with an active outbreak of Zika virus (ZIKV) are often disqualified as a donor because immunosuppressed recipients would be at risk of a donor-derived ZIKV infection. Therefore, we define ZIKV tissue tropism and the risk of donor-derived transmission. Methods We subcutaneously inoculated 15 Indian-origin rhesus macaques (RM) with a Puerto Rican isolate of ZIKV (PRVABC59). All RMs were inoculated in mid to early gestation. We inoculated during pregnancy because plasma viremia is typically prolonged in pregnancy and we wanted to model tissue tropism for donor-derived transmission in the worst scenario of prolonged viremia. At 30, 65, and 105 days post-infection (dpi), the animals were euthanized and comprehensive necropsies were performed, which evaluated a minimum of 60 tissues per animal. ZIKV RNA was quantified in tissues via qRT-PCR. Results Plasma viremia duration was >10 days in 13 of 15 RMs. ZIKV RNA was most commonly detected in lymph nodes, with 19/45 lymph nodes that were vRNA positive in 5 RMs at 30 dpi. There were 15/45 vRNA positive lymph nodes at 60 dpi and 8/38 at 105 dpi. Reproductive and maternal fetal-interface (MFI) tissues were the second most commonly positive tissues. Twenty-five MFI tissues, including the amniotic/chorionic membrane, decidua, placenta, uterus, and placental bed, were positive, with 10/53 positive at 30 dpi, 14/24 positive at 60 dpi and 1/47 positive at 105 dpi. Other vRNA positive tissues included the primary bronchus, femoral vein, kidney, thyroid, lung, colon, mammary gland, pericardium, hand nerve, and sciatic nerve in 1–2 RMs at one of the three timepoints. Conclusions We found ZIKV RNA most frequently within lymph nodes. Lymph nodes are included in lung and small bowel transplants, indicating that these transplants could pose a risk of donor-derived ZIKV transmission. Virus detection within other commonly transplanted tissues, such as the kidney and blood vessels was much less common. We did not determine what fraction of vRNA comes from replication-competent virus in each tissue; some tissues with vRNA might not contain virions that could initiate new infections. Donor-derived Zika virus transmission from other commonly transplanted organs, such as the liver, seems unlikely since no viral RNA was detected in this organ

Neonatal Development in Prenatally Zika Virus-Exposed Infant Macaques with Dengue Immunity

Infants exposed to Zika virus (ZIKV) prenatally may develop birth defects, developmental deficits, or remain asymptomatic. It is unclear why some infants are more affected than others, although enhancement of maternal ZIKV infection via immunity to an antigenically similar virus, dengue virus (DENV), may play a role. We hypothesized that DENV immunity may worsen prenatal ZIKV infection and developmental deficits in offspring. We utilized a translational macaque model to examine how maternal DENV immunity influences ZIKV-exposed infant macaque neurodevelopment in the first month of life. We inoculated eight macaques with prior DENV infection with ZIKV, five macaques with ZIKV, and four macaques with saline. DENV/ZIKV-exposed infants had significantly worse visual orientation skills than ZIKV-exposed infants whose mothers were DENV-naive, with no differences in motor, sensory or state control development. ZIKV infection characteristics and pregnancy outcomes did not individually differ between dams with and without DENV immunity, but when multiple factors were combined in a multivariate model, maternal DENV immunity combined with ZIKV infection characteristics and pregnancy parameters predicted select developmental outcomes. We demonstrate that maternal DENV immunity exacerbates visual orientation and tracking deficits in ZIKV-exposed infant macaques, suggesting that human studies should evaluate how maternal DENV immunity impacts long-term neurodevelopment

DataSheet_1_Control of maternal Zika virus infection during pregnancy is associated with lower antibody titers in a macaque model.docx

IntroductionZika virus (ZIKV) infection during pregnancy results in a spectrum of birth defects and neurodevelopmental deficits in prenatally exposed infants, with no clear understanding of why some pregnancies are more severely affected. Differential control of maternal ZIKV infection may explain the spectrum of adverse outcomes.MethodsHere, we investigated whether the magnitude and breadth of the maternal ZIKV-specific antibody response is associated with better virologic control using a rhesus macaque model of prenatal ZIKV infection. We inoculated 18 dams with an Asian-lineage ZIKV isolate (PRVABC59) at 30-45 gestational days. Plasma vRNA and infectious virus kinetics were determined over the course of pregnancy, as well as vRNA burden in the maternal-fetal interface (MFI) at delivery. Binding and neutralizing antibody assays were performed to determine the magnitude of the ZIKV-specific IgM and IgG antibody responses throughout pregnancy, along with peptide microarray assays to define the breadth of linear ZIKV epitopes recognized.ResultsDams with better virologic control (n= 9) cleared detectable infectious virus and vRNA from the plasma by 7 days post-infection (DPI) and had a lower vRNA burden in the MFI at delivery. In comparison, dams with worse virologic control (n= 9) still cleared detectable infectious virus from the plasma by 7 DPI but had vRNA that persisted longer, and had higher vRNA burden in the MFI at delivery. The magnitudes of the ZIKV-specific antibody responses were significantly lower in the dams with better virologic control, suggesting that higher antibody titers are not associated with better control of ZIKV infection. Additionally, the breadth of the ZIKV linear epitopes recognized did not differ between the dams with better and worse control of ZIKV infection.DiscussionThus, the magnitude and breadth of the maternal antibody responses do not seem to impact maternal virologic control. This may be because control of maternal infection is determined in the first 7 DPI, when detectable infectious virus is present and before robust antibody responses are generated. However, the presence of higher ZIKV-specific antibody titers in dams with worse virologic control suggests that these could be used as a biomarker of poor maternal control of infection and should be explored further.</p

Quantitative definition of neurobehavior, vision, hearing and brain volumes in macaques congenitally exposed to Zika virus.

Congenital Zika virus (ZIKV) exposure results in a spectrum of disease ranging from severe birth defects to delayed onset neurodevelopmental deficits. ZIKV-related neuropathogenesis, predictors of birth defects, and neurodevelopmental deficits are not well defined in people. Here we assess the methodological and statistical feasibility of a congenital ZIKV exposure macaque model for identifying infant neurobehavior and brain abnormalities that may underlie neurodevelopmental deficits. We inoculated five pregnant macaques with ZIKV and mock-inoculated one macaque in the first trimester. Following birth, growth, ocular structure/function, brain structure, hearing, histopathology, and neurobehavior were quantitatively assessed during the first week of life. We identified the typical pregnancy outcomes of congenital ZIKV infection, with fetal demise and placental abnormalities. We estimated sample sizes needed to define differences between groups and demonstrated that future studies quantifying brain region volumes, retinal structure, hearing, and visual pathway function require a sample size of 14 animals per group (14 ZIKV, 14 control) to detect statistically significant differences in at least half of the infant exam parameters. Establishing the parameters for future studies of neurodevelopmental outcomes following congenital ZIKV exposure in macaques is essential for robust and rigorous experimental design