Fig 1.
Study Design and cohort definitions.
The 23 pregnancies in this study are grouped into Cohorts I-V according to the dam’s viral exposure(s) and antiretroviral therapy (ART) regimens. Once the chronic set point was reached following intrarectal (IR) SIV exposure, the animals began the first ART regimen of tenofovir disoproxil fumarate (TDF), emtricitabine (FTC), and dolutegravir sodium (DTG). Thirty days before breeding, animals were switched to a new ART regimen of TDF/FTC/Raltegravir (RAL). Arrowheads denote a switch in ART regimen. Animals were bred until pregnancy was confirmed by ultrasound. On or around gestational day (GD) 30, animals were exposed subcutaneously (SC) to either ZIKV or PBS (mock). Maternal fetal-interface (MFI) and fetal/embryonic tissues were collected on the date of pregnancy loss or birth (~GD 165). Animals that did not deliver naturally by GD 170 had Cesarean sections (C-sections). Macaque silhouettes were prepared by L. Raasch and are not restricted by copyright.
Fig 2.
ZIKV viremia in macaque plasma. Copies of viral RNA were detected by ZIKV-specific RT-qPCR. Mean ZIKV plasma viremia are displayed in orange for Cohort I, blue for Cohort II (SIV-/ZIKV+ +ART), and red for Cohort III (SIV-/ZIKV+). Bars represent the standard error of the mean (SEM).
Fig 3.
*Animal F and fetus died on the day of clinical C-section (GD 170) due to anesthesia complications. **The fetus of Animal Q died 5 days post-due date (GD 175). Macaque silhouettes were prepared by L. Raasch and are not restricted by copyright.
Fig 4.
ZIKV was detected in tissues from the maternal-fetal interface (MFI) and dam in all cases of early pregnancy loss.
Cohort I (SIV+/ZIKV+ +ART) animals are in orange, Cohort II (SIV-/ZIKV+ +ART) animals are in blue, and Cohort III (SIV-/ZIKV+) animals are in red. (a) ZIKV was detected in MFI and maternal tissues from Cohorts I-III by ZIKV-specific RT-qPCR. The placenta was segmented into cotyledons, labeled as ’a’, ’b’, and ’c’, and a sample was obtained from each layer (decidua, parenchyma, chorionic plate) within every cotyledon. Maternal tissues were taken by biopsy at the time of C-section. (b) Representative image of ZIKV RNA (red staining) detected by in-situ hybridization (ISH) in the first placental disc from a case of pregnancy loss (Pregnancy K). Here, there was marked diffuse villous parenchymal staining extending from the basal plate to the chorionic trophoblastic shell with transmural segmental sparing of villi.
Fig 5.
ZIKV was detected in tissues from the fetus/embryo in all cases of early pregnancy loss.
Cohort I (SIV+/ZIKV+ +ART) animals are in orange, Cohort II (SIV-/ZIKV+ +ART) animals are in blue, and Cohort III (SIV-/ZIKV+) animals are in red. (a) ZIKV was detected in fetal/embryonic tissues from cases of early pregnancy loss by ZIKV-specific RT-qPCR. LOD denotes the limit of detection. (b) Representative image of ZIKV RNA (red staining) distribution in an embryo from a case of early pregnancy loss (Pregnancy N). Here, ZIKV RNA was detected in the periosteum and musculature of the head and body tissues. The asterisk denotes the vertebral column of the embryo.
Fig 6.
All ZIKV-exposed animals developed robust IgM and neutralizing antibody responses.
(a) ELISA determined Anti-ZIKV IgM levels at 0, 1, 2, and 3 weeks post infection (WPI). (b) Neutralizing antibody levels were measured at baseline and 17, 20, or 27 days post infection (DPI) by PRNT 90. Bar graphs depict the mean antibody levels for each cohort at the respective timepoints. Error bars represent the standard deviation.