Developmental and reproductive safety of AZD1222 (ChAdOx1 nCoV-19) in mice.

AZD1222 (ChAdOx1 nCoV-19) is a COVID-19 vaccine that is not yet licensed for use during pregnancy. To support the inclusion of pregnant and breastfeeding people in AZD1222 clinical studies, a non-clinical developmental and reproductive toxicity study was performed to evaluate its effects on fertility and reproductive processes of female CD-1 mice during the embryofetal development phase, and postnatal outcomes during the littering phase. Immunogenicity assessments were also made in dams, fetuses, and pups. There were no vaccine-related unscheduled deaths throughout the study. Furthermore, there were no vaccine-related effects on female reproduction, fetal or pup survival, fetal external, visceral, or skeletal findings, pup physical development, and no abnormal gross pathology findings in pups or dams. Antibody responses raised in dams were maintained throughout gestation and postnatal periods, and seroconversion in fetuses and pups indicate placental and lactational transfer of immunoglobulins. Together with clinical data from non-pregnant people, these results support the inclusion of pregnant and breastfeeding people in AZD1222 clinical studies.

A gene expression resource generated by genome-wide lacZ profiling in the mouse.

Knowledge of the expression profile of a gene is a critical piece of information required to build an understanding of the normal and essential functions of that gene and any role it may play in the development or progression of disease. High-throughput, large-scale efforts are on-going internationally to characterise reporter-tagged knockout mouse lines. As part of that effort, we report an open access adult mouse expression resource, in which the expression profile of 424 genes has been assessed in up to 47 different organs, tissues and sub-structures using a lacZ reporter gene. Many specific and informative expression patterns were noted. Expression was most commonly observed in the testis and brain and was most restricted in white adipose tissue and mammary gland. Over half of the assessed genes presented with an absent or localised expression pattern (categorised as 0-10 positive structures). A link between complexity of expression profile and viability of homozygous null animals was observed; inactivation of genes expressed in ≥ 21 structures was more likely to result in reduced viability by postnatal day 14 compared with more restricted expression profiles. For validation purposes, this mouse expression resource was compared with Bgee, a federated composite of RNA-based expression data sets. Strong agreement was observed, indicating a high degree of specificity in our data. Furthermore, there were 1207 observations of expression of a particular gene in an anatomical structure where Bgee had no data, indicating a large amount of novelty in our data set. Examples of expression data corroborating and extending genotype-phenotype associations and supporting disease gene candidacy are presented to demonstrate the potential of this powerful resource.