ABSTRACT Support is requested for a Keystone Symposia conference entitled Infections in Pregnancy: Pathogenic Mechanisms, Experimental Advances and Clinical Strategies, organized by Drs. Helen Lazear, Carolyn Coyne and David Aronoff. The conference will be held in Santa Fe, New Mexico from January 22-25, 2023. The placenta generally provides a robust barrier to the fetal compartment across which relatively few microbes are able to penetrate, and functions together with other defenses at the maternal-fetal interface to protect against congenital infections. Nonetheless, congenital pathogens including human cytomegalovirus, Zika virus, Toxoplasma gondii, and group B streptococcus can cause fetal loss, growth restriction, birth defects, and developmental delays. The list of congenital pathogens continues to grow; for example, the recently emergent virus SARS-CoV-2, can cause devastating adverse pregnancy outcomes independent of vertical transmission. In addition to pathogenic effects on the fetus and neonate, infections during pregnancy can have distinct impacts on maternal health, owing to the physiologic and immunologic effects of pregnancy. As such, there is a need to better understand the pathogenic mechanisms of congenital infections and immune defenses at the maternal-fetal interface, as well as to develop improved vaccine, treatment, and diagnostic strategies to combat congenital infections. But in many cases these infections can be difficult to study due to limitations in experimental systems and challenges in designing studies with human patients. This Keystone Symposia conference will bring together researchers investigating infections in pregnancy from a range of perspectives including basic biology, pathogenesis models, clinical studies, and patient care. The program is designed to highlight the new advances in understanding the pathogenic mechanisms of congenital infections. Other sessions will share recent developments in experimental systems for studying congenital infections, in addition to providing details on the latest developments in vaccines, therapeutics, and diagnostics. The program will also be designed to consider the effects of infections during pregnancy on maternal health, as well as on fetal, infant, and child health. This conference will provide an opportunity for researchers from diverse backgrounds to exchange ideas and develop new collaborations to promote future research on infections during pregnancy. Finally, this conference is being paired with another Keystone Symposia meeting on Maternal-Fetal Crosstalk. This will allow participants at both conference the chance to network and develop new collaborations through shared sessions and meals.

PROJECT NARRATIVE The placenta generally provides a robust barrier to the fetal compartment yet a few pathogens, such as SARS- CoV-2, can penetrate the barrier to cause devastating adverse pregnancy outcomes. Moreover, progress on understanding and combatting infections during pregnancy is hampered by limitations in experimental systems and challenges in designing studies with human patients. This Keystone Symposia conference will provide an opportunity for researchers from diverse backgrounds to exchange ideas and develop new collaborations to promote future research on infections during pregnancy.