Environmental mixtures, immune function, and vaccine antibody response in children - Project Summary I am an environmental epidemiologist and exposure scientist by training with a primary research interest in the impact of environmental exposures on immune function and vaccine response – a critical public health issue highlighted by COVID-19. The goal of this proposal is to obtain training and acquire the skills necessary to become an independent investigator at the air pollution-immunology-infectious disease nexus. I have assembled a world-class mentoring team with interdisciplinary expertise in immunology, toxicology, biostatistics, data science, exposure science, exposomics, and epidemiology. The proposed training plan includes formal coursework, field work, clinical observations, laboratory rotations, academic meetings and conferences, and a variety of activities designed for leadership and professional development. I am confident that by the end of the K99 phase of this proposal, my existing expertise combined with the training proposed in this project will allow me to establish myself as an independent investigator in a tenure-track faculty position, with the skillset to build my future independent research program integrating exposure science, epidemiology, and infectious diseases. For this proposal, I will leverage the Programming Research in Growth, Environment and Social Stress (PROGRESS) cohort, an ongoing longitudinal pregnancy/birth cohort based in Mexico City to investigate the impact of ambient environmental pollutants on the antibody response to routine vaccinations. Specifically, I will: 1) build a daily ozone model for Mexico City, which will be integrated with our existing models for fine particulate matter, nitrogen dioxide, and temperature that already exists for the area; 2) assess the association between these ambient environmental pollutants with vaccine antibody levels to routine vaccinations; 3) assess the association between the same pollutants and levels of several specific cell types involved in vaccine response; and 4) explore whether the associations between ambient environmental pollutants and vaccine antibody levels are partially or fully mediated through the immune cell population subsets assessed in #3). This research proposal has several innovations, including the generation of new exposure data (the first of its kind in Mexico City), the use of cutting-edge statistical approaches, and its leverage of both extant data and new measurements that addresses a unique research question while maximizing cost effectiveness. If successful, this work will be able to significantly foster interdisciplinary research and advance our understanding of a critical and urgent public health issue.