UC Davis

Early-life antibiotic treatment is common in infants, but the consequences on respiratory health have not been examined. This is although it has been shown in mouse models that antibiotic treatment can adversely impact the response to respiratory pathogens, including infection with influenza virus. Our research examined whether early-life antibiotic treatment in infant rhesus macaques adversely impacted the developing lung and immune system. We found that antibiotic treatment could alter pulmonary gene expression, lung function, weight gain with age, and circulating immune cell concentrations, with effects found in male monkeys and not female monkeys. This occurred in the presence and absence of influenza A H1N1 virus infection. A fecal microbiota transplant after antibiotic treatment reversed some, but not all, effects. We further examined whether antibiotic treatment influenced the memory T cell response to infection and found compartment-dependent effects of antibiotics on the frequency of memory T cells and interferon-γ+ memory T cells. Our results are consistent with other studies that have found antibiotic treatment can have a more pronounced effect in males and highlight the importance of examining whether early-life interventions can have sexually dimorphic effects. Additionally, our results support the need for interventions that can counteract the consequences of antibiotic treatment, which could promote the health and well-being of infants.