Kinetics of inflammatory response following intramuscular injection of aluminum adjuvant.

摘要

Aluminum-containing adjuvants are widely used in human and veterinary vaccines, but their mechanism of action is not well understood. Recent evidence suggests an important role for inflammation in the immune response to aluminum-adjuvanted vaccines. To better understand this process, vaccines with aluminum adjuvant were injected into naive or previously immunized mice and the injection sites were characterized for the corresponding primary and secondary immune response at different time points after immunization. Inflammatory cells appeared at the injection site between two hours and six hours after primary vaccination, dominated by neutrophils at first and followed by other types of cells, including eosinophils, macrophages, and dendritic cells. The number of cells at the injection site increased over time, except neutrophils, which decreased in number after day 2. In secondary immunized mice, a faster and more robust recruitment of eosinophils, macrophages, and dendritic cells was observed at the injection site. Phagocytosis of aluminum adjuvant was observed in vivo, and was predominantly performed by macrophages. Since neutrophils accumulated first in response to aluminum adjuvanted vaccines, we evaluated their role by specifically depleting them using a monoclonal antibody before vaccination. However, this treatment did not affect the recruitment of other inflammatory cells and did not change the quality and quantity of the subsequent humoral response.