Systematic optimization of a domestic nose-only aerosol exposure system for respiratory pathogen research in nonhuman primates

Imported aerosol exposure systems for nonhuman primates are often costly and limited in availability, restricting advanced research on respiratory pathogens. To address this, a domestically developed nose-only aerosol exposure system was systematically evaluated and optimized to enhance performance and accessibility. Comprehensive assessment of aerosol generation, transmission, and sampling components revealed key areas for improvement, which were targeted through four modifications: adoption of a vibrating mesh nebulizer for physiologically relevant particle sizes, reduction of plenum chamber volume to minimize losses, shortening of transmission pathways, and addition of 0.25% newborn calf serum to sampling media for viral preservation. These changes collectively minimized viral viability loss during aerosol delivery. The optimizations resulted in a 2.19 log 10 -units increase in spray factor (SF), enabling aerosol concentrations to exceed 10 4.43 50% cell culture infectious dose (CCID 50 )/L at the exposure port using 10 7.25 CCID 50 /mL viral titer in the generator. Functional validation with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Cynomolgus macaques suggested successful viral delivery and infection, evidenced by detectable viral shedding and seroconversion. The optimized system provides a viable alternative to imported equipment, addressing challenges of high costs and limited availability. This approach validates a feasible methodology for advancing domestic capabilities in respiratory infectious disease research and holds potential for future applications in vaccine development and pandemic preparedness.