Effects of long-distance running on serum opsonic activity measured by chemiluminescence

Exhaustive exercise such as long-distance running has been shown to increase susceptibility to infection. In order to investigate whether serum opsonic activity plays a role in such conditions, we utilized luminol-dependent and lucigenin-dependent chemiluminescence (LmCL and LgCL). We took serum samples from 24 male marathon runners before and after running 30 km. Neutrophils were isolated from the peripheral blood of healthy volunteers. Serum opsonic activity was examined by measuring neutrophil ROS stimulated with zymosan particles opsonized by the serum samples. Immunoglobulin and complement levels in the serum were also measured. After a 30 km run, the maximum light emission was increased and the time to reach the maximum light emission was shortened significantly (p < 0.05) in LmCL. However, there were no significant changes in the immunoglobulin and complement levels. The increase of ROS production may suggest that serum opsonic activity is accelerated after running 30 km. Thus, serum opsonic activity might not play a significant role in the susceptibility to infection after long-distance running.