Abstract
Pathogenic microorganisms, such as bacteria and viruses, readily enter the oral cavity because it is
constantly exposed to outside air, for which actions of salivary immune components functioning as the
frontline defense mechanism are important. Human-β-defensin-2 (HBD-2) plays an important role in
prevention of upper airway infection. It is secreted by airway epithelial cells and salivary glands and
contributes to antimicrobial activity against viruses and bacteria. We previously reported that antimicrobial
peptide expression is suppressed by temporary or chronic exercise stress, leading to susceptibility to upper
airway infection. In this study, focusing on moderate exercise considered to increase intraoral immune
function, we investigated the influence of one-year exercise training on the oral local immune function and
Streptococcus mutans-suppressing effect. The salivary HBD-2 levels were 35.9±7.4 and 60.4±8.7 pg/mL
before and after intervention, respectively, showing that it significantly increased (p<0.001). Regarding
the Streptococcus mutans-suppressing effect, a significant bacterial growth-inhibitory effect was noted
after intervention compared with that before intervention (p<0.01). Focusing on moderate exercise training
considered to increase intraoral immune function, the influence of one-year exercise training on the oral
local immune function and Streptococcus mutans growth-inhibitory effect was investigated.
