Infection is the major cause of health impairment in elderly persons. Immune function declines with age. In order to keep the elderly in good health, it is necessary to control the age-associated decline of their immune function. Components of a non-specific immune system arc neutrophils, macrophages and NK cells. A specific immune system is composed of T lymphocytes and B lymphocytes. T lymphocytes differentiate in the thymus. Age-associated atrophy of the thymus causes a decline in T lymphocyte function. It is essential in aging of the immune system. B lymphocytes produce immunoglobulin to act as antibodies. With aging, abnormal antibodies such as autoantibodies and monoclonal immunoglobulin increase, and the number of normal antibodies compared to foreign antigens decrease. Exercise influences the autonomic nervous system, hypothalamo-hypophyseal system, and immune system. Moderate exercise enhances immune function, and severe exercise causes immune function decline. Immune function declines after a severe single bout of exercise, and an “open window” of infections occurs. Appropriate exercise training may improve immune function. Recently, it was shown that exercise training for one year increased the contents of secretory immunoglobulin A in saliva in elderly persons. This result suggests that long-term exercise training improves immune function in elderly persons.

Objective: The purpose of this study was to examine the effects of Coenzyme Q10 (CoQ10) supplementation on salivary secretory immunoglobulin A (SIgA) and health-related Quality of Life (QOL) in middle-aged and elderly individuals. Methods: Sixty healthy middle-aged and elderly individuals were assigned randomly to a CoQ10 supplementation group (n = 30) or a placebo supplementation group (n = 30) using a double blind method. Subjects took 150 mg CoQ10 or placebo per day for 8 weeks. Salivary SIgA secretion rate and SF-36 test (physical and mental health-related QOL) were determined before and after the intervention. Results: CoQ10 group showed that a tendency to increase of salivary SIgA secretion rate (p = 0.08), although placebo group did not show significant change. Physical health-related QOL did not significantly change in both groups. Vitality and mental health scores, which were subscale of mental health-related QOL, were significantly increased after the intervention in CoQ10 group (p < 0.05), although placebo group did not show significant change. Conclusion: 8 weeks of CoQ10 supplementation may bolster SIgA-mediated oral immunity and mental health-related QOL in middle-aged and elderly individuals.

To investigate the effect of intense exercise on immunological factors in saliva, we measured secretory immunoglobulin A (sIgA), lactoferrin and fibronectin. We used a reliable saliva collection method that has already been reported. Timed saliva samples were obtained from 16 healthy young males. Samples were collected before, immediately after, 1 day after and 5 days after endurance running (42.195 km) . The concentrations (μg/ml) of sIgA, lactoferrin and fibronectin were measured by ELISA, and the secretion rates (μg/min) of each were calculated. Immediately after the exercise, the concentration of total protein in saliva increased significantly, but the sIgA secretion rate decreased to 53%. The secretion rates of both lactoferrin and fibronectin did not change significantly. The local immune system plays an important role in mucosal surface defense against upper respiratory tract infection. The sIgA level in the oral cavity was temporarily decreased after intense exercise. A decreased sIgA secretion rate might partly explain the increased susceptibility to upper respiratory tract infection after endurance exercise.

The purpose of this study was to investigate the relation between alterations of salivary secretory immunoglobulin A (SIgA) and the occurrence of upper respiratory tract infections (URTI) in rugby football players.We examined the relationship between the onset of URTI and the daily alterations of SIgA levels in 32 male collegiate rugby football players (20.5±1.3 years) during summer training camp for 36 days.Total of 6 in 32 subjects had the appearance of URTI symptoms (18 %). SIgA secretion rate decreased significantly in the middle of training camp compared to the baseline (P＜0.05). Furthermore, SIgA secretion rate during the appearance of URTI (13.7±1.1μg/min) were significantly lower than that without symptoms (19.2±1.4 μg/min, P＜0.01). These results suggest that serial monitoring of SIgA may be useful to assess the risk status of URTI affection in athletes.

The purpose of this study was to investigate the effects of Lactobacillus gasseri OLL2809 (MG2809) intake on salivary secretory immunoglobulin A (SIgA) secretion and incidence of upper-respiratory tract infection (URTI) symptoms among college rugby athletes. Sixty-seven subjects were assigned to a MG2809 group (n = 33) or a placebo group (n = 34) using a double-blind procedure. Each subject took MG2809 or placebo tablets for 9 weeks. Resting saliva samples were collected before (0 week) and after 2, 4, 6, 8, and 9 weeks of the MG2809 intakes. A log of URTI symptoms was kept every day during the study period. Our results showed that salivary SIgA level was significantly increased at 6 weeks in the MG2809 group (p < 0.05), although the placebo group did not show significant change. The duration of URTI symptoms episode in the MG2809 group was significantly shorter than that in the placebo (p < 0.05). These results suggest that regular intake of MG2809 may enhance oral immune function mediated by SIgA and reduce the risk of URTI in athletes.

It is generally accepted that visually impaired individuals generally have a low aerobic capacity, which may be partly attributed to a lack of physical activity, and have hypothesized that their response to exercise may differ from that of normal-sighted people. In this study, we investigated the effect of exercise on local immunity in the oral cavity in 24 visually impaired males (n=8 ; totally blind group, n=16 ; partially sighted group) and 8 normal-sighted males. The subjects performed submaximal graded bicycle ergometer exercise to an intensity of 75% heart rate max for 12 min. Before and immediately after exercise, we collected timed saliva samples and measured secretory immunoglobulin A (sIgA) .
The totally blind group had lower levels of aerobic capacity and a lower sIgA secretion rate compared to the partially sighted and sighted groups. Immediately after exercise, the sIgA secretion rate tended to increase in the totally blind group.
It is suggested that the exercise-induced response of local immunity in the totally blind group differed from that in the other groups.

It is generally accepted that secretory immunoglobulin A (sIgA) is a major effector of local immunity in the oral cavity. The salivary sIgA level is known to be temporarily decreased after an acute single bout of intense exercise. On the other hand, the effect of continuous exercise training on salivary sIgA has been controversial. In the present study, we collected timed saliva samples from collegiate kendoists using the reliable saliva collection method that has already been reported. The collection was performed before, during and after a traditional high-intensity 10-day training camp during the coldest part of the winter. We investigated the effect of repetitious intense exercise training on resting sIgA levels in saliva.
The subjects were 19 males and 8 females (age: 19.9±0.5 years) who took part in the camp. We obtained saliva samples before the camp, on the first and the 10th days of the camp, and 4 and 10 days after the camp at 5 p. m. The concentration of sIgA was measured by ELISA, and the sIgA secretion rate was calculated.
The resting sIgA secretion rate decreased significantly during the camp. It remained at a lower level 4 and 10 days after the camp compared to the initial level, although it tended to recover gradually. Prolonged suppression of the resting sIgA secretion rate during a traditional winter kendo training camp might be induced by repetition of high-intensity training.

The purpose of the present study was to investigate the effects of long-term exercise training on immune function in elderly individuals. This study was conducted on 27 sedentary subjects including 7 males and 20 females aged 66.1±4.2 yrs. (range of 60 to 77 yrs.) who participated in a 12-month exercise program. The subjects attended the exercise program 4.4 ± 1.7 times per month. Peripheral blood samples were taken prior to, and at 5 and 12 months during the exercise training program. Each lymphocyte subset (natural killer: NE, T, cytotoxic T: Tc, helper T: Th, memory-Th and NKT) count in the samples was measured using flow cytometry. Results indicated that NE and Tc cell counts were not significantly altered. Whereas, T and Th cell counts were significantly elevated after 12 months, and memory-Th and NET cell counts were significantly elevated after 5 and 12 months of exercise training. These results suggest that long-term exercise training may be a stimu lus to increase and or maintain immune function in elderly individuals.