sIgA Secretion Research Articles

Influence of a Fed or Fasted State on the s-IgA Response to Prolonged Cycling in Active Men and Women

This study investigated the effect of a fed or fasted state on the salivary immunoglobulin A (s-IgA) response to prolonged cycling. Using a randomized, crossover design, 16 active adults (8 men and 8 women) performed 2 hr of cycling on a stationary ergometer at 65% of maximal oxygen uptake on 1 occasion after an overnight fast (FAST) and on another occasion 2 hr after consuming a 2.2-MJ high-carbohydrate meal (FED). Timed, unstimulated whole saliva samples were collected immediately before ingestion of the meal, immediately preexercise, 5 min before cessation of exercise, immediately postexercise, and 1 hr postexercise. The samples were analyzed for s-IgA concentration, osmolality, and cortisol, and saliva flow rates were determined to calculate s-IgA secretion rate. Saliva flow rate decreased by 50% during exercise (p < .05), and s-IgA concentration increased by 42% (p < .05), but s-IgA secretion rate remained unchanged. There was a 37% reduction in s-IgA:osmolality postexercise (p < .05), and salivary cortisol increased by 68% (p < .05). There was no effect of FED vs. FAST on these salivary responses. The s-IgA concentration, secretion rate, and osmolality were found to be significantly lower in women than in men throughout the exercise protocol (p < .05); however, there was no difference between genders in saliva flow rate, s-IgA:osmolality ratio, or cortisol. These data demonstrate that a fed or fasted state 2 hr before exercise does not influence resting s-IgA or the response to prolonged cycling. Furthermore, these results show lower levels of s-IgA and osmolality in women than in men at rest.

Massage After Exercise-Responses of Immunologic and Endocrine Markers: A Randomized Single-Blind Placebo-Controlled Study

The effectiveness of massage for postexercise recovery remains unclear, despite numerous studies on this issue. The aim of this study was to determine the effect of massage on endocrine and immune functions of healthy active volunteers after intense exercise. After repeated Wingate tests, the effects of whole-body massage and placebo on salivary cortisol, immunoglobulin A (IgA), and total protein levels were compared using a between-group design. Sixty healthy active subjects (23 women, 37 men) underwent 2 exercise protocol sessions at least 2 weeks apart and at the same time of day. The first session familiarized participants with the protocol. In the second session, after a baseline measurement, subjects performed a standardized warm-up followed by three 30-second Wingate tests. After active recovery, subjects were randomly allocated to massage (40-minute myofascial induction) or placebo (40-minute sham electrotherapy) group. Saliva samples were taken before and after the exercise protocols and after recovery. In both groups, the exercise protocol induced a significant increase in cortisol (p < 0.001), decrease in salivary IgA (sIgA) (p < 0.001), and increase in total proteins (p = 0.01) in saliva. Generalized estimating equations showed a significant effect of massage on sIgA rate (p = 0.05), a tendency toward significant effect on salivary total protein levels (p = 0.10), and no effect on salivary flow rate (p = 0.55) or salivary cortisol (p = 0.39). The sIgA secretion rate was higher after the recovery intervention than at baseline among women in the massage group (p = 0.03) but similar to baseline levels among women in the placebo group (p = 0.29). Massage may favor recovery from the transient immunosuppression state induced by exercise in healthy active women, of particular value between high-intensity training sessions or competitions on the same day.

Salivary immunoglobulin A response at rest and after exercise following a 48 h period of fluid and/or energy restriction

The aim was to investigate the effects of a 48 h period of fluid, energy or combined fluid and energy restriction on salivary IgA (s-IgA) responses at rest and after exercise. Thirteen healthy males (age 21 (sem 1) years) participated in four randomised 48 h trials. In the control trial participants received their estimated energy (12,154 (sem 230) kJ/d) and water (3912 (sem 140) ml/d) requirements. On fluid restriction (FR) participants received their energy requirements and 193 (sem 19) ml water/d to drink and on energy restriction (ER) participants received their water requirements and 1214 (sem 25) kJ/d. Fluid and energy restriction (F+ER) was a combination of FR and ER. After 48 h, participants performed a 30 min treadmill time trial (TT) followed by rehydration (0-2 h) and refeeding (2-6 h). Unstimulated saliva was collected at 0, 24 and 48 h, post-TT, and 2 and 6 h post-TT. Saliva flow rate (sflw) and s-IgA (ELISA) remained unchanged in control conditions and on ER. However, 48 h on FR decreased sflw (64 %) which most probably accounted for the increase in s-IgA concentration (P < 0.01). Despite a decrease in sflw (54 %), s-IgA concentration did not increase on F+ER, resulting in a decreased s-IgA secretion rate by 24 h (0 h: 20 (sem 2); 24 h: 12 (sem 2) microg/min; P < 0.01). Post-TT s-IgA secretion rate was not lower compared with 48 h on any trial. s-IgA secretion rate returned to within 0 h values by 6 h post-TT on F+ER. In conclusion, a 24-48 h period of combined F+ER decreased s-IgA secretion rate but normalisation occurred upon refeeding.

Autonomic neurotransmitters modulate immunoglobulin A secretion in porcine colonic mucosa

Secretory immunoglobulin A (sIgA) plays a crucial role in mucosal surface defense. We tested the hypothesis that colonic sIgA secretion is under enteric neural control. Immunohistochemistry of the porcine distal colonic mucosa revealed presumptive cholinergic and adrenergic nerve fibers apposed to secretory component (SC)-positive crypt epithelial cells and neighboring IgA + plasmacytes. The cholinomimetic drug carbamylcholine elicited rapid, atropine-sensitive IgA secretion into the luminal fluid bathing mucosal explants mounted in Ussing chambers. The adrenergic receptor agonist norepinephrine also increased IgA secretion, an action inhibited by phentolamine. These effects were independent of agonist-induced anion secretion. In Western blots of luminal fluid, both agonists increased the density of protein bands co-immunoreactive for IgA and SC. Mucosal exposure to enterohemorrhagic Escherichia coli did not affect IgA secretion, and carbamylcholine treatment did not affect mucosal adherence of this enteropathogen. Acetylcholine and norepinephrine, acting respectively through muscarinic cholinergic and alpha-adrenergic receptors in the colonic mucosa, stimulate sIgA secretion and may enhance mucosal defense in vivo.

Changes in Mucosal and Humoral Atopic-Related Markers and Immunoglobulins in Elite Cyclists Participating in the Vuelta a España

Atopic-related factors, humoral and mucosal immunoglobulins (Ig), and cortisol were measured in 17 professional cyclists competing in the 2003 Vuelta a España (a three-week multi-stage race). Venous blood and saliva samples were obtained the morning before the start of the race (T0), on the first rest day after 10 days of racing (T1), and before the start of the last stage after 21 days of racing (T2). Atopic-related factors, IgE, eosinophil cationic protein (ECP), and eosinophils, were significantly altered during the race. Serum IgE (T1: + 10 %) and ECP (salivary, T1: 113 % and serum, T2: 155 %) were significantly increased, while eosinophils (T1: - 32 %, T2: - 55 %) were significantly lower, than pre-race levels. Salivary sIgA secretion rate was significantly decreased at T2 (- 36 %). Pearson product-moment correlations revealed a modest correlation between salivary sIgA and salivary ECP (T1: r = 0.30; T2: r = 0.48; p < 0.01). Serum IgM, total IgG, IgG1, IgG2, IgA levels, at T1 and T2, and cortisol at T2, were significantly lower than pre-race levels. In conclusion, the elevation in IgE and ECP suggests an up-regulation of atopic-related factors in professional cyclists participating in the Vuelta a España. The correlation between salivary sIgA and salivary ECP indicates a role for sIgA in mediating mucosal inflammation. The alterations in Ig levels may indicate Ig isotype switching. An increasing state of hormonal fatigue may have influenced the observed immune alterations.

Modulation of intestinal mucosal immunity by dietary polyunsaturated fatty acids in chickens

This study was undertaken to investigate the effects of dietary polyunsaturated fatty acids (PUFA) on intestinal immune responses and cytokines secretions in chickens at nutrition-immunity level. The proportion of CD3+CD8+ lymphocytes of intestinal mucosa in CO group was higher on d 21 than that in FO (p < 0.01) and PO (p < 0.05) group. The proportion of CD3+CD4+ lymphocytes of FO group was greatly significantly higher on d 21, relative to PO or CO group. The FO treatment enhanced the sIgA concentration in jejunum on d 42, compared with CO and PO group. Fish oil and corn oil had similar effects on enhancing IL-2 secretion of PBMC, and converse effects on IL-4 secretion. Compared with PO group, chickens supplemented with fish oil or corn oil had greater concentration of intestinal mucosal membrane phospholipids on d 21 and d 42. In conclusion, the changes of intestinal lymphocytes membrane phospholipids in FO or CO group would modulate lipid second messengers. The changes of CD expression would affect sIgA secretion of intestinal lymphocytes. Diet supplemented with corn oil or fish oil can affect cytokines secretion of PBMC in chickens, which works on systemic and mucosal immune response.

Salivary IgA Responses to Prolonged Intensive Exercise following Caffeine Ingestion

Prolonged, intensive exercise is associated with a reduction in concentration and secretion of salivary IgA (s-IgA). Saliva composition and secretion are under autonomic nervous system control, and caffeine ingestion, a widespread practice among athletes for its ergogenic properties, is associated with increased sympathetic nervous system activation. Therefore, this study investigated the influence of caffeine ingestion on s-IgA responses to prolonged, intensive exercise. In a randomized crossover design, 11 endurance-trained males cycled for 90 min at 70% VO2peak on two occasions, having ingested 6 mg x kg(-1) body mass of caffeine (CAF) or placebo (PLA) 1 h before exercise. Whole, unstimulated saliva samples were collected before treatment (baseline), preexercise, after 45 min of exercise (midexercise), immediately postexercise, and 1 h postexercise. Venous blood samples were collected from a subset of six of these subjects at baseline, preexercise, postexercise, and 1 h postexercise. An initial pilot study found that caffeine ingestion had no effect on s-IgA concentration, secretion rate, or saliva flow rate at rest. Serum caffeine concentration was higher on CAF than PLA at preexercise, postexercise, and 1 h postexercise (P < 0.001). Plasma epinephrine concentration was higher on CAF than PLA at pre- and postexercise (P < 0.05). s-IgA concentration was higher on CAF than PLA at mid- and postexercise (P < 0.01), and s-IgA secretion rate was higher on CAF than PLA at midexercise only (P < 0.02). Caffeine ingestion did not affect saliva flow rate. Saliva alpha-amylase activity and secretion rate were higher on CAF than PLA (main effect for trial, P < 0.05). These findings suggest that caffeine ingestion before intensive exercise is associated with elevated s-IgA responses during exercise, which may be related to increases in sympathetic activation.

Most probable origin of coeliac disease is low immune globulin A in the intestine caused by malfunction of Peyer’s patches

Coeliac disease frequency increases by obscure reasons and affects in some Western countries as much as 1% of the populations. The second one of monozygotic twins does not develop the disease in 100% but only in 20-50%. To unravel these mysteries, literature was searched to determine the disease background and find suggestions for research and prevention. The causal antigen of coeliac disease is gluten of wheat that is neutralised in the intestine by secretory immune globulin A (sIgA). SIgA is secreted by the secondary (lymphoid) immune system that develops in a newborn infant after the primary (central) immune organs thymus and bone marrow have been primed with antigens of the intestine. Predisposed infants are sensitive for development of coeliac disease during the time without sIgA secretion into the intestine. The risk of the disease diminishes when sIgA cycles of gluten neutralisation develop. Peyer's patches (PP) of the secondary immune system play a central role in the cycles and possibly do not function well in the case of coeliac disease. Coeliac disease in predisposed infants may be prevented by delay of bread consumption till the time of normal sIgA secretion and by application of a challenge period with gluten (see Discussion). It is concluded that sIgA secretion into body cavities and malfunction of immune cells in PP should be included in the future research of coeliac disease as well as in more allergic diseases (type 1 diabetes, Crohn disease, asthma, hay fever).

The Impact of Abbreviated Progressive Muscle Relaxation on Salivary Cortisol and Salivary Immunoglobulin A (sIgA)

This study examined the acute effects of relaxation training on salivary cortisol and salivary immunoglobulin A (sIgA). Members of age- and gender-matched undergraduate student pairs were randomly assigned to an experimental or control group. Forty-one experimental subjects were led through Abbreviated Progressive Relaxation Training (APRT) during a 1-h laboratory session; 14 control subjects merely sat quietly in the laboratory for an equal amount of time. All subjects provided pre- and post-intervention saliva samples and self-report data on state anxiety, perceived stress, and relaxation levels. Heart rate was also monitored immediately before and after APRT or quiet sitting. Results indicated that a brief relaxation exercise led to experimental subjects having significantly lower levels of post-intervention salivary cortisol (p = .036) and significantly higher levels of post-intervention sIgA concentration (p < .001) and secretion rate (p < .001) than control subjects. The data suggest that relaxation training may play a role in immunoenhancement.

The effects of carbohydrate supplementation during repeated bouts of prolonged exercise on saliva flow rate and immunoglobulin A

The purpose of this study was to assess the effect of carbohydrate (CHO) feeding during different periods of two 90-min cycling bouts (the first bout began at 09:00 h and the second bout began at 13:30 h) at 60% maximal oxygen uptake ([Vdot]O2max) on saliva flow rate and saliva immunoglobulin A (sIgA) responses to the second exercise bout. The study consisted of three investigations: carbohydrate supplementation during (1) the first hour of the recovery interval (CHO-REC), (2) during the first bout of exercise and (3) during the second bout of exercise. Each investigation included two trials completed in a counterbalanced order and separated by at least 4 days. Participants consumed a lemon-flavoured 10% w/v carbohydrate beverage or placebo (22 ml · kg−1 body mass) in the first hour of the recovery interval (n = 8) and 500 ml just before exercise, followed by 250 ml every 20 min during exercise in the first (n = 9) and second exercise bouts (n = 9). Timed unstimulated saliva samples were collected at 10 min before exercise, after 48 – 50 min of exercise and during the last 2 min of exercise, at 1 h post exercise, 2 h post exercise (first exercise bout only), and 18 h post exercise (second exercise bout only). Venous blood samples were taken 5 min before exercise and immediately after exercise for both exercise bouts in all trials. The main findings of the present study were as follows. First, carbohydrate ingestion during both exercise bouts, but not during the recovery interval, better maintained plasma glucose concentrations and attenuated the increase in plasma adrenaline and cortisol concentrations after the second exercise bout compared with placebo. Second, carbohydrate feeding had no effect on saliva flow rate and sIgA secretion rate compared with placebo. Third, saliva flow rate and sIgA concentration returned to pre-exercise bout 1 values within 2 h in all trials. Fourth, there was no delayed effect of exercise on oral immunity. These findings suggest that carbohydrate ingestion during the first or second bout of exercise, but not during the recovery interval, is likely to better maintain plasma glucose concentrations and attenuate the responses of plasma stress hormones to a second exercise bout than ingestion of fluid alone. Two bouts of 90 min cycling at 60% [Vdot]O2max on the same day appears to inhibit saliva flow rate during the second exercise bout but does not alter sIgA transcytosis. Our results show that carbohydrate ingestion during any period of two prolonged exercise bouts does not induce different effects on oral immunity compared with placebo.

Effects of competition, exercise, and mental stress on secretory immunity

It has been suggested that the psychological stress associated with competitive sports events may help to explain the increased susceptibility to respiratory infections due to reductions in secretory immunity. In the current study, we investigated the influence of competitive exercise and psychological stress on secretory immunoglobulin A (s-IgA). Salivary s-IgA and heart rate were measured in 62 healthy young recreationally active men at rest and, in a between-subjects design, following one of four 8-min tasks: mental arithmetic, cycling at workloads of 60 to 180 W (mean = 146 W), mental arithmetic while cycling, or competitive cycling. Mental arithmetic was associated with significant increases in s-IgA concentration (mean = 49 μg · min−1) and s-IgA secretion rate (mean = 25 μg · ml−1) compared with rest, while mental arithmetic combined with exercise was associated with a significant increase in s-IgA concentration only (mean = 124 μg · min−1). In contrast, competitive exercise and exercise alone did not influence s-IgA concentration or secretion rate. Heart rate increased modestly to mental arithmetic (mean = 7 beats · min−1) and substantially, and similarly, to the three exercise tasks (mean = 56(62 beats · min−1). The hypothesis that the psychological stress of competitive exercise contributes to increased susceptibility to infection via reductions in s-IgA requires further investigation.

Preganglionic parasympathectomy decreases salivary SIgA secretion rates from the rat submandibular gland

Immunoglobulin A (IgA) is transported into saliva by salivary cells expressing the polymeric immunoglobulin receptor (pIgR). In rat salivary glands, autonomic nerves stimulate this process. To examine how nerves affect pIgR-mediated IgA secretion, the chorda-lingual nerve was sectioned. One week after preganglionic parasympathectomy, both the stimulated and unstimulated rates of salivary IgA secretion were reduced, despite similar glandular amounts of IgA. Biochemical analysis of cells from parasympathectomised and control glands indicated reduced membrane expression of pIgR. It appears the removal of long-term parasympathetic input has affected the routing of pIgR within salivary cells and reduced the SIgA transport into saliva.

Salivary IgA response to prolonged exercise in a hot environment in trained cyclists

The aim of this study was to determine the effects of prolonged exercise in hot conditions on saliva IgA (s-IgA) responses in trained cyclists. On two occasions, in random order and separated by 1 week, 12 male cyclists cycled for 2 h on a stationary ergometer at 62 (3)% V(.)O(2 max) [194 (4) W; mean (SEM)], on one occasion (HOT: 30.3 degrees C, 76% RH) and on another occasion ( 20.4 degrees C, 60% RH). Water was available ad-libitum. Venous blood samples and 2-min whole unstimulated saliva samples were collected at pre, post and 2 h post-exercise. The s-IgA concentration was determined using a sandwich-type ELISA. Exercising heart rate, rating of perceived exertion, rectal temperature, corrected body mass loss (P<0.01) and plasma cortisol (P<0.05) were greater during HOT. The decrease in plasma volume post-exercise was similar on both trials [HOT: -6.7 (1.1) and -6.6 (1.3)%; P<0.01]. Saliva flow rate decreased post-exercise by 43% returning to pre-exercise levels by 2 h post-exercise (P<0.05) with no difference between trials. Saliva IgA concentration increased post-exercise (P<0.05) with no difference between trials. Saliva IgA secretion rate decreased post-exercise by 34% returning to pre-exercise levels by 2 h post-exercise (P<0.05) with no difference between trials. These data show that a prolonged bout of exercise results in a reduction in s-IgA secretion rate. Additionally, these data demonstrate that performing prolonged exercise in the heat, with ad libitum water intake, does not influence s-IgA responses to prolonged exercise.

The effect of single and repeated bouts of prolonged cycling and circadian variation on saliva flow rate, immunoglobulin A and α-amylase responses

The purpose of this study was to establish the effect of exercise at different times of day on saliva flow rate, immunoglobulin A (sIgA) concentration and secretion rate, and alpha-amylase activity, and to establish how these parameters change following a second exercise bout performed on the same day. In a counterbalanced design, eight male volunteers participated in three experimental trials separated by at least 4 days. On the trial with afternoon exercise only, the participants cycled for 2 h at 60% VO2max starting at 14:00 h. On the other two trials, participants performed either two bouts of exercise at 60% VO2max for 2 h (the first started at 09:00 h and the second started at 14:00 h) or a separate resting trial. Unstimulated saliva samples were obtained 10 min before exercise, after 58 - 60 min and during the last 2 min of exercise, and at 1 h and 2 h after exercise. Venous blood samples were taken 5 min before exercise and immediately after exercise for both bouts. Participants remained fasted between 23:00 h on the day before the trials and 18:00 h on the day of the trial. Circadian variations were found in sIgA concentration, which decreased with time from its highest value in the early morning to its lowest value in the evening, and salivary alpha-amylase secretion rate, which increased from its lowest value in the morning to its highest value in the late afternoon. Cycling at 60% VO2max for 2 h significantly decreased saliva flow rate, increased sIgA concentration and alpha-amylase activity, but did not influence sIgA secretion rate. Performing prolonged cycling at different times of day did not differentially affect the salivary and plasma hormonal responses in the short term. Performance of a second prolonged exercise bout elicited a greater plasma stress hormone response but did not appear to compromise oral immunity acutely. These findings also suggest that, in terms of saliva secretion, sIgA and alpha-amylase responses, a 3 h rest is enough to recover from previous strenuous exercise. During such exercise, sympathetic stimulation appears to be strong enough to inhibit saliva flow rate; however, it appears that it does not increase sIgA output via transcytosis.

Intranasal delivery of chitosan–DNA vaccine generates mucosal SIgA and anti-CVB3 protection

Coxsackievirus B3 infections are common causes of acute and chronic myocarditis with no effective prophylactic treatment available. We describe here a prophylactic strategy using chitosan–DNA intranasal immunization to induce CVB3 specific immune responses. Intranasal administration with chitosan–DNA complex prepared by votexing DNA with chitosan, a natural mucus absorption enhancer, resulted in transgenic DNA expression in mouse nasopharynx. Mice immunized with chitosan–DNA (pcDNA3-VP1) encoding VP1, major structural protein of CVB3, produced much higher levels of serum IgG and mucosal secretory IgA compared to mice treated with pcDNA3-VP1 or pcDNA3. Increased virus-specific cytotoxic activity of spleen cells derived from chitosan–DNA vaccinated mice was also determined. Chitosan-pcDNA3-VP1 intranasal immunization resulted in 42.9% protection of mice against lethal CVB3 challenge and a significant reduction of viral load after acute CVB3 infection. Meanwhile no myonecrosis or infiltrating immune cells indicating ongoing myocarditis was detected in hearts of surviving mice treated with chitosan–DNA. Together, Our data show that intranasal delivery of chitosan–DNA vaccine successfully induced mucosal SIgA secretion and might be a promising vaccine candidate to protect against CVB3 infection.

Immune and oxidative changes during and following the Western States Endurance Run.

Changes in immune and oxidative stress parameters were measured in ultramarathon runners competing in the 160-km Western States Endurance Run. Forty-five runners agreed to provide blood and saliva samples the morning before the race event, at the 90-km aid station, and 5 - 10 min post-race. Upper respiratory tract infection (URTI) during the two-week period post-race was assessed retrospectively by telephone interviews. Forty subjects completed 90-km (race time, 13.1 +/- 0.3 h), and 31 completed the 160-km race event (27.0 +/- 0.4 h). The blood neutrophil and monocyte counts rose 249 % and 214 %, respectively, in the 31 finishers. Salivary IgA (sIgA) secretion rate decreased significantly from 508 +/- 40 micro g/min pre-race, to 287 +/- 39 micro g/min at 90-km, and 254 +/- 30 micro g/min post-race (50 % decrease). Significant increases were measured in cytokines at 90-km and post-race, with post-race IL-10 increasing 9.5-fold, IL-1ra 6.1-fold, IL-6 50.2-fold, and IL-8 2.5-fold over pre-race levels. Post-race indicators of oxidative stress, F (2)-isoprostane and lipid hydroperoxides, increased 33 % and 88 %, respectively. Pearson product-moment correlations revealed positive correlations at 90-km between F (2)-isoprostane and IL-6 (r = 0.31, p = 0.048), IL-10 (r = 0.31, p = 0.050), and IL-8 (r = 0.43, p = 0.005), but no other significant relationships between immune and oxidative stress indicators at 90-km and post-race. In the group of runners completing at least 90 km of the race, 26 % reported an URTI episode during the two-week period post-race. A low sIgA secretion rate at 90-km was the best predictor of post-race URTI (173 +/- 34 micro g/min in those who later acquired URTI compared to 325 +/- 40 micro g/min in those without URTI, p = 0.007). In conclusion, a modest correlation was found between cytokines and F (2)-isoprostane at 90-km when the greatest oxidative stress occurred, but no other significant correlations in immune and oxidative stress indicators during and following a 160-km ultramarathon race event were noted. About one in four ultramarathoners reported URTI during the two-week period post-race, and a low sIgA secretion rate mid-race best predicted URTI occurrence.

Learned helplessness, generalized self-efficacy, and immune function

Generalized self-efficacy is considered one of important personality traits that determine psychological and physiological stress responses. The present study examined the interaction effects of generalized self-efficacy and controllability of acute stress on salivary secretory immunoglobulin A (s-IgA), task performance, and psychological stress responses in a typical learned helplessness paradigm. Twenty low and 19 high self-efficacy undergraduate women performed two response selection tasks one after another. In the first task, they were exposed to controllable or uncontrollable aversive noise. The second task was identical for all, but perceived controllability was higher for the high self-efficacy group than the low. Performance under uncontrollable condition was lower than controllable condition. The interaction of self-efficacy and controllability was observed only on the s-IgA variable; increase of secretion of s-IgA secretion under stressor uncontrollability was more prominent in the low self-efficacy group than the high. These results suggested that generalized self-efficacy was a moderator of the stressor controllability effect on secretory immunity.

Salivary IgA response to prolonged exercise in a cold environment in trained cyclists.

The purpose of the present study was to determine the effect of a prolonged bout of exercise in freezing cold conditions on saliva immunoglobulin A (s-IgA) responses in endurance-trained males. Using a randomized cross-over design, 15 trained male cyclists cycled for 2 h on a stationary ergometer at 70% VO(2max) in an environmental chamber on one occasion at a temperature of -6.4 +/- 0.1 degrees C (cold) and on another occasion at a temperature of 19.8 +/- 0.2 degrees C (control). Trials began at 12:30 h to avoid the fall in s-IgA concentration that occurs during the morning hours. Unstimulated whole-saliva samples were collected over a 2-min period at preexercise, postexercise, and 2-h postexercise. The s-IgA concentration was determined using a sandwich-type ELISA method. Saliva flow rate decreased postexercise by 31%, returning to preexercise levels by the 2-h postexercise collection (main effect of time: < 0.01). The decrease in saliva flow rate postexercise in the control trial (39% compared with 22% on cold trial) approached significance (interaction: = 0.08) and may have accounted for the corresponding increase in s-IgA concentration postexercise in the control trial (s-IgA concentration: control preexercise; 91 +/- 12; postexercise; 110 +/- 13 mg x L(-1); < 0.05). Saliva IgA secretion rate decreased postexercise by 19.5% returning to preexercise levels by 2-h postexercise measure (main effect of time: < 0.05). These data show that performing a bout of prolonged exercise results in a reduction in s-IgA secretion rate. Additionally, these data demonstrate that performing prolonged exercise in freezing cold conditions does not influence saliva flow rate or s-IgA secretion rate responses to prolonged exercise.

INFLUENCE OF VITAMIN C SUPPLEMENTATION ON SALIVARY IGA CHANGES FOLLOWING AN ULTRAMARATHON

PURPOSE: This randomized study measured the influence of vitamin C (N = 15) compared to placebo (N = 13) supplementation on salivary IgA (sIgA) changes in runners competing in an ultramarathon race. METHODS: Seven days prior to the race, subjects ingested in randomized, double-blind fashion three 500-mg tablets of vitamin C or placebo each day. On race day, blood and saliva samples were collected 1 h pre-race, after 32 km of running, and then again immediately post-race. During the race, runners received 1 l/h carbohydrate beverages (60 g/l) with vitamin C (150 mg/l) or without in a double-blinded fashion. The runners also ingested 2–3 carbohydrate gel packs per hour (25 g each). RESULTS: Subjects in both groups ran 68.7 ± 3.3 km in 9.85 ± 0.36 hours and maintained an intensity of 75.7 ± 1.9% maximal heart rate throughout the ultramarathon race. Plasma ascorbic acid was higher in the vitamin C compared to placebo group pre-race, and increased significantly in the vitamin C group during the race. Saliva volume, sIgA concentration, sIgA secretion, and sIgA: saliva protein ratio all decreased significantly during the race (27–43%, p < 0.001), but the pattern of change in all saliva measures did not differ significantly between groups. No significant correlations were found between post-race plasma vitamin C, oxidative, and saliva measures. CONCLUSION: These data indicate that vitamin C supplementation does not serve as a countermeasure to sIgA changes in runners during or following a competitive ultramarathon race. Supported by grant from the Gatorade Sports Science Institute.

The effects of stress management on symptoms of upper respiratory tract infection, secretory immunoglobulin A, and mood in young adults

Objective: To investigate the efficacy of a stress management programme on symptoms of colds and influenza in 27 university students before and after the examination period. Method: The incidence of symptoms, levels of negative affect, and secretion rate of secretory immunoglobulin A (sIgA) were recorded for 5 weeks before treatment, for the 4 weeks of treatment, and for 8 weeks after treatment in treated subjects and in 25 others who did not participate in stress management. Results: Symptoms decreased in treated subjects but not in controls during and after the examination period. Although sIgA secretion rate increased significantly after individual sessions of relaxation, resting secretion rate of sIgA did not increase over the course of the study. Negative affect decreased after examinations in both groups, but was not affected by treatment. Conclusion: Stress management reduced days of illness independently of negative affect and sIgA secretion rate. Although the component of treatment responsible for this effect has yet to be identified, psychological interventions may have a role in reducing symptoms of upper respiratory tract infection.