Salivary concentrations of IL-8 and IL-1ra after HIIT and MICT in young, healthy adults: A randomized exercise study.

The purpose of this study was to determine whether six weeks of high intensity interval training (HIIT) would lead to greater changes in resting concentrations of salivary IL-8 and IL-1ra than moderate intensity continuous training (MICT) in young, healthy adults, and to determine whether changes in IL-8 and IL-1ra after six weeks of either HIIT or MICT were associated with changes in maximal exercise capacity (VO2max). Participants were randomly assigned to 6 weeks of HIIT (n = 12) or MICT (n = 11), matched for workload. Saliva samples were collected at the beginning (T1) and end (T2) of the intervention, and analyzed for IL-8 and IL-1ra. Participants in both groups had significant improvements in VO2max; there were no group differences in improvements. A greater reduction in IL-8 was observed in the MICT group when compared to the HIIT group (HIIT median: -9.5; MICT median: -82.3 pg/µg of protein; U = 11.5, p < 0.001). When combining the HIIT and MICT group, there were significant reductions in IL-8 from T1 to T2. There was no correlation between changes in IL-8 (r < 0.00) or IL-1ra (r = -0.013) with changes in VO2max. In conclusion, 6 weeks of exercise training leads to a reduction in IL-8; MICT may lead to greater reductions when compared to HIIT. Future research examining longer intervention periods is needed to further elucidate the effects of HIIT and MICT on different pro and anti-inflammatory cytokines.

Characterization of casein-derived peptide bioactivity: Differential effects on angiotensin-converting enzyme inhibition and cytokine and nitric oxide production.

Lactic acid bacteria (LAB) are used as starter cultures in the production of fermented dairy products and have the potential to confer bioactivity relevant to cardiovascular health, as they possess extensive proteolytic systems that liberate small bioactive peptides from larger milk proteins. Certain casein-derived peptides released by various LAB strains during fermentation have been shown to reduce hypertension and to modulate the immune system. We investigated the growth and peptide production of 2 LAB strains, Lactobacillus helveticus R0389 and Lactocaseibacillus rhamnosus R0011, their immunomodulatory activities, as well as their abilities to inhibit the angiotensin-converting enzyme (ACE). Peptide fractions collected from the cell-free supernatant of both medium-grown and milk fermentation cultures were assessed for ACE-inhibitory activity and their effects on the production of proinflammatory and regulatory cytokines by human THP-1 monocytes. Cultures were grown in medium, with or without supplementation with 0.1% casein, or in 3.25% milk fermented with each LAB strain. Casein supplementation increased the growth rate of both LAB strains, and significantly increased ACE-inhibitory activity of peptide fractions collected from both L. helveticus R0389 and L. rhamnosus R0011 cultures grown for 12 h. Fermentation peptide fractions of L. rhamnosus R0011 showed comparable ACE-inhibitory activity to known ACE inhibiting peptides Val-Pro-Pro and Ile-Pro-Pro (up to 79% inhibition) with a significant difference between culture peptide fractions and acidified and nonacidified control fractions collected after 6 d of fermentation. Many milk and casein-derived peptides reported in previous studies have been identified as part of a larger bioactive fraction. We synthesized a group of these peptides to individually assess both ACE-inhibitory and immunomodulatory activity. The known ACE inhibitors Val-Pro-Pro and Ile-Pro-Pro showed similar ACE inhibition to previously published results, while also inducing the production of the regulatory cytokine IL-10 by monocytes in the presence and absence of a proinflammatory stimulant. These synthesized peptides could also induce the production of nitric oxide (NO), a potent vasodilator, in human endothelial cell cultures. Investigating the relationships among these bioactive properties could improve the use of probiotic organisms and their secreted products in the food industry.

Cytokine-specific central monoamine alterations induced by interleukin-1, -2 and -6.

Cytokine-specific alterations of monoamine activity were evident in the hypothalamus, hippocampus and prefrontal cortex 2 h following peripheral administration of recombinant interleukin (IL)-1 beta, IL-2 and IL-6 (200 ng, i.p.) in male, BALB/c mice. IL-1 induced the broadest range of neurochemical changes, affecting central norepinephrine (NE), serotonin (5-HT) and dopamine (DA) activity. In particular, IL-1 enhanced NE turnover in the hypothalamus and hippocampus, 5-HT turnover in the hippocampus and prefrontal cortex (owing to increased utilization and reduced content of the transmitters in these brain regions), and enhanced DA utilization in the prefrontal cortex. IL-6 increased 5-HT and DA activity in the hippocampus and prefrontal cortex in a manner similar to IL-1, but failed to affect central NE activity. Moreover, IL-2 increased hypothalamic NE turnover (reflecting a profound increase in NE utilization) and enhanced DA turnover in the prefrontal cortex, but did not influence central 5-HT activity. Hence, these cytokines differentially altered neurochemical activity in brain regions that mediate neuroimmune interactions and that are influenced by physical and psychological stressors. In addition to the neurochemical changes, plasma corticosterone concentrations were profoundly enhanced in IL-1-treated animals, but not significantly altered by IL-2 or IL-6 treatment. The IL-1-induced corticosterone elevations did not significantly correlate with alterations of hypothalamic NE activity.

Role of norepinephrine in suppressed IgG production in epilepsy-prone mice.

The responses of two substrains of Balb/c mice (Epilepsy Prone and Epilepsy Resistant) to immunization with sheep red blood cells (SRBC) were examined to determine whether chronic neurochemical differences between the two strains could influence B cell function. Anti-SRBC IgG production in the Epilepsy Prone (EP) strain was reduced relative to the Epilepsy Resistant (ER) strain, while anti-SRBC IgM production was unaffected. No differences were found in in vitro antibody (Ab) production or T lymphocyte function between the EP and ER strains, suggesting that in vivo conditions rather than an intrinsic cellular defect are responsible for reduced IgG production by EP mice. Basal splenic norepinephrine (NE) levels were significantly higher in EP mice than those in ER mice, and remained significantly higher following immunization. ER mice treated with the beta 2 adrenergic agonist terbutaline on days 4, 5 and 6 after immunization produced significantly lower numbers of IgG PFC than did saline treated controls. Addition of NE during later stages of in vitro immunization suppressed both anti-SRBC IgM and IgG production by splenic lymphocytes from Balb/c mice, and NE was found to decrease IFN gamma production. These observations suggest that dysregulation of splenic NE can have an impact on the immune response.

Immunomodulatory properties of fermented soy and dairy milks prepared with lactic acid bacteria.

Fermented soy and dairy milk preparations provide a means for delivering lactic acid bacteria and their fermentation products into the diet. Our aims were to test immunomodulatory bioactivity of fermented soy beverage (SB) and dairy milk blend (MB) preparations on human intestinal epithelial cells (IEC) and to determine the impact of freezing medium on culture survival prior to bioactivity analyses. Fermented SB and MB were prepared using pure or mixed cultures of Streptococcus thermophilus ST5, Bifidobacterium longum R0175, and Lactobacillus helveticus R0052. Immunomodulatory bioactivity was assessed by testing selected SB and MB ferments on tumor necrosis factor alpha (TNFalpha)-treated IEC and measuring effects on Interleukin-8 (IL-8) production. Impact of timing of ferment administration relative to this pro-inflammatory challenge was investigated. The most pronounced reductions in IEC IL-8 production were observed when IEC were treated with either SB or MB ferment preparations prior to TNFalpha challenge. These results indicate that freezing-stable MB and SB ferments prepared with selected strains can modulate IEC IL-8 production in vitro, and suggest that yogurt-like fermented soy formulations could provide a functional food alternative to milk-based fermented products.

Proliferative capacity of senescent lymphocytes. II. Monoclonal antibody stimulation of mucosal and systemic lymphocytes via T cell activation molecules, CD3 epsilon, T cell receptor V beta 8 chain, and phosphatidylinositol-linked anchored receptors THY-1 and LY-6A.2/TAP.

The proliferative capacity of senescent mucosal and systemic lymphocytes was studied in response to monoclonal antibody (Mab) stimulation of T cell activation molecules, CD3 epsilon, V beta 8a chain of the T cell receptor (TcR-V beta 8), Thy-1, and Ly-6A.2/TAP. The percentage of positive cells, fluorescence intensities, and proliferative responses of lymphocytes from the spleen and mesenteric lymph nodes (mln) of individual C57BL/6J male mice were compared at 2, 4, 12, 20, and 30 months of age. Mabs F23.1, 145-C11, Jij.10, and D7 were used to measure TCR-V beta 8a, CD3 epsilon, Thy-1, and Ly6A.2/TAP expressions, respectively. Optimal dose and kinetic studies were determined. There were no significant age-related changes in the percentage of splenic cells expressing CD3 epsilon, TCR-V beta 8a, Thy-1, and Ly6A.2, as well as their fluorescence intensities on the cell surface as measured flow cytometry. For mln cells, the percentage of cells expressing TCR-V beta 8a, Thy-1, and Ly6A.2 did not significantly change with age. A significant age-related increase was found in the percentage of mln cells expressing CD3 epsilon. The fluorescence intensities of CD3 epsilon, TCR-V beta 8a, and Ly6A.2 expression on the cell surface of mln cells significantly increased with age. Mabs anti-TcR-V beta 8a and anti-CD3 epsilon stimulation of splenic lymphocytes in culture for 3 days revealed a significant decline in proliferative responses after 12 months of age. When splenic cells were stimulated with Mab anti-CD3 epsilon in combination with optimal doses of phorbol myristate acetate (PMA) in culture for 3 days, there was a two-fold elevation in the proliferative response with a significant decline occurring after 20 months of age. Mab anti-TcR-V beta 8a and Mab anti-CD3 epsilon plus PMA stimulation of mln lymphocytes consistently revealed a significant decline in proliferative responses only after 20 months of age. Both splenic and mln cells showed a significant decline in proliferative responses to Mab anti-Thy-1 stimulation after 12 months of age. There was no age-related change in the proliferation of splenic and mln cells to Mab anti-Ly6A.2 activation. These results indicate that the onset and rate of age-related decline in the proliferative capacity of lymphocytes after stimulation with Mabs anti-CD3 epsilon and anti-TcR-V beta 8 chain changes much later and slower in the mln than those of the spleen.(ABSTRACT TRUNCATED AT 400 WORDS)

Regional accumulation of Pgp-1+ memory cells in senescent mucosal immune system.

The proportion of memory cells expressing the Pgp-1 surface marker, and subsets of T cells expressing L3T4 (CD4+ helper cells), Lyt-2 (CD8+ suppressor/cytotoxic cells), LFA-1 (lymphocyte function-associated antigen-1), and interleukin-2 receptors (IL-2R) on the cell surface in the spleen, regional lymph nodes (PLN), mesenteric LN (MLN), bronchial or mediastinal LN (BLN), Peyer's patches (PP), thymus, and bone marrow (BM) was studied in C57BL/6J mice of varying ages. Monoclonal antibodies (Mabs) IM7.8.1, FD4, GK1.5, 3.155, and FD441.8 were used to measure Pgp-1, IL-2R, L3T4 Lyt-2, and LFA-1 expressions, respectively. Optimal dose and kinetic studies were determined. The percentages of positive cells were determined by monoclonal antibody staining and flow cytometry or immunofluorescence microscopy. Using flow cytometric analysis, we found significant age-associated increases in the percentages of Pgp-1+ cells in the MLN as compared with a slight, but not significant, increase in the spleen. There were significant age-related increases in the percentages of Lyt-2+ cells in the spleen with no change in the MLN. The percentages of cells with the other phenotypic markers, L3T4, LFA-1, and IL-2R did not change with age in the spleen or MLN. Using immunofluorescence microscopy, the percentages of Thy-1.2+, Lyt-1+, and Lyt-2+ cells in different anatomical immune tissues did not change with age, except in the BLN and PP where there were significant age-related declines of the percentages of Thy-1.2+ and Lyt-2+ cells in the BLN, and of Lyt-1+ cells in the PP. These results indicate elevated levels of Pgp-1+ memory senescent cells in the MLN and these age-related shifts or changes in T lymphocyte subsets with age could contribute to the conserved immune responsiveness of senescent mucosal T lymphocytes.

Suppressed T cell and macrophage function in the "reeler" (rl/rl) mutant, a murine strain with elevated cerebellar norepinephrine concentration.

The effects of neurochemical alterations in specific brain regions on the immune system were examined in reeler (rl/rl) mice, a neurologic mutant strain having an abnormally high concentration of cerebellar norepinephrine (NE). Following immunization with sheep red blood cells, lower numbers of IgM-producing B cells were found in rl/rl mice than in B6C3Fea/a controls. Interleukin-1 (IL-1) production by splenic macrophages from rl/rl mice was reduced compared to B6C3F3a/a controls, as was the proliferative response of splenic T lymphocytes from rl/rl mice activated with an anti-CD3 monoclonal antibody. Levels of IL-4, interferon-gamma and IL-2 produced by splenic T lymphocytes from rl/rl mice were also lower than those of B6C3Fea/a controls. Rl/rl mice do not have an intrinsic defect in the ability to produce IgM, as lipopolysaccharide activated splenic lymphocytes from rl/rl mice produced levels of IgM similar to those of controls. This suggests that defective function in the T lymphocyte and/or macrophage population rather than in the B cell population may underlie the defect in IgM production. No significant alterations were observed in basal splenic levels of NE or neuropeptides in rl/rl mice relative to controls. The reeler mouse model shows that alterations in immune function are present in a strain with inherited alterations in cerebellar noradrenergic innervation and NE concentration.

Interleukin-2-induced enhancement of an antigen-specific IgM plaque-forming cell response is mediated by the sympathetic nervous system.

Interleukin (IL)-2, a lymphokine produced by activated T-cells, stimulates T-cell proliferation and differentiation and potentiates B-cell production of antigen-specific immunoglobulins. IL-2 also increases hypothalamic norepinephrine turnover without affecting plasma corticosterone levels, which suggests that it selectively impacts on central sites that mediate sympathetic outflow to lymphoid organs. Because sympathetic stimulation during the early phases of an immunoglobulin (Ig)M plaque-forming cell (PFC) response to sheep red blood cells results in an increase in the subsequent number of antibody-forming cells, we assessed whether the enhancing effects of IL-2 on the PFC response are mediated by the sympathetic nervous system. The peak splenic IgM PFC response was increased in male Sprague-Dawley rats and BALB/c mice administered recombinant human IL-2 (50, 100 or 200 ng i.p.) in close temporal congruity with sheep red blood cell administration (i.e., 1 day before or immediately before immunization), compared with vehicle-treated controls. IL-2 administered at a later interval after immunization (i.e., 2 days) did not increase the number of antibody-forming cells. Intact sympathetic innervation of the spleen was required for the IL-2-induced immunoenhancement to occur because cutting the splenic nerve 10 days prior to IL-2 administration blocked the lymphokine's potentiation of the IgM PFC response. The immunostimulatory effects of IL-2 were also blocked in mice administered the beta adrenergic antagonist propranolol (5 mg/kg) immediately and 1 day after IL-2 administration. The alpha adrenergic antagonist phentolamine (5 mg/kg) had no effect.(ABSTRACT TRUNCATED AT 250 WORDS)