Search

The study was undertaken considering age-related changes in susceptibility to experimental autoimmune encephalomyelitis (EAE) and a putative role of spleen in pathogenesis of this disease. The phenotypic and functional characteristics of T splenocytes were examined in young (3-month-old), middle-aged (8-month-old) and aged (26-month-old) Dark Agouti rats immunized for EAE with rat spinal cord in complete Freund's adjuvant The rat susceptibility to EAE induction, as well as the number of activated CD4+CD134+ lymphocytes retrieved from their spinal cords progressively decreased with aging. To the contrary, in rats immunized for EAE the number of activated CD4+ splenocytes, i.e., CD4+CD134+, CD4+CD25+FoxP3 and CD4+CD40L+ cells, progressively increased with aging. This was associated with age-related increase in (i) CD4+ splenocyte surface expression of CD44, the molecule suggested to be involved in limiting emigration of encephalitogenic CD4+ cells from spleen into blood and (ii) frequency of regulatory T cells, including CD4+CD25+FoxP3 + cells, which are also shown to control encephalitogenic cell migration from spleen into the central nervous system. In favor of expansion of T-regulatory cell pool in aged rats was the greater concentration of IL-10 in unstimulated, Concanavalin A (ConA)- and myelin basic protein (MBP)-stimulated splenocyte cultures from aged rats compared with the corresponding cultures from young ones. Consistent with the age-related increase in the expression of CD44, which is shown to favor Th1 effector cell survival by interfering with CD95-mediated signaling, the frequency of apoptotic cells among CD4+ splenocytes, despite the greater frequency of CD95+ cells, was diminished in splenocyte cultures from aged compared with young rats. In addition, in control, as well as in ConA-and MBP-stimulated splenocyte cultures from aged rats, despite of impaired CD4+ cell proliferation, IFN-gamma concentrations were greater than in corresponding cultures fro

The study investigated strain specificities in age-related differences in CD8+ T cell-and microglial cell-mediated mechanisms implicated in induction/perpetuation and/or control of neuroinflammation in experimental autoimmune encephalomyelitis (EAE) in Albino Oxford (AO) and Dark Agouti (DA) rats exhibiting age-related changes in the susceptibility to EAE in the opposite direction (increase in relatively resistant AO rats vs decrease in DA rats). In the inductive phase of EAE, the greater number of fully differentiated effector CD8+ T lymphocytes was found in draining lymph nodes (dLNs) from aged rats of both strains than in strain-matched young rats, but this was particularly prominent in AO rats, which exhibited milder EAE of prolonged duration compared with their DA counterparts. Consistently, dLN IFN-gamma+ and IL-17+ CD8+ T cell counts were greater in aged AO than in DA rats. Additionally, the magnitudes of myelin basic protein (MBP)-induced rise in the frequency of IFN-gamma+ and IL-17+ CD8+ T cells (providing important help to neuroantigen-specific CD4+ T cells in EAE models characterized by clinically mild disease) were greater in dLN cell cultures from aged AO rats. Consistently, the magnitudes of MBP-induced rise in the frequency of both IFN-gamma+ and IL-17+ CD8+ T cells were greater in spinal cord mononuclear cell cultures from aged AO rats compared with their DA counterparts. Besides, with aging CD4+ CD25+ Foxp3+/CD8+ CD25+ Foxp3+ regulatory T cell ratio changed in spinal cord in the opposite direction. Consequently, in aged AO rats it was shifted towards CD8+ CD25+ Foxp3+ regulatory T cells (exhibiting lower suppressive capacity) when compared with DA rats. Moreover, the frequency of CX3CR1+ cells among microglia changed with aging and the disease development. In aged rats, in the effector phase of EAE it was lower in AO than in DA rats. This was accompanied by higher frequency of cells expressing IL-1 beta (whose down-regulation is central for CX3CR1

This study was undertaken considering that, despite the broad use of the unopposed estrogen replacement therapy in elderly women, data on estrogen influence on the functional capacity of dendritic cells (DCs), and consequently immune response are limited. We examined the influence of 17 beta-estradiol on phenotype, cytokine secretory profile, and allostimulatory and polarizing capacity of splenic (OX62+) conventional DCs from 26-month-old (aged) Albino Oxford rats matured in vitro in the presence of LPS, a TLR4 agonist, and R848, a TLR7/8 agonist In the presence of 17 beta-estradiol, DCs from aged rats exhibited an impaired ability to mature upon stimulation with LPS, as shown by the lower surface density of MHC II and costimulatory CD80 and CD86 molecules. 17 beta-Estradiol alone enhanced CD40 expression in OX62+ DCs without affecting the expression of other costimulatory molecules, thereby confirming that the expression of this molecule is regulated independently from the regulation of other costimulatory molecules. However, although R848 upregulated the expression of MHC II and CD80 and CD40 costimulatory molecules on DCs, 17 beta-estradiol diminished the effect of this TLR agonist only on MHC II expression. In conjunction, the previous findings suggest that LPS and R848 elicit changes in the expression of costimulatory molecules via triggering differential intracellular signaling pathways. Furthermore, 17 beta-estradiol diminished the stimulatory influence of both LPS- and R848-matured OX62+ DCs on allogeneic CD4+ T lymphocyte proliferation in a mixed lymphocyte reaction (MLR). Moreover, as shown in MLR, the exposure to 17 beta-estradiol during LPS- and R848-induced maturation diminished Th1- and enhanced Th17-driving capacity and reduced Th1-driving capacity of OX62+ DCs, respectively. This suggests that LPS and R848 affect not only the surface phenotype, but also functional characteristics of OX62+ DCs triggering distinct intracellular signaling pathways. Coll

The study examined the putative role of ovarian hormones in shaping of rat peripheral T-cell compartment during post-reproductive period. In 20-month-old rats ovariectomized (Ox) at the very end of reproductive period, thymic output, cellularity and composition of major TCR alpha beta+peripheral blood lymphocyte and splenocyte subsets were analyzed. Ovariectomy led to the enlargement of CD8 + peripheral blood lymphocyte and splenocyte subpopulations. This reflected: (i) a more efficient thymic generation of CD8 + cells as indicated by increased number of CD4+CD8+double positive and the most mature CD4CD8+TCR alpha beta(high) thymocytes and CD8 + recent thymic emigrants (RTEs) in peripheral blood, but not in the spleen of Ox rats, and (ii) the expansion of CD8 + memory/activated peripheral blood lymphocytes and splenocytes. The latter was consistent with a greater frequency of proliferating cells among freshly isolated memory/activated CD8 + peripheral blood lymphocytes and splenocytes and increased proliferative response of CD8 + splenocytes to stimulation with plate-bound anti-CD3 antibody. The former could be related to the rise in splenic IL-7 and IL-15 mRNA expression. Although ovariectomy affected the overall number of CD4 + T cells in none of the examined compartments, it increased CD4+FoxP3 + peripheral blood lymphocyte and splenocyte counts by enhancing their generation in periphery. Collectively, the results suggest that ovariectomy-induced long-lasting disturbances in ovarian hormone levels (mirrored in diminished progesterone serum level in 20-month-old rats) affects both thymic CD8 + cell generation and peripheral homeostasis and leads to the expansion of CD4+FoxP3 + cells in the periphery, thereby enhancing autoreactive cell control on account of immune system efficacy to combat infections and tumors.

Compared with females, male Dark Agouti (DA) rats immunized for experimental autoimmune encephalomyelitis (EAE) with rat spinal cord homogenate in complete Freund's adjuvant (CFA) exhibited lower incidence of the disease, but the maximal neurological deficit was greater in the animals that developed the disease. Consistently, at the peak of the disease greater number of reactivated CD4+CD134+CD45RC- T lymphocytes was retrieved from male rat spinal cord. Their microglia/-macrophages were more activated and produced greater amount of prototypic proinflammatory cytokines in vitro. Additionally, oppositely to the expression of mRNAs for IL-12/p35, IL-10 and IL-27/p28, the expression of mRNA for IL-23/p19 was upregulated in male rat spinal cord mononuclear cells. Consequently, the IL-17+:IFN-gamma+ cell ratio within T lymphocytes from their spinal cord was skewed towards IL-17+ cells. Within this subpopulation, the IL-17+IFN-gamma+:IL-1 7+IL-10+ cell ratio was shifted towards IL-17+IFN-gamma+ cells, which have prominent tissue damaging capacity. This was associated with an upregulated expression of mRNAs for IL-1 beta and IL-6, but downregulated TGF-beta mRNA expression in male rat spinal cord mononuclear cells. The enhanced GM-CSF mRNA expression in these cells supported the greater pathogenicity of IL-17+ T lymphocytes infiltrating male spinal cord. In the inductive phase of the disease, contrary to the draining lymph node, in the spinal cord the frequency of CD 134+ cells among CD4+ T lymphocytes and the frequency of IL-17+ cells among T lymphocytes were greater in male than in female rats. This most likely reflected an enhanced transmigration of mononuclear cells into the spinal cord (judging by the lesser spinal cord CXCL12 mRNA expression), the greater frequency of activated microglia/macrophages and the increased expression of mRNAs for Th17 polarizing cytokines in male rat spinal cord mononuclear cells. Collectively, the results showed cellular and molecular mech

The study was undertaken considering: i) that relative proportion of distinct subsets of splenic dendritic cells (DCs) is strain-specific and predictive for the susceptibility to autoimmune diseases; ii) age-related changes in endocytic, allostimulatory and polarizing capacity of splenic OX62+ DCs from Albino Oxford rats (relatively resistant to Th1/Th17-mediated diseases) and iii) strain specificities in age-related changes of mouse DCs. To ascertain whether there are strain specificities in age-related rat DC changes, we examined the influence of aging on OX62+ DCs from Dark Agouti (DA) rats prone to Th1/Th17-mediated autoimmune diseases. The study provided additional evidence that the predominance of CD4-cells within OX62+ DCs from young adult rats correlates with their susceptibility to Th1/Th17-mediated diseases. Consistently, lipopolysaccharide (LPS)-matured DCs from 3-month-old (young) rats exhibited Th1 driving force when co-cultured with allogeneic CD4+ T cells. This most likely reflected enhanced TNF-alpha and iNOS expression. Comparing with young rats, OX62+ DCs from 26-month-old (aged) rats showed: i) diminished endocytic capacity; ii) impaired ability to mature in vitro upon LPS stimulation (as indicated by lower MHC II, CD86 and CD40 surface expression), which is consistent with the increase in their IL-10 production, and iii) diminished allostimulatory capacity and loss of Th1-driving capacity in the mixed lymphocyte reaction. The latter, probably, reflected greater IL-10 production by LPS-stimulated DC from aged rats, as well as lower CD40 density on their surface. Overall, our findings suggest that aging might affect DA rat capability to mount an efficient Th1 immune response, and consequently susceptibility to Th1/Th17-mediated pathology.

This study explores the role of ovarian hormones in the phenotypic shaping of peripheral T-cell pool over the reproductive lifespan of rats. For this purpose, 2-month-old prepubertally ovariectomised (Ox) rats, showing oestrogen and progesterone deficiency, and 11-month-old Ox rats, exhibiting only progesterone deficiency, were examined for thymus output, and cellularity and composition of major TCR alpha beta+ peripheral blood lymphocyte (PBL) and splenocyte subsets. Although ovariectomy increased thymic output in both 2- and 11-month-old rats, the count of both CD4+ and CD8+ PBLs and splenocytes increased only in the former. In the blood and spleen of 11-month-old Ox rats only the count of CD8+ cells increased. Although ovariectomy affected the total CD4+ count in none of the examined compartments from the 11-month-old rats, it increased CD4+FoxP3+ PBL and splenocyte relative proportions over those in the age-matched controls. The age-related differences in the cellularity and the major subset composition in Ox rats were linked to the differences in the ovarian steroid hormone levels registered in 2- and 11-month-old rats. The administration of progesterone to Ox rats during the seven days before the sacrificing confirmed contribution of this hormone deficiency to the ovariectomy-induced changes in the TCR alpha beta+ PBL and splenocyte pool from 11-month-old rats. The expansion of the CD8+ splenocyte subset in the 11-month-old Ox rats reflected increases in cellularity of memory and, particularly, nave cells. This was due to greater thymic output of CD8+ cells and homeostatic proliferation than apoptosis in 11-month-old Ox rats when compared with age-matched sham-Ox control rats. The homeostatic changes within CD8+ splenocyte pool from 11-month-old Ox rats, most likely, reflected the enhanced splenic IL-7 and TGF-beta mRNA expression. Overall, in adult female rats, circulating oestrogen and progesterone provide maintenance of T-cell counts, a diversity of T-cell

The present study, through quantification of tyrosine hydroxylase (TH) expression and catecholamine (CA) content in the presence and in the absence of alpha-methyl-p-tyrosine (AMPT), a TH inhibitor, in adult thymic organ (ATOC) and thymocyte culture, demonstrated that thymic cells produce CAs. In addition, in ATOC an increase in beta(2)-adrenoceptor (AR) mRNA expression and beta(2)-AR thymocyte surface density was registered. Furthermore, AMPT (10(-4) M), as propranolol (10(-4) M), augmented thymocyte apoptosis and diminished thymocyte proliferation in ATOC. Propranolol exerted these effects acting on CD3(high) thymocytes. However, in thymocyte cultures, propranolol (10(-6) M) acting on the same-thymocyte subset exerted the opposing effect on thymocyte apoptosis and ConA-stimulated proliferation. This suggested that, depending on thymocyte microenvironment, differential effects can be induced through the same type of AR. Additionally, arterenol (10(-8) to 10(-6) M), similar to propranolol, diminished apoptosis, but increased ConA-stimulated thymocyte proliferation in thymocyte culture. However, differently from propranolol, arterenol affected manly CD3- thymocyte subset, which harbors majority of alpha(1)-AR+ thymocytes. Additionally, arterenol showed a dose-dependent decrease in efficiency of thymocyte apoptosis and proliferation modulation with the rise in its concentration. Considering greater affinity of arterenol for alpha(1)-ARs than for beta(2)-ARs, the previous findings could be attributable to increased engagement of beta(2)-ARs with the rise of arterenol concentration. Consistently, in the presence of propranolol (10(-6) M), a beta-AR blacker, the arterenol (10(-8) M) effects on thymocytes were augmented. In conclusion, thymic endogenous CAs, acting through distinct AR types and, possible, the same AR type (but in different cell microenvironment) may exert the opposing effects on thymocyte apoptosis/proliferation. (C) 2014 Elsevier B.V. All rights reserved

Aging is associated with the decline in immune response to infectious agents and tumors and increasing risk of autoimmunity, but the incidence of autoimmune diseases does not increase in the elderly. To elucidate the cellular and molecular mechanisms influencing clinical expression of autoimmunity in aged animals, the phenotypic and functional characteristics of mononuclear cells isolated from the spinal cords of 3-month-old (young) and 26-month-old (aged) Dark Agouti rats immunized to induce experimental autoimmune encephalomyelitis (EAE) - the model of multiple sclerosis, the most common autoimmune disease of the central nervous system, were examined. Aged rats were less susceptible to EAE induction, and the neurological and histological picture was milder in those rats which developed the clinically manifested disease. At the peak of the disease, several times fewer mononuclear cells and T lymphocytes were isolated from the spinal cords of aged rats compared with the young ones. The frequency of CD4+ cells among TCR alpha beta+ lymphocytes, as well as that of reactivated CD134(OX40)+ cells within its CD4+ T-lymphocyte subpopulation, was less in spinal cords of aged compared with young rats. Additionally, CD134 surface density on CD4+ lymphocytes was decreased in the spinal cord of aged rats. The changes in CD134 expression most likely reflected in part age-related intrinsic changes in CD4+ lymphocytes as the expression of this molecule was also impaired on in vitro stimulated naive CD4+ splenocytes from aged rats compared with young animals. In addition, greater frequency of CD8+ lymphocytes with regulatory phenotypes could also contribute to impaired CD4+ cell reactivation in aged rats. The increased apoptosis of CD4+ cells from aged rats was consistent with their impaired reactivation and it was accompanied by the greater frequency of CD4+CD11b+CD45(int/high) cells, which are supposed to be actively engaged in apoptotic cell phagocytosis and to have immunoregul

Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis, a prototype of Th1/Th17-mediated organ-specific autoimmune disease. In the rat, susceptibility to development of these diseases is shown to be strain-and age-dependent. In adult rats of distinct strains, it correlates with splenic dendritic cell (DC) subset composition, which also exhibit age-related changes. The aim of this study was to examine influence of aging on: i) Albino Oxford (relatively resistant to EAE) and Dark Agouti (susceptible to EAE) rat development of EAE and ii) their splenic conventional (OX62+) DC population in respect to its subset composition and expression of mRNAs for proinflammatory and immunosuppressive cytokines. We used 3-month-old (young) and 26-month-old (aged) rats of AO and DA strain. The rats were immunized for EAE with rat spinal cord homogenate in complete Freund's adjuvant and clinical course of the disease was followed. Fresh OX62+DCs were examined for the expression of CD4 (using flow cytometry) and genes encoding cytokines influencing DC activation/maturation (TNF-alpha and IL-6) using RT-PCR. Additionally, in vitro lipopolysaccharide (LPS) activated/matured DCs were examined for the expression of genes encoding cytokines controlling Th1/Th17 cell polarization using RT-PCR. With aging, AO rats became more susceptible, whereas DA rats largely lose their susceptibility to the induction of EAE. In AO rats aging shifted CD4+: CD4-DC ratio towards CD4- cells, producing large amount of proinflammatory cytokines, whereas in DA rats CD4+: CD4-DC ratio remained stable with aging. In fresh DCs from rats of both the strains the expression of TNF-alpha mRNA increased with aging, whereas that of IL-6 mRNA decreased and increased in DCs from AO and DA rats, respectively. Following in vitro LPS stimulation OX62+ DCs from aged AO rats up-regulated the expression of mRNA for IL-23p19 (specific subunit of IL-23; crucial for sustained IL-17 production) and

The study was aimed to define the putative role of ovarian hormones in shaping thymocyte apoptosis and proliferation during thymic involution. Thymocytes from young adult and middle-aged rats ovariectomized (Ox) before puberty were examined for apoptosis and proliferation. Apoptosis and proliferation were measured in fresh thymocyte suspensions and in their 18-hour cultures, and fresh thymocyte suspensions, respectively. The thymocyte population and the major thymocyte subsets were analyzed following triple staining using anti-CD4 and anti-CD8 monoclonal antibodies and 7-AAD to label apoptotic or proliferating cells. The frequency of apoptotic cells was lower in thymocyte suspensions and cultures from Ox rats of both ages. This reflected in a diminished frequency of apoptotic cells amongst CD4+CD8+ double positive (DP) and CD4+CD8- single positive (SP), and DP cells in young and middle-aged Ox rats, respectively. Additionally, in thymocyte cultures from Ox rats the frequency of apoptotic cells amongst CD4+CD8- and CD4-CD8+ SP cells decreased with age, but increased within DP and CD4-CD8- double negative (DN) subsets, reaching in the former subset from middle-aged Ox rats higher values than in age-matched controls. The frequency of proliferating cells was also lower in Ox rats than in controls. This reflected the lower frequency of cycling cells amongst CD4+CD8- SP and CD4-CD8+ SP thymocytes in young rats, and DP and CD4-CD8+ SP thymocytes in middle-aged rats. Besides, in both SP and DP thymocyte subsets from Ox rats the frequency of proliferating cells declined with age. In conclusion, thymocyte apoptosis and proliferation exhibit ovarian hormone-dependent thymocyte subset specific alterations during thymic involution., Cilj istraživanja je bio da se definiše značaj hormona ovarijuma za razvoj promena u apoptozi i proliferaciji timocita tokom involucije timusa. U tom cilju apoptoza i proliferacija timocita ispitivana je kod prepubertetno ovariektomisanih (Ox) mladih (uzrasta 2 meseca) i sredovečnih pacova (uzrasta 11 meseci). Apoptoza je određivana u suspenziji sveže izolovanih timocita i nakon njihove 18- časovne kultivacije, a proliferacija u suspenziji sveže izolovanih timocita. Procenat apoptotičnih i proliferišućih ćelija je određivan u celokupnoj populaciji timocita, i unutar glavnih subpopulacija ovih ćelija, koje su razdvojene na osnovu ekspresije CD4/CD8 molekula, metodom protočne fluorocitometrije, korišćenjem 7-aminoaktinomicina D (7-AAD). Procenat ćelija u apoptozi je bio značajno manji u suspenzijama svežih timocita koji su izolovani iz Ox životinja i u njihovim kulturama nego u onim izolovanim iz kontrolnih životinja. Ovaj nalaz je odražavao smanjenu učestalost ćelija u apoptozi u CD4+CD8+ dvostruko pozitivnoj (DP) i CD4+CD8- jednostruko pozitivnoj (JP) subpopulaciji timocita kod mladih i u DP subpopulaciji kod sredovečnih Ox pacova. U kulturama timocita koji su izolovani iz sredovečnih Ox pacova uočeno je smanjenje učestalosti ćelija u apoptozi unutar subpopulacija CD4+CD8- i CD4-CD8+ JP timocita, a povećanje unutar DP i CD4-CD8- dvostruko negativne (DN) subpopulacije ovih ćelija. Učestalost proliferišućih ćelija je takođe bila niža u suspenzijama timocita izolovanih iz Ox pacova nego u onim izolovanim iz kontrolnih životinja. Ovo je odražavalo smanjenu proliferaciju CD4+CD8- i CD4-CD8+ JP timocita kod mladih, a DP i CD4-CD8+ JP timocita kod sredovečnih pacova. Procentualna zastupljenost proliferišućih ćelija u subpopulacijama JP i DP timocita je bila veća kod mladih nego kod sredovečnih Ox pacova. U zaključku, tokom involucije timusa dolazi do promena u apoptozi i proliferaciji timocita koje su specifične za pojedine subpopulacije timocita i zavisne od prisustva hor

Starenje dovodi do promena skoro svnh komponenti urođenog i stečenog imuniteta. Brojna istraživanja kod čoveka i miša su pokazala promene u fenotipu i funkciji dendritskih ćelija (DĆ) takom starenja i ukazala na značajne specijes specifične razlike. Budući da nema podataka, a uticaju starenja na DĆ pacova, ispitivane su kanvencionalne OH62+ DĆ (kDĆ) izolovane iz slezina mladih (3 meseca) i starih (26 meseci) AO pacova. Određivana je zastupljenost glavnih subpopulacija ovih ćelija, ekspresija MHC II i kostimulatornih molekula i sposobnost preuzimanja antigena u suspenzijama sveže izolovanih ćelija, kao i njihove fenotiiske i funkcijske karakteristike nakon in vitro stimulacije lipopalisaharidom (LPS). U suspenziji sveže izolovanih slezinskih kDĆ starih nađena je veća zastupljenost CD11b+CD4- ćelija, manja površinska gustina CD80 i CD86 molekula (što ukazuje na manji stepen zrelosti) i pokazano da su one efikasnije u endocitoznoj aktivnosti posredovanoj manoznim receptorom. Ovi nalazi se mogu povezati sa većom količinom iRNK za IL-10 u frakciji ćelija slezine niske gustine starih pacova. Izraženija „spontana" aktivacija/maturacija kDĆ starih životinja u kulturi sugergiše da starenjem uslovljene promene u sazrevanju kDĆ in vivo najverovatnije nastaju usled supresivnog delovanja IL-10, koga produkuju ćelije iz njihovog okruženja. Nakon in vitro stimulacije LPS-om, kDĆ starih živatinja su ispoljile zreliji fenotipski profil u odnosu na kDĆ mladih životinja i pokazale izmenjenu sposobnost stimulacije alogenih CD4+ T ćelija u mešanoj leukocitnoj reakciji. Osim taga, nakon stimulacije LPS-om, u kDĆ starih životinja je nađena povećana ekspresija iRNK za TNF-alfa (što bi, makar delimično, moglo da o6jasni opisane fenotipske promene) i iRENK za IL-12/IL-23, p 40 i IL-23 p19, dok je ekspresija iRNK za IL-10 i IL-12 p35 bila smanjena. U zaključku, rezultati pokazuju da tokom ctapenja dolazi do promene u odnosu subpopulacija kDĆ u slezini, da se menja njihova sposobnost sazrevanj