Reduced Delayed-type Hypersensitivity Response Research Articles

Combination therapy of phosphatidylserine liposome with cyclosporine A improves nephrotoxicity and attenuates delayed-type hypersensitivity response

This study aimed to evaluate the antioxidant capacity of phosphatidylserine liposome (PS) against oxidative stress due to cyclosporine A (CsA) and concurrent administration of PS and CsA on the attenuation of immune response. The effect of oral PS was evaluated on biochemical and oxidative renal markers and histopathology of nephrotic rats receiving CsA. The effect of co-administration of PS with CsA was also assessed on DTH (delayed-type hypersensitivity) reaction of immunized rats. The cytokines production level of IL-2 (Interleukin-2) and IFN-γ (Interferon gamma) was measured in immunized rat's splenocytes. PS treatment significantly (P < 0.05) reduced Cr and BUN of serum and MDA (malondialdehyde) in kidney tissue, and increased SOD (superoxide dismutase) and CAT (Catalase) of kidney tissue in CsA-nephrotic rats. Histopathology data indicated significantly (P < 0.05) nephrotoxicity improvement after 25-day treatment with PS. Furthermore, CsA plus PS administration significantly reduced DTH response and cytokines production of IL-2 and IFN-γ in immunized rats. In conclusion, coadministration of CsA plus PS may overcome oxidative stress and improve the performance of organ transplantation or autoimmune therapy.

Effects of thymol and carvacrol on T-helper cell subset cytokines and their main transcription factors in ovalbumin-immunized mice

Thymol and carvacrol, two main components of thyme, have several valuable effects on the immune system. This study aims to evaluate the effects of these components on T-helper (TH) cell responses and their subsets in mice immunized with ovalbumin. The effects of these components on: a specific in vivo immune response were evaluated by assessing changes in delayed-type hypersensitivity (DTH); ex vivo splenocyte proliferative responses were evaluated using a BrdU assay gene expression of cytokines and key transcription factors involved in T-cells subset differentiation among the mouse splenocytes were assessed using real-time polymerase chain reaction (PCR); and splenocyte cytokine formation (ex vivo) and levels of the cytokines in mouse sera were measured by ELISA. Mice treated with thymol or carvacrol had reduced DTH responses (26% and 50%, respectively) compared with control mice. Thymol and carvacrol each diminished splenocyte proliferation to nearly 65–72% of control levels (p < 0.01). These agents also led to decreased TH1 [interleukin (IL)-2, interferon (IFN)-γ)], TH2 (IL-4) and TH17 (IL-17A) levels in the splenocyte cultures and in the sera of mice but increased levels of IL-10 and transforming growth factor (TGF)-β. Treated immunized mice showed significantly reduced T-box 21 (T-bet) expression from 3.8 [± 0.3]-fold in untreated ovalbumin-immunized mice to 0.9 [± 0.4]-(thymol) and 0.8 [± 0.2]-fold (carvacrol) (p < 0.01). GATA binding protein 3 (GATA-3) expression declined from 3.4 [± 0.4]- to 0.5 [± 0.3]-fold (thymol) and 0.6 [± 0.4]-fold (carvacrol), whereas RORγc decreased from 13.4 [± 1.6]- to 1.5 [± 0.6]-fold (thymol) and 0.8 [± 0.4]-fold (carvacrol) (p < 0.001). As carvacrol and thymol each suppressed the antigen-specific immune response by reducing TH cell-related cytokines\\specific transcription factors, this indicated their potential to modulate destructive immune responses attributed to T-cells over-activation.

Production of endocannabinoids by activated Tcells and Bcells modulates inflammation associated with delayed-type hypersensitivity.

Endocannabinoids are endogenous ligands for the cannabinoid (CB) receptors which include anandamide (AEA) and 2-arachidonyl glycerol (2-AG). 2-AG has been linked to inflammation due to its elevated expression in animal models of autoimmunity and hypersensitivity. However, administration of exogenous 2-AG has been shown to suppress inflammation making its precise role unclear. In the current study, we investigated the role of 2-AG following immunization of C57BL/6 (BL6) mice with methylated BSA (mBSA) antigen, which triggers both delayed-type hypersensitivity (DTH) and antibody response. We found that while naïve Tcells and Bcells expressed low levels of 2-AG, expression significantly increased upon activation. Furthermore, mBSA-immunized mice exhibited higher 2-AG concentration than naïve mice. Exogenous 2-AG treatment (40mg/kg) in mBSA-immunized mice led to reduced DTH response, and decreased Th1 and Th17-associated cytokines including IL-6, IL-2, TNF-α, and the IgG response. Addition of 2-AG to activated popliteal lymph node (PopLN) cell cultures also inhibited lymphocyte proliferation. Together, these data show for the first time that activated T and Bcells produce 2-AG, which plays a negative regulatory role to decrease DTH via inhibition of T-cell activation and proliferation. Moreover, these findings suggest that exogenous 2-AG treatment can be used therapeutically in Th1- or Th17-driven disease.

Solar ultraviolet radiation exposure influences the immune response to immunization: Results from an Australian clinical trial

Background Exposure to ultraviolet radiation (UVR) causes systemic immune suppression. The effect of natural levels of UVR exposure on the primary immune response to vaccination has not been previously reported. Method The Australian Ultraviolet Radiation and Immunity Study was conducted in the Australian cities of Canberra (35o2’S) and Townsville (19o1’S) from July 1010 to August 2011. Healthy volunteers (n=222) aged 18–40 years were immunised subcutaneously with keyhole limpet haemocyanin (KLH). Acute personal UVR exposure was measured by electronic UVR wrist dosimeters worn for five days pre- and post-vaccination, and by sun exposure diary. Cumulative UVR exposure was quantified by microtopographic analysis of silicone impressions of sun-exposed skin. Potential confounders were measured (e.g. serum 25-OH vitamin D). Immune function measured over a 21-day period post-vaccination included: anti-KLH IgG1 levels; KLH-specific delayed-type hypersensitivity (DTH) response; and quantification of T-helper (CD4+) lymphocyte subsets. Results In multiple regression models, higher acute UVR exposure on the day prior (‘Day 5’) to vaccination (p=0.015), and Days 5-8 and 5-9 (p=0.039 and p=0.025, respectively) were associated with reduced DTH response to KLH challenge at day 21 post-vaccination.”Change in T-helper 17 cell percentage between pre- and post-vaccination time points differed in direction when comparing the low and high UVR exposure groups (-0.39%vs.0.31%; p=0.004). There was no association between UVR exposure and anti-KLH IgG1. 25-OH vitamin D was not associated with immune function outcomes. Conclusions Acute UVR exposures, relevant to day-to-day activities, modulates the cell-mediated primary immune responses to KLH vaccination.

Skin Tolerance is Supported by the Spleen

The repeated application of antigens results in the induction of tolerance. Lymph nodes are responsible for this reaction by producing suppressor cells. Using an in vivo transplantation model, we showed recently that stromal cells from different lymph nodes induce different cell populations for suppression, which all produce a tolerogenic phenotype. In this study, we were interested in the role of the spleen in these tolerance reactions. Therefore, tolerance was induced via feeding or injecting ovalbumin several times in control and splenectomized mice. The delayed-type hypersensitivity (DTH) was measured as well as the cell subset composition of the spleen. The spleen of peripherally tolerized mice showed higher proliferation activity and a specific antibody production compared with orally tolerized mice, where regulatory T cells were predominantly found. Tolerance induction after removal of the spleen resulted in a reduced DTH response in antigen fed animals, whereas skin tolerance induction failed. In conclusion, the results illustrate that lymph nodes from different areas employ their individual pathways for similar immune reactions, and the spleen is part of this reaction initiated at the peripheral site.

Paradoxical Effect of Pertussis Toxin on the Delayed Hypersensitivity Response to Autoantigens in Mice

BackgroundPertussis toxin (PTX), an exotoxin of Bordetella pertussis, enhances the development of experimental autoimmune diseases such as experimental autoimmune uveitis (EAU) and experimental autoimmune encephalomyelitis (EAE) in rodent models. The mechanisms of the promotion of experimental autoimmune diseases by PTX may be based upon PTX-induced disruption of the blood eye/brain barriers facilitating the infiltration of inflammatory cells, the modulation of inflammatory cell migration and the enhancement of the activation of inflammatory cells. We hypothesized that the facilitation of experimental autoimmunity by PTX suggests that its influence on the in vivo immune response to auto-antigen may differ from its influence on non-self antigens.Methodology/Principal FindingsWe have evaluated the effect of PTX on the simultaneous generation of delayed type hypersensitivity (DTH) responses and autoimmune responses to uveitogenic interphotoreceptor retinoid binding protein peptide (IRBP161–180), encephalitogenic myelin oligodendrocyte glycoprotein peptide (MOG35–55) or ovalbumin (OVA). PTX injection of mice immunized to IRBP peptide161–180 led to (i) the development of EAU as shown by histopathology of the retina, (ii) pro-inflammatory cytokine production by splenocytes in response to IRBP peptide 161–180, and (iii) symptomatic EAE in mice immunized with encephalitogenic MOG peptide35–55. However, mice that received PTX had a reduced DTH response to IRBP161–180 peptide or MOG peptide35–55 when challenged distal to the site affected by autoreactive T cells. Moreover, footpad challenge with MOG35–55 peptide reduced EAE in mice immunized with MOG peptide. In contrast, the use of PTX when immunizing with OVA protein or an OVA immunogenic peptide did not affect the DTH response to OVA.Conclusions/SignificanceThe results suggest that that the reduced DTH response in mice receiving PTX may be specific for autoantigens and autoantigen-reactive T cells are diverted away from ectopic sites that received the autoantigen and towards the tissue site of the autoantigen.

An Environmental Androgen, 17β-Trenbolone, Affects Delayed-Type Hypersensitivity and Reproductive Tissues in Male Mice

Recently, a growth promoter for farm animals, trenbolone acetate, was identified as an environmental androgen that potentially affects reproduction. Because androgens also suppress immunity, it was hypothesized that an active metabolite of trenbolone acetate, 17β-trenbolone (TB), might impair immune responses. Castrated adult CD-1 mice were injected daily with either one of two different doses of 17β-trenbolone (TB), testosterone propionate (TP), or corn oil (vehicle). The antigen-specific immune response was assessed by measuring delayed-type hypersensitivity (DTH) responses. Reproductive response was assessed by measuring reproductive tissue mass and determining testosterone concentrations. Mice treated with TB or TP displayed larger reproductive tissue mass than males treated with corn oil. Furthermore, males exposed to the highest dose of TB displayed a reduced DTH response compared to vehicle-treated animals. In comparison, TP, at a similar dose, only minimally reduced the DTH response. These data support the reproductive and potentially immunosuppressive effects of this environmental androgen, and raise the possibility of health concerns for individuals or populations in contact with high concentrations of TB.

Immunobiological changes of in vivo glucocorticoid depleted male Swiss albino rats

Whether endogenous deficiency of adrenal corticosteroid by unilateral adrenalectomy leads to any modulation of macrophage response is not clear and needs investigation in detail. We performed unilateral adrenalectomy on male Swiss albino rats. Fractions of splenic macrophages were isolated and their functional activities were determined. To test the effect of adrenal hormone insufficiency (after unilateral adrenalectomy) on the cell mediated and humoral immune response, sheep red blood cells were injected, then the delayed type hypersensitivity (DTH) response and the number of antibody secreting plasma cells were determined. Studies reported herein indicate that in vivo glucocorticoid (GC) insufficiency due to unilateral adrenalectomy decreases chemotactic migration, myeloperoxidase enzyme release, and lysozyme release from rat splenic macrophages that were also related to the induction of cell mediated and humoral immune responses. The maximum number of plaque was obtained from control cells isolated from spleen after 10 days from the control rats, whereas the number of plaque was decreased in spleens isolated 20 days after unilateral adrenalectomy. Our study also showed time dependent decrease in foot pad swelling in the unilaterally adrenalectomized rats where endogenous GC was reduced with respect to control indicating reduced DTH response in case of GC insufficiency. We found slower clearance of bacterial burden from the blood and spleen isolated from unilaterally adrenalectomized rats with respect to control. Thus on one hand partially GC insufficient animals show altered macrophage response and on the other hand it heightens the persistence (in vivo) of Staphylococus aureus. The study may be helpful in understanding that adrenal corticosteroid insufficiency due to adrenalectomy interferes with immune functions, which may also support the hypothesis that endogenous GC plays a role in regulating immune response.

DYSFUNCTION OF DENDRITIC CELLS FOLLOWING TRAUMA MEDIATES SUPPRESSION OF DELAYED TYPE HYPERSENSITIVITY RESPONSE IN MICE

Dendritic cells (DCs) participate in the afferent (sensitization) phase of delayed type hypersensitivity (DTH) response, which is suppressed after severe injury. However, whether DCs functions alter after severe injury remains unclear. Herein BALB/c mice were underwent severe injury and then sensitized with 2,4-dinitrofluorobenzene (DNFB) at different time-point post-injury, 5 days later mice were challenged with DNFB and then (24 h later) DTH response was determined. The results showed that DTH response on day 1 post-injury was most significantly decreased and draining lymph nodes (DLN) cells proliferation and IL-2, IL-12 and IFN-gamma production were reduced, whereas IL-6, IL-10 production were augmented. After 24 h sensitization of DNFB, purified DCs from DLN of 1 day post-injury showed lower percentage of MHCII+CD11c+cells, less IL-12 secretion and weaker transferring ability for DTH to recipient mice than that of sham-injured mice. After 6d sensitization of DNFB, DLN cells from injured mice also showed suppressed transferring ability for DTH. Supplementation of sensitized DCs from DLN of sham-injured or injured mice, in the meantime of skin sensitization of DNFB, could partially restore reduced DTH response of injured mice. These data strongly suggested that dysfunction of dendritic cells following trauma mediates suppression of delayed type hypersensitivity response in mice and supplementation of sensitized DCs, regardless of from injured or control host, into injured mice can alleviate this immunosuppression.

Nasal application of a naturally processed and presented T cell epitope derived from TCR AV11 protects against adjuvant arthritis

Reactivity towards TCR peptides plays an important role in the regulation of several experimental autoimmune diseases. In a previous paper, we showed the TCRAV11 usage by an arthritogenic T cell clone isolated from a rat with adjuvant arthritis (AA). Moreover, we identified three immunogenic peptides in AV11: AV11 24-40, 41-55 and 66-80. In the present study, we show that T cells directed towards all three epitopes are part of the immune repertoire. The strongest delayed-type hypersensitivity (DTH) reaction was observed against the peptide derived from the third framework region, peptide AV11 66-80. DTH reactions to this peptide were detectable in naive rats and increased significantly after AA induction. Interestingly, modulation of the AV11 66-80 T cell response by nasal AV11 66-80 administration resulted in reduced DTH responses and in a strong inhibition of AA. These findings suggest that during the natural course of AA, T cells directed towards the third framework region of AV11 do not have a disease regulatory function, but instead play a role in the deterioration of AA.

Effects of preinduced Candida-specific systemic cell-mediated immunity on experimental vaginal candidiasis

It has been postulated that systemic cell-mediated immunity (CMI) is an important host defense factor against recurrent vaginal infections caused by Candida albicans. Using an estrogen-dependent murine model of vaginal candidiasis, we have previously shown that mice inoculated vaginally with C. albicans acquire a persistent vaginal infection and develop Candida-specific Th1-type systemic CMI. In the present study, experimental vaginitis was monitored in the presence of preinduced systemic Candida-specific CMI. Mice immunized systemically with C. albicans culture filtrate antigens (CaCF) in complete Freund's adjuvant (CFA) had Th1-type reactivity similar to that of vaginally infected mice. CaCF given to mice intravenously induced Candida-specific suppressor T (Ts) cells. Mice preimmunized with CaCF-CFA and given a vaginal inoculum of C. albicans had positive delayed-type hypersensitivity (DTH) reactivity from the time of vaginal inoculation through 4 weeks. Conversely, mice infected in the presence of Ts cells had significantly reduced DTH responses throughout the 4-week period in comparison with naive infected mice. However, the presence of Th1-type Candida-specific DTH cells or Ts cells, either induced in mice prior to vaginal inoculation or adoptively transferred at the time of inoculation, had no effect on the vaginal Candida burden through 4 weeks of infection. A similar lack of effects was obtained in animals with lower Candida population levels resulting from a reduction in or absence of exogenous estrogen. These results suggest that systemic Th1-type CMI demonstrable with CaCF is unrelated to protective events at the level of the vaginal mucosa.

The immunosuppressive effect of hepatocytes in rats

The immunosuppressive effect of hepatocytes was examined experimentally by heart allograft and delayed-type-hypersensitivity (DTH) reactions. The hepatocyte inoculation (1 X 10(7) of BDE (of the major histocompatibility complex haplotype RT1u), LEW (RT1l), and DA (RT1a) into the spleens of LEW rats significantly prolonged the survival of BDE heart allografts to 14.3 +/- 2.7 (mean +/- SD), 9.2 +/- 0.8, and 10.8 +/- 2.3 days respectively, compared with 6.7 +/- 0.8 days in controls (p less than 0.01). Moreover, the BDE hepatocytes had a significantly prolonged survival compared to the LEW (p less than 0.01) and DA (0.02 less than p less than 0.05) groups. BDE hepatocyte (donor specific) inoculation 4 and 7 days before priming with the spleen cells reduced DTH responses in the LEW rats to 44.6 +/- 4.8 per cent, and 74.2 +/- 8.0 per cent, respectively. DA hepatocyte inoculation (third party) 4 and 7 days prior to priming reduced DTH responses to 72.5 +/- 11.5 per cent, and 76.5 +/- 11.9 per cent, respectively. All DTH responses were significantly suppressed after hepatocyte inoculation compared to 100 per cent in the controls (p less than 0.01). Moreover, the inoculation of BDE hepatocytes (donor specific) 4 days prior to the priming significantly reduced DTH responses compared to the group primed 7 days before (p less than 0.01). From these results we concluded that hepatocytes produced not only non-specific but also donor specific immunosuppressive effects through T cell immune reaction. Moreover, donor specific immunosuppressive effects were induced at least 4 to 7 days after hepatocyte inoculation.

A decreased functional capacity of CD4+ T cells underlies the impaired DTH reactivity in old mice

The data presented in this paper show that the in vivo delayed-type-hypersensitivity (DTH) reaction to both H-2 and non-H-2 alloantigens declines with increasing age. It is also shown that cells generated in vitro are capable to transfer DTH to young naive syngeneic recipients. Using this in vitro system it could be demonstrated that cells from old CBA/Rij mice induced lower DTH responses than cells from young CBA/Rij mice. Depletion experiments with the effector T cell population showed that the DTH effetor phase is mediated by CD4+ T cells. Lower responses in old mice were not due to increased suppressor T cell activity, since after removal of the CD8+ T cells old CD4+ cells were still less effective in the generation of DTH effector T cells than young CD4+ cells. Addition of IL-2 containing supernatant to in vitro cultures did not improve the subsequent DTH response. From these data it can be concluded that the reduced DTH responses in old mice are not solely due to CD8+ suppressor cell activity and/or lack of IL-2, but that rather intrinsic defects of the CD4+ T cell population appear to play a major role in the impaired DTH reactivity during ageing.

Abnormality of the Delayed Type Hypersensitivity (DTH) Response to Bordetella Pertussis in Spontaneously Hypertensive Rats (SHR)

The delayed type hypersensitivity (DTH) response of spontaneously hypertensive rats (SHR) was compared with that of Wistar Kyoto rats (WKY), a normotensive strain. SHR showed a lower DTH response to Bordetella pertussis than WKY, especially 48 to 72 hr after antigenic challenge. These results were observed before appearance of abnormality of antibody formation or blood pressure. The reduced DTH responses of SHR were partially restored by either transfer of WKY thymocytes or treatment with levamisole. Conversely, the transfer of SHR thymocytes into WKY rats tended to diminish the DTH response. These findings suggest that SHR have a disfunction of'T lymphocytes involved in DTH response (e.g., increase of suppressor cells and/or decrease of helper cells).