Cyclophosphamide-modified murine peritoneal macrophages induce CD4+ T contrasuppressor cells that protect contact sensitivity T effector cells from suppression

BACKGROUND

Cyclophosphamide (CY) is one of the most widely used alkylating agents in the treatment of various cancers and some autoimmune diseases. Numerous reports suggest that CY exerts immunoregulatory effects. Animal studies have shown CY affects contact sensitivity (CS) response by depleting CD4⁺CD25⁺ T regulatory cells and CD8⁺ T suppressor (Ts) cells. In a mouse model of CS, we previously showed that in vivo treatment with CY shapes the immunogenic/immunoregulatory balance of peritoneal macrophages. The aim of the current study is to verify if macrophages (Mf) from CY-treated mice are indeed able to induce immunoregulatory cells that could protect from suppression.

METHODS

Adoptive cell transfer of CS was used to examine immunomodulating properties of peritoneal Mf from CY-treated mice. Isolation of peritoneal Mf from animals that were (Mf-CY) or were not (Mf) treated with CY were cultured to identify cytokine repertoire. Further, we assessed spleen cell (SPLC) cytokine production following immunization with trinitrophenyl-conjugated Mf from donors treated (TNP-Mf-CY) or non-treated (TNP-Mf) with CY.

RESULTS

In vitro experiments identified that Mf-CY produce more IL-6, TNF-α and TGF-β than naïve Mf. Further, immunization with peritoneal TNP-Mf-CY induces CD4⁺ T contrasuppressor cells (Tcs) cells that protect CS-effector cells from suppression. Higher IL-17A secretion was observed from TNP-Mf-CY-treated mouse SPLC compared to SPLC from TNP-Mf injected mice suggesting that this cytokine might be important in mediating contrasuppression in this model.

CONCLUSIONS

Our results show that in vivo treatment with CY influences mouse peritoneal Mf to induce CD4+ Tcs cells that protect CS-effector cells from suppressive signals of Ts cells.

Epicutaneous immunization with ovalbumin and CpG induces TH1/TH17 cytokines, which regulate IgE and IgG2a production

BACKGROUND

Subcutaneous allergen-specific immunotherapy is a standard route for the immunotherapy of allergic diseases. It modulates the course of allergy and can generate long-term remission. However, subcutaneous allergen-specific immunotherapy can also induce anaphylaxis in some patients, and therefore additional routes of administration should be investigated to improve the safety and tolerability of immunotherapy.

OBJECTIVE

We sought to determine whether epicutaneous treatment with antigen in the presence of a Toll-like receptor 9 agonist can suppress TH2-mediated responses in an antigen-specific manner.

METHODS

Epicutaneous immunization was performed by applying a skin patch soaked with ovalbumin (OVA) plus CpG, and its suppressor activity was determined by using the mouse model of atopic dermatitis. Finally, adoptive cell transfers were implemented to characterize the regulatory cells that are induced by epicutaneous immunization.

RESULTS

Epicutaneous immunization with OVA and CpG reduces the production of OVA-specific IgE and increases the synthesis of OVA-specific IgG2a antibodies in an antigen-specific manner. Moreover, eosinophil peroxidase activity in the skin and production of IL-4, IL-5, IL-10, and IL-13 are suppressed. The observed reduction of IgE synthesis is transferable with T-cell receptor (TCR) αβ(+)CD4(+)CD25(-) cells, whereas IgG2a production is dependent on both TCRαβ(+) and TCRγδ(+) T cells. Further experiments show that the described phenomenon is myeloid differentiation primary response 88, IFN-γ, and IL-17A dependent. Finally, the results suggest that epicutaneous immunization with OVA and CpG decreases the synthesis of OVA-specific IgE and skin eosinophil peroxidase activity in mice with ongoing skin allergy.

CONCLUSION

Epicutaneous application of protein antigen in the presence of adjuvant could be an attractive needle-free and self-administered immunotherapy for allergic diseases.

From Mysterious Supernatant Entity to miRNA-150 in Antigen-Specific Exosomes: a History of Hapten-Specific T Suppressor Factor

Soon after the discovery of T suppressor cells by Gershon in 1970, it was demonstrated that one subpopulation of these lymphocytes induced by i.v. hapten injection suppresses contact sensitivity response mediated by effector CD4+ or CD8+ T cells in mice through the release of soluble T suppressor factor (TsF) that acts antigen specifically. Our experiments showed that biologically active TsF is a complex entity consisting of two subfactors, one antigen specific and other non-specific, produced by differently induced populations of cells. In following years, we found that the antigen-specific subfactor is a light chain of IgM antibody that is produced by B1a lymphocytes. However, the exact nature of non-specific part remained a mystery for about 30 years. Our current studies characterized TsF as regulatory miRNA-150 carried by T suppressor cell-derived exosomes that are antigen specific due to a surface coat of IgM antibody light chains produced by B1a cells. The present communication briefly summarizes our studies on TsF that led to discovery of regulating miRNA that acts antigen specifically to suppress immune response.

Epicutaneous Immunization with Collagen Induces TCRαβ Suppressor T Cells That Inhibit Collagen-Induced Arthritis

BACKGROUND

We have shown previously, in an animal model of multiple sclerosis and in TNBS-induced colitis, that epicutaneous (EC) immunization with protein antigen induces T suppressor cells that strongly inhibit the inflammatory response in contact hypersensitivity reactions.

METHODS

EC immunization was performed by applying to the shaved skin of the mouse dorsum a gauze patch soaked with a solution containing various amounts of type II collagen (COLL II) in a volume of 100 µl of PBS on days 0 and 4. On day 7 the patches were removed and mice were intradermally (i.d.) immunized with COLL II to induce collagen-induced arthritis (CIA).

RESULTS

Our study shows that EC immunization with 100 or 30 μg of COLL II reduces disease severity, whereas lower doses (10 or 3 μg) do not affect CIA. Decreased disease severity observed after EC immunization with COLL II correlates with reduced myeloperoxidase activity in joint tissue and with reduced production of anti-citrullinated protein and anti-COLL II IgG2a antibodies. Transfer experiments show that EC immunization with COLL II induces suppressor cells that belong to the population of TCRαβ lymphocytes and that EC-induced suppression declines with time. Both in vitro and in vivo experiments show that IL-17A plays an important role in EC-induced suppression of CIA. EC application of COLL II at the first signs of CIA also results in disease suppression.

CONCLUSIONS

The suppression of inflammatory responses by T suppressor cells induced through EC immunization of a protein antigen may become an attractive noninvasive therapeutic method for a variety of clinical situations.

Epicutaneous immunization with TNP-Ig and Zymosan induces TCRαβ+ CD4+ contrasuppressor cells that reverse skin-induced suppression via IL-17A

BACKGROUND

Our previous work showed that epicutaneous (EC) immunization with protein antigen e.g. TNP-conjugated mouse immunoglobulin (TNP-Ig) in the form of a patch prior to hapten sensitization inhibits Th1-mediated contact hypersensitivity (CHS) in mice. We also found that suppression of CHS was mediated by TCRαβ+ CD4+ CD8+ T suppressor cells producing TGF-β. The aim of this study was to investigate the role of innate immunity in the suppression of CHS.

METHODS

Mice were immunized by applying gauze patches containing protein antigen alone or in the presence of zymosan, and were then tested for the CHS response. Adoptive cell transfer experiments were used to study the mechanisms involved in the reversal of skin-induced suppression. The influence of EC immunization on cytokine production by lymph node cells was measured by ELISA.

RESULTS

We found that EC immunization with TNP-Ig and zymosan before trinitrophenyl chloride sensitization reverses skin-induced suppression, demonstrated in vivo and in vitro. The reversal of skin-induced suppression was transferable by antigen-specific TCRαβ+ CD4+ T contrasuppressor cells. Furthermore, we showed that the contrasuppression was IL-17A-dependent and TLR2- and MyD88-independent.

CONCLUSIONS

Our work strongly suggests that EC immunization with protein antigen and zymosan reverses skin-induced suppression and that this approach may be a potential tool to increase the immunogenicity of weakly immunogenic antigens.

Epicutaneous immunization with phosphorylcholine conjugated to bovine serum albumin (PC-BSA) and TLR9 ligand CpG alleviates pneumococcal pneumonia in mice

BACKGROUND

Epicutaneous (EC) immunization is a potential new strategy of a needle-free and self-administrable immunization by using a topically applied patch to deliver vaccine. We have previously shown that EC immunization with various protein antigens inhibits both Th1- and Tc1-mediated contact hypersensitivity (CHS) in mice. Our further work showed that maneuver of EC immunization with an antigen and Toll-like receptor (TLR) ligands prior to hapten sensitization reverses skin-induced suppression.

METHODS

Animal model of pneumococcal pneumonia was used to study efficacy of EC induced immunopotentiation.

RESULTS

Current work showed that EC immunization with phosphorylcholine conjugated to bovine serum albumin (PC-BSA) and CpG prior to Streptococcus pneumoniae infection results in smaller decrease of body weight when compared to PBS treated mice. Consistent with the behavioral observations and body weight, smaller numbers of bacteria were quantitated in lung homogenates of mice patched with PC-BSA and CpG prior inoculation with S. pneumonia when compared to mice patched with PBS alone. In vitro experiments showed that lymph node cells and spleen cells from mice EC immunized with PC-BSA plus CpG produced high levels of IFN-γ and IL-17A when compared to PBS or PC-BSA or CpG treated mice.

CONCLUSION

This work shows that EC immunization with PC-BSA plus TLR9 ligand CpG may be a potential tool to boost immunity to S. pneumoniae.

Partial depletion of natural gut flora by antibiotic aggravates collagen induced arthritis (CIA) in mice

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory disease that affects about 1% of the adult population and occurs twice as frequently among women than men. At present it is accepted that pathogenesis of RA is based on inflammatory response mediated by CD4(+) Th1 and Th17 lymphocytes. The most commonly applied model imitating RA is the collagen induced arthritis (CIA). A growing evidence shows that there is a correlation between microbial dysbiosis and human pathology which includes autoimmunity, allergic diseases, obesity, inflammatory bowel disease (IBD), metabolic syndrome.

METHODS

Collagen induced arthritis was used to study influence of natural gut flora on course of rheumatoid arthritis.

RESULTS

Current work employing CIA model showed that partial depletion of natural gut flora with orally administered antibiotic Baytril (enrofloxacin) aggravates disease severity when compared to control mice. Observed partial depletion of both aerobic and anaerobic bacteria did not affect animal body weight. Additionally, in vitro study showed increased production of IFN-? and IL-17A and decreased release of IL-4 by axillary lymph node cells (ALNC) isolated from mice treated with antibiotic and induced CIA when compared to positive control. Furthermore, treatment with antibiotic prior to CIA induction results in augmented production of IFN-?, IL-17A and IL-6 by mesenteric lymph node cells (MLNC).

CONCLUSION

Presented data suggest that alteration of gut microbiota via use of enrofloxacin may play a role in modulating arthritis symptom severity in this mouse model.

Epicutaneous immunization with protein antigen TNP-Ig alleviates TNBS-induced colitis in mice

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory autoimmune disease with limited treatment modalities. The animal model of colitis induced by treatment with trinitrobenzene sulfonic acid (TNBS-colitis) is commonly used to test new therapies of this disease. In our previous work we found that epicutaneous (EC) immunization with protein antigen induced a state of profound immunosuppression that inhibited inflammatory response in contact sensitivity, in experimental autoimmune encephalomyelitis (EAE) and in allogeneic skin graft rejection.

METHODS

TNBS-induced colitis was used as an experimental model.

RESULTS

In our current work, we showed that EC immunization with TNP-conjugated mouse immunoglobulin (TNP-Ig) prior to induction of TNBS-colitis alleviates disease severity what was determined by the body weight, the length and the weight of the colon, the histological activity index (HAI) and myeloperoxidase activity (MPO). Observed amelioration of the disease in TNP-Ig patched mice was accompanied with decreased production of IFN-γ and IL-17A by splenocytes. Additionally, spleen cells isolated from mice EC immunized with TNP-Ig prior to colitis induction showed increased production of IL-10 suggesting that this cytokine might be involved in inhibiting inflammatory response in the colon.

CONCLUSION

This work shows that EC immunization with protein antigen prior to TNBS-colitis induction ameliorates disease and observed suppression of inflammatory response in the colon might be mediated by IL-10.

Epicutaneous immunization with hapten-conjugated protein antigen alleviates contact sensitivity mediated by three different types of effector cells

BACKGROUND

Allergic contact dermatitis (ACD) is a common clinical condition in industrialized countries and often causes occupational diseases. Animal model of contact sensitivity (CS) is commonly used to study ACD in mice and can be induced by skin application of haptens. It has been previously shown that CS is mediated by CD4(+) or CD(8+) T effector cells. More recently it was found that also liver NK cells can play a role of CS effector cells in mice.

METHODS

The aim of the present study was to test whether skin-induced suppression could inhibit CS response in vivo.

RESULTS

Here we show that EC immunization of normal mice with hapten conjugated protein antigen prior to hapten sensitization suppresses Th1, Tc1 and NK mediated CS responses.

CONCLUSIONS

These data strongly suggest that maneuver of EC immunization may have important implications for designing therapeutic schemes aimed at modulating unwanted immune responses in contact hypersensitivity.

Epicutaneous immunization with DNP-BSA induces CD4+ CD25+ Treg cells that inhibit Tc1-mediated CS

As we have shown previously that protein antigen applied epicutaneously (EC) in mice inhibits TNP-specific Th1-mediated contact sensitivity (CS), we postulated that the maneuver of EC immunization might also suppress Tc1-dependent CS response. Here we showed that EC immunization of normal mice with 2,4-dinitrophenylated bovine serum albumin (DNP-BSA) applied on the skin in the form of a patch induces a state of subsequent unresponsiveness due to regulatory T cells (Treg) that inhibited sensitization and elicitation of effector T-cell responses. Suppression is transferable in vivo by TCRαβ(+) CD4(+) CD25(+) lymphocytes harvested from lymph nodes (LNs) of skin-patched animals. Flow cytometry revealed that EC immunization with DNP-BSA increased TCRαβ(+) CD4(+) CD25(+) FoxP3(+) lymphocytes in subcutaneous LNs, suggesting that observed suppression was mediated by Treg cells. Further, in vitro experiments showed that EC immunization with DNP-BSA prior to 1-fluoro-2,4-dinitrobenzen sensitization suppressed LN cell proliferation and inhibited production of TNF-α, IL-12 and IFN-γ. Using a transwell system or anti-CTLA-4 mAb, we found that EC induced suppression required direct Treg-effector cell contact and is CTLA-4-dependent.

Participation of iNKT cells in the early and late components of Tc1-mediated DNFB contact sensitivity: cooperative role of γδ-T cells

Prior studies of classical 24 h responses in TNP-Cl (picryl chloride) allergic contact sensitivity (CS), showed mediation by Th1 cells in CBA mice, and established that 24 h elicitation of responses requires an early 2 h CS-initiating component dependent on iNKT cells, IL-4 and B-1 B cells. Here, we studied the other form of cytotoxic T cell (Tc1) CS in DNFB sensitized BALB/c mice and determined that similar CS-initiation also is required. We systematically tested each step of the initiation pathway in this model. Thus, DNFB Tc1 CS was significantly impaired in iNKT cell deficient CD1d(-/-) and Jα18(-/-) mice, IL4Rα(-/-) and STAT-6(-/-) mice, and also in pan B-cell deficient JH(-/-) mice. Further, the Tc1 DNFB CS-initiating component, like Th1 response to TNP-Cl, was elicited by only 1-day after immunization, due to B-1 cells. In summary, we show that CS-Initiation also is required in Tc1 CS. Further, we have newly determined regulatory support of both the early and late components of DNFB induced Tc1 CS by iNKT cells and γδ-T cells. In summary, both iNKT cells and assisting γδ-T cells are involved in initiating and effector phases of DNFB induced CS.