[Show abstract][Hide abstract] ABSTRACT: We have reported that prophylactic as well as therapeutic administration of neem leaf glycoprotein (NLGP) induces significant restriction of solid tumor growth in mice. Here, we investigate whether the effect of such pretreatment (25µg/mice; weekly, 4 times) benefits regulation of tumor angiogenesis, an obligate factor for tumor progression. We show that NLGP pretreatment results in vascular normalization in melanoma and carcinoma bearing mice along with downregulation of CD31, VEGF and VEGFR2. NLGP pretreatment facilitates profound infiltration of CD8+ T cells within tumor parenchyma, which subsequently regulates VEGF-VEGFR2 signaling in CD31+ vascular endothelial cells to prevent aberrant neovascularization. Pericyte stabilization, VEGF dependent inhibition of VEC proliferation and subsequent vascular normalization are also experienced. Studies in immune compromised mice confirmed that these vascular and intratumoral changes in angiogenic profile are dependent upon active adoptive immunity particularly those mediated by CD8+ T cells. Accumulated evidences suggest that NLGP regulated immunomodulation is active in tumor growth restriction and normalization of tumor angiogenesis as well, thereby, signifying its clinical translation.
PLoS ONE 11/2014; 9(11):e110040. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have generated a polyclonal antibody against a novel immunomodulator, neem leaf glycoprotein (NLGP) that can react to a specific 47Kd subunit of NLGP. Generated anti-NLGP antibody (primarily IgG2a) was tested for its anti-tumor activity in murine carcinoma (EC, CT-26), sarcoma (S180) and melanoma (B16Mel) tumor models. Surprisingly, tumor growth restriction was only observed in CT-26 carcinoma models, without any alteration in other tumor systems. Comparative examination of antigenicity between four different tumor models revealed high expression of CEA-like protein on the surface of CT-26 tumors. Subsequent examination of the cross-reactivity of anti-NLGP antibody with purified or cell bound CEA revealed prominent recognition of CEA by anti-NLGP antibody, as detected by ELISA, Western Blotting and immunohistochemistry. This recognition seems to be responsible for anti-tumor function of anti-NLGP antibody only on CEA-like protein expressing CT-26 tumor models, as confirmed by ADCC reaction in CEA+ tumor systems where dependency to anti-NLGP antibody is equivalent to anti-CEA antibody. Obtained result with enormous therapeutic potential for CEA+ tumors may be explained in view of the epitope spreading concept, however, further investigation is crucial.
[Show abstract][Hide abstract] ABSTRACT: Carcinoembryonic antigen (CEA) is one of the promising tumor antigens mainly associated with carcinoma of the colon, lung, breast, etc. and received wide attention for cancer immunotherapy. Neem leaf glycoprotein (NLGP), an effective immunomodulator, is able to generate humoral and cellular immune responses in murine tumor models. We have generated a monoclonal antibody (mAb) against NLGP by fusing NLGP-immunized mice splenocytes with nonsecretory myeloma cells. A highly anti-NLGP mAb secreting clone (1C8; IgG2a in nature) has been identified and propagated in culture. 1C8 recognizes human CEA as good as NLGP by enzyme linked immunosorbent assay, Western blotting, and immunoprecipitation. 1C8 detects CEA on colon cancer tissues by immunochistochemistry. By flow cytometry, 1C8 specifically reacts with CEA human (Colo-205, HCT-116, and HT-29) and mouse (CT-26) colon cancer cells, but it showed minimum reactivity with CEA human (MCF7, SiHa, and SCC084) and mouse (B16MelF10) cancer cells. This anti-NLGP 1C8 mAb revealed significant antitumor activity and better survivability in vivo in animals bearing mouse (CT-26 in BALB/c) and human (Colo-205 in athymic nude) CEA cancer cells. 1C8 has no direct influence on proliferation and migration of CEA cells, however, NK cell-dependent strong antibody-dependent cellular cytotoxicity reaction toward CEA cells and normalization of angiogenesis are chiefly associated with tumor growth restriction. Obtained results provided a new immunotherapeutic approach for the effective management of CEA tumors.
[Show abstract][Hide abstract] ABSTRACT: Aim: Neem leaf glycoprotein (NLGP) matures human myeloid and mouse bone marrow-derived dendritic cells (DCs). (NLGP) also therapeutically restricts the mouse established sarcoma growth by activating CD8(+) T cells along with increased proportion of tumor residing CD11c(+) DCs. Here, we intended to find out whether CD8(+) T cells become cytotoxic to sarcoma cells after presentation of sarcoma antigen by NLGP-matured DCs to restrict murine sarcoma growth. Materials & methods: NLGP was prepared from matured neem(Azadirachta indica) leaves. Solid sarcoma tumor in Swiss mice was developed by subcutaneous inoculation of sarcoma cells. GMCSF-IL-4 generated DCs were matured with NLGP and pulsed with sarcoma antigen for immunotherapy. Status of CD8+CD69+T cells was studied by flow cytometry and secretion of cytokines was measured by ELISA. RT-PCR was used to monitor the status of perforin, granzyme B. Results: NLGP-matured sarcoma antigen-pulsed DCs (DCNLGPTAg) inhibit mouse sarcoma growth. DCNLGPTAg immunization enhances CD8(+) T-cell number within tumor-infiltrating lymphocytes and tumor-draining lymph nodes along with increased perforin and granzyme B expression. Antigen-specific T-cell proliferation and IFN-γ secretion were significantly higher in DCNLGP- and DCNLGPTAg-immunized mice groups. In vivo CD8(+) T-cell depletion abrogated the DCNLGPTAg-mediated tumor growth restriction. Conclusion: DCNLGPTAg restricts CD8(+) T-cell-dependent mouse established sarcoma growth, related to the optimum antigen presentation by DCs to CD8(+) T cells.
[Show abstract][Hide abstract] ABSTRACT: In the present study, we observed a marked variation in the expression of PKCα and PKCδ isotypes in B16F10 melanoma tumor cells compared to the normal melanocytes. Interestingly, the tumor instructed expression or genetically manipulated overexpression of PKCα isotype resulted in enhanced G1 to S transition. This in turn promoted cellular proliferation by activating PLD1 expression and subsequent AKT phosphorylation, which eventually resulted in suppressed ceramide generation and apoptosis. On the other hand, B16F10 melanoma tumors preferentially blocked the expression of PKCδ isotype, which otherwise could exhibit antagonistic effects on PKCα-PLD1-AKT signaling and rendered B16F10 cells more sensitive to apoptosis via generating ceramide and subsequently triggering caspase pathway. Hence our data suggested a reciprocal PKC signaling operational in B16F10 melanoma cells, which regulates ceramide generation and provide important clues to target melanoma cancer by manipulating the PKCδ-ceramide axis.
PLoS ONE 03/2014; 9(3):e91656. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Tumor-associated macrophages (TAMs) are preferentially M2 skewed and promote tumor growth, angiogenesis, invasion, and/or metastasis. In this study, we have analyzed the in vitro immunomodulatory potential of a non-toxic neem leaf glycoprotein (NLGP) in reprogramming Stage III supraglottic laryngeal tumor cell lysate (SLTCL) induced M2 TAMs to their classical anti-tumor shape (M1). Data generated from this study support that NLGP is effective in preventing the SLTCL induced generation (CD68(+)CD206(+)IL-10(high) to CD68(+)CD206(-)IL-10(low) TAMs) and functions (NO(low) to NO(high), MHC-I(low) to MHC-I(high), CD80(low) to CD80(high)) of pro-tumorous M2 macrophages, which in turn associated with sustained anti-tumor effector functions by promoting cytotoxic T cell activities and suppressing regulatory T cells. Furthermore, our data also suggest that NLGP prevents M2 skewness of TAMs by downregulating phosphorylation of targeted STAT3.
[Show abstract][Hide abstract] ABSTRACT: Dasatinib (DAS) is a potent inhibitor of the BCR-ABL, SRC, c-KIT, PDGFR, and ephrin tyrosine kinases that has demonstrated only modest clinical efficacy in melanoma patients. Given reports suggesting that DAS enhances T cell infiltration into the tumor microenvironment, we analyzed whether therapy employing the combination of DAS plus dendritic cell (DC) vaccination would promote superior immunotherapeutic benefit against melanoma. Using a M05 (B16.OVA) melanoma mouse model, we observed that a 7-day course of orally-administered DAS (0.1 mg/day) combined with a DC-based vaccine (VAC) against the OVA257-264 peptide epitope more potently inhibited tumor growth and extended overall survival as compared with treatment with either single modality. The superior efficacy of the combinatorial treatment regimen included a reduction in hypoxic-signaling associated with reduced levels of immunosuppressive CD11b(+)Gr1(+) myeloid-derived suppressor cells (MDSC) and CD4(+)Foxp3(+) regulatory T (Treg) populations in the melanoma microenvironment. Furthermore, DAS + VAC combined therapy upregulated expression of Type-1 T cell recruiting CXCR3 ligand chemokines in the tumor stroma correlating with activation and recruitment of Type-1, vaccine-induced CXCR3(+)CD8(+) tumor-infiltrating lymphocytes (TILs) and CD11c(+) DC into the tumor microenvironment. The culmination of this bimodal approach was a profound "spreading" in the repertoire of tumor-associated antigens recognized by CD8(+) TILs, in support of the therapeutic superiority of combined DAS + VAC immunotherapy in the melanoma setting.
[Show abstract][Hide abstract] ABSTRACT: Therapy with neem leaf glycoprotein (NLGP) inhibits murine B16-melanoma in vivo and improves survivability. Studies on tumor-microenvironment (TME) from NLGP treated mice (NLGP-TME) suggests that anti-tumor effect is directly associated with enhanced CD8+T cell activity, dominance of type 1 cytokines/chemokine network with downregulation of suppressive cellular functions. NLGP-TME educated CD8+T cells showed higher perforin and granzymeB expression with greater in vitro cytotoxicity against B16 melanoma. These CD8+T cells showed proportionally lower FasR expression, denotes prevention from activation induced cell death by NLGP. Accumulated evidences strongly suggest NLGP influenced normalized TME allows CD8+T cells to perform optimally to inhibit melanoma growth.
[Show abstract][Hide abstract] ABSTRACT: Content of tumor microenvironment (TME) is varied greatly among different types of laryngeal tumors, namely, supraglottic, glottic and subglottic tumors. These three different TMEs shape infiltrating monocytes/macrophages towards M2 genotypes in variable degrees. Results obtained from in vitro studies demonstrated extent of expression of M2 phenotypic features on macrophages was maximum after their exposure to supraglottic laryngeal tumor cell lysates (SLTCL) than glottic or subglottic lysates. Moreover, M2 macrophages generated under influence of SLTCL show less nitric oxide production, greater IL-10: IL-12 ratio and poor antigen presentation. Co-culture of such M2 macrophages with T cells from healthy donors resulted decreased activation of T cells and T cell mediated tumor cell cytotoxicity, than, glottic or subglottic. SLTCL mediated macrophage polarization is STAT3 dependent and might be one of the major factors for severe immune paralysis leading to poor prognosis of supraglottic laryngeal tumor bearer following standard treatment.
[Show abstract][Hide abstract] ABSTRACT: Immune evasion within the tumor microenvironment supports malignant growth and is also a major obstacle for successful immunotherapy. Multiple cellular components and soluble factors coordinate to disrupt protective immune responses. Although stromal cells are well-known for their parenchymal supportive roles in cancer establishment and progression, we demonstrate for the first time, to our knowledge, that tumor-derived vascular pericytes negatively influence CD4(+) T cell activation and proliferation, and promote anergy in recall response to Ag by CD4(+)CD44(+) T cells via regulator of G protein signaling 5- and IL-6-dependent pathways. Our data support a new specific role for tumor-derived pericytes in the immune evasion paradigm within the tumor microenvironment and suggest the targeting of these cell populations in the context of successful immunotherapeutics for the treatment of cancer.
The Journal of Immunology 06/2013; · 5.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have observed restriction of the murine sarcoma growth by therapeutic intervention of neem leaf glycoprotein (NLGP). In order to evaluate the mechanism of tumor growth restriction, here, we have analyzed tumor microenvironment (TME) from sarcoma bearing mice with NLGP therapy (NLGP-TME, in comparison to PBS-TME). Analysis of cytokine milieu within TME revealed IL-10, TGFβ, IL-6 rich type 2 characters was switched to type 1 microenvironment with dominance of IFNγ secretion within NLGP-TME. Proportion of CD8(+) T cells was increased within NLGP-TME and these T cells were protected from TME-induced anergy by NLGP, as indicated by higher expression of pNFAT and inhibit related downstream signaling. Moreover, low expression of FasR(+) cells within CD8(+) T cell population denotes prevention from activation induced cell death. Using CFSE as a probe, better migration of T cells was noted within TME from NLGP treated mice than PBS cohort. CD8(+) T cells isolated from NLGP-TME exhibited greater cytotoxicity to sarcoma cells in vitro and these cells show higher expression of cytotoxicity related molecules, perforin and granzyme B. Adoptive transfer of NLGP-TME exposed T cells, but not PBS-TME exposed cells in mice, is able to significantly inhibit the growth of sarcoma in vivo. Such tumor growth inhibition by NLGP-TME exposed T cells was not observed when mice were depleted for CD8(+) T cells. Accumulated evidences strongly suggest NLGP mediated normalization of TME allows T cells to perform optimally to inhibit the tumor growth.
PLoS ONE 06/2013; 8(6):e66501. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have observed earlier that therapeutic treatment with neem leaf glycoprotein (NLGP) inhibits murine B16-melanoma growth in vivo and improves survivability of treated mice. Anti-tumor effect of NLGP is directly associated with enhanced CD8(+) T cell activity and downregulation of suppressive cellular functions. Objective of this present study is to know the efficacy of NLGP in comparison to two popular drugs, Cisplatin and Sunitinib malate (Sutent) in relation to the modulation of tumor microenvironment (TME). Analysis of cytokine milieu within TME revealed IL-10, TGFβ, IL-6 rich type 2 characters was significantly switched to type 1 microenvironment with dominance of IFNγ and IL-2 within NLGP-TME, which was not found in other cases; however Cisplatin-TME appeared better in type 2 to type 1 conversion than Sutent-TME as evidenced by RT-PCR, ELISA and immunohistochemical analysis. NLGP-TME educated CD8(+) T cells exhibited greater cytotoxicity to B16 Melanoma cells in vitro and these cells showed comparatively higher expression of cytotoxicity related molecules, perforin and granzyme B than Cisplatin-TME and Sutent-TME educated T cells. Adoptive transfer of NLGP-TME exposed T cells, but not PBS-TME exposed cells in mice, is able to significantly inhibit the growth of melanoma in vivo. Such tumor growth inhibition was in significantly lower extent when therapeutic CD8(+) T cells were exposed to either Cisplatin-TME or Sutent-TME or control-TME. Accumulated evidences strongly suggest that non toxic NLGP normalized TME allows T cells to perform optimally than other TMEs under study to inhibit the melanoma growth.
International immunopharmacology 06/2013; · 2.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Tolerogenic dendritic cells (DCs) are a subset of DCs characterized by abundant indoleamine 2, 3 dioxygenase (IDO) expression. IDO may be co-operatively induced in DCs by regulatory T (Tregs) cells and various DC maturation agents. Tregs are markedly amplified in the physiological system of cancer patients, inducing over tolerance in DCs that leads to the hyper accumulation of immunosuppressive IDO in tumor microenvironment, thereby, hampering anti-tumor immunity. Consequently, a major focus of current immunotherapeutic strategies in cancer is to minimize IDO, which is possible by reducing Tregs and using various IDO inhibitors. Neem leaf glycoprotein (NLGP), a natural and nontoxic immunomodulator, demonstrated several unique immunoregulatory activities. Noteworthy activities of NLGP are to mature DCs and to inhibit Tregs. As Tregs are inducer of IDO in DCs and hyperactive Tregs is a hallmark of cancer, we anticipated that NLGP might abrogate IDO induction in DCs by inhibiting Tregs. Evidences are presented here that in a co-culture of DCs and Tregs isolated from cervical cancer stage IIIB (CaCx-IIIB) patients, NLGP does inhibit IDO induction in DCs by curtailing the over expression of Cytotoxic T-Lymphocyte Antigen 4 (CTLA4) on Tregs and concomitantly induces optimal DC maturation. In contrast, in the presence of LPS as maturation agent the DCs displays a tolerogenic profile. This finding suggests the reduction of tolerogenecity of DCs in CaCx-IIIB patients by reducing the IDO pool using NLGP. Accordingly, this study sheds more light on the diverse immunomodulatory repertoire of NLGP.
[Show abstract][Hide abstract] ABSTRACT: In spite of sufficient data on Neem Leaf Glycoprotein (NLGP) as a prophylactic vaccine, little knowledge currently exists to support the use of NLGP as a therapeutic vaccine. Treatment of mice bearing established sarcomas with NLGP (25 µg/mice/week subcutaneously for 4 weeks) resulted in tumor regression or dormancy (Tumor free/Regressor, 13/24 (NLGP), 4/24 (PBS)). Evaluation of CD8(+) T cell status in blood, spleen, TDLN, VDLN and tumor revealed increase in cellular number. Elevated expression of CD69, CD44 and Ki67 on CD8(+) T cells revealed their state of activation and proliferation by NLGP. Depletion of CD8(+) T cells in mice at the time of NLGP treatment resulted in partial termination of tumor regression. An expansion of CXCR3(+) and CCR5(+) T cells was observed in the TDLN and tumor, along with their corresponding ligands. NLGP treatment enhances type 1 polarized T-bet expressing T cells with downregulation of GATA3. Treg cell population was almost unchanged. However, T∶Treg ratios significantly increased with NLGP. Enhanced secretion/expression of IFNγ was noted after NLGP therapy. In vitro culture of T cells with IL-2 and sarcoma antigen resulted in significant enhancement in cytotoxic efficacy. Consistently higher expression of CD107a was also observed in CD8(+) T cells from tumors. Reinoculation of sarcoma cells in tumor regressed NLGP-treated mice maintained tumor free status in majority. This is correlated with the increment of CD44(hi)CD62L(hi) central memory T cells. Collectively, these findings support a paradigm in which NLGP dynamically orchestrates the activation, expansion, and recruitment of CD8(+) T cells into established tumors to operate significant tumor cell lysis.
PLoS ONE 01/2013; 8(1):e47434. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have evaluated the toxicity profile of a unique immunomodulator, neem leaf glycoprotein (NLGP) on different physiological systems of Swiss mice and Sprague Dawley rats. NLGP injection, even in higher doses than effective concentration caused no behavioral changes in animals and no death. NLGP injection increased the body weights of mice slightly without any change in organ weights. NLGP showed no adverse effect on the hematological system. Moreover, little hematostimulation was noticed, as evidenced by increased hemoglobin content, leukocyte count and lymphocyte numbers. Histological assessment of different organs like brain, liver, kidney, spleen and lymph nodes revealed no alterations in the organ microstructure of the NLGP treated mice and rats. Histological normalcy of liver and kidney was further confirmed by the assessment of liver enzymes like alkaline phosphatase, SGOT, SGPT and nephrological products like urea and creatinine. NLGP has no apoptotic effect on immune cells like T cells but induces proliferation of mononuclear cells collected from mice and rats. Number of CD4(+), CD8(+) T cells, DX5(+) NK cells, CD11b(+) macrophages and CD11c(+) dendritic cells is upregulated by NLGP without a significant change in CD4(+)CD25(+)Foxp3(+) regulatory T cells. Type 1 cytokines, like IFNγ also increased in serum with a decrease in type 2 cytokines. Total IgG content, especially IgG2a increased in NLGP treated mice. These type 1 directed changes help to create an anti-tumor immune environment that results in the restriction of carcinoma growth in mice. Accumulated evidence strongly suggests the non-toxic nature of NLGP. Thus, it can be recommended for human use in anti-cancer therapy.
International immunopharmacology 11/2012; · 2.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background & objectives: Interferon alpha 2b (IFNα2b) has been reported to regulate several immune functions efficiently to enhance the cytotoxic activity of NK and T cells towards various forms of tumours. The objective of the present study was to evaluate the efficacy of IFNα2b in overcoming disease induced and/or treatment associated imunosuppression of tongue squamous cell carcinoma (TSCC) patients undergoing chemotherapy for better clinical outcome. Methods: Seven TSCC patients under cisplatin + 5-fluorouracil chemotherapy in combination with IFNα2b were assessed for various immunohaematological parameters before treatment, after chemotherapy and after IFNα2b therapy. Results: Deterioration of the haematological and immune responses was detected in immunosuppressed TSCC patients after chemotherapy. IFNα2b treatment led to a recovery in these parameters in most of the patients. Greater number of T/NK cells and enhanced secretion of type 1 cytokines were also noted. Haematological complications were reduced after completion of the therapy. Immune- and haematostimulation were also observed in patients with partial response. No positive clinical response was detected in one patient. Interpretation & conclusions: IFNα2b appears to be an effective immunostimulator having clinical impact to combat the immunosuppression in TSCC patients. Successful immunostimulation by IFNα2b may help TSCC patients in clinical improvement. The findings of this preliminary study need to be confirmed on a large number of patients with TSCC.
The Indian Journal of Medical Research 07/2012; 136(1):54-9. · 1.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Axitinib, a tyrosine kinase inhibitor of vascular endothelial growth factor receptors, has demonstrated modest efficacy when applied as a single agent in the setting of advanced-stage melanoma. On the basis of the reported ability of axitinib to 'normalize' the tumor vasculature, we hypothesize that combination therapy using axitinib plus specific peptide-based vaccination would promote superior activation and recruitment of protective T cells into the melanoma microenvironment, leading to enhanced treatment benefit. Using a subcutaneous M05 (B16.OVA) melanoma model, we observed that a treatment regimen consisting of a 7-day course of axitinib (0.5 mg/day provided orally) combined with a subcutaneous vaccine [ovalbumin (OVA) peptide-pulsed syngenic dendritic cells adenovirally engineered to produce IL-12p70] yielded superior protection against melanoma growth and extended overall survival when compared with animals receiving either single modality therapy. Treatment benefits were associated with: (a) a reduction in suppressor cell (myeloid-derived suppressor cells and Treg) populations in the tumor, (b) activation of tumor vascular endothelial cells, and (c) activation and recruitment of type-1, vaccine-induced CD8 T cells into tumors. These results support the therapeutic superiority of combined vaccine+axitinib immunotherapy and the translation of such approaches into the clinic for the treatment of patients with advanced-stage melanoma.
Melanoma research 04/2012; 22(3):236-43. · 2.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have recently shown that effective cytokine gene therapy of solid tumors in HLA-A2 transgenic (HHD) mice lacking murine MHC class I molecule expression results in the generation of HLA-A2-restricted CD8(+) T effector cells selectively recognizing tumor blood vessel-associated pericytes and/or vascular endothelial cells. Using an HHD model in which HLA-A2(neg) tumor (MC38 colon carcinoma or B16 melanoma) cells are not recognized by the CD8(+) T cell repertoire, we now show that vaccines on the basis of tumor-associated blood vessel Ags (TBVA) elicit protective Tc1-dependent immunity capable of mediating tumor regression or extending overall survival. Vaccine efficacy was not observed if (HLA-A2(neg)) wild-type C57BL/6 mice were instead used as recipient animals. In the HHD model, effective vaccination resulted in profound infiltration of tumor lesions by CD8(+) (but not CD4(+)) T cells, in a coordinate reduction of CD31(+) blood vessels in the tumor microenvironment, and in the "spreading" of CD8(+) T cell responses to alternate TBVA that were not intrinsic to the vaccine. Protective Tc1-mediated immunity was durable and directly recognized pericytes and/or vascular endothelial cells flow-sorted from tumor tissue but not from tumor-uninvolved normal kidneys harvested from these same animals. Strikingly, the depletion of CD8(+), but not CD4(+), T cells at late time points after effective therapy frequently resulted in the recurrence of disease at the site of the regressed primary lesion. This suggests that the vaccine-induced anti-TBVA T cell repertoire can mediate the clinically preferred outcomes of either effectively eradicating tumors or policing a state of (occult) tumor dormancy.
The Journal of Immunology 02/2012; 188(4):1782-8. · 5.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have shown that neem leaf glycoprotein (NLGP) inhibits the regulatory T cell (Tregs) induced suppression of tumoricidal functions of CD14(+)CD68(+) monocyte/macrophages (MO/Mφ) from human peripheral blood. Cytotoxic efficacy of MO/Mφ toward macrophage sensitive cells, U937, is decreased in presence of Tregs (induced), however, it was increased further by supplementation of NLGP in culture. Associated Treg mediated inhibition of perforin/granzyme B expression and nitric oxide release from MO/Mφ was normalized by NLGP. Altered status of signature cytokines, like, IL-12, IL-10, IL-6, TNFα from MO/Mφ under influence of Tregs is also rectified by NLGP. Tregs significantly enhanced the expression of altered marker, mannose receptor (CD206) on CD68(+) cells that was downregulated upon NLGP exposure. In addition to tumoricidal functions, antigen presenting ability of MO/Mφ is hampered by Treg induced downregulation of CD80, CD86 and HLA-ABC. NLGP upregulated these molecules in MO/Mφ even in the presence of Tregs. Treg mediated inhibition of MO/Mφ chemotaxis in contact dependent manner was also normalized partially by NLGP, where participation of CCR5 was documented. Overall results suggest that Treg influenced pro-tumor MO/Mφ functions are rectified in a significant extent by NLGP to create an anti-tumor immune environment.
International immunopharmacology 12/2011; 12(2):326-33. · 2.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In an aim to rectify dysregulated CC chemokine receptor (CCR5)/ligand (RANTES, MIP-1α, MIP-1β) status of monocytes/macrophages in tongue squamous cell carcinoma (TSCC; n = 12) patients, we have tested interferon α2b (IFNα2b), a novel immunomodulator with wide use in the management of several forms of cancer. IFNα2b can upregulate reduced CCR5 expression and increases the suppressed secretory status of its ligands, as evidenced from in vitro studies on monocytes/macrophages from the peripheral blood of TSCC patients as well as healthy individuals. Isolated monocytes of TSCC patients (n = 5) undergoing chemotherapeutic treatment along with IFNα2b immunotherapy demonstrated significant upregulation in CCR5 expression and secretion of corresponding ligands. These rectifications in receptor/ligand levels are reflected in improved CCR5-dependent migration of monocytes/macrophages after IFNα2b treatment. The rectified chemokine profile and cellular migration translate into better tumoricidal and antigen-presenting functions of these cells. Accordingly, enhanced T-cell-mediated tumor cell killing is demonstrated upon IFNα2b treatment. Translating dual benefits on monocyte/macrophage functions, IFNα2b may emerge as a potential form of immunotherapy for TSCC patients that may be combined with standard chemotherapy for better clinical outcome.
Human immunology 10/2011; 73(1):38-47. · 2.55 Impact Factor