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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antineoplastic Agents / immunology*
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Antineoplastic Agents / pharmacology
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Azadirachta / chemistry
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Azadirachta / immunology
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CD8-Positive T-Lymphocytes / drug effects
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CD8-Positive T-Lymphocytes / immunology*
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CD8-Positive T-Lymphocytes / metabolism
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Cell Line, Tumor
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Cell Proliferation / drug effects
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Cytotoxicity, Immunologic / drug effects
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Cytotoxicity, Immunologic / immunology
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Female
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Glycoproteins / immunology*
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Glycoproteins / pharmacology
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Immunohistochemistry
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Interferon-gamma / immunology
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Interferon-gamma / metabolism
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Lymphocyte Activation / drug effects
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Lymphocyte Activation / immunology
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Mice
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Plant Leaves / chemistry
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Plant Leaves / immunology
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Plant Proteins / immunology*
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Plant Proteins / pharmacology
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Receptors, CCR5 / genetics
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Receptors, CCR5 / immunology
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Receptors, CCR5 / metabolism
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Receptors, CXCR3 / genetics
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Receptors, CXCR3 / immunology
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Receptors, CXCR3 / metabolism
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Reverse Transcriptase Polymerase Chain Reaction
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Sarcoma, Experimental / drug therapy
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Sarcoma, Experimental / immunology*
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Sarcoma, Experimental / pathology
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Spleen / drug effects
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Spleen / immunology
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Spleen / pathology
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Survival Analysis
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Time Factors
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Tumor Burden / drug effects
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Tumor Burden / immunology
Substances
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Antineoplastic Agents
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Cxcr3 protein, mouse
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Glycoproteins
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Plant Proteins
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Receptors, CCR5
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Receptors, CXCR3
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Interferon-gamma
Grants and funding
The work was partially supported by Indian Council of Medical Research, New Delhi (grant Immuno/18/11/08/2006-ECD-I; 3/2/2/188/2009/NCD-III to AM), Council of Scientific and Industrial Research, New Delhi (grants SRA (Scientists's Pool Scheme No: 8463A to AB); 09/030(0063)/2011-EMR-I to SB); 09/030(0050)/2008-EMR-I to SB), from University Grant Commission, New Delhi (grant F.2-3/2000 (SA-1) to KKG) and from Department of Science and Technology, New Delhi (INSPIRE Fellowship number 2011/188 to SG). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.