Immunomodulatory effects of copper nanoparticles against mitogen-stimulated rat splenic and thymic lymphocytes.

In the present study, we have evaluated the effects of copper (Cu) nanoparticles (NPs) on the primary B-and T-lymphocytes proliferation, cytokine levels, and bio-distribution through in vitro, in vivo and ex-vivo studies to allow the possible exploitations of CuNPs in biomedical applications. CuNPs were characterized by UV-Visible spectroscopy, transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). The proliferative response of lymphocytes was studied by 3H-thymidine incorporation assay and lymphocyte viability through trypan blue assay. The bio-distribution of CuNPs into lymphoid organs was examined by using ex-vivo imaging system. Cytokine levels in plasma of control and CuNPs treated animal groups were determined by enzyme-linked immunosorbent assay (ELISA) method along with other biochemical analysis. CuNPs significantly suppressed the proliferation of primary splenic and thymic lymphocytes in a dose dependent manner. Ex-vivo imaging exhibited the distribution of CuNPs in spleen and thymus. Oral administration of CuNPs (2 mg and 10 mg/kg body weight) significantly inhibited the proliferation of splenic and thymic lymphocytes along with lowered cytokines levels (TNF-alpha and IL-2) on comparison with controls. The results indicated the significant inhibition of lymphocytes proliferative response and secretion of cytokines, thus unveiling the immunomodulatory effects of CuNPs.

Ex vivo fluorescence imaging for the identification of rhodamine-labeled bovine serum albumin and chitosan-coated gold and silver nanoparticles.

Therapeutic potential and toxic effects of in vivo administered gold nanoparticles (GNPs) and silver nanoparticles (SNP) depend on distribution in tissues. Rhodamine (Rho) labeled bovine serum albumin (BSA) and chitosan (Chi) were prepared by covalent conjugation and were characterized by fluorescence spectral analysis. GNP and SNP were coated with the labeled conjugates of BSA and chitosan by adsorption. The soluble Rho-BSA or Rho-Chi conjugates, uncoated, and conjugate-coated GNP, and SNP were orally administered into 8-week-old rats. After 24 h, rats were euthanized and the liver, kidney, spleen, and thymus were dissected. The tissues were examined ex vivo using a small animal in vivo imaging system. The liver, kidney, and thymus displayed higher fluorescence due to increased accumulation of Rho-BSA or Rho-Chi conjugate-coated nanoparticles (NPs) in the tissues as compared to the spleen where lower fluorescence was noticed. Tissues obtained from rats that were administered Rho-BSA or Rho-Chi conjugate-coated GNP and SNP showed tenfold higher fluorescence intensity as compared to tissues from rats that were given soluble conjugates or NP alone. The results strongly suggest significant tissue distribution of NP following oral administration.

Immunotoxic effects of gold and silver nanoparticles: Inhibition of mitogen-induced proliferative responses and viability of human and murine lymphocytes in vitro.

Understanding the effects of nanoparticles (NP) on immune cell functions is essential in designing safe and effective NP-based in vivo drug delivery systems. The immunomodulatory potential of gold nanoparticles (GNP) and silver nanoparticles (SNP) was investigated in vitro using murine splenic and human peripheral blood lymphocytes (PBL) in terms of effects on viability and mitogen-induced proliferation. Hydrodynamic size and number of NP were characterized using NP tracking analysis (NTA); modal diameters of GNP and SNP were 28 (±1.5) and 66 (± 2.7) nm, respectively, with a unimodal distribution. Lymphocytes were incubated with GNP or SNP in the presence/absence of B- or T-cell mitogens and proliferative responses then determined using [3H]-thymidine incorporation. Concanavalin A (T-cell-specific) and lipopolysaccharide- (B-cell-specific) stimulated responses of murine splenic lymphocytes, as well as phytohemagglutinin (T-cell-specific) and pokeweed mitogen- (B-and T-cell specific) induced responses of human lymphocytes, were significantly inhibited by GNP (25-200 µg/ml) and SNP (12.5-50 µg/ml). However, [3H]-thymidine incorporation by unstimulated lymphocytes was unaffected in the presence of GNP or SNP. Viability of lymphocytes was determined using trypan blue dye exclusion and was significantly inhibited only at 200 µg GNP/ml and 25 or 50 µg SNP/ml. As mitogen responses are most useful to provide supportive mechanistic information on primary immunotoxicologic functional observations, and so far more comprehensive data (in vivo and in vitro) is still needed, the results nevertheless suggest to us that GNP and SNP might potentially be able to modulate immune responses by impacting on lymphocyte activation.

Differential expression of alkaline phosphatase gene in proliferating primary lymphocytes and malignant lymphoid cell lines.

Alkaline Phosphatase (APase) activity has been shown to be enhanced specifically in mitogen stimulated B lymphocytes committed to proliferation, but not in T lymphocytes. APase gene expression was analyzed in proliferating murine and human primary lymphocytes and human malignant cell lines using reverse transcriptase and real time PCR. In mitogen stimulated murine splenic lymphocytes, enhancement of APase activity correlated well with an increase in APase gene expression. However, in mitogen stimulated murine T lymphocytes and human PBL despite a vigorous proliferative response, no increase in APase enzyme activity or gene expression was observed. A constitutive expression of APase activity concomitant with APase gene expression was observed inhuman myeloma cell line, U266 B1. However, neither enzyme activity nor gene expression of APase were observed in human T cell lymphoma, SUPT-1. The results suggest a differential expression of APase activity and its gene in proliferating primary lymphocytes of mice and humans. The specific expression of APase activity and its gene only in human myeloma cells, but not in proliferating primary B cells can be exploited as a sensitive disease marker.