Immunomodulation Properties of Solid-State Fermented Laetiporussulphureus Ethanol Extracts in Chicken Peripheral Blood Monocytes In Vitro

Laetiporus sp. is recognized as a fungal species traditionally used for medicinal purposes. This study investigated the in-vitro effects of solid-state fermented Laetiporussulphureus ethanol extracts (LSE) for their immunomodulatory potential. Bioactive levels detected in the LSE on different days throughout the fermentation period revealed that the 12th day was the most efficient, with 7.19 ± 0.66 GAE/g DM crude phenolic content, 2.71 ± 0.03 UAE/g DM crude triterpenoid content, 12.93 ± 0.88 GCE/g DM crude polysaccharides, and 96.44 ± 0.2 mg/g DM ergosterol content. In-vitroLSE tests on chPBMC showed no cytotoxicity within a range of 0.05-1 mg/mL, but LPS-inhibited cell viability was improved, as well as LPS-induced nitric oxide (NO) production and mRNA levels of nuclear factor kappa B (NFB), Toll-like receptor 4 (TLR4), inducible nitric oxide synthase (iNOS), and interleukin (IL)-1were attenuated Furthermore, the direct application of LSE on chPBMC showed a small but not significant increase in NFB, TLR4, and iNOS mRNA expression compared with the control group. These results indicate the potential of LSE to modulate LPS-triggered inflammation processes involving TLR4 and NFB mediation. However, further experiments are required to determine the specific pathway.(AU)

Immunomodulation Properties of Solid-State Fermented Laetiporussulphureus Ethanol Extracts in Chicken Peripheral Blood Monocytes In Vitro

Laetiporus sp. is recognized as a fungal species traditionally used for medicinal purposes. This study investigated the in-vitro effects of solid-state fermented Laetiporussulphureus ethanol extracts (LSE) for their immunomodulatory potential. Bioactive levels detected in the LSE on different days throughout the fermentation period revealed that the 12th day was the most efficient, with 7.19 ± 0.66 GAE/g DM crude phenolic content, 2.71 ± 0.03 UAE/g DM crude triterpenoid content, 12.93 ± 0.88 GCE/g DM crude polysaccharides, and 96.44 ± 0.2 mg/g DM ergosterol content. In-vitroLSE tests on chPBMC showed no cytotoxicity within a range of 0.05-1 mg/mL, but LPS-inhibited cell viability was improved, as well as LPS-induced nitric oxide (NO) production and mRNA levels of nuclear factor kappa B (NFB), Toll-like receptor 4 (TLR4), inducible nitric oxide synthase (iNOS), and interleukin (IL)-1were attenuated Furthermore, the direct application of LSE on chPBMC showed a small but not significant increase in NFB, TLR4, and iNOS mRNA expression compared with the control group. These results indicate the potential of LSE to modulate LPS-triggered inflammation processes involving TLR4 and NFB mediation. However, further experiments are required to determine the specific pathway.

Production by human squamous cell carcinoma of a factor inducing activation and proliferation of immune cells.

OBJECTIVE: To examine supernatants (SNs) of human squamous cell carcinoma of the head and neck cell lines for soluble tumor-derived factors capable of inducing activation and proliferation of human immune cells. DESIGN: The SN of squamous cell carcinoma of the head and neck cell line PCI-50 was cultured in serum-free medium and tested for the ability to induce expression of activation antigens, proliferation, cytotoxicity against tumor cell targets and cytokine production by purified human natural killer (NK) and CD4+ T cells. RESULTS: Supernatant of PCI-50 promoted expression of the following activation markers on NK and T cells: CD25 (interleukin-2R-alpha), HLA-DR (major histocompatibility complex class II), CD54 (ICAM-1), CD71 (transferrin receptor), and CD69 (activation-inducing molecule). In addition, SN induced and significantly sustained (P < .01) proliferation of human unseparated peripheral blood lymphocytes and NK or T cells in culture. Purified human NK or T cells cultured in the presence of the SN and IL-2 (120 IU/mL) had significantly higher antitumor cytotoxicity than that mediated by NK or T cells cultured in AIM-V medium and IL-2. The SN induced cytokine (interferon gamma, tumor necrosis factor alpha, interleukin-6) production in purified NK or T cells. When the SN was fractionated by molecular weight-based filtration into fractions greater and less than 30 kd, the growth- and cytotoxicity-promoting activities were consistently detectable in the greater than 30-kd fraction. CONCLUSIONS: Culture SN of squamous cell carcinoma of the head and neck cell lines contain a soluble factor(s) capable of activating NK and CD4+ T cells and of promoting growth and antitumor cytotoxicity of these lymphocyte subsets in vitro.

Antitumor activities of subsets of human IL-2-activated natural killer cells in solid tissues.

Human NK cells can be separated into two functionally distinct subpopulations based on the ability to rapidly respond to IL-2 by adherence to solid surfaces. To determine functions of the NK cell subsets in solid tumor tissues, adherent (A) and nonadherent (NA) NK cells were evaluated for their ability to infiltrate multicellular tumor spheroids in vitro, to kill carcinoma (CA) cell targets in these spheroids, and to mediate antitumor activity in vivo. A-NK cells were less cytolytic than NA-NK cells against CA targets in single cell suspensions or in monolayers. However, A-NK cells showed a significantly better ability than NA-NK cells to infiltrate tumor tissues and kill tumor cells in spheroids of human squamous cell CA of the head and neck or breast CA. Perilesional delivery of human A-NK cells and IL-2 resulted in regression of established human squamous cell carcinoma of the head and neck tumors growing subcutaneously in immunosuppressed nude mice. Similarly, in a xenograft model of human gastric CA metastatic to liver of nude mice, a single intrasplenic injection of A-NK cells in combination with i.p. infusions of IL-2 significantly reduced the number of established hepatic metastases (p < 0.007) and prolonged survival of the mice (p < 0.003). In contrast, NA-NK cells were ineffective in either of the in vivo xenograft tumor models. These findings demonstrate that A-NK cells represent a biologically unique and important subset of NK cells that, in contrast to the rest of NK cells, function as effector cells in solid tumor tissues and, consequently, have a great antitumor therapeutic potential.

Proliferation of hematopoietic cell lines induced by a soluble factor derived from human squamous cell carcinomas of the head and neck.

The supernatant of a cell line of squamous cell carcinoma of the head and neck (SCCHN), PCI-50, was previously shown to induce activation, promote proliferation and increase antitumor cytotoxicity of freshly purified human natural killer (NK) cells and CD4+ T lymphocytes [Arch Otolaryngol Head Neck Surg (1994) in press]. This supernatant was found also to promote the growth of a variety of hematopoietic cell lines, including Jurkat, THP-1, K562, NK-92 or Epstein-Barr-virus-transformed B cell lines. The Jurkat cell line was selected as a reporter cell in an 18-h proliferation assay established to measure the growth-promoting activity of PCI-50 supernatant. The presence of soluble tumor-derived factors able to induce proliferation of Jurkat cells was demonstrated in the supernatant produced by several other SCCHN cell lines but not in that produced by a gastric cancer cell line (HR) or renal cell carcinoma line (5117G8). The growth-promoting PCI-50 supernatant was shown to contain 28 +/- 0.5 pg/ml interleukin-6 (IL-6) in vitro but was negative for interferon gamma, IL-1, IL-2, IL-4, tumor necrosis factor alpha, granulocyte/macrophage-colony-stimulating factor and IL-12. The addition of any of these recombinant cytokines to Jurkat cell cultures did not significantly promote growth, while PCI-50 supernatant was consistently growth-stimulatory. This supernatant neither enhanced intracellular Ca2+ concentration in Jurkat cells nor induced up-regulation of activation antigens on the cell surface, although it supported growth of Jurkat cells in the absence of IL-2. The growth-promoting activity in the PCI-50 supernatant was acid-labile at pH 2 for 4 h, heat-resistant at 96 degrees C for 1 h and sensitive to treatments with trypsin and pepsin. Preincubation of the PCI-50 producer cells with tunicamycin or cyclohexamide reduced the level of growth-promoting activity in the supernatant. A partial purification of this activity was achieved using Amicon filtration, chromatography on concanavalin-A-Sepharose and then a hydroxyapatite column and high-pressure liquid chromatography gel filtration. The partially purified glycoprotein had a molecular mass of 50-70 kDa, as determined by gel filtration.

Signaling via CD7 molecules on human NK cells. Induction of tyrosine phosphorylation and beta 1 integrin-mediated adhesion to fibronectin.

We have previously reported that CD7 expressed on resting human NK cells is a signal-transducing molecule, which upon ligation with mAb induces a rapid increase in cytoplasmic free calcium, secretion of IFN-gamma, and augmented NK activity against K562 targets. We now demonstrate that Ab-mediated clustering of CD7 molecules on NK cells results in enhanced phosphorylation on tyrosine residues of intracellular proteins of 60, 70, 80, 97, and 120 kDa. In the presence of genistein, a specific inhibitor of protein tyrosine kinase, the enhanced level of tyrosine phosphorylation was blocked, indicating that CD7 may induce signaling via activation of tyrosine kinases. Cross-linking of CD7 or CD16 molecules with primary and secondary Abs, as well as stimulation of NK cells with phorbol ester (PMA) or with calcium ionophore A23187 also induced beta 1 integrin-mediated adhesion of these cells to fibronectin (FN)-coated plastic surfaces. In contrast, cross-linking of CD2 expressed on the surface of NK cells had no significant effect on NK cell adhesion to FN. This adhesion was not associated with up-regulation of expression of alpha 4 beta 1 or alpha 5 beta 1 FN receptors on NK cells, but it required an intact cytoskeleton. The CD7-induced adhesion to FN was mediated by alpha 4 beta 1 and alpha 5 beta 1 integrins, as it was partially blocked by FN connective segment-1 peptide (EILDVPST), the alpha 4 beta 1-binding domain, as well as by RGD-containing peptides, the alpha 5 beta 1-binding domain, but not by EILEVPST or RGE control peptides. NK cell binding to FN was also partially inhibited by mAb to alpha 4, alpha 5, and beta 1 integrins. The mechanism by which cross-linking of CD7 or CD16 on NK cells induced adhesion to FN appeared to involve both protein tyrosine kinase and protein kinase C, because this adhesion was blocked in the presence of either genistein or a protein kinase C inhibitor, staurosporin. Our data demonstrate that signals transduced via triggering of either CD7 or CD16 molecules are involved in the regulation of the functional activity of beta 1 integrins on NK cells.

Transfer of interleukin 2 receptor genes into squamous cell carcinoma. Modification of tumor cell growth.

OBJECTIVE: Human squamous cell carcinomas of the head and neck (SCCHN) have been shown to express interleukin 2 receptor (IL-2R), and binding of the ligand, IL-2, to the receptor results in tumor growth inhibition in vitro or in vivo in an SCCHN xenograft model in nude mice. To optimize growth inhibitory effects of IL-2, expression of the alpha or gamma chains of IL-2R in SCCHN was experimentally modified by transfection of tumor cells with the respective IL-2R genes or the lacZ gene as control. DESIGN: Using plasmid vectors containing the IL-2R alpha chain gene under the control of a cytomegalovirus promoter or the IL-2R gamma chain gene under the control of a Rous sarcoma virus promoter, the IL-2R genes were transferred by lipofection into SCCHN cell lines. Stable transfectants were selected, cloned by limiting dilution, and clones were compared with the parental cell lines for their sensitivity to the growth-inhibitory effect of IL-2. RESULTS: Transfer of the IL-2R alpha chain gene into SCCHN cells resulted in significant upregulation of expression of the IL-2R alpha chain on tumor cell surface but not in increased tumor growth inhibition by IL-2. In contrast, SCCHN IL-2R gamma transfectants, which expressed IL-2R gamma chain transcripts as confirmed in RNase protection assays, were significantly inhibited in growth and were sensitive to lower concentrations of IL-2 than the parental cell lines. CONCLUSIONS: Genetic modification of IL-2R expression on IL-2R-positive tumor cells in culture significantly alters their proliferative response to IL-2. These observations open a way for developing new strategies for therapy of SCCHN based on direct interactions of IL-2 with its receptor on tumor cells.