Increased Lymphocyte Proliferation Research Articles

Effects of polychlorinated biphenyls (PCB) on California sea lion (Zalophus californianus) lymphocyte functions upon in vitro exposure

Polychorinated biphenyl (PCB) congeners are a cause for concern due to their persistence in the environment, their lipophilic properties that cause them to bio-accumulate in top predators, and their adverse effects on mammalian health. For example, the common urogenital carcinoma reported in California sea lions (Zalophus californianus) (CSL) is associated with high tissue levels of PCBs, but the mechanisms responsible for this association are unknown. This study investigated the effect of exposure to six PCB congeners and a congener mix at low and environmentally relevant concentrations on NK cell-like and T cell activity using in vitro assays on cryopreserved lymph node mononuclear cells isolated from dead CSL. Non dioxin-like congeners 153 and 180 increased lymphocyte proliferation at 5 and 10 ppm, while congener 138 decreased proliferation by up to 43% at 15 ppm. Dioxin-like PCBs 118 and 169 did not affect lymphocyte proliferation, while the effects of congener 105 depended on the mitogen concentration; these did not correlate with their predicted toxic equivalent factors. NK cell-like activity was affected only by the highest concentration of PCBs tested; it was increased by non-dioxin-like congeners 138 and 153, and decreased by dioxin-like congener 169. The PCB congener mix suggested that the effects of PCB congeners were not simply additive. Our results concur with effects of PCBs reported for other pinniped's lymphocytes and add further experimental support to the observation that dioxin-like PCBs are not the most toxic congeners for marine mammals, contrary to effects in other species. This is the first evidence of in vitro suppression of NK cell-like cytotoxicity by a dioxin-like congener in a pinniped. More importantly, the observed results suggest that PCBs can modulate the CSL immune system, increasing exposed individuals’ susceptibility to viral and oncogenic challenges.

Role of Melatonin in Modulation of Immune Status of Pregnant Female Indian Short Nosed Fruit Bat Cynopterus Sphinx

Pregnancy is associated with profound immunological changes that are characterized by a strong activation of certain components of the innate immune defense and a down-regulation of adaptive immune functions. This shift in balance of the immune system towards an innate dominance is thought to be important for the maintenance of pregnancy. Based on our observation in the short nosed fruit bat Cynopterus sphinx, a seasonal breeder, we show for the first time that melatonin injection to the pregnant females significantly increases lymphocyte proliferation of spleen and consequently the circulating level of lymphocytes and percent stimulation ratio of splenocytes, thereby improving immune status during pregnancy. We have reported earlier that during pregnancy melatonin level increases significantly which in turn might improve the maternal immunity. Towards establishing this inference we used a physiological dose of p-chlorophenylalanine (p-CPA), an indirect antagonist of melatonin, which reduced circulatory melatonin level and thereby reduced the immune status. It is conceived that specific immune adaptation is conveyed to the fetus through placental transfer of melatonin thereby controlling fetal immunity as well. This could be an adaptation during pregnancy to protect the mother from various external threats.

Structural characterization, antioxidant activity, and immunological activity in vitro of polysaccharides from fruiting bodies of Suillus granulatus

Two polysaccharide fractions, SGP I-b and SGP II-b, were purified from the fruiting bodies of Suillus granulatus. The assayed relative molecular masses of SGP I-b and SGP II-b were approximately 17.31 and 10.16 kDa, respectively. SGP I-b consisted of fucose, mannose, glucose, and galactose, whereas SGP II-b consisted of rhamnose, fucose, mannose, glucose, and galactose. The structures of SGP I-b and SGP II-b were preliminarily analyzed through methylation analysis and nuclear magnetic resonance spectroscopy. The results of in vitro antioxidant assays revealed that SGP II-b demonstrated good scavenging ability for hydroxyl and DPPH radicals but poor reduction capacity and scavenging for superoxide anions. SGP I-b did not exhibit any significant antioxidant activities. SGP II-b could also significantly increase lymphocyte proliferation in vitro, however, SGP I-b had no significant effect. Practical applications Suillus granulatus is a wild, edible medicinal fungus distributed in Northeastern China. S. granulatus polysaccharides (SGP) already be prove have special bioactivities. In the current study, SGP were purified and characterized, and the antioxidant activities and immunomodulatory effects were also assayed. Our work will contribute to the utilization of SGP as natural antioxidants and/or immunity-enhancing agents in food and pharmaceutical industries.

Polysaccharide structure and immunological relationships of RG-I pectin from the bee pollen of Nelumbo nucifera

From the bee pollen of Nelumbo nucifera, we used hot water extraction and chromatographic fractionation on DEAE-cellulose and Sepharose CL-6B to purify polysaccharides (WNPP) to homogeneity. WNPP-2-RG (3.8 × 105 Da) consisted primarily of Rha (11.5%), GalA (12.0%), Gal (41.2%) and Ara (29.7%). Structure analysis showed that this polysaccharide is a RG-I type pectin containing AG-I and AG-II side chains comprised of 1,5-L-Ara (25.6%), t-D-Gal (12.0%), and 1,6-D-Gal (18.3%) as the primary linkage types. Immunological activity assays demonstrated that WNPP-2-RG increased lymphocyte proliferation and macrophage phagocytosis, and induced production of NO. Compared to WNPP-2-RG, its hydrolysates (RG-8H-P) had no effect on lymphocyte proliferation, although they did promote macrophage phagocytosis and decreased NO production. Our results suggest that Gal side chain residues may play a crucial role in macrophage phagocytosis, whereas Ara is unimportant for NO production and neither Gal nor Ara impact lymphocyte proliferation.

Edible plant-derived essential oils synergistically enhance the Th1, Th2 and anti-inflammatory cytokines in neonatal cord blood monocytic cell line

ABSTRACT Edible medicinal plants Curcuma longa, Kaempferia galanga and Zingiber officinale are considered to be suitable for pregnant mother and neonates. Their essential oils are claimed to have therapeutic effects, yet its immunomodulatory activities need to be investigated. To validate the immunomodulatory effect, cord blood monocyte cells (CBMCs) treated with different concentrations of essential oils ranging from 0 to 40 µg/ml. K. galanga oil at 40 µg/ml concentrations upregulated IFN-γ at 49.23 pg/ml, while C. longa oil downregulated the IL-10 at 10.45 pg/ml showing immunostimulant activity on CBMCs. However, Z. officinale oil showed no significant result at any concentration. K. galanga and C. longa oils also showed an increase in lymphocyte proliferation in a dose-dependent manner. The present study was aimed to evaluate the immunomodulatory potentialities of essential oils which will attract the interest of researchers and pharmaceutical industries for clinical studies and other applications in the therapy of diseases related to neonatal infections.

Covering the Cover

Covering the Cover

Ex-vivo assessment of drug response on breast cancer primary tissue with preserved microenvironments

ABSTRACTInteraction between cancerous, non-transformed cells, and non-cellular components within the tumor microenvironment plays a key role in response to treatment. However, short-term culture or xenotransplantation of cancer specimens in immunodeficient animals results in dramatic modifications of the tumor microenvironment, thus preventing reliable assessment of compounds or biologicals of potential therapeutic relevance.We used a perfusion-based bioreactor developed for tissue engineering purposes to successfully maintain the tumor microenvironment of freshly excised breast cancer tissue obtained from 27 breast cancer patients and used this platform to test the therapeutic effect of antiestrogens as well as checkpoint-inhibitors on the cancer cells.Viability and functions of tumor and immune cells could be maintained for over 2 weeks in perfused bioreactors. Next generation sequencing authenticated cultured tissue specimens as closely matching the original clinical samples. Anti-estrogen treatment of cultured estrogen receptor positive breast cancer tissue as well as administration of pertuzumab to a Her2 positive breast cancer both had an anti-proliferative effect. Treatment with anti-programmed-death-Ligand (PD-L)-1 and anti-cytotoxic T lymphocyte-associated protein (CTLA)-4 antibodies lead to immune activation, evidenced by increased lymphocyte proliferation, increased expression of IFNγ, and decreased expression of IL10, accompanied by a massive cancer cell death in ex vivo triple negative breast cancer specimens.In the era of personalized medicine, the ex vivo culture of breast cancer tissue represents a promising approach for the pre-clinical evaluation of conventional and immune-mediated treatments and provides a platform for testing of innovative treatments.

Granulocyte-macrophage colony-stimulating factor, a potent adjuvant for polarization to Th-17 pattern: an experience on HIV-1 vaccine model.

Cytokines are mediators for polarization of immune response in vaccines. Studies show that co-immunization of DNA vaccines with granulocyte-macrophage colony-stimulating factor (GM-CSF) can increase immune responses. Here, experimental mice were immunized with HIV-1tat/pol/gag/env DNA vaccine with GM-CSF and boosted with recombinant vaccine. Lymphocyte proliferation with Brdu and CTL activity, IL-4, IFN-γ, IL-17 cytokines, total antibody, and IgG1 and IgG2a isotypes were assessed with ELISA. Results show that GM-CSF as adjuvant in DNA immunization significantly increased lymphocyte proliferation and IFN-γ cytokines, but CTL response was tiny increased. Also GM-CSF as adjuvant decreased IL-4 cytokine vs mere vaccine group. IL-17 in the group that immunized with mixture of DNA vaccine/GM-CSF was significantly increased vs DNA vaccine group. Result of total antibody shows that GM-CSF increased antibody response in which both IgG1 and IgG2a increased. Overall, results confirmed the beneficial effect of GM-CSF as adjuvant to increase vaccine immunogenicity. The hallmark result of this study was to increase IL-17 cytokine with DNA vaccine/GM-CSF immunized group. This study for the first time provides the evidence of the potency of GM-CSF in the induction of IL-17 in response to a vaccine, which is important for control of infection such as HIV-1.

Purification, characterization, and bioactivities of a polysaccharide from mycelial fermentation of Bjerkandera fumosa

In this work, a novel polysaccharide (named DBFM3) was isolated from mycelia of Bjerkandera fumosa by DEAE-32 and Sepharose CL–6B column chromatography. High-performance gel permeation chromatography showed that DBFM3 was homogeneous, with an average molecular weight of 1.8×105Da. Structural characteristics of the purified fraction were investigated by high-performance liquid chromatography (HPLC), FT-IR, and NMR. HPLC analysis indicated that DBFM3 was composed of mannose, galacturonic acid, and galactose at molar ratios of 1:18.16:0.702. Spectral analysis suggested that DBFM3 had (1→6), (1→3,6), (1→3) linkages and pyranose conformation. Antioxidant assay in vitro showed that DBFM3 exhibited 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activity, and has protective effect against DNA damage and damage to SH-SY5Y cells induced by H2O2. Immunological tests indicated that DBFM3 significantly increased lymphocyte proliferation in vitro. Furthermore, DBFM3 increased the proliferation of lymphocytes in the presence of concanavalin A or lipopolysaccharide as mitogen.

Nanotized Curcumin and Miltefosine, a Potential Combination for Treatment of Experimental Visceral Leishmaniasis.

Leishmaniasis chemotherapy remains very challenging due to high cost of the drug and its associated toxicity and drug resistance, which develops over a period of time. Combination therapies (CT) are now in use to treat many diseases, such as cancer and malaria, since it is more effective and affordable than monotherapy. CT are believed to represent a new explorable strategy for leishmaniasis, a neglected tropical disease caused by the obligate intracellular parasite Leishmania In the present study, we investigated the effect of a combination of a traditional Indian medicine (ayurveda), a natural product curcumin and miltefosine, the only oral drug for visceral leishmaniasis (VL) using a Leishmania donovani-hamster model. We developed an oral nanoparticle-based formulation of curcumin. Nanoformulation of curcumin alone exhibited significant leishmanicidal activity both in vitro and in vivo In combination with miltefosine, it exhibited a synergistic effect on both promastigotes and amastigotes under in vitro conditions. The combination of these two agents also demonstrated increased in vivo leishmanicidal activity accompanied by increased production of toxic reactive oxygen/nitrogen metabolites and enhanced phagocytic activity. The combination also exhibited increased lymphocyte proliferation. The present study thus establishes the possible use of nanocurcumin as an adjunct to antileishmanial chemotherapy.

Divergent hypersensitivity responses following topical application of the quaternary ammonium compound, didecyldimethylammonium bromide

Didecyldimethylammonium bromide (DDAB) is a fourth generation dialkyl-quaternary ammonium compound (QAC) that is used in numerous products for its antimicrobial properties. While many QACs have been associated with allergic disease, the toxicity and sensitization of DDAB have not been thoroughly investigated. The purpose of these studies was to evaluate the irritancy and sensitization potential of DDAB following dermal application in a murine model. DDAB induced significant irritancy (0.0625–2%), evaluated by ear swelling in female BALB/c mice. Initial evaluation of the sensitization potential was conducted using the local lymph node assay (LLNA) at concentrations ranging from 0.0625% to 2%. A concentration-dependent increase in lymphocyte proliferation was observed with a calculated EC3 value of 0.057%. Immune cell phenotyping along with local and systemic IgE levels were evaluated following 4 and 14 days of dermal application. Phenotypic analyses revealed significant and dose-responsive increases in the absolute number of B-cells, CD4+ T-cells, CD8+ T-cells, and dendritic cells in the draining lymph nodes (DLNs) following 4 and 14 days of dermal exposure with significant increases in the number of activated B-cells and dendritic cells. However, increased activation of CD4+ T-cell and CD8+ T-cells was only observed following four days of DDAB exposure. Exposure to DDAB also induced increased production of IgE as evaluated by phenotypic analysis of DLN B-cells (IgE+ B-cells) and measurement of total serum IgE levels following 14 days but not four days of dermal application. Significant increases in gene expression were observed in the DLN (Il-4, Il-10, and ox40l) and ear (tslp) following 4 and 14 days of DDAB exposure. These results demonstrate the potential for development of irritation and hypersensitivity responses to DDAB following dermal exposure and raise concerns about the effects of exposure duration on hypersensitivity responses.

Role of Melatonin in Modulation of Immune Status of Pregnant Female Indian Short Nosed Fruit Bat Cynopterus Sphinx

Pregnancy is associated with profound immunological changes that are characterized by a strong activation of certain components of the innate immune defense and a down-regulation of adaptive immune functions. This shift in balance of the immune system towards an innate dominance is thought to be important for the maintenance of pregnancy. Based on our observation in the short nosed fruit bat Cynopterus sphinx, a seasonal breeder, we show for the first time that melatonin injection to the pregnant females significantly increases lymphocyte proliferation of spleen and consequently the circulating level of lymphocytes and percent stimulation ratio of splenocytes, thereby improving immune status during pregnancy. We have reported earlier that during pregnancy melatonin level increases significantly which in turn might improve the maternal immunity. Towards establishing this inference we used a physiological dose of p-chlorophenylalanine (p-CPA), an indirect antagonist of melatonin, which reduced circulatory melatonin level and thereby reduced the immune status. It is conceived that specific immune adaptation is conveyed to the fetus through placental transfer of melatonin thereby controlling fetal immunity as well. This could be an adaptation during pregnancy to protect the mother from various external threats.

Differential effects of palmitoleic acid on human lymphocyte proliferation and function.

BackgroundPalmitoleic acid (PA) is a n-7 monounsaturated fatty acid (MUFA) secreted by adipose tissue and related to decreased insulin resistance in peripheral tissues. Evidences have been shown that PA also decreased proinflammatory cytokine expression in cultured macrophages. Although studies have shown that other fatty acids (FAs) modulate several lymphocyte functions, the specific effect of PA on these cells is unknown. The aim of the present study was to evaluate the possible influence of PA on activation and differentiation of human lymphocytes in comparison to oleic acid (OA).MethodsHuman lymphocytes were isolated from peripheral blood of health men and cultured in the presence of growing concentrations of PA or OA (5 to 200 μM), for 24 h. After that, cells were collected and cytotoxicity evaluated by flow cytometry. Then, we analyzed proliferative capacity in lymphocytes treated with non toxic concentrations of PA and OA (25 and 50 μM, respectively), in the presence or absence of concanavalin A (ConA). The Th1/Th2/Th17 cytokine production was determined by the Cytometric Bead Array. CD28 and CD95 surface expression and T regulatory cell percentage were determined by flow cytometry.ResultsWe observed that PA is toxic to lymphocytes above 50 μM. PA promoted a decrease of lymphocyte proliferation stimulated by ConA in both concentrations. PA also decreased CD28 externalization and increased CD95. On the other hand, OA did not alter these parameters. In the same way, PA reduced IL6, IFN-gamma, TNF-alpha and IL17A production in both concentration and IL2 only at 50 μM (in the presence of ConA). OA promoted IFN-gamma reduction in both concentrations and an increase of IL-2, IL4 and IL10 at 25 μM. Both fatty acids decreased the percentage of T regulatory cells.ConclusionIn conclusion, PA promoted a suppressive effect on lymphocyte proliferation characterized by a decrease of Th1 and Th17 response, and co-stimulatory molecule (CD28). However, OA increased lymphocyte proliferation through IL2 production and Th2 response. These results also show a more suppressive effect of PA on lymphocytes in comparison to OA.

Immunological consequences of immunization with tumor lysate vaccine and propranolol as an adjuvant: A study on cytokine profiles in breast tumor microenvironment

In this study, we sought out to study the anti-cancer effects of propranolol (Pro) in combination with tumor lysate vaccine on lymphocyte proliferation activities as well as on IL-2, IL-4, IL-10, IL-12, IL-17 and IFN-γ cytokine concentration in the tumor microenvironment (TME). A tumor model was established in inbred Balb/C mice using transplantation of tumor to the flank of native mice. Tumor-bearing mice were immunized with lysate tumor cells (vaccine), a combination of Pro/Vaccine (Vac). Control groups consisted of tumor-bearing mice receiving only propranolol or PBS three times with one week interval via subcutaneous (s.c) injection. One week after the last immunization, tumor was removed, homogenate was prepared and the levels of IL-12, IL-17, 1L-2, IL-10, IL-4, IFN-γ cytokine concentrations were evaluated by commercial ELISA kits. In addition, spleen cell suspension was used for the lymphocyte proliferation assay using the BrdU method. Results from this study indicated that Pro/Vac had the ability to significantly increase lymphocyte proliferation, and to suppress tumor growth. Administration of breast tumor lysates with propranolol increased the concentration of IL-12, IL-17, 1L-2 and IFN-γ cytokines in tumor microenvironment. This study has proved the efficiency of propranolol as an adjuvant in combination with the tumor vaccine model on tumor suppression via cytokine pattern modulation in tumor microenvironment.

Virulence Associated Genes-Deleted Salmonella Montevideo Is Attenuated, Highly Immunogenic and Confers Protection against Virulent Challenge in Chickens.

To construct a novel live vaccine against Salmonella enterica serovar Montevideo (SM) infection in chickens, two important bacterial regulatory genes, lon and cpxR, which are associated with invasion and virulence, were deleted from the wild type SM genome. Attenuated strains, JOL1625 (Δlon), JOL1597 (ΔcpxR), and JOL1599 (ΔlonΔcpxR) were thereby generated. Observations with scanning electron microscopy suggested that JOL1625 and JOL1599 cells showed increased ruffled surface which may be related to abundant extracellular polysaccharide (EPS) production. JOL1597 depicted milder ruffled surface but showed increased surface corrugation. ConA affinity-based fluorometric quantification and fluorescence microscopy revealed significant increases in EPS production in JOL1625 and JOL1599. Four weeks old chickens were used for safety and immunological studies. The mutants were not observed in feces beyond day 3 nor in spleen and cecum beyond day 7, whereas wild type SM was detected for at least 2 weeks in spleen and cecum. JOL1599 was further evaluated as a vaccine candidate. Chickens immunized with JOL1599 showed strong humoral responses, as indicated by systemic IgG and secretory IgA levels, as well as strong cell-mediated immune response, as indicated by increased lymphocyte proliferation. JOL1599-immunized groups also showed significant degree of protection against wild type challenge. Our results indicate that Δlon- and/or ΔcpxR-deleted SM exhibited EPS-enhanced immunogenicity and attenuation via reduced bacterial cell intracellular replication, conferred increased protection, and possess safety qualities favorable for effective vaccine development against virulent SM infections.

Potentiation of human papilloma vaccine candidate using naloxone/alum mixture as an adjuvant: increasing immunogenicity of HPV-16E7d vaccine.

Many types of human papillomaviruses (HPVs) have been identified, with some leading to cancer and others to skin lesions such as anogenital warts. Studies have demonstrated an association between oncogenic HPV and cervical cancer and many researchers have focused on therapeutic vaccines development. At present, the modulatory effect of opioids on the innate and acquired immune system is characterized. Antagonists of opioid receptors such as naloxone (NLX) can contribute to the shifting Th2 response toward Th1. Herein; we studied the adjuvant activity of NLX/Alum mixture for improvement of the immunogenicity of HPV-16E7d vaccine. The mice were administered different regimens of vaccine; E7d, E7d-NLX, E7d-Alum, E7d-NLX-Alum, NLX, alum and PBS via subcutaneous route for three times with two weeks interval. Two weeks after the last immunization, the sera were assessed for total antibody, IgG1 and IgG2a with an optimized ELISA method. The splenocytes culture supernatant was analyzed by ELISA for the presence of IL-4, IFN-γ and IL-17 cytokines and lymphocyte proliferation was evaluated with Brdu method. Immunization of mice with HPV-16 E7d vaccine formulated in NLX/Alum mixture significantly increased lymphocyte proliferation and Th1 and Th17 cytokines responses compared to other experimental groups. Analysis of humoral immune responses revealed that administration of vaccine with NLX/Alum mixture significantly increased specific IgG responses and also isotypes compared to control groups. NLX/Alum mixture as an adjuvant could improve cellular and humoral immune responses and the adjuvant maybe useful for HPV vaccines model for further studies in human clinical trial.

Development of recombinant vaccine candidate molecule against Shigella infection

Shigellosis is an acute bacillary diarrheal disease caused by the gram negative bacillus Shigella. The existence of multiple Shigella serotypes and their growing resistance to antibiotics stress the urgent need for the development of vaccine that is protective across all serotypes. Shigella’s IpaB antigen is involved in translocon pore formation, promotes bacterial invasion and induces apoptosis in macrophages. S. Typhi GroEL (Hsp 60) is the immunodominant antigen inducing both arms of immunity and has been explored as adjuvant in this study. The present study evaluates the immunogenicity and protective efficacy of recombinant IpaB domain-GroEL fusion protein in mice against lethal Shigella infection. The IpaB domain and GroEL genes were fused using overlap extension PCR and cloned in pRSETA expression vector. Fused gene was expressed in Escherichia coli BL-21 cells and the resulting 90 KDa fusion protein was purified by affinity chromatography. Intranasal (i.n.) immunization of mice with fusion protein increased the IgG and IgA antibody titers as compared to the group immunized with IpaB and GroEL and control PBS immunized group. Also IgG1 and IgG2a antibodies induced in fusion protein immunized mice were higher than co-immunized group. Significant increase in lymphocyte proliferation and cytokine levels (IFN-γ, IL-4 and IL-10), indicates induction of both Th1 and Th2 immune responses in both immunized groups. Immunization with fusion protein protected 90–95% of mice whereas 80–85% survivability was observed in co-immunized group against lethal challenge with S. flexneri, S. boydii and S. sonnei. Passive immunization conferred 60–70% protection in mice against all these Shigella species. Organ burden and histopathology studies also revealed significant decrease in lung infection as compared to the co-immunized group. Since IpaB is the conserved dominant molecule in all Shigella species, this study will lead to an ideal platform for the development of safe, efficacious and cost-effective recombinant vaccine against Shigella serotypes.

Lack of TAK1 in dendritic cells inhibits the contact hypersensitivity response induced by trichloroethylene in local lymph node assay

Trichloroethylene (TCE) is a ubiquitous environmental contaminant. Occupational TCE exposure has been associated with severe, generalized contact hypersensitivity (CHS) skin disorder. The development of CHS depends on innate and adaptive immune functions. Transforming growth factor-β activated kinase-1 (TAK1) controls the survival of dendritic cells (DCs) that affect the immune system homeostasis. We aimed to investigate the role of TAK1 activity in DC on TCE-induced CHS response. Control mice and DC-specific TAK1 deletion mice were treated with 80% (v/v) TCE using local lymph node assay (LLNA) to establish a TCE-induced CHS model. The draining lymph nodes (DLNs) were excised and the lymphocytes were measure for proliferation by BrdU-ELISA, T-cell phenotype analysis by flow cytometry and signaling pathway activation by western blot. The ears were harvested for histopathological analysis. Control mice in the 80% TCE group displayed an inflammatory response in the ears, increased lymphocyte proliferation, elevated regulatory T-cell and activated T-cell percentages, and more IFN-γ producing CD8+ T cells in DLNs. In contrast to control mice, DC-specific TAK1 deletion mice in the 80% TCE group showed an abolished CHS response and this was associated with defective T-cell expansion, activation and IFN-γ production. This effect may occur through Jnk and NF-κB signaling pathways. Overall, this study demonstrates a pivotal role of TAK1 in DCs in controlling TCE-induced CHS response and suggests that targeting TAK1 function in DCs may be a viable approach to preventing and treating TCE-related occupational health hazards.

Evaluation of the irritancy and hypersensitivity potential following topical application of didecyldimethylammonium chloride

Didecyldimethylammonium chloride (DDAC) is a dialkyl-quaternary ammonium compound that is used in numerous products for its bactericidal, virucidal and fungicidal properties. There have been clinical reports of immediate and delayed hypersensitivity reactions in exposed individuals; however, the sensitization potential of DDAC has not been thoroughly investigated. The purpose of these studies was to evaluate the irritancy and sensitization potential of DDAC following dermal exposure in a murine model. DDAC induced significant irritancy (0.5 and 1%), evaluated by ear swelling in female Balb/c mice. Initial evaluation of the sensitization potential was conducted using the local lymph node assay (LLNA) at concentrations ranging from 0.0625–1%. A concentration-dependent increase in lymphocyte proliferation was observed with a calculated EC3 value of 0.17%. Dermal exposure to DDAC did not induce increased production of IgE as evaluated by phenotypic analysis of draining lymph node B-cells (IgE + B220+) and measurement of total serum IgE levels. Additional phenotypic analyses revealed significant and dose-responsive increases in the absolute number of B-cells, CD4 + T-cells, CD8 + T-cells and dendritic cells in the draining lymph nodes, along with significant increases in the percentage of B-cells (0.25% and 1% DDAC) at Day 10 following 4 days of dermal exposure. There was also a significant and dose-responsive increase in the number of activated CD44 + CD4 + and CD8 + T-cells and CD86 + B-cells and dendritic cells following exposure to all concentrations of DDAC. These results demonstrate the potential for development of irritation and hypersensitivity responses to DDAC following dermal exposure and raise concerns about the use of this chemical and other quaternary ammonium compounds that may elicit similar effects.

Boron Induces Lymphocyte Proliferation and Modulates the Priming Effects of Lipopolysaccharide on Macrophages.

Chemical mediators of inflammation (CMI) are important in host defense against infection. The reduced capacity of host to induce the secretion of these mediators following infection is one of the factors in host susceptibility to infection. Boron, which has been suggested for its role in infection, is reported in this study to increase lymphocyte proliferation and the secretion of CMI by the lipopolysaccharide (LPS)-stimulated peritoneal macrophages in BALB/c mice. Boron was administered to mice orally as borax at different doses for 10 consecutive days, followed by the stimulation of animals with ovalbumin and isolation of splenocytes for proliferation assay. The lymphocyte subsets were determined by flow cytometry in spleen cell suspension. The mediators of inflammation, TNF-α, IL-6, IL-1β and nitric oxide (NO), were measured in culture supernatant of LPS-primed macrophages isolated from borax treated mice. TNF and ILs were measured by ELISA. NO was determined by Griess test. The expression of inducible nitric oxide synthase (iNOS) in macrophages was studied by confocal microscopy. Results showed a significant increase in T and B cell populations, as indicated by an increase in CD4 and CD19, but not CD8, cells. Boron further stimulated the secretion of TNF-α, IL-6, IL-1β, NO and the expression of iNOS by the LPS-primed macrophages. The effect was dose dependent and most significant at a dose level of 4.6 mg/kg b. wt. Taken together, the study concludes that boron at physiological concentration induces lymphocyte proliferation and increases the synthesis and secretion of pro-inflammatory mediators by the LPS-primed macrophages, more specifically the M1 macrophages, possibly acting through Toll-like receptor. The study implicates boron as a regulator of the immune and inflammatory reactions and macrophage polarization, thus playing an important role in augmenting host defense against infection, with possible role in cancer and other diseases.