Lymphocyte Proliferation Activity Research Articles

Modification of sPD1 with CRT induces potent anti-tumor immune responses in vitro and in vivo

As a key factor for tumor occurrence and development, tumor cells escape immune surveillance and inhibit the body immune killer effect through negative signaling pathways. In this research, we designed and expressed the fusion protein CRT-sPD1 to block PD1/PDL1 negative signal pathway, indirectly bind CRT to the tumor cell surface and to increase the cell immunogenicity activity. Results from western blotting, flow cytometry (FCM) and ELISA showed that the cell lines that stably express CRT, PD1 and CRT-sPD1 protein were obtained and the transfected cellular supernatant contained PD1 and CRT-sPD1 could bind to PDL1 on the surface of EL4 cells. Vitro experiments indicated the secreted mCRT-sPD1 protein could bind to PDL1 and enhance lymphocyte proliferation and CTL activity. We also found that fusion protein CRT-sPD1 could activate and induce the immune system to kill the tumor cells, specifically inhibit the tumor growth and prolong the survival period in mouse tumor model. And all these suggested that CRT-sPD1 could be used as drug development and utilization of cancer immunotherapy.

MUC1-2VNTR DNA Vaccine Induces Immune Responses in Mouse Model with Multiple Myeloma

To investigate the humoral and cellular immune responses induced by MUC1-2VNTR DNA vaccine in multiple myeloma (MM) tumor-bearing mice. In vitro, multiple myeloma cells were transfected by plasmid pcDNA3.1-2VNTR/myc-hisB with Lipofectamine2000. The above-mentioned mouse myeloma cells were inoculated subcutaneously into female BALB/c mice for establishing tumor-bearing animal models. These female BALB/c mice were immunized with pcDNA-2VNTR/myc-hisB or pcDNA/myc-hisB. The cytotoxic T lymphocyte (CTL) activity was detected by the LDH method and the spleen lymphocyte proliferation activity was detected by CCK-8 method. After immunization of BALB/c tumor-bearing mice with recombinant plasmid for 25 days, the tumor mass (0.5605 ± 0.2065 g) was significantly lighter than that in the empty plasmid control group (1.521 ± 0.6985 g) (P < 0.01) and the control group (1.5315 ± 0.5425 g) (P < 0.01). The difference of tumor mass was not statislically significant between empty plasmid control group (1.521 ± 0.6985 g) and the control group (1.5315 ± 0.5425 g) (P > 0.05). The CTL and NK cell activity was significantly higher in the group of intramuscular injection with recombinant plasmid than that in control group. The spleen lymphocyte proliferation was statistically significantly increased after being immunized with recombinant plasmid pcDNA3.1-2VNTR/myc-hisB, compared with empty vector (P < 0.01). The results showed that MUC1-2VNTR gene immunization could induce anti-tumor effect in MM tumor-bearing mice. MUC1-2VNTR DNA immunization can elicit both humoral and cellular tumor specific immune response to multiple myeloma in MM tumor-bearing mice. It suggested that the MUC1-2VNTR DNA vaccine may be a potential treatment measure for patients with MM.

The splenocyte proliferative response and cytokine secretion in mice after oral administration of commercial gold nanocolloid

Owing to their unique physicochemical properties, gold nanoparticles find numerous biomedical applications. Experiments on rodents prove that the main target organs of gold nanoparticles entering an organism are the liver and spleen, whose reticuloendothelial system removes foreign particles from the bloodstream. Through interactions with resident tissue macrophages, nanoparticles can evoke a systemic immunological response. The aim of this study has been to determine the effect of oral administration of commercial gold nanocolloid, recommended by the producer inter alia as a dietary supplement, on the proliferative activity and cytokine secretion by murine splenocytes. The colloid was given to the animals in three different doses (0.25, 2.5, 25 ppm), for three different time periods (7, 14, 28 days). The influence of nanogold on splenocyte functions was time-dependent and the various doses were distinguished by distinct modes of action. The lowest dose had a pro-inflammatory or immunostimulating effect, enhancing the synthesis of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α). The effect of the highest dose can be considered as a pro-inflammatory, or immunotoxic one, because the stimulated cytokine synthesis was accompanied by a drastic decline in the proliferative activity of lymphocytes. The medium dose, while inhibiting the synthesis of pro-inflammatory cytokines of macrophages, simultaneously stimulated the proliferation of lymphocytes. All the doses also modulated the synthesis of IL-2, which may implicate their effect on the immunoregulatory mechanisms of an organism. The effect of alimentary administration of gold nanocolloid on the immune system seems to be difficult to predict, hence a risk that this type of dietary supplements might have some adverse impact on the immunity cannot be excluded, especially after their chronic administration.

α-Amylase-assisted extraction of polysaccharides from Panax ginseng

In this paper, α-amylase-assisted extraction was used to isolate the polysaccharide that remained in hot water-extracted ginseng. The yield of the polysaccharide was 9.0%, almost equal to that of the hot water-extracted polysaccharide. Using anion exchange and gel permeation chromatography, the polysaccharide was fractionated into a neutral polysaccharide fraction and six pectic fractions. The neutral fraction accounted for 76% of the polysaccharide and contained both amylopectin and amylose. The pectic polysaccharide fractions were identified to be arabinogalactan, type-I rhamnogalacturonan and homogalacturonan-type pectin by high-performance liquid chromatography, Fourier transform-infrared and nuclear magnetic resonance analysis. Structural and lymphocyte proliferation activity results showed that these polysaccharides were different from those extracted by hot water, indicating that ginseng contains complex polysaccharides with diverse structures, which results in its diverse pharmacological activities. The α-amylase-assisted extraction is a novel method for preparing ginseng polysaccharides and could be applied toward the further study and exploration of ginseng. These findings provide technical and theoretical support for ginseng pharmacology.

IMMUNOSTIMULATORY EFFECT OF FATTY ACID FROM STAR FISH (ACANTHASTER PLANCI) ON LYMPHOCYTE PROLIFERATION IN-VITRO

The aims of this study were to investigate lymphocyte proliferation activity and to identify chemical constituents of active fractions of star fish Acanthaster planci. A. planci was collected from Ternate Island, North Moluccas, extracted with distilled methanol and water, partitioned with gradient chloroform-hexane-methanol-water and fractionated in column chromatography using silica gel and hexane-ethyl acetate-methanol. The active compound had been purified by Thin Layer Chromatography (TLC) and identified by Gas Chromatography-Mass Spectrometry (GC-MS). The lymphocyte proliferation activity was measured based on % Stimulation Index (SI) from sample absorbency and control absorbency. The result showed that the 3 fractions of hexane fraction exhibited lymphocyte proliferation activity. Fraction 1 was able to increase lymphocyte proliferation at 48 hours and 72 hours by 55% (80 µl/ml) and 88% (160 µl/ml) increase, and fraction 2 had 77% (160 µl/ml) and 86% (640 µl/ml) increase. Meanwhile, fraction 3 had 75% (640 µl/ml) and 89% (640 µl/ml) increase. Metabolite analysis of active fraction using GC-MS yielded a number of chemical constituents that was dominated by fatty acid. The study concluded that star fish A. planci from Ternate Island has a potential source of immunostimulator.

Preoperative Bile Replacement Improves Immune Function for Jaundiced Patients Treated with External Biliary Drainage

BackgroundAlthough preoperative biliary drainage in jaundiced patients is controversial, external biliary drainage (EBD) is beneficial for infection control in patients with biliary cancers. When EBD is performed, additional bile replacement (BR) has the benefit of improving impaired intestinal barrier function, but the detailed mechanism remains unknown. We examined the effect of bile replacement on immune functions over the duration of BR in jaundiced patients. MethodsFifteen patients were enrolled into this prospective study. BR was started soon after the total serum bilirubin concentration reached 5.0 mg/dl and was continued for 14 days. Drained bile was given two times orally (2 × 100 ml/day). Concanavalin A (Con A)- and phytohemagglutinin (PHA)-stimulated lymphocyte proliferation and serum diamine oxidase (DAO) activity were measured before starting and during BR. Twenty patients with EBD and no BR were analyzed as a control group. ResultsSerum liver enzymes, prothrombin time–international normalized ratio (PT-INR), and responses to Con A and PHA gradually improved over the 14 days of BR, but percentages of lymphocytes and DAO levels did not. PT-INR, and Con A and PHA responses did not improve during EBD in the control group. PT-INR significantly decreased in patients with a greater fraction of their drained bile replaced. ConclusionsOur results indicate that preoperative BR using as large a quantity of bile as possible is useful for improving blood coagulability and cellular immunity in patients with EBD.

Increased antitumor activity of tumor-specific peptide modified thymopentin.

Thymopoietin pentapeptide (thymopentin, TP5), an immunomodulatory peptide, has been successfully used as an immune system enhancer for treating immune deficiency, cancer, and infectious diseases. However, poor penetration into tumors remains a key limitation to the efficacy and application of TP5. iRGD (CRGDK/RGPD/EC) has been introduced to certain anticancer agents, and increased specific tumor penetrability of drugs and cell internalization have been observed. In the present study, we fused this iRGD fragment with the C-terminal of TP5 to yield a new product, TP5-iRGD. Cell attachment assay showed that TP5-iRGD exhibits more extensive attachment to the melanoma cell line B16F10 than wild-type TP5. Tumor cell viability assay showed that iRGD conjugation with the TP5 C-terminus increases the basal antiproliferative activity of the pentapeptide against the melanoma cell line B16F10, the human lung cancer cell line H460, and the human breast cancer cell line MCF-7. Subsequent injections of TP5-iRGD inhibited invivo melanoma progression more efficiently than the native TP5. Murine spleen lymphocyte proliferation assay also showed that TP5-iRGD and the parent pentapeptide feature nearly identical spleen lymphocyte proliferation activities. We built an integrin αvβ3 and TP5-iRGD computational binding model to investigate the mechanism by which TP5-iRGD promotes increased activity further. Conjugation with iRGD promotes binding to integrin αvβ3, thereby increasing the tumor-homing efficiency of the resultant peptide. These experimental and computational observations of increased TP5-iRGD activity help broaden the usage of TP5 and reflect the great application potential of the peptide as an anticancer agent.

Enzymatic hydrolysis optimization of Paphia undulata and lymphocyte proliferation activity of the isolated peptide fractions.

The immune system is important in preventing and controlling various infectious diseases. Immunoactive peptides derived from food proteins could exert immunomodulatory activity without side effects. Paphia undulata with high-protein is suitable for the production of immunoactive peptides. The objective of this study was to optimize the hydrolysis parameters to maximize the immune activity of hydrolysates from Paphia undulata. Hydrolysis parameters, including temperature, time and the ratio of alkaline protease to Paphia undulata meat (E/S), were optimized by response surface methodology with a central composite design. The optimum conditions were obtained as follows: temperature, 51 °C; time, 3.14 h; E/S, 4,321 U g(-1) (Paphia undulata meat). Furthermore, hydrolysates obtained under the optimum conditions were fractionated by ultrafiltration and gel filtration on a Sephadex G-25 column. After two-step isolation, the isolated fractions (P2 and P3) including the peptides Pro-His-Thr-Cys, Val-Gly-Try-Thr, Glu-Phe, Leu-Phe, and Glu-Gly-Ala-Lys, Trp-Ile or Trp-Leu, respectively, could significantly enhance lymphocyte proliferation ability. These results showed that response surface methodology and two-step separation were efficient for recovery of low-molecular-weight peptides with high spleen lymphocyte proliferation activity, and the isolated fractions of Paphia undulata hydrolysates are potential ingredients for development of functional foods.

Immune-enhancing activity of polysaccharides from Cyrtomium macrophyllum

The goal of the present study was to investigate the immune-enhancing activity of polysaccharides from Cyrtomium macrophyllum (CMP). Two experiments were carried out. In immunosuppression experiment, the immune-enhancing effect of CMP in immunosuppressive mice was performed. The results showed that CMP at high and medium doses was able to overcome the CY-induced immunosuppression, significantly increases the thymus and spleen indices, enhances lymphocyte proliferation activity and macrophage function, improves immunoglobulin and cytokines levels compared with negative control group. In macrophage immunomodulatory experiment, the immune-enhancing effect of CMP in RAW264.7 cells was measured. The results showed that CMP induced the elevation of NO production, TNF-α secretion and iNOS protein of RAW264.7 cells. CMP can also strongly increase NF-κB levels in nuclear, which is an important transcription factor that can modulate expressions of iNOS, NO and TNF-α. Therefore, the CMP could be an effective immunomodulatory agent.

Ganoderma atrum polysaccharide evokes antitumor activity via cAMP-PKA mediated apoptotic pathway and down-regulation of Ca2+/PKC signal pathway

Ganoderma atrum polysaccharide (PSG-1) has been commonly suggested as a candidate for prevention and therapy of cancer. We investigated the antitumor effect and the underlying molecular mechanisms of PSG-1. The results showed that PSG-1 inhibited tumor growth and resulted in tumor cell apoptosis in vivo. Here, the data revealed that PSG-1 caused a markedly increase in cAMP and PKA activities, rather than cGMP and PKC. Moreover, the treatment of PSG-1 induced a dramatic increase in the protein level of PKA. In contrast, the expression of PKC and intracellular [Ca2+]i were inhibited. Our study also revealed that treatment with PSG-1 increased the spleen and thymus weights, lymphocyte proliferation and macrophage phagocytic activity in tumor-bearing mice. Taken together, we conclude that PSG-1 could inhibit the tumor growth, possibly in part by enhancing the induction of apoptosis through cAMP-PKA signaling pathway and down-regulation of Ca2+/PKC signal pathway, activating host immune function in S180-bearing mice.

A new recombinant hybrid polypeptide and its immunologic adjuvant activity for inactivated infectious bursal disease vaccine

Both bursin (Lys-His-Gly-NH2) and Gagnon's peptides (Lys-Asn-Pro-Tyr) can induce B-cell differentiation. However, it is unclear whether a recombinant hybrid polypeptide consisting of a tandem array of 14 copies of bursin and two copies of Gagnon's peptide can induce the proliferative activity of lymphocytes. Here, this recombinant hybrid polypeptide was expressed in Escherichia coli and purified by SDS-PAGE. Various assays showed that it not only promoted B-lymphocyte proliferation in vitro but also increased the titers of antibodies directed against infectious bursal disease virus fourfold in the sera of chickens vaccinated with the inactivated infectious bursal disease virus vaccine. The recombinant hybrid polypeptide also reduced the pathological lesions in the bursa of Fabricius caused by infectious bursal disease virus BC6/85. Our results show that this recombinant hybrid polypeptide may be a promising immune adjuvant.

Comparing the effect of Toll-like receptor agonist adjuvants on the efficiency of a DNA vaccine

We have investigated whether poly(I:C) Toll-like receptor 3 (TLR3) and resiquimod Toll-like receptor 7 (TLR7) agonists can serve as vaccine adjuvants and promote the efficiency of therapeutic DNA vaccination against tumors expressing the human papilloma virus 16 (HPV-16) E7 protein. For this purpose, C57BL/6 mice were inoculated with 2 × 10(5) TC-1 cells, and they were then immunized with HPV-16 E7 DNA vaccine alone or with 50 μg of resiquimod or poly(I:C) individually. We found that poly(I:C) and resiquimod could induce more antigen-specific lymphocyte proliferation and cytolytic activity compared to vaccination with E7 DNA alone. While E7 DNA had no significant inhibitory effect on tumor growth, co-administration of poly(I:C) and resiquimod with E7 DNA induced significant tumor regression. Peripheral and local cytokine assays demonstrated that co-administration of poly(I:C) and resiquimod with E7 DNA induced circulating antigen-specific IFN-γ and nonspecific intratumoral IL-12. TLR3 and TLR7 agonists can be used to enhance the immune response to DNA vaccine immunogens. Taken together, these data indicate that combined vaccination with DNA encoding HPV-16 E7 plus TLR agonists provides a strategy for improving the efficacy of a vaccine as a possible immunotherapeutic strategy for cervical cancer.

Co-delivery of LIGHT expression plasmid enhances humoral and cellular immune responses to HIV-1 Nef in mice

The immunogenicity and efficacy of a DNA vaccine can be greatly enhanced when a gene adjuvant is used. LIGHT, a member of TNF superfamily, can function as a costimulatory molecule for human naïve T cells to proliferate and can be a potential gene adjuvant. In the current study, the eukaryotic expression plasmid pcDNA-nef was constructed by inserting a full-length nef gene into pcDNA3.1(+), and an in vitro transfection experiment suggested that the nef gene could be expressed successfully in mammalian cells. BALB/c mice were immunized with HIV-1 nef DNA vaccine plasmids alone or in combination with LIGHT expression plasmids, and the specific humoral and cellular immune responses were measured. The data showed that HIV-1 nef DNA vaccine plasmids could induce anti-Nef antibodies, Nef-specific lymphocyte proliferation and CTL activity, whereas stronger specific immune responses were induced in mice when co-immunizing with HIV-1 nef DNA vaccine plasmids and LIGHT expression plasmids, suggesting that the eukaryotic expression vector encoding HIV-1 nef is capable of inducing specific immune responses towards HIV-1 Nef and that LIGHT could be considered as a gene adjuvant for HIV-1 DNA vaccination.

Morbillivirus Control of the Interferon Response: Relevance of STAT2 and mda5 but Not STAT1 for Canine Distemper Virus Virulence in Ferrets

The V proteins of paramyxoviruses control the innate immune response. In particular, the V protein of the genus Morbillivirus interferes with the signal transducer and activator of transcription 1 (STAT1), STAT2, and melanoma differentiation-associated protein 5 (mda5) signaling pathways. To characterize the contributions of these pathways to canine distemper virus (CDV) pathogenesis, we took advantage of the knowledge about the mechanisms of interaction between the measles virus V protein with these key regulators of innate immunity. We generated recombinant CDVs with V proteins unable to properly interact with STAT1, STAT2, or mda5. A virus with combined STAT2 and mda5 deficiencies was also generated, and available wild-type and V-protein-knockout viruses were used as controls. Ferrets infected with wild-type and STAT1-blind viruses developed severe leukopenia and loss of lymphocyte proliferation activity and succumbed to the disease within 14 days. In contrast, animals infected with viruses with STAT2 or mda5 defect or both STAT2 and mda5 defects developed a mild self-limiting disease similar to that associated with the V-knockout virus. This study demonstrates the importance of interference with STAT2 and mda5 signaling for CDV immune evasion and provides a starting point for the development of morbillivirus vectors with reduced immunosuppressive properties. The V proteins of paramyxoviruses interfere with the recognition of the virus by the immune system of the host. For morbilliviruses, the V protein is known to interact with the signal transducer and activator of transcription 1 (STAT1) and STAT2 and the melanoma differentiation-associated protein 5 (mda5), which are involved in interferon signaling. Here, we examined the contribution of each of these signaling pathways to the pathogenesis of the carnivore morbillivirus canine distemper virus. Using viruses selectively unable to interfere with the respective signaling pathway to infect ferrets, we found that inhibition of STAT2 and mda5 signaling was critical for lethal disease. Our findings provide new insights in the mechanisms of morbillivirus immune evasion and may lead to the development of new vaccines and oncolytic vectors.

In vitro testing of immunosupressive effects of mesenchymal stromal cells on lymphocytes stimulated with alloantigens

Mesenchymal stromal cells (MSC) derived from adult bone marrow or adipose tissue offer the potential to open a new frontier in medicine. MSC are involved in modulating immune response and tissue repair in vitro and in vivo. Experimental evidence and preliminary clinical studies have demonstrated that MSC exhibit an important immunomodulatory function in patients with graft versus host disease (GVHD) following allogeneic hematopoietic stem cell transplantation. The immunosuppressive properties of MSC have already been exploited in the clinical setting. However the precise mechanisms are being still investigated. We examined the immunosuppressive function of MSC by coculturing them with stimulated HLA incompatible allogeneic lymphocytes in a mixed lymphocyte culture test. The metabolic and proliferative activity of lymphocytes was determined by MTT test. After stimulation with alloantigens the presence of MSC caused significant decrease of absorbance levels by 62% (P<0.01), 26% (P<0.01) and 6% (P=0.0437) in comparison to positive control depending on the MSC/lymphocyte ratio (1:5, 1:50, 1:500). The mitogenic stimulation of lymphocytes with fMLP or PHA was also significantly reduced during MSC cocultivation. The absorbance was reduced by 42% (P<0.001) and 67% (P<0.001). Allogeneic bone marrow is an ideal source of MSC for clinical application. The experiments confirmed the dose-dependent inhibitory effect of MSC on lymphocyte proliferation triggered by cellular or mitogenic stimulation. The mixed lymphocyte culture test offers a simple method for characterization and verification of the immunosuppressive potential of MSC, being prepared for clinical use.

CTLA4 mediated targeting enhances immunogenicity against PRRSV in a DNA prime/killed virus boost strategy

Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of porcine reproductive and respiratory syndrome (PRRS), causing heavy economic losses to the swine industry all over the world. As current vaccination strategies could only confer limited and incomplete protection against PRRSV infection, a safe and efficient PRRSV vaccine is urgently needed. Vaccination with cytotoxic-T-lymphocyte-associated protein 4 (CTLA4) and antigen fusion expression plasmid which could target antigens to antigen presenting cells (APCs) has shown promising improvement of immunogenicity to antigens. In the present study, a fusion expression plasmid of CTLA4 and PRRSV GP5 was constructed. PRRSV-specific antibodies, neutralizing antibodies (NAs), cytokines of IFNγ and IL4, and the lymphocyte proliferation activity were analyzed in mice immunized with the constructed plasmids. Immunization of mice with the CTLA4 targeted plasmid leads to a significant enhancement of humoral and cellular immune responses. Moreover, this effect could be further augmented when the mice were boosted with a killed PRRSV vaccine after DNA vaccine priming. Our data imply that both the APC-target and heterologous prime-boost strategies could be used to improve the immune efficacy of vaccines against PRRSV in pigs in the future.

Influence of β-endorphin on the proliferative and phagocytic activities of peripheral blood cells of men and women from different age groups

It has been found that β-endorphin modulation of lymphocyte proliferative activity in male donors is mainly observed at a relatively young age (in groups aged 20–29 and 30–39 years), it gradually becomes lower with age, and disappears in donors at aged 50–60 years. At the same time, women have a prolonged modulating effect of peptide on proliferation. In women aged 50–59 years, the peptide has a marked promotional effect on spontaneous proliferation at concentrations of 10−7, 10−8, and 10−10 M induced by a suboptimal concentration of phytohemagglutinin (PHA) at 10−10 M, while in women aged 30–39 years, β-endorphin suppresses PHA-induced proliferative response. In men aged 20–29 years, β-endorphin stimulates the uptake capacity of neutrophils, whereas in those aged 50–59 years, this capacity is suppressed by β-endorphin. In female donors from any age groups, β-endorphin was not found to influence the activity of neurophils.

Efficacy of a DNA Vaccine Carrying Eimeria maxima Gam56 Antigen Gene against Coccidiosis in Chickens

To control coccidiosis without using prophylactic medications, a DNA vaccine targeting the gametophyte antigen Gam56 from Eimeria maxima in chickens was constructed, and the immunogenicity and protective effects were evaluated. The ORF of Gam56 gene was cloned into an eukaryotic expression vector pcDNA3.1(zeo)+. Expression of Gam56 protein in COS-7 cells transfected with recombinant plasmid pcDNA-Gam56 was confirmed by indirect immunofluorescence assay. The DNA vaccine was injected intramuscularly to yellow feathered broilers of 1-week old at 3 dosages (25, 50, and 100 µg/chick). Injection was repeated once 1 week later. One week after the second injection, birds were challenged orally with 5×104 sporulated oocysts of E. maxima, then weighed and killed at day 8 post challenge. Blood samples were collected and examined for specific peripheral blood lymphocyte proliferation activity and serum antibody levels. Compared with control groups, the administration of pcDNA-Gam56 vaccine markedly increased the lymphocyte proliferation activity (P<0.05) at day 7 and 14 after the first immunization. The level of lymphocyte proliferation started to decrease on day 21 after the first immunization. A similar trend was seen in specific antibody levels. Among the 3 pcDNA-Gam56 immunized groups, the median dosage group displayed the highest lymphocyte proliferation and antibody levels (P<0.05). The median dosage group had the greatest relative body weight gain (89.7%), and the greatest oocyst shedding reduction (53.7%). These results indicate that median dosage of DNA vaccine had good immunogenicity and immune protection effects, and may be used in field applications for coccidiosis control.

Immunopathogenesis of Sarcoidosis and Risk of Malignancy: A Lost Truth?

The hypothesis of a relationship between sarcoidosis and malignancy was firstly formulated in 1972 by Brincker. He documented an association of sarcoid reactions or sarcoidosis with 19 lymphomas and associated malignancies. Based on various epidemiological studies, for more than 20 years sarcoidosis has been considered as a condition at increased risk for cancer, particularly lymphoproliferative disorders. The existence of a sarcoidosis-lymphoma syndrome was therefore proposed, highlighting, as a potential mechanism, the uncontrolled lymphocyte proliferation and mitotic activity. A reduced ability to eliminate an antigen and chronic inflammation have been suggested as triggering events. Leading to a reduced tumor immune surveillance, a diminished myeloid dendritic cells (mDC) function, despite up-regulated co-stimulatory and maturation markers, was also raised as potential mechanism. However, some subsequent studies have questioned the presence of a close association between the two entities and have explained those previously published as the result of selection bias and misclassification. Recently, a Swedish population-based cohort study documented a significant overall excess incidence of cancer among sarcoidosis patients, especially those with multiple hospitalizations or admission in older age, emphasizing again a potential neoplastic risk. Therefore, currently, whether these patients have an increased risk of developing malignant lesions is still debated. Larger and unbiased studies are needed before drawing definite conclusions.

Compound DNA vaccine encoding SAG1/ SAG3 with A2/B subunit of cholera toxin as a genetic adjuvant protects BALB/c mice against Toxoplasma gondii

BackgroundIntracellular parasites, such as T. gondii, present a plurality of antigens because of the complexity of its life cycle. Compound DNA vaccines bring a new approach and hope for the treatment of toxoplasmosis. In this study, a DNA vaccine encoding two major surface antigens SAG1, SAG3 from T. gondii, with A2/B subunit of cholera toxin as a genetic adjuvant was constructed.MethodsBALB/c mice were immunized intramuscularly with PBS, pcDNA3.1, pSAG1, pSAG1/SAG3 and pSAG1/SAG3-CTXA2/B three times separately. Immunized mice were tested for IgG antibody and IFN-γ and IL-4 production by ELISA. The proliferation of T cells was measured by DNA synthesis assay and the lymphocyte subsets of spleen cells by flow cytometry. All the immunized mice were challenged with 103 highly virulent RH tachyzoites of Toxoplasma gondii intraperitoneally and the survival times were recorded.ResultsAn enhanced production of IgG antibodies, antigen-specific lymphocyte proliferation and IFN-γ production from splenic cells were induced in mice immunized with pSAG1/SAG3 compared to mice immunized with pSAG1 (P<0.05). Introduction of CTXA2/B further enhanced the Th1 cell-mediated immunity with higher levels of IFN-γ, lymphocyte proliferation activity and percentage of CD8+ T-cells. When challenged with lethal doses of T. gondii (1×103), all control mice (PBS and empty plasmid group) died within 6 days. Mice immunized with pSAG1 died within 8 days. While 20% and 40% survival rate were achieved from mice immunized with pSAG1/SAG3 and pSAG1/SAG3-CTXA2/B.ConclusionsThis study indicates the compound DNA vaccine encoding T. gondii antigens SAG1, SAG3 with CTXA2/B gene was a promising DNA vaccine candidate against toxoplasmosis, which could effectively enhance the humoral and cellular immune response and prolong survival time in vaccinated mice.