ABSTRACT
Listeria monocytogenes (L. monocytogenes, LM) is an excellent tumor vaccine vector. In this study, recombinant LM vaccine candidate expressing human papillomavirus type 16 (HPV16) E7 protein was constructed and its charactericts were determined. Through homologous recombination, E7 gene was cloned in frame with the LM4 Phly promoter-signal sequence, and introduced into the chromosome of LM4. The recombinant strain named LM4△hly::E7 with the plasmid-free and antibiotic-resistant gene-free was constructed. LM4△hly::E7 could express and secrete E7-LLO fusion protein; its size is 66 kDa and has immunological activity. Furthermore, LM4△hly::E7 could multiply in RAW264.7 macrophages by confocal laser scanning microscope. Additionally, LM4△hly::E7 could induce specific antibodies against E7 in immunized mice in ELISA. Also, the 50% lethal dose (LD₅₀) of LM4△hly::E7 strain was 3.863×10⁹ CFU (Colony-Forming Units) in C57BL/6 mice with intraperitoneal immunization, which was more attenuated than wild type LM4. Mice immunized with LM4△hly::E7 did not show obvious pathological change. These data show that LM4△hly::E7 expressing E7-LLO fusion protein has good safety, which may provide the materials for research of antitumor effect and would be a promising vaccine candidate for cervical cancer.
Subject(s)
Animals , Mice , Cancer Vaccines , Allergy and Immunology , Listeria monocytogenes , Mice, Inbred C57BL , Papillomavirus E7 Proteins , Allergy and Immunology , Papillomavirus Infections , Plasmids , Recombinant Fusion Proteins , Allergy and Immunology , Vaccines, Attenuated , Allergy and Immunology , Viral Vaccines , Allergy and ImmunologyABSTRACT
Background The role of polysaccharides isolated from the Ganoderma species of fungi in innate immunity has recently become a topic of research. Although some work has been conducted concerning Ganoderma lucidum, the characteristics of polysaccharides isolated from Ganoderma neojaponicum (Imazeki) as immunomodulatory agents are largely unknown. The aims for this study were to isolate and characterize the intracellular polysaccharides (IPSs) and extracellular polysaccharides (EPSs) of G. neojaponicum from STR reactor. Results The production of EPS and IPS was optimized on day 4 of the cultivation time in 2 L STR reactor based on the amount of biomass yield, total carbohydrate, β-glucan and a-glucan content. Further analysis, both the EPSs and IPSs showed the enhancement on proliferation and increment of phagocytosis activities of macrophage (RAW264.7) cell lines. Using an oral toxicity test, we also observed that 2000 mg/kg body weight/day dosage of dried G. neojaponicum mycelium does not cause any significant toxic effects on Sprague-Dawley rats in 14 d of administration. Conclusion The findings of this study indicate that the IPSs and EPSs of G. neojaponicum have the potential to be used as immunomodulating agents to stimulate the innate immune system for fighting infectious diseases. The polysaccharides from G. neojaponicum have to be further commercially explored as an alternative for medicinal Ganoderma variety of G. lucidum production.
Subject(s)
Polysaccharides/isolation & purification , Polysaccharides/chemistry , Ganoderma , Immunologic Factors , Phagocytosis , Toxicity Tests, Acute , beta-Glucans/analysis , Cell Proliferation , Immunity, Innate , MacrophagesABSTRACT
Objective To establish a glucocorticoid receptor knockdown model of human macrophage cell line U937 with RNA interference technique. Methods Two RNAi recombinant plasmids (named pSilencer 3.1-GR 1 and pSilencer 3.1-GR 2) targeting to GR gene were constructed. After RNAi recombinant plasmids were transfected into human macrophage cell line U937, the expressions of GR mRNA and GR protein were evaluated with RT-PCR and Western blotting respectively. The transcriptional activation function of GR was evaluated through the detection of relative luciferase activity after dexamethasone treatment. Results Two RNAi recombinant expression plamids were constructed and identified by sequencing. pSilencer 3.1-GR 2 transfection could inhibit not only GR mRNA and protein expressions, but also transcriptional activation function of GR specially; pSilencer 3.1-GR 1 transfection had no significant changes as compared to normal control. Conclusion A glucocorticoid receptor knockdown model has been established successfully, which offers a new method for the further research of GR biological functions.