Eimeria maxima Rhomboid-like Protein 5 Provided Partial Protection against Homologous Challenge in Forms of Recombinant Protein and DNA Plasmid in Chickens

Eimeria maxima (E. maxima) is one of the most prevalent species that causes chicken coccidiosis on chicken farms. During apicomplexan protozoa invasion, rhomboid-like proteins (ROMs) cleave microneme proteins (MICs), allowing the parasites to fully enter the host cells, which suggests that ROMs have the potential to be candidate antigens for the development of subunit or DNA vaccines against coccidiosis. In this study, a recombinant protein of E. maxima ROM5 (rEmROM5) was expressed and purified and was used as a subunit vaccine. The eukaryotic expression plasmid of pVAX–EmROM5 was constructed and was used as a DNA vaccine. Chickens who were two weeks old were vaccinated with the rEmROM5 and pVAX–EmROM5 vaccines twice, with a one-week interval separating the vaccination periods. The transcription and expression of pVAX–EmROM5 in the injected sites were detected through reverse transcription PCR (RT-PCR) and Western blot (WB) assays. The cellular and humoral immune responses that were induced by EmROM5 were determined by detecting the proportion of CD4+ and CD8+ T lymphocytes, the cytokine levels, and the serum antibody levels. Finally, vaccination-challenge trials were conducted to evaluate the protective efficacy of EmROM5 in forms of the recombinant protein (rEmROM5) and in the DNA plasmid (pVAX–EmROM5) separately. The results showed that rEmROM5 was about 53.64 kDa, which was well purified and recognized by the His-Tag Mouse Monoclonal antibody and the chicken serum against E. maxima separately. After vaccination, pVAX–EmROM5 was successfully transcribed and expressed in the injected sites of the chickens. Vaccination with rEmROM5 or pVAX–EmROM5 significantly promoted the proportion of CD4+/CD3+ and CD8+/CD3+ T lymphocytes, the mRNA levels of the cytokines IFN-γ, IL-2, IL-4, IL-17, TNF SF15, and IL-10, and specific IgG antibody levels compared to the control groups. The immunization also significantly reduced the weight loss, oocyst production, and intestinal lesions that are caused by E. maxima infection. The anticoccidial index (ACI)s of the vaccinated groups were beyond 160, showing moderate protection against E. maxima infection. In summary, EmROM5 was able to induce a robust immune response and effective protection against E. maxima in chickens in the form of both a recombinant protein and DNA plasmid. Hence, EmROM5 could be used as a candidate antigen for DNA vaccines and subunit vaccines against avian coccidiosis.

HPV16 E6 Gene Polymorphisms and the Functions of the Mutation Site in Cervical Cancer Among Uygur and Han Women in Xinjiang

Background: To investigate the genotype distribution of human papillomavirus (HPV) in infected Uygur and Han women in Xinjiang; analyze the HPV16 E6 gene polymorphism site and relationship with the development of cervical cancer.Methods: The HPV16 E6 sequence was analyzed using the European standard prototype to perform an evolutionary tree. HPV16 E6-295T/350T, 295G/350G, and 295T/350G GV230 vectors were stably transfected into cervical cancer C33A cells to analyze the cell proliferation, migration and invasion, apoptosis by CCK8 and clonogenic assays, transwell and cell scratch assays, FACS experiments. Results: The total HPV infection rate was 26.390% (760/2879), whereas the Uygur 22.87% (196/857) and the Han was 27.89% (564/2022) (P < 0.05). Among 110 mutations, 65 cases of E6 genes were mutated at nucleotide 350 (T350G) with the leucine changing to valine (L83V). Moreover, there were 7 cases of E6 gene mutated at nucleotide 295 (T295G) with aspartic changing to glutamic (D64E). When E6 vector(s) of mutations sites were transfected into C33A cells, they were found to promote cellular proliferation, migration, invasion, and inhibit apoptosis. The 295T/350G had the strongest effect on C33A cells and 295G/350G was significantly stronger than 295T/350T (P < 0.05).Conclusions: The positive HPV infection rates differed between the Uygur and Han in Xinjiang, and the genotype distribution of infection was different. After transfecting C33A cells with different eukaryotic expression vectors, the 295T/350G mutation site promoted the proliferation，migration, and invasion of C33A cells to a greater extent than 295G/350G; however, 295G/350G had a stronger effect than 295T/350T.

Clonorchis sinensis Granulin Promotes Malignant Transformation of Hepatocyte Through EGFR-Mediated RAS/MAPK/ERK and PI3K/Akt Signaling Pathways

The biological functions of growth factor, such as granulins, have been explored in parasites, and we elucidated that Clonorchis sinensis granulin (CsGRN) promoted the metastasis of hepatocellular carcinoma in our previous study. However, it is still unclear for the malignant transformation role of CsGRN in normal human hepatocytes. In this study, by transfecting pEGFP-C1-CsGRN eukaryotic expression plasmid, a cell line with stable overexpression of CsGRN in normal hepatocyte (LO2-GRN cells) was constructed. The effects on cell proliferation were detected by carrying out cell counting kit-8 (CCK8) assay and colony formation assay. Additionally, we conducted flow cytometry analysis to determine whether the proliferation of CsGRN was due to cell cycle arrest. Subsequently, the migration ability and the invasion ability of LO2-GRN cells were evaluated through wound-healing assay and transwell assay. Meanwhile, the levels of the markers of RAS/MAPK/ERK and PI3K/Akt signaling pathways activation in LO2-GRN cells were assessed by quantitative RT-PCR and Western blot. Our results indicated that CsGRN promoted the proliferation of LO2 cells by regulating the expression of cell-cycle-related genes. Moreover, the overexpression of CsGRN regulates malignant metastasis of liver cells by inducing the upregulation of epithelial–mesenchymal transition (EMT) marker proteins. Furthermore, both mRNA and protein expression levels of p-EGFR, RAS, p-ERK, p-AKT, p-PI3K, and p-braf have been enhanced by CsGRN. These results showed that CsGRN promoted the malignant transformation of hepatocytes by regulating epidermal growth factor receptor (EGFR)-mediated RAS/MAPK/ERK and PI3K/Akt signaling pathways, which suggested that CsGRN could serve as a novel oncoprotein during Clonorchis sinensis–associated malignant transformation of hepatocytes.

Targeted regulation of plasmid DNA expression in eukaryotic cells with a methylated-DNA-binding activator

Purpose: Targeted regulation of transfected extra-chromosomal plasmid DNA typically requires the integration of 9 - 20 bp docking sites into the plasmid. Here, we report an elegant approach, The Dpn Adaptor Linked Effector (DAL-E) system, to target fusion proteins to 6-methyladenosine in GATC, which appears frequently in popular eukaryotic expression vectors and is absent from endogenous genomic DNA. Methods: The DNA-binding region from the DpnI endonuclease binds 6-methyladenosine within the GATC motif. We used a Dpn-transcriptional activator (DPN7-TA) fusion to induce gene expression from transiently transfected pDNAs. Results: We validated methylation-dependent activity of DPN7-TA with a panel of target pDNAs. We observed stronger transactivation when GATC targets were located upstream of the transcriptional start site in the target pDNA. Conclusion: DAL-E, consisting of a 108 aa, 12 kD DNA-binding adaptor and a 4 bp recognition site, offers a genetically-tractable, tunable system that can potentially be redesigned to recruit a variety of regulators (e.g. activators, silencers, epigenome editors) to transfected plasmid DNA.

LB19. Intramuscular therapeutic immunization targeting RelMtb/MIP-3 induces immune signatures associated with better TB control in vivo compared to

Background Tuberculosis (TB) is one of the leading causes of death from a single infectious agent worldwide. The lengthy treatment regimen reflects the unique ability of a subpopulation of “persister” bacteria to remain in a nonreplicating state in the infected host through various adaptive strategies, including induction of the stringent response. The key stringent response enzyme, RelMtb, is essential for long-term Mycobacterium tuberculosis (Mtb) survival under physiologically relevant stresses in vitro and in animal lungs. Recently, our group has generated a therapeutic, parenteral, relMtb DNA vaccine, which induces RelMtb-specific cellular immunity and augments the activity of the first-line drug isoniazid against active TB in mice and guinea pigs. Our group also has applied a novel vaccination strategy involving the fusion of an antigen of interest with the immature dendritic cell (iDC)-targeting chemokine MIP-3α/CCL20, which significantly enhances antigen-specific T-cell responses. We sought to determine if this iDC-targeting strategy improves the immunogenicity of the therapeutic relMtb DNA vaccine. Methods We cloned the relMtb and chemokine MIP-3α genes into the eukaryotic expression plasmid pSectag2b. We conducted an immunogenicity study using C57BL/6J mice, comparing the T-cell responses between the relMtbvs. MIP-3α/relMtb DNA intramuscular vaccination groups. Results Intramuscular administration of the DNA vaccine expressing the MIP-3α/relMtb gene fusion induced increased production of various Mtb-protective cytokines (IL-17α, IL-2, TNF-α, IFN-γ) in various mouse tissues, including the spleen, draining lymph nodes and peripheral blood mononuclear cells, relative to the vaccine expressing relMtb alone. Conclusion Intramuscular immunization with a DNA vaccine expressing relMtb/MIP-3α induces robust in vivo Mtb-protective immune signatures, suggesting this may be a promising adjunctive approach in combination with standard anti-TB therapy. Disclosures All Authors: No reported disclosures

Synergistic Regulatory Effect of Inhibin and Anti-Müllerian Hormone on Fertility of Mice

Inhibin (INH) and anti-Müllerian hormone (AMH) are essential in ovarian folliculogenesis and play an inhibitory role in mammalian fertility. However, the interactive effect of INH and AMH on the animal reproduction remains unknown. This study aimed to determine the possible interaction and synergy between INH and AMH in steroidogenesis by primary granulosa cells, and investigate their synergistic effect on fertility in mice. In in vitro granulosa cell culture system, we found that the treatment of either INHA or AMH had no significant effect on basal estradiol and progesterone production, whereas both significantly attenuated FSH-induced steroid hormone secretion. Importantly, combined treatment with INHA and AMH showed additive inhibitory effect on FSH-induced estradiol and progesterone production, accompanying a significant downregulation in the expression of FSH-stimulated CYP19A1, HSD3B, CYP11A1, StAR transcripts. The interrelationship of INH and AMH combinations was further investigated through active immune neutralization strategy. Female mice were immunized against INH and AMH eukaryotic expression plasmids, and the litter size was recorded after successfully mating. We observed that both INH and AMH plasmids were able to induce either anti-AMH or anti-INH antibodies in the immunized mice. In comparison with the control group, co-immunization with INH and AMH plasmids induced higher levels of estradiol, resulting in more litter size. Moreover, there was no significant difference on the offspring's weight between each group. Collectively, the results of the present study suggest that INH and AMH have synergistic effect in regulating steroidogenesis and the litter size in mice.

Designing of DNA Vaccine Based on a Secretory Form of Major Capsid Protein of Human Papillomavirus Type 18

More than 99% of cervical cancers are associated with human papillomaviruses (HPVs) worldwide. Current HPV vaccines are safe, highly immunogenic, with effective immunity against specific HPV types. However, DNA vaccines are a new appealing platform which can be considered for designing the HPV vaccines. This study aimed to construct a recombinant eukaryotic expression plasmid containing L1 of HPV-18, tissue plasminogen activators (tPA), and pan HLA DR-binding epitope (PADRE) genes into the pVAX1 vector. The L1, tPA, and PADRE genes were amplified in a thermocycler. The polymerase chain reaction (PCR) products were cloned and insertion of the genes was confirmed using colony PCR, restriction enzymes analysis, and sequencing methods. Indirect immunofluorescence, RT-PCR, and western blot assays were applied to identify the target gene in HEK-293 cells. Total IgG and its isotypes in immunized mice were measured by enzyme-linked immunosorbent assay technique. Western blot analysis showed a protein band of about 67.5 kDa in supernatant and cell lysate of transfected cells. The results of mice immunization with different constructs (group 1: the pVAX-L1, group 2: pVAX-tPA-PADRE-L1, group 3: pVAX1, and group 4: PBS as controls) indicated that the pVAX1-tPA-PADRE-L1 construct induced a significantly higher level of total IgG than pVAX1-L1 (p=0.003). In conclusion, pVAX1-tPA-PADRE-L1 recombinant plasmid is a highly immunogenic construct and suggests as a promising candidate for vaccine development against HPV type 18 in low-middle-income countries.

A Method for Rapid Screening, Expression, and Purification of Antimicrobial Peptides

In this study, a method for the rapid screening, expression and purification of antimicrobial peptides (AMPs) was developed. AMP genes were fused to a heat-resistant CL7 tag using the SLOPE method, and cloned into Escherichia coli and Pichia pastoris expression vectors. Twenty E. coli and ten P. pastoris expression vectors were constructed. Expression supernatants were heated, heteroproteins were removed, and fusion proteins were purified by nickel affinity (Ni-NTA) chromatography. Fusion proteins were digested on the column using human rhinovirus (HRV) 3C protease, and AMPs were released and further purified. Five AMPs (1, 2, 6, 13, 16) were purified using the E. coli expression system, and one AMP (13) was purified using the P. pastoris expression system. Inhibition zone and minimum inhibitory concentration (MIC) tests confirmed that one P. pastoris¬-derived and two E. coli-derived AMPs have the inhibition activity. The MIC of AMP 13 and 16 from E. coli was 24.2 μM, and the MIC of AMP 13 from P. pastoris was 8.1 μM. The combination of prokaryotic and eukaryotic expression systems expands the universality of the developed method, facilitating screening of a large number of biologically active AMPs, establishing an AMP library, and producing AMPs by industrialised biological methods.