Modulation of hepatitis C virus core DNA vaccine immune responses by co-immunization with CC-chemokine ligand 20 (CCL20) gene as immunoadjuvant

Efficacy and Safety of Nasal Immunisation with Somatostatin DNA Vaccine for Growth Promotion in Fattening Pigs

This study aimed to evaluate the efficacy and safety of the SS DNA vaccine on growing pigs. Randomly, 147 pigs were divided into four groups, treatment 1 (T1, 3 × 109 CFU/mL, n = 39), T2 (3 × 108 CFU/mL, n = 35), T3 (3 × 107 CFU/mL, n = 35) and control group (phosphate-buffered saline, n = 38). All animals received two vaccinations separated by 45 days and the same diet and management. The results showed that all treatment groups (T1, T2 and T3) had significantly higher slaughter weight (d 185) than the Ctrl group (p < 0.05), and daily gain between 50 and 110 days of age was significantly higher in all treatment groups than in the Ctrl group (p < 0.05). Antibody-positive pigs have significantly higher daily weight gain than that in antibody-negative pigs (p < 0.05). The results of the meat quality analysis showed no significant changes between the P (antibody-positive pigs) and N (antibody-negative pigs) groups. Furthermore, the results showed that antibody titres at 110 and 185 days had a significant positive correlation with the daily weight gain (p < 0.05) and a significant negative correlation with the backfat thickness (p < 0.05). Evaluating the safety of vaccines by PCR amplification of target genes (GS/2SS), faecal, soil and water samples had no target genes detected by PCR amplification in these samples after 5 days, and no GS/2SS were detected in the blood and tissues for the experimental period. Moreover, no abnormalities were found in pathological sections of the P group compared with the N group. In conclusion, SS DNA vaccines can promote the growth of fattening pigs to a certain extent without altering the meat quality, and it has no effects on the safety of the surrounding environment.

Hepatitis C virus DNA vaccines: a systematic review

BACKGROUND

Vaccination against HCV is an effective measure in reduction of virus-related public health burden and mortality. However, no prophylactic vaccine is available as of yet. DNA-based immunization is a promising modality to generate cellular and humoral immune responses. The objective of this study is to provide a systematic review of HCV DNA vaccines and investigate and discuss the strategies employed to optimize their efficacies.

METHODS

MEDLINE (PubMed), Web of Science, Scopus, ScienceDirect, and databases in persian language including the Regional Information Centre for Science & Technology (RICeST), the Scientific Information Database and the Iranian Research Institute for Information Science and Technology (IranDoc) were examined to identify studies pertaining to HCV nucleic acid vaccine development from 2000 to 2020.

RESULTS

Twenty-seven articles were included. Studies related to HCV RNA vaccines were yet to be published. A variety of strategies were identified with the potential to optimize HCV DNA vaccines such as incorporating multiple viral proteins and molecular tags such as HBsAg and Immunoglobulin Fc, multi-epitope expression, co-expression plasmid utilization, recombinant subunit immunogens, heterologous prime-boosting, incorporating NS3 mutants in DNA vaccines, utilization of adjuvants, employment of less explored methods such as Gene Electro Transfer, construction of multi- CTL epitopes, utilizing co/post translational modifications and polycistronic genes, among others. The effectiveness of the aforementioned strategies in boosting immune response and improving vaccine potency was assessed.

CONCLUSIONS

The recent progress on HCV vaccine development was examined in this systematic review to identify candidates with most promising prophylactic and therapeutic potential.

Chemokine-Adjuvanted Plasmid DNA Induces Homing of Antigen-Specific and Non-Antigen-Specific B and T Cells to the Intestinal and Genital Mucosae

Plasmid DNA is a promising vaccine platform that together with electroporation can elicit significant systemic Ab responses; however, immunity at mucosal sites remains low. In this study, we sought to program T and B cells to home to the gastrointestinal and vaginal mucosae using genetic chemokine adjuvants and assessed their impact on immune homeostasis in various distinct immune compartments. BALB/c mice were immunized i.m. with plasmid DNA encoding a model Ag HIV-1 Env gp140 and selected chemokines/cytokine and boosted intravaginally with gp140 recombinant protein. Isolated splenocytes, intestinal lymphocytes, and genital lymphocytes as well as serum and intestinal luminal contents were assessed for Ag-specific reactivity. In addition, flow cytometric analysis was performed to determine the impact on immune homeostasis at these sites. Different molecular chemokine/cytokine adjuvants effected significant alterations to the recruitment of B and T cells to the spleen, vaginal and intestinal mucosae, for example CCL25 enhanced splenic and vaginal Ag-specific T cell responses whereas CCL28 increased the levels of specific T cells only in the vaginal mucosa. The levels of Ab could be modulated in the systemic circulation, as well as the vaginal vault and intestinal lumen, with CCL20 playing a central role. Our data demonstrate that the CCL20, CCL25, and CCL28 genetic chemokine adjuvants enhance the vaccine Ag-specific humoral and cellular responses and induce homing to the intestinal and female genital mucosae.

A sensitive and rapid chemiluminescence immunoassay for point-of-care testing (POCT) of copeptin in serum based on high-affinity monoclonal antibodies via cytokine-assisted immunization

Purpose: Antibodies are key reagents in the development of immunoassay. We attempted to develop high-performance CPP immunoassays using high-affinity monoclonal antibodies prepared via cytokine-assisted immunization.

Methods: We used fetal liver tyrosine kinase 3 ligand (Flt3L), CC subtype chemokine ligand 20 (CCL20), and granulocyte-macrophage colony-stimulating factor (GM-CSF) to assist traditional subcutaneous immunization of preparing high-affinity monoclonal antibodies, and further to develop high-performance immunoassay methods for CPP.

Results: This novel immune strategy significantly enhanced immune response against CPP. Six anti-CPP monoclonal antibodies (mAbs) with high affinity were successfully screened and selected for application in a fully automated magnetic chemiluminescence immunoassay (CLIA). This robust and rapid assay can efficiently detect CPP in the range of 1.2–1250 pmol L^–1 with a detection limit of 6.25 pmol L^–1. Significantly, the whole incubation process can be completed in 30 min as compared to about 4.5 hr for the control ELISA kit. Furthermore, this assay exhibited high sensitivity and specificity, low intra-assay and inter-assay coefficients of variation (CVs < 15%). The developed assay was applied in the detection of CPP in 115 random serum samples and results showed a high correlation with data obtained using a commercially available ELISA kit (correlation coefficient, 0.9737).

Conclusion: Our assay could be applied in the point-of-care testing of CPP in the serum samples, and also the method developed in this study could be adopted to explore the detection and diagnosis of other biomarkers for various diseases.

CCL17 combined with CCL19 as a nasal adjuvant enhances the immunogenicity of an anti-caries DNA vaccine in rodents

AIM

CCL19 and its receptor CCR7 are essential molecules for facilitating the trafficking of mature dendritic cells (DCs) and helping to establish a microenvironment in lymphoid tissues to initiate primary immune responses, whereas CCL17 is required in the CCR7-CCL19-dependent migration of DCs. In this study we examined whether co-administration of CCL17 and CCL19 could enhance the immunogenicity of an anti-caries DNA vaccine, pCIA-P, in rodents.

METHODS

Plasmids encoding CCL17 (pCCL17/VAX) and CCL19 (pCCL19/VAX) were constructed. BALB/c mice were intranasally administered pCCL17/VAX, pCCL19/VAX, or pCCL17/VAX plus pCCL19/VAX, the migration of DCs to the spleen and draining lymph nodes (DLNs) was assessed with flow cytometry. The mice were co-administered pCIA-P; and the anti-PAc antibodies in the serum and saliva were detected with ELISA. Wistar rats were orally challenged with Streptococcus mutans and then administered pCIA-P in combination with pCCL17/VAX, pCCL19/VAX, or pCCL17/VAX plus pCCL19/VAX. The amount of S mutans sustained on rat molar surfaces was assessed using a colony forming assay. Caries activity was scored with the Keyes method.

RESULTS

Co-administration of the CCL17 and CCL19 genes in mice caused a greater increase in the number of mature DCs in the spleen and DLNs compared with administration of CCL17 or CCL19 genes alone. CCL17 and CCL19 double-adjuvant plus pCIA-P induced significantly higher levels of anti-PAc salivary IgA and anti-PAc serum IgG antibody in mice, and strengthened the ability of pCIA-P in inhibiting the colonization of S mutans on rat tooth surfaces. The caries activity of the combined adjuvant group was significantly lower than that of the pCCL17/VAX or the pCCL19/VAX group.

CONCLUSION

A nasal adjuvant consisting of a combination of CCL17 and CCL19 attracts more mature DCs to secondary lymphoid tissues, inducing enhanced antibody responses against the anti-caries DNA vaccine pCIA-P and reducing S mutans infection in rodents.