Assessment of the Immunoprotective Efficacy of Recombinant 14-3-3 Protein and Dense Granule Protein 10 (GRA10) as Candidate Antigens for Rabbit Vaccines against Eimeria intestinalis

Eimeria intestinalis infects rabbits, causing severe intestinal coccidiosis. Prolonged anticoccidial drug use might lead to coccidia resistance and drug residues in food. Thus, vaccines are required to control rabbit coccidiosis. In this study, recombinant E. intestinalis 14-3-3 and GRA10 proteins (rEi-14-3-3 and rEi-GRA10) were obtained via prokaryotic expression and used as recombinant subunit vaccines. Fifty 30-day-old rabbits were randomly grouped as follows: PBS-uninfected group, PBS-infected group, Trx-His-S control group, and rEi-14-3-3 and rEi-GRA10 immunized groups. The rabbits were subcutaneously immunized twice at 2-week intervals, challenged with 7 × 104 sporulated oocysts, and sacrificed 14 days later. The protective effects were assessed via clinical signs, relative weight gain, oocyst reduction, mean intestinal lesion score, ACI (anticoccidial index), cytokine, and specific antibody levels in sera. The rEi-14-3-3 and rEi-GRA10 groups had higher relative weight gain rates of 81.94% and 73.61% (p < 0.05), and higher oocyst reduction rates of 86.13% and 84.87% (p < 0.05), respectively. The two immunized groups had fewer intestinal lesions (p < 0.05) and higher IgG levels (p < 0.05). Higher levels of IL-2, IL-4, and IFN-γ cytokines in the rEi-14-3-3 group (p < 0.05) and a higher level of IFN-γ in the rEi-GRA10 group (p < 0.05) were observed. The ACI values of the rEi-14-3-3 and rEi-GRA10 groups were 168.24 and 159.91, with good and moderate protective effects, respectively. Both rEi-14-3-3 and rEi-GRA10 induced humoral immunity in the rabbits. In addition, rEi-14-3-3 induced Th1- and Th2-type immune responses. Both recombinant proteins were protective against E. intestinalis infection in rabbits, with rEi-14-3-3 showing a better protective effect.

Two formulations of coronavirus disease-19 recombinant subunit vaccine candidate made up of S1 fragment protein P1, S2 fragment protein P2, and nucleocapsid protein elicit strong immunogenicity in mice

INTRODUCTION

Coronavirus disease (COVID-19) is ongoing as a global epidemic and there is still a need to develop much safer and more effective new vaccines that can also be easily adapted to important variants of the pathogen. In the present study in this direction, we developed a new COVID-19 vaccine, composed of two critical antigenic fragments of the S1 and S2 region of severe acute respiratory syndrome coronavirus 2 as well as the whole nucleocapsid protein (N), which was formulated with either alum or alum plus monophosphoryl lipid A (MPLA) adjuvant combinations.

METHODS

From within the spike protein S1 region, a fragmented protein P1 (MW:33 kDa) which includes the receptor-binding domain (RBD), another fragment protein P2 (MW:17.6) which contains important antigenic epitopes within the spike protein S2 region, and N protein (MW:46 kDa) were obtained after recombinant expression of the corresponding gene regions in Escherichia coli BL21. For use in immunization studies, three proteins were adsorbed with aluminum hydroxide gel and with the combination of aluminum hydroxide gel plus MPLA.

RESULTS

Each of the three protein antigens produced strong reactions in enzyme-linked immunosorbent assays and Western blot analysis studies performed with convalescent COVID-19 patient sera. In mice, these combined protein vaccine candidates elicited high titer anti-P1, anti-P2, and anti-N IgG and IgG2a responses. These also induced highly neutralizing antibodies and elicited significant cell-mediated immunity as demonstrated by enhanced antigen-specific levels of interferon-γ (INF-γ) in the splenocytes of immunized mice.

CONCLUSION

The results of this study showed that formulations of the three proteins with Alum or Alum + MPLA are effective in terms of humoral and cellular responses. However, since the Alum + MPLA formulation appears to be superior in Th1 response, this vaccine candidate may be recommended mainly for the elderly and immunocompromised individuals. We also believe that the alum-only formulation will provide great benefits for adults, young adolescents, and children.

Shingrix for Herpes Zoster: A Review

Herpes zoster (HZ), also known as shingles, results from reactivation of the latent varicella-zoster virus (VZV), which commonly causes chickenpox in childhood. Greater than 90% of adults are infected with this virus, putting them at risk for reactivation. HZ presents as a painful, vesicular rash distributed in a unilateral and dermatomal pattern along dorsal root or cranial nerve ganglia. The rash often presents with prodromal symptoms and progresses to include clear vesicular clusters, evolving through stages of pustulation, ulceration, and crusting. HZ therapy currently involves the use of antiviral agents and pain management; however, HZ prophylaxis has been strongly recommended in older adults through vaccination with a live attenuated vaccine, Zostavax®. A new recombinant subunit vaccine, HZ/su (Shingrix®), is the subject of this review. In clinical trials, HZ/su demonstrated an overall vaccine efficacy of 97.2% among participants 50 years of age or older, indicating a significantly reduced risk of HZ in these individuals. Shingrix® was approved by the US FDA in October 2017 as HZ prophylaxis.

Vaccination of sows with a dendritic cell-targeted porcine epidemic diarrhea virus S1 protein-based candidate vaccine reduced viral shedding but exacerbated gross pathological lesions in suckling neonatal piglets

Porcine epidemic diarrhea virus (PEDV) poses a serious threat to swine worldwide as evidenced by its recent introduction into the USA and the devastating economic impact it caused to the USA swine industry. Commercial vaccines against PEDV are available but their efficacies are inadequate. Therefore, vaccines with improved efficacy are needed to effectively control PEDV infections. We previously determined the immunogenicity of a novel dendritic cell (DC)-targeted PEDV S1 protein-based subunit vaccine in weaned piglets in which the PEDV antigen was targeted to DCs through a porcine Langerin-specific antibody. In this study, we evaluated the protective efficacy of this DC-targeting vaccine by immunizing sows at 5 and 2 weeks prior to farrowing and by challenging the 5-day-old piglets with PEDV. The results showed that immunization of sow with DC-targeted PEDV vaccine did not eliminate faecal virus shedding in piglets but significantly reduced faecal viral RNA levels in the early days after virus challenge. The vaccine also reduced the amount of PEDV antigen in intestinal tissues presented with intestinal villi regrowth. However, the DC-targeted vaccine neither mitigated PEDV clinical signs nor affected viral RNA loads in intestinal tissues of piglets. In the vaccinated sow, DC-targeted PEDV vaccine enhanced T helper 1-like cluster of differentiation (CD)4 T cell responses and induced IgG but not IgA-specific immune responses. The suckling piglets in the DC-targeted vaccine group showed increased gross pathological lesions in the small intestine. Results in this study provide insights into the effects of sow cellular immune responses to PEDV infection in suckling piglets.

Safety and immunogenicity of an AS01-adjuvanted varicella-zoster virus subunit candidate vaccine against herpes zoster in adults >=50 years of age

BACKGROUND

An adjuvanted varicella-zoster virus glycoprotein E (gE) subunit vaccine candidate for herpes zoster is in development. In this trial we compared the safety, reactogenicity, and immunogenicity of the vaccine antigen combined with different adjuvant doses.

METHODS

This was a phase II, observer-blind, randomized, multinational study. Adults ≥50 years old were randomized 4:4:2:1 to be vaccinated at months 0 and 2 with gE combined with a higher (AS01B) or lower (AS01E) dose adjuvant, unadjuvanted gE, or saline. Following each dose, solicited events were recorded for 7 days and unsolicited adverse events for 30 days. Serious adverse events were collected for 1 year. Cell-mediated and humoral immune responses were assessed at baseline and following each dose.

RESULTS

No vaccine-related severe adverse events were reported. Solicited adverse events were generally mild to moderate and transient. For all gE-based vaccines, pain was the most common local symptom and fatigue the most common general symptom. Immune responses were significantly enhanced by AS01B and AS01E compared to unadjuvanted gE and were significantly stronger for gE/AS01B than for gE/AS01E.

CONCLUSIONS

AS01 improved the immunogenicity of gE while retaining acceptable safety and reactogenicity profiles. The enhancement of gE-specific cellular and humoral responses was adjuvant dose dependent.

CLINICAL TRIALS REGISTRATION

NCT00802464.

Plant-derived EpCAM antigen induces protective anti-cancer response

Immunotherapy holds great promise for treatment of infectious and malignant diseases and might help to prevent the occurrence and recurrence of cancer. We produced a plant-derived tumor-associated colorectal cancer antigen EpCAM (pGA733) at high yields using two modern plant expression systems. The full antigenic domain of EpCAM was efficiently purified to confirm its antigenic and immunogenic properties as compared to those of the antigen expressed in the baculovirus system (bGA733). Recombinant plant-derived antigen induced a humoral immune response in BALB/c mice. Sera from those mice efficiently inhibited the growth of SW948 colorectal carcinoma cells xenografted in nude mice, as compared to the EpCAM-specific mAb CO17-1A. Our results support the feasibility of producing anti-cancer recombinant vaccines using plant expression systems.

Protection conferred by recombinant Yersinia pestis antigens produced by a rapid and highly scalable plant expression system

Plague is still an endemic disease in different regions of the world. Increasing reports of incidence, the discovery of antibiotic resistance strains, and concern about a potential use of the causative bacteria Yersinia pestis as an agent of biological warfare have highlighted the need for a safe, efficacious, and rapidly producible vaccine. The use of F1 and V antigens and the derived protein fusion F1-V has shown great potential as a protective vaccine in animal studies. Plants have been extensively studied for the production of pharmaceutical proteins as an inexpensive and scalable alternative to common expression systems. In the current study the recombinant plague antigens F1, V, and fusion protein F1-V were produced by transient expression in Nicotiana benthamiana by using a deconstructed tobacco mosaic virus-based system that allowed very rapid and extremely high levels of expression. All of the plant-derived purified antigens, administered s.c. to guinea pigs, generated systemic immune responses and provided protection against an aerosol challenge of virulent Y. pestis.