Virus-like particles in poultry disease: an approach to effective and safe vaccination.

The poultry industry, a cornerstone of global food security, faces dynamic challenges exacerbated by viral diseases. This review traces the trajectory of poultry vaccination, evolving from traditional methods to the forefront of innovation Virus-Like Particle (VLP) vaccines. Vaccination has been pivotal in disease control, but traditional vaccines exhibit some limitations. This review examines the emergence of VLPs as a game-changer in poultry vaccination. VLPs, mimicking viruses without replication, offer a safer, targeted alternative with enhanced immunogenicity. The narrative encompasses VLP design principles, production methods, immunogenicity, and efficacy against major poultry viruses. Challenges and prospects are explored, presenting VLP vaccines as a transformative technique in poultry disease control. Understanding their potential empowers industry stakeholders to navigate poultry health management with precision, promising improved welfare, reduced economic losses, and heightened food safety.

Construction and evaluation of a Salmonella Paratyphi A vaccine candidate based on a poxA gene mutation.

Salmonella Paratyphi A, the pathogen of paratyphoid A accounts for an obviously growing proportion of cases in many areas. Therefore, development of specific paratyphoid A vaccines is needed. In the present study, the poxA gene of Salmonella Paratyphi A, encoding the aminoacyl-tRNA synthetase, was deleted successfully by the method of lambda Red recombination system, the resulting strain, ΔpoxA was characterized in respect of growth, adhesion and invasion, virulence, immunogenicity and protective efficacy. It was found that the growth of the ΔpoxA strain was significantly delayed compared with the wild type strain, the mutant ΔpoxA was less invasive to Caco-2 BBE epithelioid cells and THP-1 macrophages than the wild type strain, strain ΔpoxA was attenuated at least 1000-fold in mice, significant immune response and efficient protection were provided by the mutant ΔpoxA after oral immunization. It is concluded that the Salmonella Paratyphi A poxA deletion mutant ΔpoxA can be used as a live oral vaccine candidate against paratyphoid A.

A randomized, active-controlled, multi-centric, phase-II clinical study to assess safety and immunogenicity of a fully liquid DTwP-HepB-IPV-Hib hexavalent vaccine (HEXASIIL®) in Indian toddlers.

BACKGROUND: Combination vaccines are effective in simplifying complex vaccination schedules involving multiple vaccines. A fully liquid hexavalent diphtheria (D)-tetanus (T)-whole-cell pertussis (wP)- hepatitis B (HepB)-inactivated poliovirus (IPV)-Haemophilus influenzae b (Hib) vaccine (HEXASIIL®), manufactured by Serum Institute of India Pvt. Ltd. was tested for safety and immunogenicity following booster vaccination. METHODS: This was a phase-II/III, open label, multicentric, controlled trial in toddlers (phase II) and infants (phase III) in India. This manuscript presents results of phase II. Healthy toddlers aged 12-24 months were randomized (1:1) to receive a 0.5 ml booster dose of HEXASIIL® or comparator Pentavac SD + Poliovac, intramuscularly and followed for 28 days for safety assessment. Blood samples were collected pre-vaccination and 28 days post-vaccination to assess immunogenicity. Descriptive summary statistics were provided for safety and immunogenecity analyses. RESULTS: A total of 223 subjects were randomized. One subject droped out prior to dosing, due to consent withdrawal. Thus, 222 subjects received study vaccine (110 HEXASIIL® and 112 comparator). Frequency of solicited adverse events was comparable between HEXASIIL® and comparator (85.5 % vs 90.2 %). Most local and systemic solicited AEs were mild to moderate in severity. All events resolved completely without any sequelae and none led to subject discontinuation. No vaccine related serious AE was reported. Post vaccination, seroprotection rates against tetanus, Hib and polio type 1 and 3 were 100 % in both the groups. Seroprotection rates for diphtheria (99.1 % vs 100 %) and polio type 2 (98.2 % vs 100 %) were observed in HEXASIIL® and comparator group, respectively. For Hepatitis B, seroprotection was >99 % in both groups. Seroconversion observed for Bordetella Pertussis (94.5 % vs 95.4 %) and Pertussis Toxin (77.1 % vs 87.2 %) in HEXASIIL® and comparator group, respectively. CONCLUSION: HEXASIIL® vaccine was found to be safe and immunogenic in toddlers and supported its further clinical development in infants. Clinical Trial Registration - CTRI/2019/11/022052.

In silico and in vitro evaluation of the immunogenic potential of Leishmania donovani ascorbate peroxidase and its derived peptides.

The control and eradication of any infectious disease is only possible with a potential vaccine, which has not been accomplished for human visceral leishmaniasis (VL). The lack of vaccines may increase the risk of VL outbreaks periodically in endemic zones. Identifying a reliable vaccine candidate for Leishmania is a major challenge. Here, we considered Leishmania donovani ascorbate peroxidase (LdAPx) for its in vitro evaluation with the hope of future vaccine candidates for VL. LdAPx was selected based on its unique presence in Leishmania and virulence in VL pathogenesis. Initially, we found antibodies against recombinant LdAPx (rLdAPx) in the serum of VL patients. Therefore, using bioinformatics, we predicted and selected ten (MHC class I and II) peptides. These peptides, evaluated in vitro with PBMCs from healthy, active VL, and treated VL individuals induced PBMC proliferation, IFN-γ secretion, and Nitric Oxide (NO) production, indicating host-protective immune responses. Among them, three peptides (PEP6, PEP8, and PEP9) consistently elicited a Th1-type immune response in PBMCs. Treated VL individuals showed a stronger Th1 response compared to active VL patients and healthy subjects, highlighting these peptides' potential as vaccine candidates. Further studies are on the way toward evaluating the LdAPx-derived peptides or sub-unit vaccine in animal models against the L. donovani challenge.

Biodegradable nanoplatforms for antigen delivery: part I - state of the art review of polymeric nanoparticles for cancer immunotherapy.

INTRODUCTION: Polymeric nanoparticles used for antigen delivery against infections and for cancer immunotherapy are an emerging therapeutic strategy in promoting the development of innovative vaccines. Beyond their capability to create targeted delivery systems with controlled release of payloads, biodegradable polymers are utilized for their ability to enhance the immunogenicity and stability of antigens. AREAS COVERED: This review extensively discusses the physicochemical parameters that affect the behavior of nanoparticles as antigen-delivery systems. Additionally, various types of natural and synthetic polymers and recent advancements in nanoparticle-based targeted vaccine production are reviewed. EXPERT OPINION: Biodegradable polymeric nanoparticles have gained major interest in the vaccination filed and have been extensively used to encapsulate antigens against a wide variety of tumors. Moreover, their versatility in terms of tunning their physicochemical characteristics, and their surface, facilitates the targeting to antigen presenting cells and enhances immune response.

Single and two-dose typhoid conjugate vaccine safety and immunogenicity in HIV-exposed uninfected and HIV-unexposed uninfected Malawian children.

Vaccine safety and immunogenicity data in human immunodeficiency virus (HIV)-exposed uninfected (HEU) children are important for decision-making in HIV and typhoid co-endemic countries. In an open-label study, we recruited Malawian HEU and HIV unexposed uninfected (HUU) infants aged 9 - 11 months. HEU participants were randomized to receive Vi-tetanus toxoid conjugate vaccine (Vi-TT) at 9 months, Vi-TT at 15 months, or Vi-TT at 9 and 15 months. HUU participants received Vi-TT at 9 and 15 months. Safety outcomes included solicited and unsolicited adverse events (AE) and serious AEs (SAEs) within 7 days, 28 days, and 6 months of vaccination, respectively. Serum was collected before and at day 28 after each vaccination to measure anti-Vi IgG antibodies by enzyme-linked immunosorbent assay (ELISA). Cohort 1 (66 participants) enrollment began 02 December 2019, and follow-up was terminated before completion due to the COVID-19 pandemic. Cohort 2 (100 participants) enrollment began 25 March 2020. Solicited AEs were mostly mild, with no significant differences between HEU and HUU participants or one- and two-dose groups. All six SAEs were unrelated to vaccination. Anti-Vi geometric mean titers (GMT) increased significantly from 4.1 to 4.6 ELISA units (EU)/mL at baseline to 2572.0 - 4117.6 EU/mL on day 28 post-vaccination, and similarly between HEU and HUU participants for both one- and two-dose schedules. All participants seroconverted (>4-fold increase in GMT) by the final study visit. Our findings of comparable safety and immunogenicity of Vi-TT in HUU and HEU children support country introductions with single-dose Vi-TT in HIV-endemic countries.

Adult indication 13-valent pneumococcal conjugate vaccine clinical development overview: formulation, safety, immunogenicity (dosing and sequence), coadministration, and efficacy.

INTRODUCTION: There was no 13-valent pneumococcal conjugate vaccine (PCV13) adult antibody concentration threshold regulatory criterion for licensure - unlike the pediatric indication; consequently, for the adult indication, PCV13 serotype-specific opsonophagocytic activity (OPA) geometric mean titer (GMT) values were immunobridged to the 23-valent plain polysaccharide vaccine (PPV23) to infer efficacy against invasive pneumococcal disease (IPD). Subsequently, a double-blind, randomized, controlled PCV13 efficacy trial (CAPiTA) was performed in community-living, older adults to confirm efficacy against vaccine-serotype IPD (VT-IPD) and establish efficacy against vaccine-serotype pneumococcal community-acquired pneumonia (VT-CAP). AREAS COVERED: This article summarizes 31 publications from the PCV13 adult indication clinical development trials and other PCV13 clinical studies, organized by formulation, reactogenicity and safety, immunogenicity, coadministration, and clinical efficacy. EXPERT OPINION: PCV13 had a favorable safety profile with an OPA response generally greater than PPV23 irrespective of age and of previous pneumococcal vaccination. PCV13 primed for enhanced immune responses with subsequent PCV13 or PPV23 dosing. Conversely, PPV23 was shown to blunt the response to subsequent PCV13. CAPiTA demonstrated PCV13 efficacy for at least five years against both VT-IPD and VT-CAP. The PCV13 clinical development program provided fundamental insights into this vaccine's adult-specific immune responses and confirmed the advantages of conjugate over plain polysaccharide technology.

Unraveling devitalization: its impact on immune response and ectopic bone remodeling from autologous and allogeneic callus mimics.

Endochondral bone regeneration is a promising approach in regenerative medicine. Callus mimics (CMs) are engineered and remodeled into bone tissue upon implantation. The long-term objective is to fabricate a sustainable off-the-shelf treatment option for patients. Devitalization was introduced to facilitate storage and using allogeneic (donor) cells would further propel the off-the-shelf approach. However, allogeneic CMs for bone regeneration pose a potential antigenicity concern. Here, we explored the impact of devitalization on antigenicity and osteoinductive bone formation when implanting syngeneic or allogeneic CM in a vital or devitalized state. For this, we implanted chondrogenically differentiated rat-derived mesenchymal stromal cells using an allogeneic immunocompetent ectopic rat model. Vital syngeneic CMs demonstrated the highest bone formation, and vital allogeneic CMs showed the lowest bone formation, while both devitalized CMs showed comparable intermediate levels of bone formation. Preceding bone formation, the level of tartrate-resistant acid phosphatase staining at 7 and 14 days was proportional to the level of eventual bone formation. No differences were observed for local innate immune responses at any time point before or after bone formation. In contrast, allogeneic CMs elicit a mild adaptive immune response, which still permits bone formation in an immunocompetent environment, albeit at a reduced rate compared to the autologous living counterpart. Overall, devitalization delays bone formation when autologous CMs are implanted, whereas it accelerates bone formation in allogeneic CMs, highlighting the potential of this approach for achieving off-the-shelf treatment.

Evaluation of virulence of Aeromonas veronii strain GZ21-2 and development of a highly effective vaccine for grass carp with the potential for industrial application.

Bacterial septicemia represents a significant disease affecting cultured grass carp culture, with the primary etiological agent identified as the Gram-negative bacterium Aeromonas veronii. In response to an outbreak of septicemia in Guangzhou, we developed a formaldehyde-inactivated vaccine against an A. veronii strain designated AV-GZ21-2. This strain exhibited high pathogenicity in experimental infections across at all developmental stages of grass carp. Mortality rates for grass carp weighing 15 ± 5 g ranged from 16 % to 92 % at exposure temperatures of 19 °C-34 °C, respectively. The median lethal dose (LD50) for grass carp groups weighing 15 ± 5 g, 60 ± 10 g, 150 ± 30 g and 500 ± 50 g were determined to be 1.43, 2.52, 4.65 and 7.12 × 107(CFU/mL), respectively. We investigated the inactivated vaccine in conbination with aluminum hydroxide gel (AV-AHG), Montanide ISA201VG (AV-201VG), and white oil (AV-WO) adjuvants. This study aimed to optimize inactivation conditions and identify the adjuvant that elicits the most robust immune response. The AV-GZ21-2 inactivated bacterial solution (AV),when combined with various adjuvants, was capable of inducing a strong specific immune response in grass carp. The relative percent survival (RPS) following a lethal challenge with AV-GZ21-2 were 94 % for AV-AHG, 88 % for AV-201VG, 84 % for AV-WO and 78 % for AV alone. The minimum immunization dose of the AV-AHG vaccine was determined to be 6.0 × 107 CFU per fish, providing immunity for a duration of six months with an immune protection level exceeding 75 %. Furthermore, the AV-AHG vaccine demonstrated significant protective efficacy against various epidemic isolates of A. veronii. Consequently, we developed an inactivated vaccine targeting a highly pathogenic strain of A. veronii, incorporating an aluminum hydroxide gel adjuvant, which resulted in high immune protection and a duration of immunity exceeding six months. These findings suggest that the AV-AHG vaccine holds substantial potential for industrial application.

Low Immunogenicity of Keratinocytes Derived from Human Embryonic Stem Cells.

Epidermal transplantation is a common and widely used surgical technique in clinical medicine. Derivatives of embryonic stem cells have the potential to serve as a source of transplantable cells. However, allograft rejection is one of the main challenges. To investigate the immunogenicity of keratinocytes derived from human embryonic stem cells (ESKCs), we conducted a series of in vivo and in vitro experiments. The results showed that ESKCs have low HLA molecule expression, limited antigen presentation capabilities, and a weak ability to stimulate the proliferation and secretion of inflammatory factors in allogeneic PBMCs in vitro. In humanized immune mouse models, ESKCs elicited weak transplant rejection responses in the host. Overall, we found that ESKCs have low immunogenicity and may have potential applications in the field of regenerative medicine.

Comparing the immunogenicity of COVID-19 infection and vaccination in pregnant women as measured by anti-S IgG.

BACKGROUND: Pregnancy is a critical time for women, making them more susceptible to infectious diseases like COVID-19. This study aims to determine the immunogenicity of COVID-19 in pregnant women who have been infected compared to those who have received the inactive COVID-19 vaccine. MATERIALS AND METHODS: In this retrospective cohort study, pregnant women who received the inactivated COVID-19 vaccine (Sinopharm) and those with a history of COVID-19 infection during pregnancy were studied. Participants who had experienced stillbirth, received different COVID-19 vaccines, or had intrauterine fetal death were excluded from the study. Overall, the study included 140 participants. The participants were divided into two groups of 70 participants - pregnant women who received the Sinopharm vaccine and pregnant women who had COVID-19 infection during pregnancy. Before delivery, blood samples were collected from all mothers to evaluate the maternal immunoglobulin G (IgG) level. Blood samples were also taken from the baby's umbilical cord during delivery to measure the newborn's IgG level. Additionally, blood samples were collected from babies whose mothers showed signs of acute infection to measure their IgM levels and evaluate vertical transmission. FINDINGS: The study found a significant relationship between the mean level of maternal IgG and umbilical cord IgG within the groups (P < 0.001). The highest levels of maternal IgG (2.50 ± 2.17) and umbilical cord IgG (2.43 ± 2.09) were observed in pregnant women with a previous COVID-19 infection and no history of vaccination (P < 0.001). Only one baby was born with a positive IgM, and this baby was born to a mother who showed signs of COVID-19 infection in the last five days of pregnancy. The mother was 28 years old, with a BMI of 33; it was her first pregnancy, and she gave birth to a male newborn at term. CONCLUSION: Administering an inactivated vaccine during pregnancy can generate immunity in both the mother and the child. However, the vaccine's immunity level may not be as potent as that conferred by COVID-19 infection during pregnancy. Nonetheless, the risk of vertical transmission of COVID-19 is considered minimal and can be classified as negligible.

Hepatitis a vaccine immunogenicity and boostability in adults receiving immunosuppressive therapy and adults living with HIV: a prospective single-Centre cohort study.

INTRODUCTION: Hepatitis A (hepA) vaccination is highly immunogenic in healthy individuals, however there is uncertainty about the immunogenicity in immunocompromised populations (ICPs). METHODS: In this prospective cohort study, people living with HIV (PLWH), patients on immunosuppressive mono- and combination therapy, and controls received two hepA vaccine doses at months 0 and 6-12, or three combined hepA/B vaccine doses at months 0, 1 and 6-12. Antibody levels were measured before and at different time-points post-vaccination (T2, 6, 8, 12 months). The primary endpoint was the seroconversion rate (SCR) at T8, defined as hepA antibodies ≥20 mIU/ml. To assess boostability, an additional vaccine dose was administered 1-5 years after T12 in those with antibodies < 50 mIU/ml, with antibody measurements before and seven days after the booster dose. RESULTS: We included 150 participants. At T2 SCRs ranged between 35-58% in ICPs versus 94% in controls. Among PLWH, patients on monotherapy, combination therapy and controls SCRs at T8 were 33/34 (97%), 32/34 (94%), 25/30 (83%) and 28/28 (100%) respectively. The booster dose resulted in 71% additional seroconversion (17/24), with only patients using combination therapy not responding. CONCLUSIONS: HepA vaccination is highly immunogenic in virologically suppressed PLWH and patients on immunosuppressive monotherapy, with SCRs after the complete hepA vaccination schedule similar to controls and adequate booster responses in case of waning immunity. However, patients using immunosuppressive combination therapy as well as all ICPs who did not receive the complete hepA vaccination schedule, are at risk of non-response to vaccination and post-vaccination antibody measurements are recommended.

Delivery of SARS-CoV-2 spike and membrane genes in a single Baculoviral vector enhance the immune breadth against SARS-CoV-2 variants of concern.

Although the coronavirus pandemic has ended, new variants of concern (VOCs) continue to emerge. Therefore, novel vaccines targeting VOCs are highly warranted. We initially constructed three recombinant baculovirus-vectored vaccines (AcHERV-COVID19S) carrying the spike genes of the SARS-CoV-2 prototype, Delta, and Omicron BA.1 variants. However, the SARS-CoV-2 spike gene alone could not provide protection against multiple VOCs. To develop a universal vaccine, we constructed a recombinant baculovirus-vectored vaccine (AcHERV-COVID19 OmiM) by introducing the M gene, which is conserved among VOCs, as a secondary cellular immune antigen in addition to the S gene. AcHERV-COVID19 OmiM could provide higher protection against SARS-CoV-2 variants (prototype, Delta, BA.5 and XBB.1) compared with that of AcHERV-COVID19S. The membrane protein of SARS-CoV-2 synergizes with the S gene, thereby enhancing both humoral and cellular immunity against VOCs. Although AcHERV-COVID19 OmiM may not provide sterile protection against new variants, it may help reduce symptoms and curb viral transmission.

Phase 1 trial of an investigational Tdap booster vaccine with CpG 1018 adjuvant compared with Boostrix in healthy adults and adolescents.

This phase 1 trial assessed the safety and immunogenicity of an investigational tetanus/diphtheria/acellular pertussis vaccine combined with CpG 1018 adjuvant 1500 µg (Tdap-1018 1500 µg) or 3000 µg (Tdap-1018 3000 µg) in adults and adolescents. In this randomized, active-controlled, multicenter, dose-escalation trial, healthy participants aged 10 to 22 years received 1 dose of Tdap-1018 1500 µg, Tdap-1018 3000 µg, or Boostrix. Geometric mean concentrations (GMCs) and booster response rates (BRRs) for antibodies against pertussis (pertussis toxin, filamentous hemagglutinin, pertactin), tetanus, and diphtheria antigens, and neutralizing antibodies against pertussis toxin were assessed 4 weeks after vaccination. Safety and tolerability were assessed for solicited post-injection reactions within 7 days after vaccination and unsolicited adverse events up to 12 weeks after vaccination. Of 117 enrolled participants, 80 adults (92%) and 30 adolescents (100%) completed the study. Both Tdap-1018 formulations were generally well tolerated, with no vaccine-related serious adverse events. Frequency and severity in post-injection reactions after Tdap-1018 administration were similar to Boostrix except for higher proportions of moderate pain for Tdap-1018. In adults at week 4, ratio of GMCs and BRRs for all antigens in the 3000-µg group were similar to or higher than Boostrix, with significantly higher GMC ratios for anti-pertussis toxin (2.1 [1.5-3.0]) and anti-tetanus (1.8 [1.1-2.9]) and significantly higher BRRs for anti-pertussis toxin (difference [95% CI]: 34.5% [13.4-54.6]), anti-pertactin (19.2% [4.4-38.1]), and anti-tetanus (30.0% [3.6-52.7]) antibodies. For adolescents, in the 3000-µg group, ratio of GMCs and BRRs were similar to or higher than Boostrix for all antigens. Both Tdap-1018 formulations showed acceptable safety and tolerability profiles. Tdap-1018 3000 µg induced similar or higher immune responses than Boostrix. ACTRN12620001177943 (Australian New Zealand Clinical Trials Registry; https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=ACTRN12620001177943p).

The use of controlled human infection models to identify correlates of protection for invasive Salmonella vaccines.

Controlled human infection model (CHIM) studies, which involve deliberate exposure of healthy human volunteers to an infectious agent, are recognised as important tools to advance vaccine development. These studies not only facilitate estimates of vaccine efficacy, but also offer an experimental approach to study disease pathogenesis and profile vaccine immunogenicity in a controlled environment, allowing correlation with clinical outcomes. Consequently, the data from CHIMs can be used to identify immunological correlates of protection (CoP), which can help accelerate vaccine development. In the case of invasive Salmonella infections, vaccination offers a potential instrument to prevent disease. Invasive Salmonella disease, caused by the enteric fever pathogens Salmonella enterica serovar Typhi (S. Typhi) and S. Paratyphi A, B and C, and nontyphoidal Salmonella (iNTS), remains a significant cause of mortality and morbidity in low- and middle-income countries, resulting in over 200,000 deaths and the loss of 15 million DALYs annually. CHIM studies have contributed to the understanding of S. Typhi infection and provided invaluable insight into the development of vaccines and CoP following vaccination against S. Typhi. However, CoP are less well understood for S. Paratyphi A and iNTS. This brief review focuses on the contribution of vaccine-CHIM trials to our understanding of the immune mechanisms associated with protection following vaccines against invasive Salmonella pathogens, particularly in relation to CoP.

Safety and immunogenicity of an mRNA-based RSV vaccine in Japanese older adults aged ≥60 years: A phase 1, randomized, observer-blind, placebo-controlled trial.

BACKGROUND: Respiratory syncytial virus (RSV) represents a global health concern, including in older adults. This study assessed the safety and immunogenicity of mRNA-1345, an investigational mRNA RSV vaccine, in adults aged ≥60 years of Japanese descent. METHODS: In this phase 1, randomized, observer-blind, placebo-controlled study, participants were randomized to receive one injection of mRNA-1345 100 µg or placebo. Solicited local and systemic adverse reactions (ARs) were collected within 7 days following injection. Unsolicited adverse events (AEs) were collected up to 28 days after injection; AEs of special interest, medically attended AEs, and serious AEs were collected through end of study. Immunogenicity was assessed at baseline and months 1, 2, 3, and 6 following injection. RESULTS: Twenty-five adults of Japanese descent aged ≥60 years received one injection of mRNA-1345 100 µg (n = 21) or placebo (n = 4). mRNA-1345 was well-tolerated; the most common local and systemic solicited ARs were injection site pain, and fatigue and myalgia, respectively, which were generally mild to moderate and transient. No serious AEs were reported. Neutralizing (nAb) and binding (bAb) antibodies were detectable at baseline, consistent with prior RSV exposure. mRNA-1345 boosted RSV nAb titers and preF bAb concentrations 1 month post-injection (geometric mean fold rise: RSV-A nAb, 11.2; RSV-B nAb, 6.6; preF bAb, 9.1). Titers among mRNA-1345 recipients remained above baseline through 6 months. CONCLUSIONS: mRNA-1345 100 µg was well-tolerated among older adults of Japanese descent and induced nAbs and bAbs which were durable through 6 months, supporting its continued development. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04528719.

A recombinant pseudorabies virus surface - displaying the classical swine fever E2 protein induces specific antibodies rapidly.

Pseudorabies virus (PRV) and classical swine fever virus (CSFV) are both economically important pathogens threatening the pig industry in many countries. The triple-gene-deleted variant of PRV, herein referred to as rPRVTJ-delgE/gI/TK, has exhibited pronounced efficacy and safety profiles. This underscores its viability as a prospective vaccine vector. However, the generation of specific anti-E2 antibodies necessitates elevated immunization doses and extended durations when the extracellular domain of the E2 protein of CSFV is secreted via the recombinant rPRVTJ-delgE/gI/TK vector. To enhance the presentation of exogenous antigens by antigen-presenting cells (APCs), we engineered the E2 protein expressed on the surface of PRV particles in this study. The recombinant virus expressing the E2 protein with a heterogonous transmembrane domain was generated in the backbone of rPRVTJ-delgE/gI/TK and designated as rPRVTJ-UL44-E2. The E2 gene was fused to the 3' terminus of the UL44 gene utilizing P2A, a self-cleaving peptide sequence. The electron microscopy showed that the E2 protein was anchored on the surface of the viral particles of rPRVTJ-delgE/gI/TK-E2. The insertion of the E2 gene did not alter the native biological characteristics of the viral vector. Rabbits immunized with 107 median tissue culture infective doses (TCID50) of rPRVTJ-UL44-E2 exhibited a rapid seroconversion to anti-E2 specific antibodies within 7 days post-immunization (dpi). All the rabbits immunized with the rPRVTJ-UL44-E2 had generated antibodies specific to E2 prior to the administration of the booster immunization. However, the immunized rabbits were not protected from the CSFV C-strain challenge. Nevertheless, this strategy has notably achieved rapid induction of E2-specific non-neutralizing antibodies. These findings provide insights that the design of rPRVTJ-UL44-E2 requires optimization, thereby indicating a promising avenue for augmenting vaccine-induced immune responses.

A Randomized, Double-Blind, Parallel-Group Phase I Study Comparing the Pharmacokinetics, Safety, and Immunogenicity of CMAB015, a Candidate Secukinumab Biosimilar, with Its Reference Product Cosentyx® in Healthy Chinese Male Subjects.

Purpose: Secukinumab, a monoclonal antibody targeting interleukin (IL)-17A, is approved for the treatment of psoriasis, psoriatic arthritis, ankylosing spondylitis, non-radiographic axial spondyloarthritis, enthesitis-related arthritis, and hidradenitis suppurativa. This study compared the pharmacokinetics (PK), safety, and immunogenicity of CMAB015, a candidate secukinumab biosimilar, with the reference product secukinumab (Cosentyx®) in healthy Chinese male subjects. Patients and methods: This double-blind, parallel-group study randomized healthy Chinese male subjects (N=130) to receive either a single dose of 150 mg CMAB015 or secukinumab subcutaneously. Primary study endpoints were PK parameters such as the maximum concentration (Cmax) and area under the curve from zero to infinity (AUC0-inf), while safety and immunogenicity were secondary endpoints. Results: The 90% confidence intervals (CIs) of the geometric mean ratios (GMRs) of Cmax and AUC0-inf for CMAB015 to secukinumab were all within the bioequivalence limits (80.00-125.00%). Other PK parameters were comparable between the groups. The safety profile of CMAB015 was similar to that of secukinumab, with no serious adverse events related to treatment. The incidence of TEAEs was slightly higher in the CMAB015 group, but these events were mild to moderate in severity and did not lead to any withdrawals from the study. Immunogenicity analysis revealed low rates of anti-drug antibody (ADA) positivity, with similar rates between CMAB015 and secukinumab. Conclusion: This study demonstrated equivalent PK, comparable safety, and immunogenicity of CMAB015 to secukinumab in healthy Chinese male subjects. These findings support further clinical evaluation of CMAB015 as a secukinumab biosimilar. Trial Registration: The trial was registered on Clinicaltrials.gov (Identifier No. NCT05734482) and Chinadrugtrials.org.cn (Identifier No. CTR20230105).

New Ustekinumab Biosimilar Candidate FYB202: Pharmacokinetic Equivalence Demonstrated in a Randomized, Double-Blind, Parallel-Group, Single-Dose Trial in Healthy Subjects.

In the RUSTIC trial, pharmacokinetic (PK) similarity between the proposed ustekinumab biosimilar FYB202 and EU-approved (EU-Ref) and US-licensed ustekinumab (US-Ref) as well as between both reference drugs was assessed after a single 45-mg subcutaneous injection. Safety analyses comprised immunogenicity (antidrug antibodies, neutralizing antibodies), adverse events, and local tolerability. Overall, 491 healthy adults were randomized 1:1:1 and observed for up to 112 days; 486 completed the trial, and 478 were included in the PK analysis. All 3 comparisons showed PK similarity, since the 90% confidence intervals of the respective geometric mean ratios for area under the concentration-time curve from time 0 to infinity and maximum serum concentration were contained within the acceptance interval of 80%-125%. No clinically meaningful differences regarding overall safety, immunogenicity, and local tolerability were observed. Notably, after FYB202 administration, in fewer subjects at least 1 positive antidrug antibody result was observed compared to the reference groups (FYB202, 20%; EU-Ref, 42%; US-Ref, 51%). In conclusion, the RUSTIC trial demonstrated equivalent PK characteristics for FYB202 when compared to both EU-Ref and US-Ref ustekinumab and between both reference drugs. It provides the basis for the marketing authorization of FYB202, together with an extensive analytical characterization and the results of a confirmatory efficacy and safety trial in patients with moderate to severe plaque psoriasis.