Avian influenza viruses (AIV) are a continuous cause of concern due to their pandemic potential and devasting effects on poultry, birds, and human health. The low pathogenic avian influenza virus has the potential to evolve into a highly pathogenic avian influenza virus, resulting in its rapid spread and significant outbreaks in poultry. Over the years, a wide array of traditional and novel strategies has been implemented to prevent the transmission of AIV in poultry. Mass vaccination is still an economical and effective approach to establish immune protection against clinical virus infection. At present, some AIV vaccines have been licensed for large-scale production and use in the poultry industry; however, other new types of AIV vaccines are currently under research and development. In this review, we assess the recent progress surrounding the various types of AIV vaccines, which are based on the classical and next-generation platforms. Additionally, the delivery systems for nucleic acid vaccines are discussed, since these vaccines have attracted significant attention following their significant role in the fight against COVID-19. We also provide a general introduction to the dendritic targeting strategy, which can be used to enhance the immune efficiency of AIV vaccines. This review may be beneficial for the avian influenza research community, providing ideas for the design and development of new AIV vaccines.

Low performance of actively targeted nanomedicines required revision of the traditional drug targeting paradigm and stimulated the development of novel phage-programmed, self-navigating drug delivery vehicles. In the proposed smart vehicles, targeting peptides, selected from phage libraries using traditional principles of affinity selection, are substituted for phage proteins discovered through combinatorial avidity selection. Here, we substantiate the potential of combinatorial avidity selection using landscape phage in the discovery of Short Linear Motifs (SLiMs) and their partner domains. We proved an algorithm for analysis of phage populations evolved through multistage screening of landscape phage libraries against the MDA-MB-231 breast cancer cell line. The suggested combinatorial avidity selection model proposes a multistage accumulation of Elementary Binding Units (EBU), or Core Motifs (CorMs), in landscape phage fusion peptides, serving as evolutionary initiators for formation of SLiMs. Combinatorial selection has the potential to harness directed molecular evolution to create novel smart materials with diverse novel, emergent properties.

Salmonella remains a major pathogen in poultry production, posing significant threats to animal health and food safety. In this study, two representative isolates, Salmonella enterica serovar Enteritidis (SA03) and serovar Pullorum (SA406), were selected from multiple isolates recovered from a diseased poultry farm, as predominant serovars identified in the same production environment, for further characterization. Phenotypic identification, antimicrobial susceptibility testing, whole-genome sequencing, and in vivo virulence assessment were performed to provide an integrated genotype–phenotype comparison. Both isolates exhibited typical Salmonella characteristics, with SA03 displaying faster growth kinetics than SA406 under tested conditions. Whole-genome sequencing revealed that both isolates harbored a diverse repertoire of antimicrobial resistance (AMR) genes and virulence-associated genes. Notably, SA03 carried a broader range of AMR genes, including bla TEM-1B, aac (6′)-Iaa, and sul2 , whereas SA406 exhibited a relatively narrower resistance gene profile. A total of 344 and 340 virulence-associated genes were identified in SA03 and SA406, respectively, with both strains harboring genes related to type III secretion systems and adhesion. Phenotypic antimicrobial susceptibility testing showed partial inconsistencies with genomic predictions. Despite this, in vivo virulence was evaluated using specific-pathogen-free (SPF) chickens, revealing LD ₅₀ values of 10 ^7.8 CFU for SA03 and 10 ^8.5 CFU for SA406, indicating higher virulence of SA03. This inconsistency suggests that virulence potential may not be directly determined by gene abundance alone. Overall, this study provides an integrated characterization of representative Salmonella isolates co-circulating in a poultry farm and highlights the complexity of linking genomic features with phenotypic traits.

Background/Objectives: Targeted delivery of antigens to dendritic cells (DCs) is an effective strategy for enhancing vaccine efficacy. Methods: In this study, dual-targeting fusion proteins (GRFT-VHH54 and GRFT-VHH74) were constructed by fusing Griffithsin (GRFT), an algae-derived lectin with enveloped virus-binding properties, to DC-specific binding nanobodies (VHH54 and VHH74). Vaccines were formulated by combining the inactivated H9N2 avian influenza virus with these fusion proteins, and the potential of the fusion proteins to enhance vaccine-induced immunity in chickens was systematically evaluated. For parallel comparison, control groups included H9N2 avian influenza vaccines containing the inactivated virus alone, the inactivated virus with the immune enhancer CVCVA5, and a commercial H9N2 avian influenza inactivated vaccine. Results: At 4 weeks post-immunization, chickens vaccinated with the inactivated H9N2 virus combined with the GRFT-VHH74 fusion protein (1/2 H9+GRFT-VHH74) exhibited significantly enhanced humoral, mucosal, and cellular immune responses compared to those vaccinated with the inactivated H9N2 virus alone or the commercial H9N2 vaccine (p < 0.05). Additionally, chickens in the 1/2 H9+GRFT-VHH74 group exhibited enhanced resistance to the heterologous H9N2 subtype avian influenza virus, achieving a 90% protection rate, which was higher than that of the other groups. Conclusions: These results indicate that the GRFT-VHH74 fusion protein has significant potential for advancing the development of inactivated vaccines against the H9N2 subtype avian influenza. Furthermore, it provides valuable insights for enhancing the immunogenicity and efficacy of inactivated vaccines targeting other avian influenza subtypes.