The African swine fever virus (ASFV) causes high mortality in domestic pigs. ASFV encodes an important protein target for subunit vaccine development, CD2v, but its most effective immunological regions are not known. Herein, we generated a monoclonal antibody (mAb) named IF3 by immunizing mice against the intracellular region of the CD2v protein (CD2v-IR). 1F3 specifically recognized CD2v, which is expressed transiently in transfected Sf9 cells and also in inactivated ASFV-infected porcine alveolar macrophage (PAM) cells. The epitope recognized by 1F3 is ²⁶⁴EPSPREP²⁷⁰, which is highly conserved in ASFV genotypes. Immunization of mice with this epitope elicited an increased IgG response, including IgG1 and IgG2a subtypes, and also increased CD8⁺ T cells and cytokine expression. Overall, these results indicate that this epitope induces both humoral and cellular immune responses that may be used for ASFV-related subunit vaccine design and development.

Streptococcus agalactiae is a major contagious pathogen of bovine mastitis and causes substantial economic losses in the dairy industry. In this study, a dual-readout RPA-PfAgo detection platform targeting the conserved cfb gene of S. agalactiae was established and optimized. Seven pairs of RPA primers were designed and screened to construct the Basic-RPA assay, and six guide DNAs (gDNAs) together with a specific probe were evaluated for PfAgo-assisted detection. Field validation was performed using 153 bovine milk samples collected from five dairy-farming regions in China, and assay performance was compared with bacteriological culture and a standardized quantitative PCR (qPCR) assay. The Basic-RPA assay achieved optimal amplification at 37 °C for 30 min, with a detection limit of 1 × 10⁻³ ng/µL and no cross-reactivity with non-target bacteria. The optimized RPA-PfAgo-RTF assay detected as few as 10 copies/µL, whereas the RPA-PfAgo-LFD assay detected 100 copies/µL, and both formats showed high analytical specificity. In field milk samples, bacteriological culture detected 21 positive samples, whereas standardized real-time PCR (qPCR), RPA-PfAgo-RTF, and RPA-PfAgo-LFD each detected 33 positive samples. When compared with bacteriological culture as a conventional comparator, all three molecular assays showed 100.00% positive agreement, 90.91% negative agreement, and a Kappa value of 0.733. In addition, RPA-PfAgo-RTF and RPA-PfAgo-LFD were completely concordant with the standardized qPCR assay across all 153 samples. These results indicate that the dual-readout RPA-PfAgo platform is a rapid and reliable molecular tool for detection of S. agalactiae in bovine milk.

The breeding of high-quality beef cattle breeds is crucial for the development of animal husbandry, and whole-genome resequencing is widely applicated in the field of molecular breeding. Advantages in growth and reproductive traits exist in Pinan cattle compared with other cattle breeds, but there is limited research on its genomic mechanism. Using whole-genome resequencing, the genetic structure and genomic selection signatures in Pinan cattle were investigated in this study. Phylogenetic, cluster, and admixture analysis results indicated that Pinan cattle have a closer genetic relationship with Kholmogory cattle and China north cattle breeds. Through a selective sweep strategy, 207 and 54 candidate genes related to growth and reproduction and immunity, respectively, were identified in the Pinan cattle population. Given the crucial role of the glutamate–cysteine ligase catalytic (GCLC) gene in muscle antioxidative defense, the high frequency of allele T of the GCLC c.429 C>T locus in the Pinan cattle population might partially contribute to the advantages of Pinan cattle in growth performance. This study laid the foundation for the genetic improvement in Chinese local beef cattle and provide background for the studies on the growth and development of Pinan cattle.