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Abstract Background Porcine parvovirus (PPV) usually causes reproductive failure in sows. The objective of the present study was to analyze the phylogenetic distribution and perform molecular characterization of PPVs isolated in China, as well as to identify two field strains, LZ and JY. The data used in this study contained the available sequences for NS1 and VP2 from GenBank, as well as the two aforementioned Chinese strains. Results Phylogenetic analysis shows that the PPV sequences are divided into four groups. The early Chinese PPV isolates are Group I viruses, and nearly all of the later Chinese PPV isolates are Group II viruses. LZ belongs to group II, whereas the JY strain is a Group III virus. This is the first report on the isolation of a Group III virus in China. The detection of selective pressures on the PPV genome shows that the NS1 and VP2 genes are under purifying selection and positive selection, respectively. Moreover, the amino acids in the VP2 capsid are highly variable because of the positive selection. Conclusions Our study provides new molecular data on PPV strains in China, and emphasizes the importance of etiological studies of PPV in pigs.

Abstract Background Foot-and-mouth disease (FMD) is a highly contagious disease of livestock which causes severe economic loss in cloven-hoofed animals. Vaccination is still a major strategy in developing countries to control FMD. Currently, inactivated vaccine of FMDV has been used in many countries with limited success and safety concerns. Development of a novel effective vaccine is must. Methods In the present study, two recombinant pseudotype baculoviruses, one expressing the capsid of foot-and-mouth disease virus (FMDV) under the control of a cytomegalovirus immediate early enhancer/promoter (CMV-IE), and the other the caspid plus a T-cell immunogen coding region under a CAG promoter were constructed, and their expression was characterized in mammalian cells. In addition, their immunogenicity in a mouse model was investigated. The humoral and cell-mediated immune responses induced by pseudotype baculovirus were compared with those of inactivated vaccine. Results Indirect immunofluorescence assay (IFA) and indirect sandwich-ELISA (IS-ELISA) showed both recombinant baculoviruses (with or without T-cell epitopes) were transduced efficiently and expressed target proteins in BHK-21 cells. In mice, intramuscular inoculation of recombinants with 1 × 109 or 1 × 1010 PFU/mouse induced the production of FMDV-specific neutralizing antibodies and gamma interferon (IFN-γ). Furthermore, recombinant baculovirus with T-cell epitopes had better immunogenicity than the recombinant without T-cell epitopes as demonstrated by significantly enhanced IFN-γ production (P < 0.01) and higher neutralizing antibody titer (P < 0.05). Although the inactivated vaccine produced the highest titer of neutralizing antibodies, a lower IFN-γ expression was observed compared to the two recombinant pseudotype baculoviruses. Conclusions These results indicate that pseudotype baculovirus-mediated gene delivery could be a alternative strategy to develop a new generation of vaccines against FMDV infection.

Abstract Background Porcine reproductive and respiratory syndrome virus (PRRSV) exhibits extensive genetic variation. The outbreak of a highly pathogenic PRRS in 2006 led us to investigate the extent of PRRSV genetic diversity in China. To this end, we analyzed the Nsp2 and ORF7 gene sequences of 98 Chinese PRRSV isolates. Results Preliminary analysis indicated that highly pathogenic PRRSV strains with a 30-amino acid deletion in the Nsp2 protein are the dominant viruses circulating in China. Further analysis based on ORF7 sequences revealed that all Chinese isolates were divided into 5 subgroups, and that the highly pathogenic PRRSVs were distantly related to the MLV or CH-1R vaccine, raising doubts about the efficacy of these vaccines. The ORF7 sequence data also showed no apparent associations between geographic or temporal origin and heterogeneity of PRRSV in China. Conclusion These findings enhance our knowledge of the genetic characteristics of Chinese PRRSV isolates, and may facilitate the development of effective strategies for monitoring and controlling PRRSV in China.

Experimental autoimmune encephalomyelitis (EAE) serves as a model for studying multiple sclerosis, with immunization strategies utilizing myelin oligodendrocyte glycoprotein (MOG) 35-55 peptide, emulsified in adjuvant enriched with Mycobacterium tuberculosis (Mtb). This study examined the effects of Bacillus Calmette-Guérin (BCG) as an adjuvant, alongside the impact of MOG 35-55 peptide doses and their residual counter ions on EAE development. We found that BCG can be effectively used to induce EAE with similar incidence and severity as heat-killed H37Ra, contingent upon the appropriate MOG 35-55 peptide dose. Different immunization doses of MOG 35-55 peptide significantly affect EAE development, with higher doses leading to a paradoxical reduction in disease activity, probably due to peripheral tolerance mechanisms. Furthermore, doses of MOG 35-55 peptides with acetate showed a more pronounced effect on disease development compared to those containing trifluoroacetic acid (TFA), suggesting the potential influence of residual counter ions on EAE activity. We highlighted the feasibility of applying BCG to the establishment of EAE for the first time. Our findings emphasized the importance of MOG 35-55 peptide dosage and composition in modulating EAE development, offering insights into the mechanisms of autoimmunity and tolerance. This could have implications for autoimmune disease research and the design of therapeutic strategies.