Proofreading deficiencies of hepatitis B virus polymerase result in frequent DNA mutations in the hepatitis B virus genome. Here, we performed sequencing analysis of the hepatitis B virus polymerase gene to assess its association with the postoperative survival in 92 patients with HBV-related hepatocellular carcinoma by using the Kaplan–Meier method. The 2525, 2733, 2738, 2768, 2946, 3063, 3066, 3109, 31, 529, 735, 939, 1078, 1137, 1383, 1461, 1485, 1544, and 1613 mutation sites were identified as being associated with HCC outcomes by the log-rank test. After adjusting for clinical characteristics by using the Cox hazard model, site 31 (relative risk, 8.929; 95% confidence interval, 3.433–23.22; P = 0.000) in the spacer domain and sites 529 (relative risk, 5.656; 95% confidence interval, 1.599–19.999; P = 0.007) and 1078 (relative risk, 3.442; 95% confidence interval, 1.070–11.068; P = 0.038) in the reverse transcriptase domain of hepatitis B virus polymerase were identified as independent predictors of postoperative survival in hepatitis B virus related hepatocellular carcinoma. The mutations at the 31 (Ser314Pro), 529 (Asp480Asn), and 1078 (Ser663Ala) sites all resulted in amino acid changes in hepatitis B virus polymerase and were associated with shortened life-span. The 31 and 529 sites were located in the overlapping region for the PreS and S genes but did not induce amino acid substitution in these two regions. Our finding of the correlation between hepatitis B virus DNA polymerase mutations and hepatocellular carcinoma survival will help identify the patients subgroup with poor prognosis, and help the clinicians to refine the therapeutic decision individualized.

Herpes simplex virus type 1 (HSV-1), an α subgroup member of the human herpesvirus family, infects cells via the binding of its various envelope glycoproteins to cellular membrane receptors, one of which is herpes virus entry mediator (HVEM), expressed on dendritic cells. Here, HVEM gene-deficient mice were used to investigate the immunologic effect elicited by the HSV-1 infection of dendritic cells. Dendritic cells expressing the surface marker CD11c showed an abnormal biological phenotype, including the altered transcription of various immune signaling molecules and inflammatory factors associated with innate immunity after viral replication. Furthermore, the viral infection of dendritic cells interfered with dendritic cell function in the lymph nodes, where these cells normally play roles in activating the T-cell response. Additionally, the mild clinicopathological manifestations observed during the acute phase of HSV-1 infection were associated with viral replication in dendritic cells.

Objective: We constructed two DNA vaccines containing the receptor-binding domain (RBD) genes of multiple SARS-CoV-2 variants and used them in combination with inactivated vaccines in a variety of different protocols to explore potential novel immunization strategies against SARS-CoV-2 variants. Methods: Two DNA vaccine candidates with different signal peptides (namely, secreted and membrane signal peptides) and RBD protein genes of different SARS-CoV-2 strains (Wuhan-Hu-1, B.1.351, B.1.617.2, C.37) were used. Four different combinations of DNA and inactivated vaccines were tested, namely, Group A: three doses of DNA vaccine; B: three doses of DNA vaccine and one dose of inactivated vaccine; C: two doses of inactivated vaccine and one dose of DNA vaccine; and D: coadministration of DNA and inactivated vaccines in two doses. Subgroups were grouped according to the signal peptide used (subgroup 1 contained secreted signal peptides, and subgroup 2 contained membrane signal peptides). The in vitro expression of the DNA vaccines, the humoral and cellular immunity responses of the immunized mice, the immune cell population changes in local lymph nodes, and proinflammatory cytokine levels in serum samples were evaluated. Results: The antibody responses and cellular immunity in Group A were weak for all SARS-CoV-2 strains; for Group B, there was a great enhancement of neutralizing antibody (Nab) titers against the B.1.617.2 variant strain. Group C showed a significant increase in antibody responses (NAb titers against the Wuhan-Hu-1 strain were 768 and 1154 for Group C1 and Group C2, respectively, versus 576) and cellular immune responses, especially for variant B.1.617.2 (3240 (p < 0.001) and 2430 (p < 0.05) for Group C1 and Group C2, versus 450); Group D showed an improvement in immunogenicity. Group C induced higher levels of multiple cytokines. Conclusion: The DNA vaccine candidates we constructed, administered as boosters, could enhance the humoral and cellular immune responses of inactivated vaccines against COVID-19, especially for B.1.617.2.

HSV-2 (Herpes simplex virus type 2) is a critical viral agent that mainly causes genital herpes and life-long latent infection in the dorsal root ganglia. Gene modification via CRISPR/Cas9 Clustered regularly interspaced short palindromic repeat sequences/CRISPR associated 9) was used here to construct HSV-2 mutant strains through the deletion of fragments of the RL1 (Repeat Long element 1) and/or LAT (Latency-associated Transcript) genes. The HSV-2 mutant strains LAT-HSV-2 and RL1-LAT-HSV-2 present different biological properties. The proliferation of RL1-LAT-HSV-2 in nerve cells was decreased significantly, and the plaques induced by RL1-LAT-HSV-2 in Vero cells were smaller than those induced by LAT-HSV-2 mutant and wild-type strains. The observation of mice infected with these two mutants compared to mice infected with the wild-type strain indicated that the mutant RL1-LAT-HSV-2 has an attenuated phenotype with reduced pathogenicity during both acute and latent infections and induces a stronger specific immune response than the wild-type strain, whereas the attenuation effect was not found in mice infected with the LAT-HSV-2 mutant containing the LAT gene deletion. However, the simultaneous mutation of both the RL1 and LAT genes did not completely restrict viral proliferation in nerve cells, indicating that multiple HSV genes are involved in viral replication in the neural system. This work suggests that the HSV-2 genes RL1 and/or LAT might be involved in the virulence mechanisms in mouse infections.

The constant mutation of SARS-CoV-2 has led to the continuous appearance of viral variants and their pandemics and has improved the development of vaccines with a broad spectrum of antigens to curb the spread of the virus. The work described here suggested a novel vaccine with a virus-like structure (VLS) composed of combined mRNA and protein that is capable of stimulating the immune system in a manner similar to that of viral infection. This VLS vaccine is characterized by its ability to specifically target dendritic cells and/or macrophages through S1 protein recognition of the DC-SIGN receptor in cells, which leads to direct mRNA delivery to these innate immune cells for activation of robust immunity with a broad spectrum of neutralizing antibodies and immune protective capacity against variants. Research on its composition characteristics and structural features has suggested its druggability. Compared with the current mRNA vaccine, the VLS vaccine was identified as having no cytotoxicity at its effective application dosage, while the results of safety observations in animals revealed fewer adverse reactions during immunization.

Herpes simplex virus type 1 (HSV-1) is a very concerning pathogen due to its ability to persist in the host’s nervous system and continuously interfere with the immune system, which complicates treatment. Therefore, the development of an effective HSV-1 vaccine is crucial. In this study, we focused on an HSV-1 mutant strain, M6, which includes several deleted genes associated with viral infection virulence and latent infection function, and explored its infection of macrophages and immunological characteristics. The study found that both the attenuated strain M6 and the wild-type strain infect macrophages through the binding of the gD protein to the HVEM receptor on the macrophage surface. Compared to the wild-type strain, the attenuated M6 strain induced a milder immune response, characterized by the lower expression of immune signaling molecules and inflammatory cytokine levels. Upon reintroducing macrophages infected with the two strains into mice, the M6 strain induced lower levels of inflammatory cytokines and higher levels of chemokines in spleen cells and also slightly lower humoral and cellular immune responses than the wild-type strain. Further histopathological analysis revealed that mice in the attenuated M6 group showed more stable body weight changes and milder pathological damage in immune organs such as the liver, spleen, and lymph nodes. In conclusion, the attenuated M6 strain exhibits good immunogenicity and mild pathological side effects, suggesting its potential as an effective immunogen.