Molecular epidemiology of hepatitis B, hepatitis C, and HIV-1 co-infections in Ethiopia: Implications for disease burden and intervention strategies.

BACKGROUND: Hepatitis B virus (HBV) exhibits high prevalence rates within Ethiopia. The genetic diversity of HBV, marked by mixed genotype infections, may hold significant implications for the trajectory of disease and responses to treatment. Ethiopia grapples with a substantial public health challenge posed by co-infections involving HBV, hepatitis C virus (HCV), and human immunodeficiency virus 1 (HIV-1), particularly among vulnerable populations. METHODS: A comprehensive investigation into HBV, HCV, and HIV-1 co-infection was conducted. A total of 7,789 blood samples were meticulously analyzed, among which 815 exhibited HBV positivity. Among the HBV-positive samples, 630 were subjected to genotyping procedures, resulting in the identification of a prevalent trend of mixed infections characterized by HBV genotypes A/E/F (67.30%). Serological assessments were performed on 492 specimens to ascertain the presence of HCV and HIV-1 co-infections, revealing respective co-infection rates of 13.02% for HBV/HIV, 3.31% for HBV/HCV, and 2.07% for triple infection. RESULTS: The investigation revealed the intricate prevalence of co-infections in Ethiopia, notably underlining the continued transmission of viruses. The prominent occurrence of mixed HBV genotypes A/E/F suggests dynamic viral interactions and ongoing transmission pathways. These findings accentuate the necessity for targeted interventions and enhanced patient care, as co-infections carry significant clinical complexities. CONCLUSIONS: This study furnishes crucial insights into the molecular epidemiology of HBV, HCV, and HIV-1 co-infections in Ethiopia. The acquired knowledge can contribute to the advancement of strategies for clinical management and the formulation of public health interventions aimed at ameliorating the burden of viral infections within the nation.

Eradicating mesothelin-positive human gastric and pancreatic tumors in xenograft models with optimized anti-mesothelin antibody-drug conjugates from synthetic antibody libraries.

Mesothelin (MSLN) is an attractive candidate of targeted therapy for several cancers, and hence there are increasing needs to develop MSLN-targeting strategies for cancer therapeutics. Antibody-drug conjugates (ADCs) targeting MSLN have been demonstrated to be a viable strategy in treating MSLN-positive cancers. However, developing antibodies as targeting modules in ADCs for toxic payload delivery to the tumor site but not to normal tissues is not a straightforward task with many potential hurdles. In this work, we established a high throughput engineering platform to develop and optimize anti-MSLN ADCs by characterizing more than 300 scFv CDR-variants and more than 50 IgG CDR-variants of a parent anti-MSLN antibody as candidates for ADCs. The results indicate that only a small portion of the complementarity determining region (CDR) residues are indispensable in the MSLN-specific targeting. Also, the enhancement of the hydrophilicity of the rest of the CDR residues could drastically increase the overall solubility of the optimized anti-MSLN antibodies, and thus substantially improve the efficacies of the ADCs in treating human gastric and pancreatic tumor xenograft models in mice. We demonstrated that the in vivo treatments with the optimized ADCs resulted in almost complete eradication of the xenograft tumors at the treatment endpoints, without detectable off-target toxicity because of the ADCs' high specificity targeting the cell surface tumor-associated MSLN. The technological platform can be applied to optimize the antibody sequences for more effective targeting modules of ADCs, even when the candidate antibodies are not necessarily feasible for the ADC development due to the antibodies' inferior solubility or affinity/specificity to the target antigen.

Endoplasmic reticulum-targeting sequence enhanced the cellular immunity of a tumor-associated antigen L6-based DNA vaccine.

Cancer vaccine design to effectively eliminate tumors requires triggering strong immune reactions to elicit long-lasting humoral and cellular immunity and DNA vaccines have been demonstrated to be an attractive immunotherapeutic approach. The tumor-associated antigen L6 (TAL6) is overexpressed on the surface of different cancer cells and promotes cancer progression; therefore, it could be a potential target for cancer treatment. We have revealed that a synthetic peptide containing HLA-A2-restricted cytotoxic T lymphocyte (CTL) and B cell epitope can induce cellular and humoral immunity against TAL6-expressing cancer. To enhance the efficacy of immunotherapy, in this report, we designed an endoplasmic reticulum (ER)-targeting sequence (adenovirus E3/19K protein) at the N-terminus of TAL6 to facilitate MHC class I antigen presentation to CD8+ T cells. Transfection of mammalian cells with the plasmid containing TAL6 fused with the ER-targeting sequence (pEKL6) resulted in higher levels of TAL6 antigens in the ER than transfection with the full-length TAL6 (pL6). The plasmid pEKL6 induced both TAL6-specific CTL responses and antibody titers after intramuscular (IM) immunization with electroporation and it elicited higher levels of antigen-specific CTLs in HLA-A2 transgenic mice. Immunization with pEKL6 induced higher levels of protective antitumor immunity against tumor growth than pL6 immunization in thymoma and melanoma tumor animal models. Notably, pEKL6 elicited long-term anti-tumor immunity against the recurrence of cancers. We found that CD4+ T, CD8+ T, and NK cells are all important for the effector mechanisms of pEKL6 immunization. Thus, cancer therapy using an ER-targeting sequence linked to a tumor antigen holds promise for treating tumors by triggering strong immune reactions.

Short- and Long-term Risks of Highly Active Antiretroviral Treatment with Incident Opportunistic Infections among People Living with HIV/AIDS.

Highly active antiretroviral therapy (HAART) causes a rapid increase of CD4 + T cells counts during the first 3-6 months of treatment and may enhance the development of opportunistic infections (OIs). However, the short- and long-term effects of HAART exposure on the development of incident OIs has not been extensively studied. This nationwide longitudinal study followed up a total of 26,258 people living with HIV/AIDS (PLWHA) to ascertain the short- and long-term effects of HAART on incident OIs. During 150,196 person-years of follow-up, 6,413 (24.4%) PLWHA had new onset of OIs. After adjusting for demographics, comorbidities, and AIDS status, PLWHA who received HAART were more likely to develop OIs than those who did not receive HAART. Considering the short- and long-term effects of HAART on the development of OIs, HAART was found to be a risk factor for developing OIs during the first 90 days of treatment, but a protective factor against OIs after 180 days of HAART use. The risk for the development of active OIs significantly decreased as the duration of HAART increased (P < 0.001). Our study suggests that HAART is a risk factor for developing OIs in the short term, but is a protective factor in the long term.

Glucocorticoids may compromise the effect of gefitinib in non-small cell lung cancer.

The epidermal growth factor receptor (EGFR)-targeting tyrosine kinase inhibitors (TKIs) have shown remarkable benefits in non-small cell lung cancer (NSCLC) patients with drug-sensitive mutations in the EGFR gene. Responsive patients are usually continuously prescribed with TKIs until disease progression. Glucocorticoids (GCs) are potent homeostasis maintaining drugs and are frequently used in cancer patients to alleviate discomforts caused by anti-cancer therapies. Several previous studies reported that concomitant use of GCs may compromise the efficacy of chemo-therapeutics in patients with solid tumors. Little is known in the concomitant use of target therapy with GCs in treating NSCLC. In this study, we hypothesized that concomitant use of GCs in EGFR-TKI therapy may be detrimental and addressed this issue using cell cultures and xenograft studies followed by a retrospective population study based on data from the Taiwan national health insurance system. In cell cultures and xenograft studies, GCs were shown to unequally compromise the anti-cancer efficacy of TKIs in both PC9 and NCI-H1975 NSCLC cells models. In the retrospective population study, patients with similar disease status that were co-medicated with GCs had a significantly higher risk of disease progression.

Chimeric peptide containing both B and T cells epitope of tumor-associated antigen L6 enhances anti-tumor effects in HLA-A2 transgenic mice.

Synthetic peptides are attractive for cancer immunotherapy because of their safety and flexibility. In this report, we identified a new B cell epitope of tumor-associated antigen L6 (TAL6) that could induce antibody-dependent cellular cytotoxicity (ADCC) in vivo. We incorporated the B cell epitope with a cytotoxic T lymphocyte (CTL) and a helper T (Th) epitope to form a chimeric long peptide. We formulated the chimeric peptide with different adjuvants to immunize HLA-A2 transgenic mice and evaluate their immunogenicity. The chimeric peptide formulated with an emulsion type nanoparticle (PELC) adjuvant and a toll-like receptor 9 agonist (CpG ODN) (PELC/CpG) induced the greatest ADCC and CTL responses. The induced anti-tumor immunity inhibited the growth of TAL6-positive cancer cells. Moreover, we observed that immunization with the chimeric peptide inhibited cancer cell migration in vitro and metastasis in vivo. These data suggest that a chimeric peptide containing both B and T cell epitopes of TAL6 formulated with PELC/CpG adjuvant is feasible for cancer immunotherapy.

A HLA-A2-restricted CTL epitope induces anti-tumor effects against human lung cancer in mouse xenograft model.

Cancer immunotherapy is attractive for antigen-specific T cell-mediated anti-tumor therapy, especially in induction of cytotoxic T lymphocytes. In this report, we evaluated human CTL epitope-induced anti-tumor effects in human lung cancer xenograft models. The tumor associated antigen L6 (TAL6) is highly expressed in human lung cancer cell lines and tumor specimens as compared to normal lung tissues. TAL6 derived peptides strongly inhibited tumor growth, cancer metastasis and prolonged survival time in HLA-A2 transgenic mice immunized with a formulation of T-helper (Th) peptide, synthetic CpG ODN, and adjuvant Montanide ISA-51 (ISA-51). Adoptive transfer of peptide-induced CTL cells from HLA-A2 transgenic mice into human tumor xenograft SCID mice significantly inhibited tumor growth. Furthermore, combination of CTL-peptide immunotherapy and gemcitabine additively improved the therapeutic effects. This pre-clinical evaluation model provides a useful platform to develop efficient immunotherapeutic drugs to treat lung cancer and demonstrates a promising strategy with benefit of antitumor immune responses worthy of further development in clinical trials.

Delivery of human EV71 receptors by adeno-associated virus increases EV71 infection-induced local inflammation in adult mice.

Enterovirus71 (EV71) is now recognized as an emerging neurotropic virus in Asia and one major causative agent of hand-foot-mouth diseases (HFMD). However potential animal models for vaccine development are limited to young mice. In this study, we used an adeno-associated virus (AAV) vector to introduce the human EV71 receptors P-selectin glycoprotein ligand-1 (hPSGL1) or a scavenger receptor class-B member-2 (hSCARB2) into adult ICR mice to change their susceptibility to EV71 infection. Mice were administered AAV-hSCARB2 or AAV-hPSGL1 through intravenous and oral routes. After three weeks, expression of human SCARB2 and PSGL1 was detected in various organs. After infection with EV71, we found that the EV71 viral load in AAV-hSCARB2- or AAV-hPSGL1-transduced mice was higher than that of the control mice in both the brain and intestines. The presence of EV71 viral particles in tissues was confirmed using immunohistochemistry analysis. Moreover, inflammatory cytokines were induced in the brain and intestines of AAV-hSCARB2- or AAV-hPSGL1-transduced mice after EV71 infection but not in wild-type mice. However, neurological disease was not observed in these animals. Taken together, we successfully infected adult mice with live EV71 and induced local inflammation using an AAV delivery system.

Toll-like receptor 9-mediated protection of enterovirus 71 infection in mice is due to the release of danger-associated molecular patterns.

Enterovirus 71 (EV71), a positive-stranded RNA virus, is the major cause of hand, foot, and mouth disease (HFMD) with severe neurological symptoms. Antiviral type I interferon (alpha/beta interferon [IFN-α/ß]) responses initiated from innate receptor signaling are inhibited by EV71-encoded proteases. It is less well understood whether EV71-induced apoptosis provides a signal to activate type I interferon responses as a host defensive mechanism. In this report, we found that EV71 alone cannot activate Toll-like receptor 9 (TLR9) signaling, but supernatant from EV71-infected cells is capable of activating TLR9. We hypothesized that TLR9-activating signaling from plasmacytoid dendritic cells (pDCs) may contribute to host defense mechanisms. To test our hypothesis, Flt3 ligand-cultured DCs (Flt3L-DCs) from both wild-type (WT) and TLR9 knockout (TLR9KO) mice were infected with EV71. More viral particles were produced in TLR9KO mice than by WT mice. In contrast, alpha interferon (IFN-α), monocyte chemotactic protein 1 (MCP-1), tumor necrosis factor-alpha (TNF-α), IFN-γ, interleukin 6 (IL-6), and IL-10 levels were increased in Flt3L-DCs from WT mice infected with EV71 compared with TLR9KO mice. Seven-day-old TLR9KO mice infected with a non-mouse-adapted EV71 strain developed neurological lesion-related symptoms, including hind-limb paralysis, slowness, ataxia, and lethargy, but WT mice did not present with these symptoms. Lung, brain, small intestine, forelimb, and hind-limb tissues collected from TLR9KO mice exhibited significantly higher viral loads than equivalent tissues collected from WT mice. Histopathologic damage was observed in brain, small intestine, forelimb, and hind-limb tissues collected from TLR9KO mice infected with EV71. Our findings demonstrate that TLR9 is an important host defense molecule during EV71 infection. Importance: The host innate immune system is equipped with pattern recognition receptors (PRRs), which are useful for defending the host against invading pathogens. During enterovirus 71 (EV71) infection, the innate immune system is activated by pathogen-associated molecular patterns (PAMPs), which include viral RNA or DNA, and these PAMPs are recognized by PRRs. Toll-like receptor 3 (TLR3) and TLR7/8 recognize viral nucleic acids, and TLR9 senses unmethylated CpG DNA or pathogen-derived DNA. These PRRs stimulate the production of type I interferons (IFNs) to counteract viral infection, and they are the major source of antiviral alpha interferon (IFN-α) production in pDCs, which can produce 200- to 1,000-fold more IFN-α than any other immune cell type. In addition to PAMPs, danger-associated molecular patterns (DAMPs) are known to be potent activators of innate immune signaling, including TLR9. We found that EV71 induces cellular apoptosis, resulting in tissue damage; the endogenous DNA from dead cells may activate the innate immune system through TLR9. Therefore, our study provides new insights into EV71-induced apoptosis, which stimulates TLR9 in EV71-associated infections.

A novel HLA-A2-restricted CTL epitope of tumor-associated antigen L6 can inhibit tumor growth in vivo.

Vaccines utilizing cytotoxic T lymphocyte (CTL) epitopes are promising for the treatment of cancer and chronic infectious diseases. Tumor-associated antigen L6 (TAL6) is overexpressed in some epithelial cancer cells. In this report, we detected TAL6 expression in breast cancer tissue using quantitative reverse-transcriptase-polymerase chain reaction. We found that >80% of breast tumor tissue highly expressed TAL6 compared with adjacent normal breast tissue. To identify CTL epitopes from TAL6, we synthesized 18 peptides for HLA-A2-binding assay based on the MHC-binding motif using 4 computer prediction programs. Positive binders identified by ELISA were immunized in HLA-A2 transgenic (A2 Tg) mice. Two peptides, peptide 2 and peptide 5, induced T-cell responses in A2 Tg mice. To confirm whether these peptides could be processed and presented to induce T-cell responses in vivo, A2 Tg mice were immunized with plasmid DNA encoding TAL6. We found that both peptides 2 and 5 stimulated splenocytes from TAL6-immunized mice to secrete interferon-γ. However, only peptide 5 could induce expression of the cytolytic molecule CD107a on CD8+ T cells after immunization. Furthermore, peptide 5-immunized A2 Tg mice could inhibit the growth of TAL6-positive tumors (EL4/TAL6/HLA-A2) in A2 Tg mice but not in wild-type mice. These results demonstrate that the TAL6-derived CTL epitope could induce HLA-A2-restricted immunity against TAL6-expressing tumor cells.