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Chronic hepatitis B infection (CHB) is an area of high unmet medical need. Current standard-of-care therapies only rarely lead to a functional cure, defined as durable hepatitis B surface antigen (HBsAg) loss following treatment. The goal for next generation CHB therapies is to achieve a higher rate of functional cure with finite treatment duration. To address this urgent need, we are developing liver-targeted single-stranded oligonucleotide (SSO) therapeutics for CHB based on the locked nucleic acid (LNA) platform. These LNA-SSOs target hepatitis B virus (HBV) transcripts for RNase-H-mediated degradation. Here, we describe a HBV-specific LNA-SSO that effectively reduces intracellular viral mRNAs and viral antigens (HBsAg and HBeAg) over an extended time period in cultured human hepatoma cell lines that were infected with HBV with mean 50% effective concentration (EC50) values ranging from 1.19 to 1.66 μM. To achieve liver-specific targeting and minimize kidney exposure, this LNA-SSO was conjugated to a cluster of three N-acetylgalactosamine (GalNAc) moieties that direct specific binding to the asialoglycoprotein receptor (ASGPR) expressed specifically on the surface of hepatocytes. The GalNAc-conjugated LNA-SSO showed a strikingly higher level of potency when tested in the AAV-HBV mouse model as compared with its non-conjugated counterpart. Remarkably, higher doses of GalNAc-conjugated LNA-SSO resulted in a rapid and long-lasting reduction of HBsAg to below the detection limit for quantification, i.e., by 3 log10 (p < 0.0003). This antiviral effect depended on a close match between the sequences of the LNA-SSO and its HBV target, indicating that the antiviral effect is not due to non-specific oligonucleotide-driven immune activation. These data support the development of LNA-SSO therapeutics for the treatment of CHB infection.

BACKGROUND: Granulysin produced by cytolytic T cells directly contributes to immune defense against tuberculosis (TB). We investigated granulysin as a candidate immune marker for childhood and adolescent TB. METHODS: Peripheral blood mononuclear cells (PBMC) from children and adolescents (1-17 years) with active TB, latent TB infection (LTBI), nontuberculous mycobacteria (NTM) infection and from uninfected controls were isolated and restimulated in a 7-day restimulation assay. Intracellular staining was then performed to analyze antigen-specific induction of activation markers and cytotoxic proteins, notably, granulysin in CD4(+) CD45RO(+) memory T cells. RESULTS: CD4(+) CD45RO(+) T cells co-expressing granulysin with specificity for Mycobacterium tuberculosis (Mtb) were present in high frequency in TB-experienced children and adolescents. Proliferating memory T cells (CFSE(low)CD4(+)CD45RO(+)) were identified as main source of granulysin and these cells expressed both central and effector memory phenotype. PBMC from study participants after TB drug therapy revealed that granulysin-expressing CD4(+) T cells are long-lived, and express several activation and cytotoxicity markers with a proportion of cells being interferon-gamma-positive. In addition, granulysin-expressing T cell lines showed cytolytic activity against Mtb-infected target cells. CONCLUSIONS: Our data suggest granulysin expression by CD4(+) memory T cells as candidate immune marker for TB infection, notably, in childhood and adolescence.

BACKGROUND: T-cell responses against dormancy-, resuscitation-, and reactivation-associated antigens of Mycobacterium tuberculosis are candidate biomarkers of latent infection in humans. METHODOLOGY/PRINCIPAL FINDINGS: We established an assay based on two rounds of in vitro restimulation and intracellular cytokine analysis that detects T-cell responses to antigens expressed during latent M. tuberculosis infection. Comparison between active pulmonary tuberculosis (TB) patients and healthy latently M. tuberculosis-infected donors (LTBI) revealed significantly higher T-cell responses against 7 of 35 tested M. tuberculosis latency-associated antigens in LTBI. Notably, T cells specific for Rv3407 were exclusively detected in LTBI but not in TB patients. The T-cell IFNgamma response against Rv3407 in individual donors was the most influential factor in discrimination analysis that classified TB patients and LTBI with 83% accuracy using cross-validation. Rv3407 peptide pool stimulations revealed distinct candidate epitopes in four LTBI. CONCLUSIONS: Our findings further support the hypothesis that the latency-associated antigens can be exploited as biomarkers for LTBI.

Cell viability assays are important tools in oncological research and clinical practice to assess the tumor cell sensitivity of individual patients. The purpose of this study was to demonstrate the comparability of 3 widely used assays (MTT, ATP, calcein assays) by principal component analysis. The study included 4 different cytostatics (cisplatin, docetaxel, doxorubicin, vinblastine) and 3 different human cancer cell lines (MCF-7, A2780, doxorubicin resistant A2780adr). Ninety-three percent of the total variance of all variables included in the principal component analysis (resulting from 3 cell lines and 3 assays) could be explained by 1 principal component. Factor loadings were > 0.937 except for the variable MTT-A2780adr, which was 0.872. These results indicate the similarity of the 3 assays. A 2nd principal component analysis included literature data and showed accordance of data from this study and the literature. The MTT assay was further improved as a high-throughput screeningcapable assay. The ATP assay is able to detect effects of cytostatics already after 1 h incubation. The determination of resistance factors allowed to differentiate cytostatics into P-gp or non-P-gp substrates. In conclusion, this study provides improved microplate reader-based cell viability assays and sets a statistically solid basis for a future comparison of data obtained in different laboratories by any of the 3 assays. [ABSTRACT FROM AUTHOR]