Clearance of measles virus from persistently infected cells by short hairpin RNA.

Subacute sclerosing panencephalitis (SSPE) is a demyelinating central nervous system disease caused by a persistent measles virus (MV) infection of neurons and glial cells. There is still no specific therapy available, and in spite of an intact innate and adaptive immune response, SSPE leads inevitably to death. In order to select effective antiviral short interfering RNAs (siRNAs), we established a plasmid-based test system expressing the mRNA of DsRed2 fused with mRNA sequences of single viral genes, to which certain siRNAs were directed. siRNA sequences were expressed as short hairpin RNA (shRNA) from a lentiviral vector additionally expressing enhanced green fluorescent protein (EGFP) as an indicator. Evaluation by flow cytometry of the dual-color system (DsRed and EGFP) allowed us to find optimal shRNA sequences. Using the most active shRNA constructs, we transduced persistently infected human NT2 cells expressing virus-encoded HcRed (piNT2-HcRed) as an indicator of infection. shRNA against N, P, and L mRNAs of MV led to a reduction of the infection below detectable levels in a high percentage of transduced piNT2-HcRed cells within 1 week. The fraction of virus-negative cells in these cultures was constant over at least 3 weeks posttransduction in the presence of a fusion-inhibiting peptide (Z-Phe-Phe-Gly), preventing the cell fusion of potentially cured cells with persistently infected cells. Transduced piNT2 cells that lost HcRed did not fuse with underlying Vero/hSLAM cells, indicating that these cells do not express viral proteins any more and are "cured." This demonstrates in tissue culture that NT2 cells persistently infected with MV can be cured by the transduction of lentiviral vectors mediating the long-lasting expression of anti-MV shRNA.

Immunological persistence in 4-6 and 7-9 year olds previously vaccinated in infancy with hexavalent DTPa-HBV-IPV/Hib.

BACKGROUND: The combined diphtheria-tetanus-pertussis-hepatitis B-inactivated poliomyelitis-Haemophilus influenzae conjugate vaccine (DTP a-HBV-IPV/Hib, Infanrix Hexa() GlaxoSmithKline Biologicals, Rixensart, Belgium) is the only hexavalent vaccine currently licensed for primary and booster vaccination of infants and provides simultaneous protection against six major diseases of childhood. The persistence of the immune response in children aged 4-6 and 7-9 years of age previously vaccinated with four doses of DTP a-HBV-IPV/Hib vaccine was assessed (www.clinicaltrials.gov.au 106744 NCT00356564 and 106745 NCT00335881). METHODS: A blood sample was collected from 403 children, all of whom had received 3-dose primary vaccination and a booster dose in the second year of life with DTP a-HBV-IPV/Hib, in previous clinical vaccine trials in Germany. RESULTS: Mean time from the fourth DTP a-HBV-IPV/Hib dose until serological follow-up ranged between 3.6 and 6.4 years. After the 4th DTP a-HBV-IPV/Hib dose, in subjects who had not received additional booster doses, seroprotective antibody levels persisted up to 9 years of age in >/=90% of subjects for diphtheria, Hib and poliomyelitis, in 77.2% subjects for Hepatitis B and in 64.7% of subjects for tetanus. Anti-pertussis toxin antibodies remained detectable in no more than 38.2% of subjects. CONCLUSION: With the exception of PT , the combined DTP a-HBV-IPV/Hib induces long lasting immune response against all vaccine antigens. Falling seropositivity against PT over time supports the recommended administration of a pertussis booster dose in 5-6 year old children in Germany.

Pathogen-induced tissue-resident memory TH17 (TRM17) cells amplify autoimmune kidney disease.

Although it is well established that microbial infections predispose to autoimmune diseases, the underlying mechanisms remain poorly understood. After infection, tissue-resident memory T (TRM) cells persist in peripheral organs and provide immune protection against reinfection. However, whether TRM cells participate in responses unrelated to the primary infection, such as autoimmune inflammation, is unknown. By using high-dimensional single-cell analysis, we identified CD4+ TRM cells with a TH17 signature (termed TRM17 cells) in kidneys of patients with ANCA-associated glomerulonephritis. Experimental models demonstrated that renal TRM17 cells were induced by pathogens infecting the kidney, such as Staphylococcus aureus, Candida albicans, and uropathogenic Escherichia coli, and persisted after the clearance of infections. Upon induction of experimental glomerulonephritis, these kidney TRM17 cells rapidly responded to local proinflammatory cytokines by producing IL-17A and thereby exacerbate renal pathology. Thus, our data show that pathogen-induced TRM17 cells have a previously unrecognized function in aggravating autoimmune disease.

Immune memory to hepatitis B virus in 4-9-year old children vaccinated in infancy with four doses of hexavalent DTPa-HBV-IPV/Hib vaccine.

The combined hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio Haemophilus influenzae type b (DTPa-HBV-IPV/Hib) vaccine produces similar hepatitis B responses as the HBV monovalent vaccine. Booster vaccination of immunocompetent individuals primed against hepatitis B in infancy is currently not recommended. We investigated persisting immunity to hepatitis B in 4-6 (Study A; 106745) and 7-9 (Study B; 106744) year-old children primed in infancy and boosted in the second year of life with DTPa-HBV-IPV/Hib. Immunity was assessed by measuring persisting anti-HBs antibodies and evaluating the response to a challenge dose of HBV vaccine. At 4-6 years of age 86.0% of 186 subjects had persisting anti-HBs > or =10 mIU/ml increasing to 98.4% after the challenge. At 7-9 years of age, 78.0% of 186 subjects continued to have anti-HBs antibody concentrations > or =10 mIU/ml, increasing to 98.9% after the challenge. In both studies anti-HBs antibody GMC rose >80-fold. An anamnestic response to the HBV challenge was observed in 95.7% and 98.9% of subjects in Studies A and B, respectively. In both studies, 87% of 38 subjects with initially undetectable circulating anti-HBs antibodies (>3.3 IU/ml) achieved the 10 mIU/ml threshold after challenge; > or =97.0% of subjects with detectable antibodies before the challenge at least quadrupled their concentration. Post-vaccination anti-HBs concentrations were directly related to persisting antibody concentrations and the concentrations achieved after the booster dose in the second year of life. The HBV vaccine challenge dose was well tolerated. These studies show that primary and booster vaccination with combined DTPa-HBV-IPV/Hib (Infanrix hexa) induces sustained immune memory against hepatitis B up to age 9 years.

Rapid and sensitive detection of calreticulin type 1 and 2 mutations by real-time quantitative PCR.

BACKGROUND: The majority of patients with JAK2 V617F-negative essential thrombocythemia or primary myelofibrosis harbor mutations involving the calreticulin (CALR) gene. These mutations are located in CALR exon 9 and lead to a frameshift with subsequent alteration of the CALR protein C-terminus. They have emerged as valuable molecular markers for the diagnosis of clonal myeloproliferative diseases. Although a variety of CALR mutations have been described, two mutations, denoted type 1 and type 2, account for around 85 % of cases. The type 1 mutation encompasses a 52 bp deletion and the type 2 mutation a 5 bp TTGTC insertion. METHODS: This work describes the development and testing of quantitative real-time PCRs (qPCRs) for detecting these two mutations. RESULTS: The final type 1 CALR qPCR displayed a sensitivity of <0.1 % mutant alleles and the type 2 CALR qPCR had a sensitivity of <0.01 % mutant alleles. Additionally, two new CALR mutations are reported. CONCLUSION: These sensitive and specific qPCRs should be helpful in establishing the diagnosis and in monitoring minimal residual disease in patients during or after therapy.