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B Strains (b + strain)
Selected AbstractsInfluenza vaccination of HIV-1-positive and hiv-1-negative former intravenous drug usersJOURNAL OF MEDICAL VIROLOGY, Issue 4 2001Antonella Amendola Abstract The immunogenicity of an anti-influenza vaccine was assessed in 409 former intravenous drug user volunteers and its effect on the levels of HIV-1 RNA, proviral DNA and on CD4+ lymphocyte counts in a subset HIV-1-positive subjects was measured. HIV-1-positive individuals (n,=,72) were divided into three groups on the basis of their CD4+ lymphocyte counts, while the 337 HIV-1-negative participants were allocated into group four. Haemagglutination inhibiting (HI) responses varied from 45.8 to 70% in the HIV-1-positive subjects and were significantly higher in group four (80.7% responses to the H1N1 strain, 81.6% to the H3N2 strain, and 83% to the B strain). The percentage of subjects with HI protective antibody titres (,,1:40) increased significantly after vaccination, especially in HIV-1 uninfected subjects. Immunization caused no significant changes in CD4+ counts and in neither plasma HIV-1 RNA nor proviral DNA levels. Therefore, vaccination against influenza may benefit persons infected by HIV-1. J. Med. Virol. 65:644,648, 2001. © 2001 Wiley-Liss, Inc. [source] Humoral and Cellular Immune Responses after Influenza Vaccination in Kidney Transplant RecipientsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 10 2009S Candon It has been speculated that influenza vaccination of renal allograft recipients could be associated with de novo production and/or increased titers of anti-HLA antibodies (HLA-Ab). To directly address this issue, we recruited 66 stable renal transplant recipients and 19 healthy volunteers during the 2005,2006 vaccination campaign. At day 0 and day 30 following vaccination, HLA-Ab were screened and in parallel influenza-specific antibody and T-cell responses were assessed. Humoral postvaccinal responses to A/H1N1 and A/H3N2 strains, but not B strain, were less frequent in transplanted patients than in control subjects. Significant expansion of influenza-specific IFN-,-producing T cells was observed at similar frequencies in patients and controls. There was no correlation between cellular and humoral postvaccinal responses. No impact of sex, age or immunosuppressive regimen could be evidenced. Vaccination was not associated with any significant change in preexisting or de novo anti-HLA sensitization. No episode of allograft rejection was recorded in any of the patients. Our results suggest that flu vaccination is safe in stable renal transplanted patients. Larger studies are needed for definitive statistical proof of the safety and effectiveness, with regard to the quality of the immune response, of yearly influenza vaccination in immunosuppressed patients. [source] cagA gene variants in Malaysian Helicobacter pylori strains isolated from patients of different ethnic groupsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2005Mohamed Ramelah Abstract Helicobacter pylori infection of a distinct subtype of cagA may lead to different pathological manifestation. The aim of this study is to determine the presence of cagA gene and its variants in H. pylori infection among different ethnic groups and its effect on gastroduodenal diseases. Overall detection of cagA among the 205 clinical isolates of H. pylori was 94%. Variations in size of the 3, region of cagA gene were examined among 192 Malaysian H. pylori cagA -positive strains. Results showed that three cagA variants differing in fragment length of PCR products were detected and designated as type A (621,651 bp), type B (732,735 bp) and type C (525 bp). Although there was no association between any of the cagA subtypes with peptic ulcer disease (p > 0.05), an association between cagA subtypes with a specific ethnic group was observed. Specific- cagA subtype A strains were predominantly isolated from Chinese compared to Malays and Indians (p < 0.0005), and cagA subtype B strains were predominantly isolated from Malays and Indians compared to Chinese (p < 0.05). The cagA type A strains of H. pylori is commonly found in the Chinese patients who have a higher risk of peptic ulcer disease, thus indicating that it could be used as an important clinical biomarker for a more severe infection. [source] A phylogenetic study of human respiratory syncytial viruses group A and B strains isolated in two cities in Japan from 1980,2002JOURNAL OF MEDICAL VIROLOGY, Issue 2 2005Yuki Kuroiwa Abstract The circulation pattern and genetic evolution of respiratory syncytial virus (RSV) in Japan were examined based on 109 RSV field strains isolated over 20 seasons (1980,2002) in two cities, Sapporo and Tokyo. The second hypervariable region of the large glycoprotein (G) gene was amplified by RT-PCR and the products sequenced directly. The nucleotide sequences were compared to those representatives of RSV genotypes identified previously. Japanese group A and B isolates clustered into five and four genotypes defined previously, respectively. Another one group A and one group B genotypes, which could not be assigned to previous genotypes, were also identified. Although different genotypes usually co-circulated in each season, the isolates in proximate seasons from two communities were usually located in the same branches. Moreover, the strains with genotypes defined previously were usually isolated at the same time as each reference strain of Western countries. Several mutant group B strains with 1,20 longer amino acid G proteins were newly identified in Sapporo. These findings suggest that Japanese RSV strains underwent geographical and also temporal clustering while participating in RSV genetic evolution in a global setting. In addition, Japanese strains, especially group B, might have evolved individually in each community, sometimes changing the length of the G protein. J. Med. Virol. 76:241,247, 2005. © 2005 Wiley-Liss, Inc. [source] Construction and performance of heterologous polyketide-producing K-12- and B-derived Escherichia coliLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2010J. Wu Abstract Aims:,Escherichia coli has emerged as a viable heterologous host for the production of complex, polyketide natural compounds. In this study, polyketide biosynthesis was compared between different E. coli strains for the purpose of better understanding and improving heterologous production. Methods and Results:, Both B and K-12 E. coli strains were genetically modified to support heterologous polyketide biosynthesis [specifically, 6-deoxyerythronolide B (6dEB)]. Polyketide production was analysed using a helper plasmid designed to overcome rare codon usage within E. coli. Each strain was analysed for recombinant protein production, precursor consumption, by-product production, and 6dEB biosynthesis. Of the strains tested for biosynthesis, 6dEB production was greatest for E. coli B strains. When comparing biosynthetic improvements as a function of mRNA stability vs codon bias, increased 6dEB titres were observed when additional rare codon tRNA molecules were provided. Conclusions:,Escherichia coli B strains and the use of tRNA supplementation led to improved 6dEB polyketide titres. Significance and Impact of the Study:, Given the medicinal potential and growing field of polyketide heterologous biosynthesis, the current study provides insight into host-specific genetic backgrounds and gene expression parameters aiding polyketide production through E. coli. [source] Immunogenicity and safety of a novel liposomal influenza subunit vaccine (INFLUSOME-VAC) in young adultsJOURNAL OF MEDICAL VIROLOGY, Issue 4 2003Arie Ben-Yehuda Abstract Influenza and its complications account for substantial morbidity and mortality among young adults and especially among the elderly. In young adults, immunization provides 70,90% protection, while among the elderly the vaccine may be only 30,40% effective; hence the need for new, more immunogenic vaccines. We compared the safety and immunogenicity of a novel IL-2-supplemented liposomal influenza vaccine (designated INFLUSOME-VAC) with that of a commercial subunit vaccine and a commercial split virion vaccine in young adults (mean age 28 years) in the winter of 1999,2000. Seventy-three healthy young adults were randomly assigned to be vaccinated intramuscularly with the following: a commercial subunit vaccine (n,=,17, group A), INFLUSOME-VAC (n,=,36, group B), and a commercial split virion vaccine (n,=,20, group C). The three vaccines contained equal amounts of hemagglutinin (,15 ,g each) from the strains A/Sydney (H3N2), A/Beijing (H1N1), and B/Yamanashi. INFLUSOME-VAC induced higher geometric mean HI titers and higher-fold increases in HI titers against all three strains, compared with the two commercial vaccines. In addition, seroconversion rates for the A/Sydney and B/Yamanashi strains were significantly higher (P,<,0.05) compared with the split virion vaccine, and significantly higher for the three strains compared with the subunit vaccine (69,97% vs 35,65%, P,,,0.02). Moreover, the anti-neuraminidase response was significantly greater (P,=,0.05) in group B vs group A. INFLUSOME-VAC caused mild local pain at the injection site in a significantly higher proportion of the vaccinees (83%). Thus, INFLUSOME-VAC is an immunogenic and safe vaccine in young adults. J. Med. Virol. 69:560,567, 2003. © 2003 Wiley-Liss, Inc. [source] | |||||||||||||