P2x7 deficiency suppresses development of experimental autoimmune encephalomyelitis

Background  

The purinergic receptor P2x7 is expressed on myeloid cells as well as on CNS glial cells, and P2x7 activation has been shown to increase both glial and T-cell activation. These properties suggest a role in the development of autoimmune disease including multiple sclerosis.     

Processing of Norwalk virus nonstructural proteins by a 3C-like cysteine proteinase

Expression of Norwalk virus nonstructural polyprotein precursor in vitro resulted in rapid cotranslational cleavage at specific sites. The cleavage products were similar to those previously identified for Southampton virus, a highly related virus. We inactivated the virally encoded proteinase responsible for cleavage of the nonstructural polyprotein by mutation of the putative catalytic cysteine residue, which resulted in production of full-length polyprotein precursor. NV proteinase was expressed in Escherichia coli as a glutathione S-transferase fusion and purified by GST-affinity chromatography. Activity of the purified proteinase was demonstrated by incubation with the full-length precursor protein. trans cleavage of the nonstructural protein precursor resulted in cleavage products similar to those observed during cotranslational cleavage, however, at lesser efficiency. NV proteinase displayed sensitivities to cysteine and serine protease inhibitors similar to poliovirus 3C proteinase, suggesting that NV proteinase is a member of the viral cysteine proteinase family. We propose that the proteinase may play a regulatory role in viral replication.     

Detection of human T-lymphotropic virus (HTLV) tax sequences in New York City blood donors seronegative for HTLV types 1 and 2

A potential public health concern is the reported detection of the human T-lymphotropic virus (HTLV) tax gene in the lymphocytes of up to 11% of a low-risk group of New York City blood donors (NYBD). This study aimed to independently confirm the prevalence of HTLV tax sequences in 293 NYBD. All NYBD tested negative for antibodies to HTLV types 1 and 2 and HTLV Tax. HTLV tax sequences were not detected in the NYBD lymphocytes. These data demonstrate the lack of HTLV-1 tax in this group of NYBD at low risk for HTLV infection.     

Epitope mapping of a protective monoclonal antibody against Pneumocystis carinii with shared reactivity to Streptococcus pneumoniae surface antigen PspA

Pneumocystis carinii is an opportunistic fungal pathogen that causes pneumonia in the immunocompromised host. A protective monoclonal antibody (MAb) termed 4F11 generated against mouse-derived P. carinii was shown by indirect immunofluorescence assay (IFA) to bind surface antigens of P. carinii derived from multiple host species, including humans. We have identified multiple epitopes recognized by MAb 4F11 in two recombinant mouse P. carinii antigens. The epitopes mapped have similar proline content and positive charge distribution. The consensus 8-mer epitope recognized by MAb 4F11 is K/RPA/RPK/QPA/TP. Immune sera raised against intact mouse P. carinii recognized native antigens affinity purified with MAb 4F11 and a recombinant antigen reactive with MAb 4F11. Database searches for short, nearly exact matches to the mapped MAb 4F11 epitopes identified a bacterial surface antigen, Streptococcus pneumoniae PspA, with a similar proline-rich region. In an IFA, MAb 4F11 detected antigens on the S. pneumoniae surface, and Western blotting identified a protein in S. pneumoniae lysates consistent with the M(r) of PspA. A fragment of the S. pneumoniae PspA gene was cloned and sequenced, and the deduced amino acid sequence contained a region with strong similarity to the MAb 4F11 epitopes identified in P. carinii. The PspA recombinant polypeptide was recognized by MAb 4F11 in a Western blot. The ability of MAb 4F11 to recognize similar proline-rich epitopes may explain its ability to recognize P. carinii derived from multiple hosts and will permit testing of the epitopes recognized by this antibody in immunization against P. carinii.     

Placental inflammation and perinatal transmission of HIV-1

The effect of placental membrane inflammation on mother-to-child transmission (MTCT) of HIV-1 is reported. Placentas from HIV-1-infected women were examined as part of a perinatal HIV-1 project in Mombasa, Kenya. Polymerase chain reaction analysis was used to test for HIV-1 in the infants at birth and at 6 weeks. The maternal HIV-1 seroprevalence was 13.3% (298 of 2,235). The overall rate of MTCT of HIV-1 was 25.4%; polymerase chain reaction analysis revealed that of the 201 infants 6.0% (12) were already HIV-1-positive at birth (intrauterine transmission) and 19.4% (39) were infected during the peripartum period or in early neonatal life (perinatal transmission). The prevalence of acute chorioamnionitis was 8.8%, that of deciduitis was 10.8%, and that of villitis was 1.6%. Acute chorioamnionitis was independently associated with peripartum HIV-1 transmission but not with in utero MTCT (17.9% vs. 6.7%, respectively; adjusted odds ratio, 3.9; 95% confidence interval, 1.2-12.5; p =.025). Other correlates of perinatal MTCT were presence of HIV in the genital tract and in the baby's oral cavity and a high maternal viral load in peripheral blood. The adjusted population attributable fraction of 12.8% (95% confidence interval, 1.5%-22.8%) indicated that approximately 3% of MTCT could be prevented if acute chorioamnionitis was eliminated. We suggest that further research on the role of antimicrobial treatment in the prevention of chorioamnionitis and the reduction of peripartum MTCT needs to be performed.     

Use of multiepitope polyproteins in serodiagnosis of active tuberculosis

Screening of genomic expression libraries from Mycobacterium tuberculosis with sera from tuberculosis (TB) patients or rabbit antiserum to M. tuberculosis led to the identification of novel antigens capable of detecting specific antibodies to M. tuberculosis. Three antigens, Mtb11 (also known as CFP-10), Mtb8, and Mtb48, were tested together with the previously reported 38-kDa protein, in an enzyme-linked immunosorbent assay (ELISA) to detect antibodies in TB patients. These four proteins were also produced as a genetically fused polyprotein, which was tested with two additional antigens, DPEP (also known as MPT32) and Mtb81. Sera from individuals with pulmonary and extrapulmonary TB, human immunodeficiency virus (HIV)-TB coinfections, and purified protein derivative (PPD)-positive and PPD-negative status with no evidence of disease were tested. In samples from HIV-negative individuals, the ELISA detected antibodies in >80% of smear-positive individuals and >60% smear-negative individuals, with a specificity of approximately 98%. For this group, smears detected 81.6% but a combination of smear and ELISA had a sensitivity of approximately 93%. The antigen combination detected a significant number of HIV-TB coinfections as well as antibodies in patients with extrapulmonary infections. Improved reactivity in the HIV-TB group was observed by including the antigen Mtb81 that was identified by proteomics. The data indicate that the use of multiple antigens, some of which are in a single polyprotein, can be used to facilitate the development of a highly sensitive test for M. tuberculosis antibody detection.     

Infestation of sand lizards (<Emphasis Type="Italic">Lacerta agilis</Emphasis>) resident in the Northeastern Poland by <Emphasis Type="Italic">Ixodes ricinus</Emphasis> (L.) ticks and their infection with <Emphasis Type="Italic">Borrelia burgdorferi</Emphasis> sensu lato

Sand lizards (Lacerta agilis) were trapped and examined for ticks from May to September in 2002 and 2003 in Northeastern Poland. A total of 233 Ixodes ricinus (L.) ticks (76 larvae and 157 nymphs) was found on 31 of 235 captured lizards (13.2%). The tick infestation is relatively low compared to that of mammals and passerine birds from the same area (Siński et al. 2006, Gryczyńska et al. 2002). Tick infestation depended on the month of capture, being the highest in spring. In autumn no ticks were recorded on any of the captured lizards. The oldest lizards carried the highest number of ticks but no differences related to sex of the host were found. All the collected ticks were analysed by PCR for the presence of Borrelia burgdorferi sensu lato, the etiological agents of Lyme disease. Spirochetes were detected in 11 out of 233 (4.7%) ticks tested. Genetic analysis confirmed that the spirochetes are members of the Borrelia afzelii, B. garinii and B. burgdorferi sensu stricto genospecies. Mixed infection were not detected. The prevalence of infection was analysed in relation to months of the capture, age and sex of the lizards, but differences were not statistically significant. The obtained results suggest that lizards are probably not B. burgdorferi reservoirs, but further studies are required to confirm this.     

Immunomodulation of murine collagen-induced arthritis by N,N-dimethylglycine and a preparation of <Emphasis Type="Italic">Perna canaliculus</Emphasis>

Background  

Rheumatoid arthritis (RA) and its accepted animal model, murine collagen-induced arthritis (CIA), are classic autoimmune inflammatory diseases which require proinflammatory cytokine production for pathogenesis. We and others have previously used N, N-dimethylglycine (DMG) and extracts from the New Zealand green-lipped mussel Perna canaliculus (Perna) as potent immunomodulators to modify ongoing immune and/or inflammatory responses.     

Addressing global health through the marriage of public health and medicine: developing the University of Washington department of global health.

Widespread interest in global health issues is a common characteristic of students and faculty in schools of public health and schools of medicine. Building on strong university-based and community-based programs in global health, the University of Washington has created a unique Department of Global Health that is housed jointly in its School of Public Health and Community Medicine and its School of Medicine. The creation of this department has generated significant enthusiasm throughout the university and the Seattle community as a new paradigm for addressing global health education, research, and service. Placing the new Department of Global Health in two university schools and finding the appropriate niche for the department among the university's many global health initiatives presented challenges, as well as opportunities. This article describes the goals of the department, the process by which it was created, and what it expects to accomplish.     

Germline polymorphisms as modulators of cancer phenotypes

Identifying the complete repertoire of genes and genetic variants that regulate the pathogenesis and progression of human disease is a central goal of post-genomic biomedical research. In cancer, recent studies have shown that genome-wide association studies can be successfully used to identify germline polymorphisms associated with an individual's susceptibility to malignancy. In parallel to these reports, substantial work has also shown that patterns of somatic alterations in human tumors can be successfully employed to predict disease prognosis and treatment response. A paper by Van Ness et al. published this month in BMC Medicine reports the initial results of a multi-institutional consortium for multiple myeloma designed to evaluate the role of germline polymorphisms in influencing multiple myeloma clinical outcome. Applying a custom-designed single nucleotide polymorphism microarray to two separate patient cohorts, the investigators successfully identified specific combinations of germline polymorphisms significantly associated with early clinical relapse. These results raise the exciting possibility that besides somatically acquired alterations, germline genetic background may also exert an important influence on cancer patient prognosis and outcome. Future 'personalized medicine' strategies for cancer may thus require incorporating genomic information from both tumor cells and the non-malignant patient genome.