Effects of Lymphocyte Isolation and Timing of Processing on Detection of CD127 Expression on T Cells in Human Immunodeficiency Virus-Infected Patients

Decreases in the detection of CD127 expression on T cells of human immunodeficiency virus-infected patients by flow cytometry can occur by delayed processing or by peripheral blood mononuclear cell isolation and cryopreservation. These observations should be considered in the interpretation of functional studies and the planning of multicenter clinical trials.     

Viral protein production in homogeneous and mixed infections of cytopathic and noncytopathic BVD virus

Summary Experiments were conducted to examine dual infection of cultured cells with cytopathic and noncytopathic bovine viral diarrhea virus (BVDV). Cell monolayers infected with a noncytopathic BVDV isolate and subsequently superinfected with a cytopathic BVDV isolate were refractive to the cytopathic effects of the cytopathic BVDV isolate, as reported in the literature. Immunofluorescence staining of superinfected cultures with monoclonal antibodies specific for the cytopathic or the noncytopathic viral isolate, demonstrated that cells in superinfected cultures contained both viral biotypes. Immunoprecipitation was used to compare the temporal detection of viral induced polypeptides in superinfected cultures to that of cultures infected with a single viral biotype. In single cytopathic viral infections, viral induced polypeptides of 80 kDa and 53–56 kDa are detected simultaneously, but in superinfections a 4 h gap occurred between detection of the 53–56 kDa polypeptide and detection of the 80 kDa polypeptide.     

A comparison of research general practices and their patients with other practices--a cross-sectional survey in Trent.

BACKGROUND: When interpreting results of studies undertaken by research networks we need to know how representative volunteer practices and their registered patients are of the total population of practices and patients in their locality. AIM: To compare the following in research and non-research general practices in one region: practice and population demography, morbidity and mortality, selected performance indicators, and health outcomes. DESIGN OF STUDY: Cross-sectional survey. SETTING: Sixty-six Trent Focus Collaborative Research Network general practices and 749 other general practices in Trent, United Kingdom. METHOD: Practice characteristics and GP contract data were obtained from the NHS Executive, Quarry House, Leeds. The Trent Regional NHS Hospital Admission Database was searched to identify all relevant admissions to hospital from all practices between 1 April 1993 and 31 March 1997. Ward-linked data on cancer were obtained from the Trent Cancer Registry. RESULTS: Of the 815 general practices in Trent Region in the study period, 66 (8%) were in the Trent Focus network. They were more likely to be involved in training GPs and to have a female partner. They tended to be larger, with fewer single-handed doctors and younger GPs. Network practices prescribed a higher proportion of generics (median % prescribed/practice = 70%, versus 51%, Mann-Whitney U = 1615, P<0.0001). There were no clinically important differences between hospital admission rates between the two groups or waiting times for surgical procedures. There was no difference in the incidence of cancer and standardised mortality ratios related to the electoral wards of the GP surgery. CONCLUSION: Although there were differences in practice structure and some aspects of performance, we found no important differences in the demography of registered patients, nor in morbidity, mortality, or access to or use of secondary care.     

Lung epithelial cells and extracellular matrix components induce expression of Pneumocystis carinii STE20, a gene complementing the mating and pseudohyphal growth defects of STE20 mutant yeast

Pneumocystis carinii causes severe pneumonia in immunocompromised hosts. The binding of P. carinii to alveolar epithelial cells and extracellular matrix constituents such as fibronectin and vitronectin is a central feature of infection, which initiates proliferation of the organism. Herein, we demonstrate that P. carinii binding to lung cells specifically alters the gene expression of the organism, regulating fungal growth. Subtractive hybridization was performed to isolate P. carinii genes expressed following binding to mammalian extracellular matrix constituents. P. carinii STE20 (PCSTE20), a gene participating in mating and pseudohyphal growth of other fungi, was identified following adherence to the extracellular matrix constituents fibronectin, vitronectin, collagen, and lung epithelial cells. The expression of PCSTE20 and a related P. carinii mitogen-activated protein kinase (MAPK) kinase gene, also implicated in signaling of mating, were both specifically upregulated by binding to matrix protein. The expression of general cyclin-dependent kinases and other MAPKs not involved in mating pathways were not altered by organism binding. PCSTE20 expression was also strongly enhanced following organism attachment to A549 lung epithelial cells. When expressed in a Saccharomyces cerevisiae ste20Delta mutant, PCSTE20 suppressed defects in both mating and pseudohyphal growth. These findings are consistent with the observed proliferation and filopodial extension of Pneumocystis organisms adherent to the epithelium in the lungs of immunocompromised hosts. PCSTE20 expression appears to represent a significant component in the regulation of the life cycle of this intractable opportunistic pathogen.     

Modulation of Borrelia burgdorferi stringent response and gene expression during extracellular growth with tick cells

Borrelia burgdorferi N40 multiplied extracellularly when it was cocultured with tick cells in L15BS medium, a medium which by itself did not support B. burgdorferi N40 growth. Growth of B. burgdorferi N40 in the presence of tick cells was associated with decreased production of (p)ppGpp, the stringent response global regulator, a fourfold decrease in relA/spoT mRNA, an eightfold net decrease in bmpD mRNA, and a fourfold increase in rpsL-bmpD mRNA compared to growth of B. burgdorferi in BSK-H medium. As a result, the polycistronic rpsL-bmpD mRNA level increased from 3 to 100% of the total bmpD message. These observations demonstrate that there are reciprocal interactions between B. burgdorferi and tick cells in vitro and indicate that the starvation-associated stringent response mediated by (p)ppGpp present in B. burgdorferi growing in BSK-H medium is ameliorated in B. burgdorferi growing in coculture with tick cell lines. These results suggest that this system can provide a useful model for identifying genes controlling interactions of B. burgdorferi with tick cells in vitro when it is coupled with genetic methods to isolate and complement B. burgdorferi mutants.     

Production of herpes B virus recombinant glycoproteins and evaluation of their diagnostic potential

B virus (cercopithecine herpesvirus 1) is the only deadly alphaherpesvirus that is zoonotically transmissible from macaques to humans. The detection of humoral immune responses is the method of choice for the rapid identification of B virus-infected animals. We evaluated the diagnostic potential of recombinant B virus glycoproteins for the detection of immunoglobulin G (IgG) antibodies in monkey and human sera. Glycoproteins B, C, and E and secreted (sgG) and membrane-associated (mgG) segments of glycoprotein G (gG) were expressed in the baculovirus expression system, while gD was expressed in CHO cells. We developed recombinant protein-based IgG enzyme-linked immunosorbent assays (ELISAs) and compared their diagnostic efficacies by using B virus antibody-negative (n = 40) and -positive (n = 75) macaque sera identified by a whole antigen-based ELISA and Western blotting. The diagnostic sensitivities of the gB-, gC-, gD-, and mgG-ELISAs were 100, 97.3, 88.0, and 80.0%, respectively. The specificities of the gB-, gC-, and gD-ELISAs and of the mgG-ELISA were 100 and 97.5%, respectively. In contrast, the sensitivities and specificities of sgG- and gE-ELISAs were low, suggesting that sgG and gE are less effective diagnostic antigens. Sera from nonmacaque monkeys cross-reacted with gB, gC, and gD, and only baboon sera reacted weakly with mgG. Human herpes simplex virus type 1 (HSV-1)- and HSV-2-positive sera pools reacted with gB and gD, whereas sera from B virus-infected individuals reacted with all four antigens. These data indicate that gB, gC, gD, and mgG have a high diagnostic potential for B virus serodiagnosis in macaques, whereas mgG may be a valuable antigen for discrimination between antibodies induced by B virus and those induced by other, closely related alphaherpesviruses, including HSV-1 and -2.