Partial destruction of Borrelia burgdorferi within ticks that engorged on OspE- or OspF-immunized mice.

We determined whether Borrelia burgdorferi outer surface proteins (Osps) E and F could elicit immune responses useful for a Lyme disease vaccine. Thirty days after challenge with B. burgdorferi, mice produced antibodies to OspE but not OspF, whereas antibodies to OspF were present in sera of mice obtained 90 days after infection. Examination of sera from patients with Lyme disease revealed antibodies to OspF in a small number (14%) of early-stage disease patients but in a majority (58%) of patients with late-stage disease, while antibodies to OspE were rarely detected in patients. Mice immunized with recombinant OspE or OspF produced high titers of antibodies to OspE or OspF, respectively. OspF-immunized mice were partially protected from both intradermal syringe challenge and tick-mediated transmission of B. burgdorferi while vaccination with OspE did not confer immunity. B. burgdorferi organisms were, however, substantially destroyed within ticks that engorged on either OspE- (75% reduction in the number of spirochetes within the ticks, compared with controls) or OspF (90% reduction in the number of spirochetes within the ticks)-immunized mice.     

Impaired fear memories are correlated with subregion-specific deficits in hippocampal and amygdalar LTP

Inbred mouse strains have different genetic backgrounds that likely influence memory and long-term potentiation (LTP). LTP, a form of synaptic plasticity, is a candidate cellular mechanism for some forms of learning and memory. Strains with impaired fear memory may have selective LTP deficits in different hippocampal subregions or in the amygdala. The authors assessed fear memory in 4 inbred strains: C57BL/6NCrlBR (B6), 129S1/SvImJ (129), C3H/HeJ (C3H), and DBA/2J (D2). The authors also measured LTP in the hippocampal Schaeffer collateral (SC) and medial perforant pathways (MPP) and in the basolateral amygdala. Contextual and cued fear memory, and SC and amygdalar LTP, were intact in B6 and 129, but all were impaired in C3H and D2. MPP LTP was similar in all 4 strains. Thus, SC, but not MPP, LTP correlates with hippocampus-dependent contextual memory expression, and amygdalar LTP correlates with amygdala-dependent cued memory expression, in these inbred strains.     

Construction and characterization of affibody-Fc chimeras produced in Escherichia coli

Affibody-Fc chimeras were constructed by genetic fusion between different affibody affinity proteins with prescribed specificities and an Fc fragment derived from human IgG. Using affibody ligands previously selected for binding to respiratory syncytial virus (RSV) surface protein G and Thermus aquaticus (Taq) DNA polymerase, respectively, affibody-Fc fusion proteins showing spontaneous Fc fragment-mediated homodimerization via disulfide bridges were produced in Escherichia coli and affinity purified on protein A Sepharose from bacterial periplasms at yields ranging between 1 and 6 mg/l culture. Further characterization of the chimeras using biosensor technology showed that the affibody moieties have retained high selectivities for their respective targets after fusion to the Fc fragment. Avidity effects in the target binding were observed for the affibody-Fc chimeras compared to monovalent affibody fusion proteins, indicating that both affibody moieties in the chimeras were accessible and contributed in the binding. Fusion of a head-to-tail dimeric affibody moiety to the Fc fragment resulted in tetravalent affibody constructs which showed even more pronounced avidity effects. In addition, the Fc moiety of the chimeras was demonstrated to be specifically recognized by anti-human IgG antibody enzyme conjugates. One application for this class of "artificial antibodies" was demonstrated in a western blotting experiment in which one of the anti-RSV surface protein G affibody-Fc chimeras was demonstrated to be useful for specific detection of the target protein in a complex background consisting of a total E. coli lysate. The results show that through the replacement of the Fab portion of an antibody for an alternative binding domain based on a less complicated structure, chimeric proteins compatible with bacterial production routes containing both antigen recognition domains and Fc domains can be constructed. Such "artificial antibodies" should be interesting alternatives to, for example, whole antibodies or scFv-Fc fusions as detection devices and in diagnostic or therapeutic applications.     

Efficient generation of respiratory syncytial virus (RSV)-neutralizing human MoAbs via human peripheral blood lymphocyte (hu-PBL)-SCID mice and scFv phage display libraries

RSV is one of the major causes of pneumonia and bronchiolitis in infants and young children and is associated with high mortality. RSV neutralizing human antibody (hu-Ab) is known to mediate resistance to viral infection as well as to be an effective treatment for severe lower respiratory tract RSV infection. We have previously demonstrated that human primary and secondary immune responses can be established in severe combined immunodeficient mice engrafted with human peripheral blood lymphocytes (hu-PBL-SCID). By combining this animal model with the single-chain Fv antibody (scFv) phage display library technique, we were able to investigate further its clinical potential by generating a panel of human scFvs that exhibit both high F glycoprotein (RSV-F) binding affinities ( approximately 108 M(-1)) and strong neutralizing activities against RSV infection in vitro. Sequencing analysis of the randomly isolated anti-RSV-F scFv clones revealed that they were derived from different VH families with mutations in the complementarity-determining region 1 (CDR1). The results suggest that: (i) RSV-F-specific human immune responses and affinity maturation can be induced in hu-PBL-SCID mice; and (ii) this approach can be applied to generate large numbers of human scFvs with therapeutic potential. Despite the fact that hu-PBL-SCID mouse and human scFv phage display library have individually been established, our approach contributes a simple and significant step toward the generalization of antigen-specific human monoclonal antibody (hu-MoAb) production and their clinical applications.     

Pulmonary granuloma caused by Pseudomonas andersonii sp nov

Pulmonary granuloma is a common lesion for which gram-negative bacteria are rarely implicated as a cause. Hence, most physicians are unaware of this etiology. We isolated a gram-negative bacterium from a surgically resected pulmonary granuloma in a 42-year-old, nonimmunocompromised woman. Within the necrotizing granuloma, numerous organisms also were demonstrated by Gram stain, suggesting a cause-disease relationship. Characterization of the bacterium by sequence analysis of the 16S ribosomal gene, cellular fatty acid profiling, and microbiologic studies revealed a novel bacterium with a close relationship to Pseudomonas. We propose a new species for the bacterium, Pseudomonas andersonii. These results suggest that the differential diagnosis of a lung granuloma also should include this gram-negative bacterium as a potential causative agent, in addition to the more common infections caused by acid-fast bacilli and fungi. This bacterium was shown to be susceptible to most antibiotics that are active against gram-negative bacteria.     

Noradrenergic and opioidergic alterations in neuropathy in different rat strains

The Fischer 344 (F344) rat strain differs from the Lewis strain in the response to neuropathic pain. Recently, we found that F344 rats totally recover from mechanical allodynia induced by chronic constriction injury (CCI) of the sciatic nerve 28 days after surgery whereas Lewis rats are initiating their recovery at this time point. Thus, the use of this neuropathic pain model in these different rat strains constitutes a good strategy to identify possible target genes involved in the development of neuropathic pain. Since differences between Lewis and F344 rats in their response to pain stimuli in acute pain models have been related to differences in the endogenous opioid and noradrenergic systems, we aimed to determine the levels of expression of key genes of both systems in the spinal cord and dorsal root ganglia (DRG) of both strains 28 days after CCI surgery. Real time RT-PCR revealed minimal changes in gene expression in the spinal cord after CCI despite the strain considered, but marked changes in DRG were observed. A significant upregulation of prodynorphin gene expression occurred only in injured DRG of F344 rats, the most resistant strain to neuropathic pain. In addition, we found a significant downregulation of tyrosine hydroxylase and proenkephalin gene expression levels in both strains whereas δ-opioid receptor was found to be significantly downregulated only in injured DRG of Lewis rats although the same trend was observed in F344 rats. The data strongly suggest that dynorphins could be involved in strain differences concerning CCI resistance.     

Plasmid-mediated quinolone resistance determinant qnrS in Enterobacter cloacae

PCR was used to investigate the occurrence of the plasmid-encoded quinolone resistance determinants qnrA and qnrS among diarrhoeagenic enterobacterial isolates recovered from Hanoi, Vietnam, during the period March 2001 to April 2002. In total, 162 Escherichia coli isolates, 28 Shigella isolates and three Enterobacter cloacae isolates were negative for qnrA, while a single Ent. cloacae isolate harboured a 50-kb qnrS-positive conjugative plasmid. Cloning and sequencing identified a qnrS gene bracketed by open reading frames identical to those surrounding the qnrS gene of a Shigella flexneri isolate from Japan, thereby suggesting a common mechanism of acquisition.     

The distribution and cellular localization of the serotonin 1C receptor mRNA in the rodent brain examined by in situ hybridization histochemistry. Comparison with receptor binding distribution

The regional distribution and cellular localization of mRNA coding for the serotonin 1C receptor were investigated in tissue sections of mouse and rat brain by in situ hybridization histochemistry. Several 32P-labelled riboprobes derived from mouse genomic clones were used. The serotonin 1C receptor binding sites were visualized autoradiographically and quantified using [3H]mesulergine as ligand, in the presence of spiperone to block serotonin 1C receptors. Strong hybridization signal was observed in the choroid plexus of all brain ventricles. High levels of hybridization were also seen in the anterior olfactory nucleus, pyriform cortex, amygdala, some thalamic nuclei, especially the lateral habenula, the CA3 area of the hippocampal formation, the cingulate cortex, some components of the basal ganglia and associated areas, particularly the nucleus subthalamicus and the substantia nigra. The midbrain and brainstem showed moderate levels of hybridization. The distribution of the serotonin 1C receptor mRNA corresponded well to that of the serotonin 1C receptors. The highest levels of serotonin 1C receptor binding were observed in the choroid plexus. In addition, significant levels of the serotonin 1C receptor binding were seen in the anterior olfactory nucleus, pyriform cortex, nucleus accumbens, ventral aspects of the striatum, paratenial and paracentral thalamic nuclei, amygdaloid body and substantia nigra pars reticulata. The cingulate and retrosplenial cortices as well as the caudal aspects of the hippocampus (CA3) were also labelled. Binding in brainstem and medulla was low and homogeneously distributed. No significant binding was seen in the habenular and subthalamic nuclei. Similar findings were obtained in rat brain. These results demonstrate that, in addition to their enrichment in the choroid plexus, the serotonin 1C receptor mRNA and binding sites are heterogeneously distributed in the rodent brain and thus could be involved in the regulation of many different brain functions. The combination of in situ hybridization histochemistry with receptor autoradiography opens the possibility of examining the regulation of the serotonin 1C receptor synthesis after pharmacological or physiological alterations.     

A novel dystrophin isoform is required for normal retinal electrophysiology

Dystrophin is present in the outer plexiform layer of the retinaand is required for normal retinal function as measured by electroretinography.We describe the identification of a novel isoform of dystrophln(Dp260) present in the mouse retina. The unIque 5' terminusof the mRNA originates from a newly identified exon and is splicedin frame to exon 30 of the Duchenne muscular dystrophy (DMD)gene. The retinal isoform of dystrophln has 13 novel amino acidsas its N-terminus followed by most of the dystrophin rod domainand the cysteine-rich C-terminal domains. Analysis of mousetissues indicated this isoform of dystrophin Is expressed inretina, brain and cardiac tissue. Comparison of retinal electrophysiologyin mdx and mdx^cv3 mouse suggests that Dp260 is required fornormal retinal function.     

Identical abnormality of the short arm of chromosome 18 in two Philadelphia-positive chronic myelocytic leukemia patients with erythroblastic transformation,resulting in duplication of BCR-ABL1 fusion

Two patients with Ph-positive chronic myelocytic leukemia in erythroblastic transformation and rearrangement of the short arm of chromosome 18 are reported. Fluorescence in situ hybridization studies showed that the 18p rearrangement resulted from translocation of the main part of chromosome 22 long arm to 18p, including BCR-ABL1 fusion. The 18p abnormality resulted, thus, in loss of 18p and duplication of BCR-ABL1 in both patients. The possible relation to the erythroblastic type of blastic phase is briefly discussed. In addition an apparently intact germline ABL1 gene was duplicated and inserted into chromosome 6 at band p21 in one of these patients.