Immunodominance in Mouse and Human CD4+ T-Cell Responses Specific for the Bordetella pertussis Virulence Factor P.69 Pertactin

P.69 pertactin (P.69 Prn), an adhesion molecule from the causative agent of pertussis, Bordetella pertussis, is present in cellular and most acellular vaccines that are currently used worldwide. Although both humoral immunity and cellular immunity directed against P.69 Prn have been implicated in protective immune mechanisms, the identities of CD4⁺ T-cell epitopes on the P.69 Prn protein remain unknown. Here, a single I-A^d-restricted B. pertussis conserved CD4⁺ T-cell epitope at the N terminus of P.69 Prn was identified by using a BALB/c T-cell hybridoma. The epitope appeared immunodominant among four other minor strain-conserved P.69 Prn epitopes recognized after vaccination and B. pertussis infection, and it was capable of evoking a Th1/Th17-type cytokine response. B. pertussis P.69 Prn immune splenocytes did not cross-react with natural variants of the epitope as present in Bordetella parapertussis and Bordetella bronchiseptica. Finally, it was found that the immunodominant P.69 Prn epitope is broadly recognized in the human population by CD4⁺ T cells in an HLA-DQ-restricted manner. During B. pertussis infection, the epitope was associated with a Th1-type CD4⁺ T-cell response. Hence, this novel P.69 Prn epitope is involved in CD4⁺ T-cell immunity after B. pertussis vaccination and infection in mice and, more importantly, in humans. Thus, it may provide a useful tool for the evaluation of the type, magnitude, and maintenance of B. pertussis-specific CD4⁺ T-cell mechanisms in preclinical and clinical vaccine studies.     

Direct projections from the sacral spinal cord to the medial preoptic area in cat and guinea pig

The medial preoptic area (MPO) plays an important role in many behavioral, autonomic and endocrine functions, including micturition and genital responses. Although afferents of the MPO have been studied extensively, it is unknown whether direct lumbosacral-MPO projections exist that could convey afferent information from the pelvic organs. We hypothesized that, if such direct projections exist, MPO projecting cells would be located in the lateral part of the sacral cord, where primary afferents from pelvic and pudendal nerves terminate. We used retro- and anterograde tracing techniques in cat and guinea pig to study this. In cats, injections in the MPO resulted in labeled cells throughout the spinal cord, but with the highest density in the S1–S2 segments. In guinea pigs, labeled cells were found exclusively in the S1–S3 segments after MPO injections. Labeled cells in the sacral segments were not located in the lateral parts of the gray matter, but were found in the medial laminae VI–VII and dorsal lamina VIII in cats, and mainly in lamina X in guinea pigs. Anterograde tracing results after injections in the sacral cord in cats or guinea pigs showed labeled fibers in the MPO, just ventral to the anterior commissure. The central location of the cells of origin within the sacral cord, together with the termination pattern of the spino-MPO projections, strongly suggest a role for the spino-MPO pathway in the sensory relay of pelvic viscera, important for micturition and genital responses.     

Molecular characterization and physical localization of highly repetitive DNA sequences from Brazilian Alstroemeria species

Highly repetitive DNA sequences were isolated from genomic DNA libraries of Alstroemeria psittacina and A. inodora. Among the repetitive sequences that were isolated, tandem repeats as well as dispersed repeats could be discerned. The tandem repeats belonged to a family of interlinked Sau3A subfragments with sizes varying from 68–127 bp, and constituted a larger HinfI repeat of approximately 400 bp. Southern hybridization showed a similar molecular organization of the tandem repeats in each of the Brazilian Alstroemeria species tested. None of the repeats hybridized with DNA from Chilean Alstroemeria species, which indicates that they are specific for the Brazilian species. In-situ localization studies revealed the tandem repeats to be localized in clusters on the chromosomes of A. inodora and A. psittacina: distal hybridization sites were found on chromosome arms 2PS, 6PL, 7PS, 7PL and 8PL, interstitial sites on chromosome arms 2PL, 3PL, 4PL and 5PL. The applicability of the tandem repeats for cytogenetic analysis of interspecific hybrids and their role in heterochromatin organization are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

FISH mapping and molecular organization of the major repetitive sequences of tomato

This paper presents a bird’s-eye view of the major repeats and chromatin types of tomato. Using fluorescence in-situ hybridization (FISH) with Cot-1, Cot-10 and Cot-100 DNA as probes we mapped repetitive sequences of different complexity on pachytene complements. Cot-100 was found to cover all heterochromatin regions, and could be used to identify repeat-rich clones in BAC filter hybridization. Next we established the chromosomal locations of the tandem and dispersed repeats with respect to euchromatin, nucleolar organizer regions (NORs), heterochromatin, and centromeres. The tomato genomic repeats TGRII and TGRIII appeared to be major components of the pericentromeres, whereas the newly discovered TGRIV repeat was found mainly in the structural centromeres. The highly methylated NOR of chromosome 2 is rich in [GACA]₄, a microsatellite that also forms part of the pericentromeres, together with [GA]₈, [GATA]₄ and Ty1-copia. Based on the morphology of pachytene chromosomes and the distribution of repeats studied so far, we now propose six different chromatin classes for tomato: (1) euchromatin, (2) chromomeres, (3) distal heterochromatin and interstitial heterochromatic knobs, (4) pericentromere heterochromatin, (5) functional centromere heterochromatin and (6) nucleolar organizer region.     

Emotional dysfunction in schizophrenia spectrum psychosis: the role of illness perceptions

BACKGROUND: Assessing illness perceptions has been useful in a range of medical disorders. This study of people with a recent relapse of their psychosis examines the relationship between illness perception, their emotional responses and their attitudes to medication. METHOD: One hundred patients diagnosed with a non-affective psychotic disorder were assessed within 3 months of relapse. Measures included insight, self-reported illness perceptions, medication adherence, depression, self-esteem and anxiety. RESULTS: Illness perceptions about psychosis explained 46, 36 and 34% of the variance in depression, anxiety and self-esteem respectively. However, self-reported medication adherence was more strongly associated with a measure of insight. CONCLUSIONS: Negative illness perceptions in psychosis are clearly related to depression, anxiety and self-esteem. These in turn have been linked to symptom maintenance and recurrence. Clinical interventions that foster appraisals of recovery rather than of chronicity and severity may therefore improve emotional well-being in people with psychosis. It might be better to address adherence to medication through direct attempts at helping them understand their need for treatment.     

Monoclonal antibodies against the 70-kilodalton iron-regulated protein of Neisseria meningitidis are bactericidal and strain specific.

When grown under iron limitation, Neisseria meningitidis expresses a number of outer membrane proteins (OMPs), one of which is a 70-kilodalton (kDa) major OMP. After immunization of mice with outer membrane preparations of iron-depleted cells of strain H44/76 (B:15:P1.7,16), hybridoma cell lines producing monoclonal antibodies against the 70-kDa OMP were obtained. Some of these monoclonal antibodies demonstrated strong bactericidal activity against the homologous strain H44/76 in the presence of human complement, suggesting potential application of the 70-kDa OMP as a vaccine component. However, none of the 10 selected monoclonal antibodies was able to recognize the corresponding protein from five heterologous strains of various serosubtyping characteristics. A polyclonal anti-70-kDa OMP serum also did not react with the other strains. This result shows that immunodominant surface-exposed epitopes of the meningococcal 70-kDa iron-limitation-inducible OMP are strain specific.     

Frequency characteristics and nonlinear features of responses of cat dorsal horn neurons to random stimulation of cutaneous afferents

The system between cutaneous (suralis) afferents and dorsal horn neurons was studied for comparison with studies previously performed on the motor axon-Renshaw cell system, using the same methods. In anaesthetized or decerebrated cats, 27 dorsal horn neurons of segments L5 to S1 were recorded extracellularly in depths of 1-2.3 mm from cord dorsum. Cutaneous afferents in branches of the ipsilateral suralis nerve were stimulated with sequences of randomly occurring electrical pulses at two levels of mean rate. The responses of the dorsal horn neurons to the stimuli were evaluated in the frequency and time domain. Calculation of coherence, gain and phase functions (via spectral analysis) showed that the frequency response depended on the precise pattern on cell discharge and could vary from broad-band to low-pass or occasionally band-pass characteristics. There were minor differences in these characteristics with those of Renshaw cells. A special type of nonlinear analysis, using conditional peristimulus-time histograms, showed that the responses to test stimuli were facilitated, depressed or both by conditioning stimuli occurring some tens to a few hundred milliseconds before. Early and late response components could be conditioned individually and differently. Exponential fits to such conditioning curves yielded two time constants for depression (means of 21 and 94 ms) and one for facilitation (14 ms). Similar conditioning effects and time constants were previously found for the motor axon-Renshaw cell system although a few differences were apparent. By analogy, it is suggested that part of the long-lasting conditioning effects (with long time constants) are probably due to presynaptic mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)     

β₂-Agonists and physical performance: a systematic review and meta-analysis of randomized controlled trials

Inhaled β?-agonists are commonly used as bronchodilators in the treatment of asthma. Their use in athletes, however, is restricted by anti-doping regulations. Controversies remain as to whether healthy elite athletes who use bronchodilators may gain a competitive advantage. The aim of this systematic review and meta-analysis is to assess the effects of inhaled and systemic β?-agonists on physical performance in healthy, non-asthmatic subjects. To this end, MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched up to August 2009. Reference lists were searched for additional relevant studies. The search criteria were for randomized controlled trials examining the effect of inhaled or systemic β?-agonists on physical performance in healthy, non-asthmatic subjects. Two authors independently performed the selection of studies, data extraction and risk of bias assessment. Parallel-group and crossover trials were analysed separately. Mean difference (MD) and 95% confidence intervals were calculated for continuous data and, where possible, data were pooled using a fixed effects model. Twenty-six studies involving 403 participants (age range 7-30 years) compared inhaled β?-agonists with placebo. No significant effect could be detected for inhaled β?-agonists on maximal oxygen consumption (VO?(max)) [MD -0.14?mL?·?kg?1?·?min?1; 95% CI -1.07, 0.78; 16 studies], endurance time to exhaustion at 105-110% VO?(max) (MD -1.5 s; 95% CI -15.6, 12.6; four studies), 20-km time trial duration (MD -4.4 s; 95% CI -23.5, 14.7; two studies), peak power (MD -0.14 W?·?kg?1; 95% CI -0.54, 0.27; four studies) and total work during a 30-second Wingate test (MD 0.80 J?·?kg?1; 95% CI -2.44, 4.05; five studies). Thirteen studies involving 172 participants (age range 7-22 years) compared systemic β?-agonists with placebo, with 12 studies involving oral and one study involving intravenous salbutamol. A significant effect was detected for systemic β?-agonists on endurance time to exhaustion at 80-85% VO?(max) (MD 402 s; 95% CI 34, 770; two studies), but not for VO?(max) (placebo 42.5?±?1.7?mL?·?kg?1?·?min?1, salbutamol 42.1?±?2.9?mL?·?kg?1?·?min?1, one study), endurance time to exhaustion at 70% VO?(max) (MD 400 s; 95% CI -408, 1208; one study) or power output at 90% VO?(max) (placebo 234.9?±?16 W, salbutamol 235.5?±?18.1 W, one study). A significant effect was shown for systemic β?-agonists on peak power (MD 0.91 W?·?kg?1; 95% CI 0.25, 1.57; four studies), but not on total work (MD 7.8 J?·?kg?1; 95% CI -3.3, 18.9; four studies) during a 30-second Wingate test. There were no randomized controlled trials assessing the effects of systemic formoterol, salmeterol or terbutaline on physical performance. In conclusion, no significant effects were detected for inhaled β?-agonists on endurance, strength or sprint performance in healthy athletes. There is some evidence indicating that systemic β?-agonists may have a positive effect on physical performance in healthy subjects, but the evidence base is weak.