Low prevalence of antibodies against heat shock protein 10 of Chlamydophila pneumoniae in patients with coronary heart disease

In this study the prevalence of antibodies against the heat shock protein 10 (HSP10) of Chamydophila pneumoniae (CP) (as assessed by ELISA) in patients with coronary heart disease (CHD) and seropositive or seronegative to CP, as assessed by microimmunofluorescence (MIF), was investigated. The controls were age- and sex-matched healthy subjects. The HSP10 preparation used throughout this study was a 6-his-tagged recombinant protein preliminarily shown to be immunogenic in mice. Low level IgG reactivity against CP-HSP10 was detected in 19 out of 200 and 5 out of 100 CHD patients and controls, respectively. No IgM or IgA isotypes were found. Furthermore, there was no difference in the frequency or level of anti-HSP10 IgG between CP-positive and CP-negative sera either in patients (11/140=7.9% vs. 8/60=13%) or in healthy subjects (3/40=7.5% vs. 2/60=3.3%). Overall, our data indicate that CP-HSP10, at variance with CP-HSP60, to which it is genetically and physiologically linked, should not be regarded as a major expressed immunogen or a marker of infection by CP in CHD patients.     

The role of the pineal gland in the photoperiodic control of bird song frequency and repertoire in the house sparrow, Passer domesticus

Temperate zone birds are highly seasonal in many aspects of their physiology. In mammals, but not in birds, the pineal gland is an important component regulating seasonal patterns of primary gonadal functions. Pineal melatonin in birds instead affects seasonal changes in brain song control structures, suggesting the pineal gland regulates seasonal song behavior. The present study tests the hypothesis that the pineal gland transduces photoperiodic information to the control of seasonal song behavior to synchronize this important behavior to the appropriate phenology. House sparrows, Passer domesticus, expressed a rich array of vocalizations ranging from calls to multisyllabic songs and motifs of songs that varied under a regimen of different photoperiodic conditions that were simulated at different times of year. Control (SHAM) birds exhibited increases in song behavior when they were experimentally transferred from short days, simulating winter, to equinoctial and long days, simulating summer, and decreased vocalization when they were transferred back to short days. When maintained in long days for longer periods, the birds became reproductively photorefractory as measured by the yellowing of the birds' bills; however, song behavior persisted in the SHAM birds, suggesting a dissociation of reproduction from the song functions. Pinealectomized (PINX) birds expressed larger, more rapid increases in daily vocal rate and song repertoire size than did the SHAM birds during the long summer days. These increases gradually declined upon the extension of the long days and did not respond to the transfer to short days as was observed in the SHAM birds, suggesting that the pineal gland conveys photoperiodic information to the vocal control system, which in turn regulates song behavior.     

Helicobacter pylori as a class I carcinogen: physiopathology and management strategies

The gram-negative bacterium Helicobacter pylori is known as a persistent colonizer of the human stomach, and probably less known is that it is also involved in extraintestinal diseases. Public awareness of its contribution in the development of gastric cancer is less than 15 years old. The efficacy of the current therapies based on antibiotics against H. pylori has been limited by difficulties such as antibiotic resistance and recurrence. As a consequence, the development of promising vaccines was prompted as the best preventive measure. Unfortunately, so far vaccines failed the transition from animal models to human trials. This keynote presentation is to provide a bird's eye view of H. pylori-related gastric diseases, including gastric cancer, with a synthesis of the molecular mechanisms involved, and an exhaustive presentation and discussion of the current therapeutic guidelines and future strategies for prevention or therapy.     

Toward Developing a Universal Treatment for Fungal Disease Using Radioimmunotherapy Targeting Common Fungal Antigens

Background

Previously, we demonstrated the ability of radiolabeled antibodies recognizing the cryptococcal polysaccharide capsule to kill Cryptococcus neoformans both in vitro and in infected mice. This approach, known as radioimmunotherapy (RIT), uses the exquisite ability of antibodies to bind antigens to deliver microbicidal radiation. To create RIT reagents which would be efficacious against all major medically important fungi, we have selected monoclonal antibodies (mAbs) to common surface fungal antigens such as heat shock protein 60 (HSP60), which is found on the surface of diverse fungi; beta (1,3)-glucan, which is a major constituent of fungal cell walls; ceramide which is found at the cell surface, and melanin, a polymer present in the fungal cell wall.

Methods

MAbs 4E12, an IgG2a to fungal HSP60; 2G8, an IgG2b to beta-(1,3)-glucan; and 6D2, an IgM to melanin, were labeled with the alpha particle emitting radionuclide 213-Bismuth (²¹³Bi) using the chelator CHXA”. B11, an IgM antibody to glucosylceramide, was labeled with the beta emitter 188-Rhenium (¹⁸⁸Re). Model organisms Cryptococcus neoformans and Candida albicans were used to assess the cytotoxicity of these compounds after exposure to either radiolabeled mAbs or controls.

Results

²¹³Bi-mAbs to HSP60 and to the beta-(1,3)-glucan each reduced the viability of both fungi by 80–100%. The ²¹³Bi-6D2 mAb to melanin killed 22% of C. neoformans, but did not kill C. albicans. B11 mAb against fungal ceramide was effective against wild-type C. neoformans, but was unable to kill a mutant lacking the ceramide target. Unlabeled mAbs and radiolabeled irrelevant control mAbs caused no killing.

Conclusion

Our results suggest that it is feasible to develop RIT against fungal pathogens by targeting common antigens and such an approach could be developed against fungal diseases for which existing therapy is unsatisfactory.

     

New immunotherapeutic strategies to control vaginal candidiasis

The widespread occurrence of mucosal infections caused by Candida, in particular recurrent vulvovaginal candidiasis among fertile-age women, together with the paucity of safe candidacidal antimycotics, have prompted a great number of investigations into the immunotherapy of candidal vaginitis. This article will discuss three different experimental approaches demonstrated to be potentially transferable to human disease: (1) the use of antibodies against well-defined cell-surface adhesins or enzymes; (2) the generation of yeast killer-toxin-like candidacidal anti-idiotypic antibodies and their engineered molecular derivatives (e.g. single chains, peptides); and (3) the generation of therapeutic vaccines and immunomodulators.     

The Ag85B protein of Mycobacterium tuberculosis may turn a protective immune response induced by Ag85B-DNA vaccine into a potent but non-protective Th1 immune response in mice

Clarifying how an initial protective immune response to tuberculosis may later loose its efficacy is essential to understand tuberculosis pathology and to develop novel vaccines. In mice, a primary vaccination with Ag85B-encoding plasmid DNA (DNA-85B) was protective against Mycobacterium tuberculosis (MTB) infection and associated with Ag85B-specific CD4+ T cells producing IFN-gamma and controlling intramacrophagic MTB growth. Surprisingly, this protection was eliminated by Ag85B protein boosting. Loss of protection was associated with a overwhelming CD4+ T cell proliferation and IFN-gamma production in response to Ag85B protein, despite restraint of Th1 response by CD8+ T cell-dependent mechanisms and activation of CD4+ T cell-dependent IL-10 secretion. Importantly, these Ag85B-responding CD4+ T cells lost the ability to produce IFN-gamma and control MTB intramacrophagic growth in coculture with MTB-infected macrophages, suggesting that the protein-dependent expansion of non-protective CD4+ T cells determined dilution or loss of the protective Ag85B-specific CD4+ induced by DNA-85B vaccination. These data emphasize the need of exerting some caution in adopting aggressive DNA-priming, protein-booster schedules for MTB vaccines. They also suggest that Ag85B protein secreted during MTB infection could be involved in the instability of protective anti-tuberculosis immune response, and actually concur to disease progression.