Abstract-Using a vaccine approach, we immunized New Zealand White rabbits with a peptide containing a region of cholesteryl ester transfer protein (CETP) known to be required for neutral lipid transfer function. These rabbits had significantly reduced plasma CETP activity and an altered lipoprotein profile. In a cholesterol-fed rabbit model of atherosclerosis, the fraction of plasma cholesterol in HDL was 42% higher and the fraction of plasma cholesterol in LDL was 24% lower in the CETP-vaccinated group than in the control-vaccinated group. Moreover, the percentage of the aorta surface exhibiting atherosclerotic lesion was 39.6% smaller in the CETP-vaccinated rabbits than in controls. The data reported here demonstrate that CETP activity can be reduced in vivo by vaccination with a peptide derived from CETP and support the concept that inhibition of CETP activity in vivo can be antiatherogenic. In addition, these studies suggest that vaccination against a self-antigen is a viable therapeutic strategy for disease management. (Arterioscler

A study was performed to assess the in vivo relevance of the in vitro antagonism between fluconazole and amphotericin B against Candida albicans. Combinations of fluconazole and amphotericin B were explored for their efficacies against acute (100% mortality in 2 to 5 days) or less acute (100% mortality in 30 days) invasive candidiasis infections in mice with healthy immune systems and immunocompromised mice. Treatment efficacy was assessed by protection from mortality and/or a reduction in the fungal burden in tissue. In models of acute infection in mice with healthy immune systems or less acute infection in immunocompromised mice, combinations of fluconazole and amphotericin B were superior to fluconazole alone, and the effects were at least additive. Combination therapy was at least as efficacious as amphotericin B alone. In a different model of less acute infection in mice with healthy immune systems, combinations of fluconazole and amphotericin B showed no interactions and were no better than either drug alone. We conclude that combination therapy with fluconazole and amphotericin B is not antagonistic in vivo, in contrast to published in vitro studies, and, consequently, suggest that combination therapy should be considered in the management of clinical candidiasis.

No abstract

dChlamydia trachomatis is the causative agent of the most frequently reported bacterial sexually transmitted infection, the total burden of which is underestimated due to the asymptomatic nature of the infection. Untreated C. trachomatis infections can cause significant morbidities, including pelvic inflammatory disease and tubal factor infertility (TFI). The human immune response against C. trachomatis, an obligate intracellular bacterium, is poorly characterized but is thought to rely on cell-mediated immunity, with CD4؉ and CD8 ؉ T cells implicated in protection. In this report, we present immune profiling data of subjects enrolled in a multicenter study of C. trachomatis genital infection. CD4؉ and CD8 ؉ T cells from subjects grouped into diseasespecific cohorts were screened using a C. trachomatis proteomic library to identify the antigen specificities of recall T cell responses after natural exposure by measuring interferon gamma (IFN-␥) levels. We identified specific T cell responses associated with the resolution of infection, including unique antigens identified in subjects who spontaneously cleared infection and different antigens associated with C. trachomatis-related sequelae, such as TFI. These data suggest that novel and unique C. trachomatis T cell antigens identified in individuals with effective immune responses can be considered as targets for vaccine development, and by excluding antigens associated with deleterious sequelae, immune-mediated pathologies may be circumvented.

No abstract

Conidia, produced by the mycelial phase of dimorphic fungi, are thought to represent the infectious form of the organism but must complete a transition to the tissue-invasive, yeast-like phase for infection to ensue. Preventing such transition should effectively eliminate pathogenicity. Using Blastomyces dermatitidis as a target, murine bronchoalveolar macrophages preferentially blocked phase transition after 4 h of incubation with conidia, relatively sparing the ability of conidia to produce hyphae. H2O2, in relatively high concentrations, demonstrated the same activity. The effects of H2O2 seem irreversible, since H2O2-treated conidia that germinated at 48 h at 25 degrees C were still unable to produce yeasts over the next 5 days when incubated at 37 degrees C. Catalase could not reverse the macrophage-induced inhibition of phase transition, suggesting that nonoxidative defense mechanisms may be operative in vivo. Since conidia do not form mycelia at temperatures found in mammalian hosts, these effects may represent a novel host defense mechanism against dimorphic fungal pathogens.

Summary. The induction of heat-shock proteins has been postulated to play a role not only in thermo-adaptation, but also in phase transition of the dimorphic fungi. In this study, we used yeast and mycelial forms of the thermally dimorphic fungus Paracoccidioides brasiliensis to evaluate the effect of temperature on the induction of the heat-shock response. We also evaluated protein synthesis by P. brasiliensis caused by exposure to low pH and H202. Analysis of protein synthesis by SDS-PAGE disclosed that P. brasiliensis mycelia increased synthesis of all major constitutive proteins when stressed at 37°C and increased synthesis of three non-constitutive proteins of 134, 82 and 28 kDa at 40°C. Yeasts incubated at 40°C showed decreased synthesis of five constitutive proteins (136,98,62,57 and 54 kDa) and the appearance of three new proteins (1 34,82 and 28 kDa). There was a decrease in the synthesis of all major constitutive proteins except for three proteins of 141,136 and 16 kDa when yeast cells were incubated at 25°C. When stressed by low pH and H202, P. brasiliensis yeast increased synthesis of one (1 34 kDa) and five (1 34, 104,82,52 and 40 kDa) non-constitutive proteins, respectively. P. brasiliensis mycelia and yeast forms disclosed the same profile of protein synthesis when stressed at temperatures that trigger phase transition (37°C for mycelia; 25°C for yeast). The same profile of protein synthesis by both forms occurred when the fungi were incubated at 40°C and was similar to that of yeast cells stressed by low pH or H202, but different from the patterns produced by mycelia incubated at 37°C or yeast at 25°C. These results suggest that synthesis of stress proteins by P. brasiliensis mycelia and yeast forms at 40"C, low pH or exposed to H 2 0 2 was associated with adaptation to hostile environments. In contrast, the overall increased and decreased synthesis of major constitutive proteins by mycelia and yeast forms at 37°C and 25°C was associated with phase transition. It is unlikely that the heat-shock proteins produced in these experiments are important in the maintenance of the morphology of yeast or mycelia at their usual temperatures of growth.

The in vitro and in vivo activities of a new broad-spectrum triazole derivative, SCH 51048, against Blastomyces dermatitidis were evaluated. As determined by using the new National Committee for Clinical Laboratory Standards proposed standard for susceptibility testing of yeasts, SCH 51048 was the most active of the four agents tested in vitro against 13 strains of B. dermatitidis. In a well-described murine model of acute pulmonary blastomycosis, SCH 51048 was comparable to amphotericin B and at least 30 times more active than itraconazole. On the basis of these experiments, clinical evaluation of SCH 51048 for the use in treatment of human blastomycosis should proceed.