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There is considerable public health interest in licensing safe and effective combination vaccines. Because combination vaccines may progress rapidly from phase 1 to a pivotal phase 2 immunogenicity trial, a rigorous approach to address product issues early in development is warranted. Clinical studies to evaluate the safety, immunogenicity, and (when necessary) clinical end point efficacy of combination vaccines should be randomized and well controlled in most cases. A large phase 3 safety study (i.e., a study that enrolls thousands of vaccinees) should be included in the development plan if a phase 3 (clinical end point) efficacy trial will not be conducted. Often, the new combination vaccine under development contains immunogens that have all been previously licensed, have demonstrated efficacy in earlier clinical trials, or both. For such products, comparative immunogenicity data may be sufficient to support efficacy. When applicable, clinical data to support simultaneous administration with other relevant vaccines should be obtained. Given the complexity of combination vaccine development, early consultation with United States Food and Drug Administration can be invaluable.

The C-5 sterol desaturase gene (ERG3), essential for yeast ergosterol biosynthesis, was cloned and sequenced from Candida albicans by homology with the Saccharomyces cerevisiae ERG3. The ERG3 ORF contained 1158bp and encoded 386 deduced amino acids. The clone was used to transform a gal1 mutant derived from the Darlington strain of C. albicans, using galactose selection. The Darlington strain is known to lack Delta(5,6) sterols, i.e. to have an erg3 phenotype (Howell, S.A., et al., 1990. J. Appl. Bacteriol. 69, 692-696). The transformant (CDTR1) contained six tandem integrated ERG3GAL1 repeats, had double the abundance of ERG3 transcript found in the host strain, and synthesized ergosterol, a Delta(5,6) sterol.The Darlington strain was noted to have an abundance of ERG3 transcript. Both ERG3 alleles in Darlington were cloned and sequenced in order to look for changes that might explain the erg3 phenotype. One allele, called Dar-2, contained a stop codon in place of tryptophan-292. The other ERG3 allele, called Dar-1, had changes in three amino acids, two of which were conserved in three fungal and one plant species. EcoRI genomic fragments containing ERG3 from the Dar-1 allele and from B311, the wild-type strain, were inserted into the plasmid pRS316 and used to transform a Saccharomyces cerevisiae erg3,ura3 mutant using uracil selection. The 4.1kb ERG3 fragments from the B311 and Dar-1 both contained 1. 4kb 5' and 1.5kb 3' flanking sequences around the coding region. Transformants with ERG3 from B311 but not from Dar-1 showed restored ergosterol synthesis. One or more of these three deduced amino acids in the Dar-1 allele of ERG3 appeared critical for function.

Sequential Candida glabrata isolates were obtained from the mouth of a patient infected with human immunodeficiency virus type 1 who was receiving high doses of fluconazole for oropharyngeal thrush. Fluconazole-susceptible colonies were replaced by resistant colonies that exhibited both increased fluconazole efflux and increased transcripts of a gene which codes for a protein with 72.5% identity to Pdr5p, an ABC multidrug transporter in Saccharomyces cerevisiae . The deduced protein had a molecular mass of 175 kDa and was composed of two homologous halves, each with six putative transmembrane domains and highly conserved sequences of ATP-binding domains. When the earliest and most azole-susceptible isolate of C. glabrata from this patient was exposed to fluconazole, increased transcripts of the PDR5 homolog appeared, linking azole exposure to regulation of this gene.

The World Health Organization (WHO) has estimated that 40 million individuals are living with HIV-1 as of 2003 (UNAIDS/WHO, 2003). In addition, approximately 14,000 people are newly infected with HIV-1 each day, worldwide (UNAIDS/WHO, 2003). Thus, there is tremendous public health interest in developing safe and effective preventive HIV-1 vaccines. Vaccines have proven to be one of the most effective means of preventing serious infectious diseases. The contribution of vaccines toward markedly decreasing the incidence of many of the once-common childhood infectious diseases has been particularly notable (CDC, 1999). Thus, the public health goal is to develop an effective HIV-1 vaccine that will achieve a similar success in controlling the AIDS epidemic. However, the development of an HIV-1 vaccine has a unique and complex set of scientific, clinical, social, ethical, and economic challenges (Amara and Robinson, 2002; Esparza and Osmanov, 2003; Fast et al., 1995; Goldenthal et al.,1998; Klausner et al., 2003; Nathanson and Mathieson, 2000). Collaborative efforts in the development of an effective HIV-1 vaccine are ongoing among government agencies, academic investigators, and pharmaceutical and biotechnology companies. Even more organization on a global scale has been strongly encouraged (Klausner et al., 2003).

Sterol Δ 22 -desaturase has been purified from a strain of Candida glabrata with a disruption in the gene encoding sterol 14α-demethylase (cytochrome P-45051; CYP51). The purified cytochrome P-450 exhibited sterol Δ 22 -desaturase activity in a reconstituted system with NADPH–cytochrome P-450 reductase in dilaurylphosphatidylcholine, with the enzyme kinetic studies revealing a K m for ergosta-5,7-dienol of 12.5 μM and a V max of 0.59 nmol of this substrate metabolized/min/nmol of P-450. This enzyme is encoded by CYP61 ( ERG5 ) in Saccharomyces cerevisiae , and homologues have been shown in the Candida albicans and Schizosaccharomyces pombe genome projects. Ketoconazole, itraconazole, and fluconazole formed low-spin complexes with the ferric cytochrome and exhibited type II spectra, which are indicative of an interaction between the azole moiety and the cytochrome heme. The azole antifungal compounds inhibited reconstituted sterol Δ 22 -desaturase activity by binding to the cytochrome with a one-to-one stoichiometry, with total inhibition of enzyme activity occurring when equimolar amounts of azole and cytochrome P-450 were added. These results reveal the potential for sterol Δ 22 -desaturase to be an antifungal target and to contribute to the binding of drugs within the fungal cell.

The susceptibility of genetically defined Candida glabrata strains to killing by H2O2 and neutrophils was assessed. Fluconazole-susceptible L5L and L5D strains demonstrated survival rates higher than those of two fluconazole-resistant strains lacking the ERG11 gene coding for 14 alpha-demethylase. Fluconazole resistance can occur by mechanisms which increase fungal susceptibility to oxidative killing by H2O2 and neutrophils.

SUMMARY: We determined the small subunit (18S) ribosomal RNA sequence of the dimorphic fungus Blastomyces dermatitidis. The sequence was compared to that of fourteen other eukaryotic organisms, ten of which were higher fungi, and an evolutionary tree was constructed based on these sequences. B. dermatitidis aligned most closely with the Ascomycetes Neurospora crassa and Podospora anserina, in agreement with previous phylogenetic analysis based on morphological criteria. Phase-specific cDNA clones derived by reverse transcription of RNA isolated from the yeast and mycelial phases of B. dermatitidis were also sequenced. The 18S ribosome sequence was found to be the same in both phases. Heterogeneity was found at both the genomic and RNA level at position 1352.

We report two cases of allergic bronchopulmonary fungal disease (ABPFD) caused by Curvularia sp and associated with allergic fungal sinusitis (AFS). Curvularia lunata was cultured in one case and Curvularia senegalensis was cultured in the other. Based on these cases and a review of the literature, we discuss unusual clinical and pathologic features that can occur in ABPFD. Unusual clinical aspects of ABPFD include associated AFS, absence of asthma, progression to Churg-Strauss angiitis and granulomatosis, concomitant hypersensitivity pneumonitis, and underlying cystic fibrosis. Atypical pathologic features that may occur in ABPFD include follicular bronchiolitis, xanthomatous bronchiolitis, limited tissue invasion, fungus balls, and association with unusual fungi. Prominent follicular bronchiolitis and xanthomatous bronchiolitis were misleading histologic features in one of our cases and led to a delay in recognition of the diagnosis. Both patients presented primarily with AFS; ABPFD was detected subsequently. This suggests that a small subset of patients with AFS may be at risk for ABPFD. The goal of this review is to increase awareness of unusual clinical and pathologic manifestations of ABPFD. It is hoped that this will result in accurate diagnosis and proper therapy, especially for patients who present with atypical features. Unusual fungal species should be considered in patients who have clinical findings compatible with ABPFD but who do not demonstrate immunologic reactivity to Aspergillus sp, especially Aspergillus fumigatus. In addition, ABPFD should be considered in patients with AFS who develop new pulmonary lesions.