Immunization with a tumor-cell-lysate-loaded autologous-antigen-presenting-cell-based vaccine in melanoma

The discoveries of human melanoma-associated antigens in molecular terms have renewed interest in peptide- or peptide- and antigen-presenting-cell (APC)-based cancer vaccines. Considering the limited scope of immunization using defined peptides, we have studied an alternative approach of specific immunization with tumor-lysate-loaded autologous APC (adherent peripheral mononuclear cells cultured in 1000 U granulocyte/macrophage-colony-stimulating factor for 14 days) as a surrogate vaccine. Seventeen patients (11 with active metastatic disease) were intradermally immunized with the vaccine in a phased dose escalation (10⁵–10⁷ cells/injection) monthly for 4 months. Thirteen patients completed all four immunizations showing no toxicity (3 patients had to be taken off study because of progressive disease and 1 patient went off study as a result of myocardial infarction due to multi-vessel coronary artery disease). None has shown any immediate or delayed toxicity attributable to the immunization and none has shown any evidence of autoimmunity. One patient showed a partial regression of a subcutaneous nodule. Thirteen patients are alive after 4+ months to 30+ months (17-month median survival for the group). Nine patients showed evidence of delayed-type hypersensitivity at the vaccine sites. Monitoring of biological response in conventional natural killer or cytolytic T lymphocyte assays with pre- and post-immune peripheral blood lymphocytes revealed no consistent differences. The vaccine-infiltrating lymphocytes (VIL) from nine specimens were adequately expanded following in vitro stimulation with the respective autologous-lysate-loaded APC for phenotypic and functional analyses. Five of the nine ex vivo expanded VIL were predominantly CD8⁺. Evidence of an antigen-specific CD8⁺ T cell response (cytotoxicity and/or tumor necrosis factor production) was detected in three of the five CD8⁺ VIL. These observations suggest that this type of vaccine is feasible, that it has biological activity, and that the approach may be improved through additional strategic manipulations. Received: 27 March 1998 / Accepted: 14 May 1998     

Phylogeny of the genus trichoderma based on sequence analysis of the internal transcribed spacer region 1 of the rDNA cluster

Sequences of the internal transcribed spacer region 1 (ITS1) of the ribosomal DNA were used to determine the phylogenetic relationships of species of Trichoderma sect. Pachybasium. To this end, 85 strains-including all the available ex-type strains-were analyzed. Parsimony analysis demonstrated that the section is nonmonophyletic, distributing the 85 strains among three main groups that were supported by bootstrap values. Group A comprises two clades (A1 and A2), with A1 including T. polysporum, T. piluliferum, and T. minutisporum, while A2 included T. hamatum, T. pubescens, and T. strigosum in addition to species previously included in sect. Trichoderma (i.e., T. viride, T. atroviride, and T. koningii). The ex-type strain of T. fasciculatum formed a separate branch basal to clade A. Clade B contained the sect. Pachybasium members T. harzianum, T. fertile, T. croceum, T. longipile, T. strictipile, T. tomentosum, T. oblongisporum, T. flavofuscum, T. spirale, and the anamorphs of Hypocrea semiorbis and H. cf. gelatinosa. Sequence differences among clades A1, A2, and B were in the same order of magnitude as between each of them and T. longibrachiatum, which was used as an outgroup in these analyses. Sequence differences within clades A1, A2, and B were considerably smaller: in some cases (i.e., T. virens and T. flavofuscum; T. strictipile and H. cf. gelatinosa), the ITS1-sequences were identical, suggesting conspecifity. In other cases (e.g., T. crassum and T. longipile; T. harzianum, T. inhamatum, T. croceum, T. fertile, and H. semiorbis; T. hamatum and T. pubescens; and T. viride, T. atroviride, and T. koningii) differences were in the range of 1-3 nt only, suggesting a very close phylogenetic relationship. The sequence of a previously described aggressive mushroom competitor group of T. harzianum strains (Th2) was strikingly different from that of the ex-type strain of T. harzianum and closely related species and is likely to be a separate species. Copyright 1998 Academic Press.     

Candida shehatae — Genetic diversity and phylogenetic relationships with other xylose-fermenting yeasts

The xylose-fermenting yeasts Candida shehatae and Pichia stipitis were compared from extent of nuclear DNA complementarity and ribosomal RNA sequence similarity. Low levels of DNA relatedness confirmed that the two taxa are distinct biological species, but the similarity of rRNA sequences suggests that they only recently diverged. C. shehatae is comprised of three genetically divergent (ca. 50% DNA relatedness) subgroups that were accorded varietal status: C. shehatae var. shehatae, var. Lignosa and var. insectosa. Estimates of phylogenetic distance from rRNA sequence similarity show C. shehatae and P. stipitis to be more closely related to Pachysolen tannophilus than to Saccharomyces cerevisiae, and that all of these budding yeasts are well separated from Schizosaccharomyces pombe.     

Kuraishia MolischianaSp. Nov., the Teleomorph of Candida Molischiana

Thirty-two strains, many of them isolated from wood-associated habitats, and designated as Kuraishia (Pichia) capsulata and Candida molischiana according to their phenotype, exhibited two types of HaeIII restriction fragment patterns of their small subunit rDNA with the neighboring ITS. One fragment pattern corresponded to that of the type strain of K. capsulata, whereas the other pattern was unique to the typestrain of C. molischiana. Sequencing of the D1/D2 domain of the large subunit rDNA confirmed that the different HaeIII restriction fragment patterns of small subunit rDNA with the neighboring ITS reliably distinguished K. capsulata from C. molischiana. Ascospore formation was observed in several C. molischiana strains and K. molischiana (type strain: NCAIM Y.01725, CBS 9993) is proposed as the teleomorphic state of Candida molischiana.     

Glutamate as a differential nitrogen source for the characterization of acetylene-reducing Rhizobium strains

A majority (36 of 44) of Rhizobium japonicum strains tested reduced acetylene asymbiotically when grown on an agar medium containing 0.1% (w/v) L-glutamate as a sole nitrogen (N) source. Glutamate as N source led to pinpoint colonies and uniform glutamine synthetase activity of three selected, slow-growing acetylene-reducing strains ( R. japonicum L-259 and 110 and a cowpea-type Rhizobium 32H1). The three test strains were characterized further by antibiotic resistance, colony type, cellular morphology, and differential growth on different N sources. The evidence suggests that, in an agar medium, glutamate creates a growth condition leading to acetylene reduction activity, pinpoint colonies and pleomorphism.     

Eukaryotic Acquisition of a Bacterial Operon

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Three new anascosporic genera of the Saccharomycotina: Danielozyma gen. nov., Deakozyma gen. nov. and Middelhovenomyces gen. nov

Three new non-ascosporic, ascomycetous yeast genera are proposed based on their isolation from currently described species and genera. Phylogenetic placement of the genera was determined from analysis of nuclear gene sequences for D1/D2 large subunit rRNA, small subunit rRNA, translation elongation factor-1α and RNA polymerase II, subunits B1 and B2. The new taxa are: Deakozyma gen. nov., type species Deakozyma indianensis sp. nov. (type strain NRRL YB-1937, CBS 12903); Danielozyma gen. nov., type species Danielozyma ontarioensis comb. nov. (type strain NRRL YB-1246, CBS 8502); D. litseae comb. nov. (type strain NRRL YB-3246, CBS 8799); Middelhovenomyces gen. nov., type species Middelhovenomyces tepae comb. nov. (type strain NRRL Y-17670, CBS 5115) and M. petrohuensis comb. nov. (type strain NRRL Y-17663, CBS 8173).     

Mycobacteria mobility shift assay: a method for the rapid identification of Mycobacterium tuberculosis and nontuberculous mycobacteria

The identification of mycobacteria is essential because tuberculosis (TB) and mycobacteriosis are clinically indistinguishable and require different therapeutic regimens. The traditional phenotypic method is time consuming and may last up to 60 days. Indeed, rapid, affordable, specific and easy-to-perform identification methods are needed. We have previously described a polymerase chain reaction-based method called a mycobacteria mobility shift assay (MMSA) that was designed for Mycobacterium tuberculosis complex (MTC) and nontuberculous mycobacteria (NTM) species identification. The aim of this study was to assess the MMSA for the identification of MTC and NTM clinical isolates and to compare its performance with that of the PRA-hsp65 method. A total of 204 clinical isolates (102 NTM and 102 MTC) were identified by the MMSA and PRA-hsp65. For isolates for which these methods gave discordant results, definitive species identification was obtained by sequencing fragments of the 16S rRNA and hsp65 genes. Both methods correctly identified all MTC isolates. Among the NTM isolates, the MMSA alone assigned 94 (92.2%) to a complex or species, whereas the PRA-hsp65 method assigned 100% to a species. A 91.5% agreement was observed for the 94 NTM isolates identified by both methods. The MMSA provided correct identification for 96.8% of the NTM isolates compared with 94.7% for PRA-hsp65. The MMSA is a suitable auxiliary method for routine use for the rapid identification of mycobacteria.     

Biocontrol of the food-borne pathogens Listeria monocytogenes and Salmonella enterica serovar Poona on fresh-cut apples with naturally occurring bacterial and yeast antagonists

Fresh-cut apples contaminated with either Listeria monocytogenes or Salmonella enterica serovar Poona, using strains implicated in outbreaks, were treated with one of 17 antagonists originally selected for their ability to inhibit fungal postharvest decay on fruit. While most of the antagonists increased the growth of the food-borne pathogens, four of them, including Gluconobacter asaii (T1-D1), a Candida sp. (T4-E4), Discosphaerina fagi (ST1-C9), and Metschnikowia pulcherrima (T1-E2), proved effective in preventing the growth or survival of food-borne human pathogens on fresh-cut apple tissue. The contaminated apple tissue plugs were stored for up to 7 days at two different temperatures. The four antagonists survived or grew on the apple tissue at 10 or 25 degrees C. These four antagonists reduced the Listeria monocytogenes populations and except for the Candida sp. (T4-E4), also reduced the S. enterica serovar Poona populations. The reduction was higher at 25 degrees C than at 10 degrees C, and the growth of the antagonists, as well as pathogens, increased at the higher temperature.