A novel approach to antigen-specific deletion of CTL with minimal cellular activation using alpha 3 domain mutants of MHC class I/peptide complex

In this study, we have compared the effector functions and fate of a number of human CTL clones in vitro or ex vivo following contact with variant peptides presented either on the cell surface or in a soluble multimeric format. In the presence of CD8 coreceptor binding, there is a good correlation between TCR signaling, killing of the targets, and Fast-mediated CTL apoptosis. Blocking CD8 binding using (alpha3 domain mutants of MHC class I results in much reduced signaling and reduced killing of the targets. Surprisingly, however, Fast expression is induced to a similar degree on these CTLs, and apoptosis of CTL is unaffected. The ability to divorce these events may allow the deletion of antigen-specific and pathological CTL populations without the deleterious effects induced by full CTL activation.

Atm knock-in mice harboring an in-frame deletion corresponding to the human ATM 7636del9 common mutation exhibit a variant phenotype

ATM, the gene mutated in the human immunodeficiency disorder ataxia-telangiectasia (A-T), plays a central role in recognizing ionizing radiation damage in DNA and in controlling several cell cycle checkpoints. We describe here a murine model in which a nine-nucleotide in-frame deletion has been introduced into the Atm gene by homologous recombination followed by removal of the selectable marker cassette by Cre-loxP site-specific, recombination-mediated excision. This mouse, Abm-Delta SRI, was designed as a model of one of the most common deletion mutations (7636de19) found in A-T patients. The murine Atm deletion results in the loss of three amino acid residues (SRI; 2556-2558) but produces near full-length detectable Atm protein that lacks protein kinase activity. Radiosensitivity was observed in Atm-Delta SRI mice, whereas the immunological profile of these mice showed greater heterogeneity of T-cell subsets than observed in Atm(-/-) mice. The life span of Atm-Delta SRI mice was significantly longer than that of Atm(-/-) mice when maintained under nonspecific pathogen-free conditions. This can be accounted for by a lower incidence of thymic lymphomas in Atm-Delta SRI mice up to 40 weeks, after which time the animals died of other causes. The thymic lymphomas in Atm-Delta SRI mice were characterized by extensive apoptosis, which appears to be attributable to an increased number of cells expressing Fas ligand. A variety of other tumors including B-cell lymphomas, sarcomas, and carcinomas not seen in Atm(-/-) mice were observed in older Atm-Delta SRI animals. Thus, expression of mutant protein in Atm-Delta SRI knock-in mice gives rise to a discernibly different phenotype to Atm(-/-) mice, which may account for the heterogeneity seen in A-T patients with different mutations.

Deletion of 8p: a report of a child with normal intelligence

The case is presented of a female infant with a distal deletion of 8p (8p23.1 --> pter) whose development was monitored over a 5-year period from 12 months of age. Although previous literature has suggested that 8p deletion is associated with mild to moderate intellectual disability, the child reported here has normal intelligence. Despite initial delays in gross motor and language skills, cognitive development (assessed with the Bayley Scales of Infant Development) and intellectual ability (measured on the Stanford-Binet Intelligence Scale) were within average range. It is argued that the small number of previous case reports may have created a misleading impression of intellectual development in individuals with distal deletions of 8p.

Apoptotic deletion of Th cells specific for the 19-kDa carboxyl-terminal fragment of merozoite surface protein 1 during malaria infection

Immunity induced by the 19-kDa fragment of merozoite surface protein 1 is dependent on CD4(+) Th cells. However, we found that adoptively transferred CFSE-labeled Th cells specific for an epitope on Plasmodium yoelii 19-kDa fragment of merozoite surface protein 1 (peptide (p)24), but not OVA-specific T cells, were deleted as a result of P. yoelii infection. As a result of infection, spleen cells recovered from infected p24-specific T cell-transfused mice demonstrated reduced response to specific Ag. A higher percentage of CFSE-labeled p24-specific T cells stained positive with annexin and anti-active caspase-3 in infected compared with uninfected mice, suggesting that apoptosis contributed to deletion of p24-specific T cells during infection. Apoptosis correlated with increased percentages of p24-specific T cells that stained positive for Fas from infected mice, suggesting that P. yoelii-induced apoptosis is, at least in part, mediated by Fas. However, bystander cells of other specificities also showed increased Fas expression during infection, suggesting that Fas expression alone is not sufficient for apoptosis. These data have implications for the development of immunity in the face of endemic parasite exposure.

Germline BRCA1 promoter deletions in UK and Australian familial breast cancer patients: Identification of a novel deletion consistent with BRCA1 :psi VBRCA1 recombination

Inherited susceptibility to breast cancer results from germline mutations in one of a number of genes including BRCA1. A significant number of BRCA1-linked familial breast cancer patients, however, have no detectable BRCA1 mutation. This could be due in part to the inability of commonly used mutation-detection techniques to identify mutations outside the BRCA1 coding region. This paper addresses the hypothesis that non coding region mutations, specifically in the BRCA1 promoter, account for some of these cases. We describe a new and detailed restriction map of the 5' region of the BRCA1 gene including the nearby NBR2, psiBRCA1, and NBR1 genes and the isolation of a number of new informative hybridization probes suitable for Southern analysis. Using this information we screened DNA from lymphoblastoid cell-lines made from 114 UK familial breast cancer patients and detected one large deletion in the 5' region of BRCA1. We show that the breakpoints for this deletion are in BRCA1 intron 2 and between NBR2 and exon 2 of psiBRCA1, raising the possibility that this deletion arose via a novel mechanism involving BRCA1:psiBRCA1 recombination. We have also screened 60 familial breast cancer patients from the Australian population, using an amplification refractory mutation system (ARMS) technique described previously by our group, and found one patient with a genotype consistent with a BRCA1 promoter deletion. These findings indicate that germline BRCA1 promoter deletions are a rare and yet significant mutation event and that they could arise via a novel genetic mechanism. Hum Mutat 19:435-442, 2002. (C) 2002 Wiley-Liss, Inc.

Fast neutron mutagenesis of soybean (Glycine soja L.) produces a supernodulating mutant containing a large deletion in linkage group H

We describe for the first time the application of fast neutron mutagenesis to the genetic dissection of root nodulation in legumes. We demonstrate the utility of chromosomal deletion mutations through production of a soybean supernodulation mutant FN37 that lacks the internal autoregulation of nodulation mechanism. After inoculation with microsymbiont Bradyrhizobium japonicum, FN37 forms at least 10 times more nodules than the wild type G. soja parent and has a phenotype identical to that of chemically induced allelic mutants nts382 and nts1007 (NTS-1 locus). Reciprocal grafting of shoots and roots confirmed systemic shoot control of the FN37 nodulation phenotype. RFLP/PCR marker pUTG132a and AFLP marker UQC-IS1 which are tightly linked to NTS-1 allowed the isolation of BAC contigs delineating both ends of the deletion. The genetic/physical distance ratio in the NTS-1 region is 279 kb/cM. The deletion is estimated to be about 460 kb based on the absence of markers and bacterial artificial chromosomes (BAC) ends as well as genetic and physical mapping. Deletion break points were determined physically and placed within flanking BAC contigs.

Complete genomic sequence of the Australian south-west genotype of Sindbis virus: Comparisons with other Sindbis strains and identification of a unique deletion in the 3 '-untranslated region

Our previous studies have shown that two distinct genotypes of Sindbis (SIN) virus occur in Australia. One of these, the Oriental/Australian type, circulates throughout most of the Australian continent, whereas the recently identified south-west (SW) genetic type appears to be restricted to a distinct geographic region located in the temperate south-west of Australia. We have now determined the complete nucleotide and translated amino acid sequences of a SW isolate of SIN virus (SW6562) and performed comparative analyses with other SIN viruses at the genomic level. The genome of SW6562 is 11,569 nucleotides in length, excluding the cap nucleotide and poly (A) tail. Overall this virus differs from the prototype SIN virus (strain AR339) by 23% in nucleotide sequence and 12.5% in amino acid sequence. Partial sequences of four regions of the genome of four SW isolates were determined and compared with the corresponding sequences from a number of SIN isolates from different regions of the World. These regions are the non-structural protein (nsP3), the E2 gene, the capsid gene, and the repeated sequence elements (RSE) of the 3'UTR. These comparisons revealed that the SW SIN viruses were more closely related to South African and European strains than to other Australian isolates of SIN virus. Thus the SW genotype of SIN virus may have been introduced into this region of Australia by viremic humans or migratory birds and subsequently evolved independently in the region. The sequence data also revealed that the SW genotype contains a unique deletion in the RSE of the 3'UTR region of the genome. Previous studies have shown that deletions in this region of the SIN genome can have significant effects on virus replication in mosquito and avian cells, which may explain the restricted distribution of this genotype of SIN virus.

Monte Carlo simulation of the basic features of the GE Millennium MG single photon emission computed tomography gamma camera

Objective - To describe and validate the simulation of the basic features of GE Millennium MG gamma camera using the GATE Monte Carlo platform. Material and methods - Crystal size and thickness, parallel-hole collimation and a realistic energy acquisition window were simulated in the GATE platform. GATE results were compared to experimental data in the following imaging conditions: a point source of 99mTc at different positions during static imaging and tomographic acquisitions using two different energy windows. The accuracy between the events expected and detected by simulation was obtained with the Mann–Whitney–Wilcoxon test. Comparisons were made regarding the measurement of sensitivity and spatial resolution, static and tomographic. Simulated and experimental spatial resolutions for tomographic data were compared with the Kruskal–Wallis test to assess simulation accuracy for this parameter. Results - There was good agreement between simulated and experimental data. The number of decays expected when compared with the number of decays registered, showed small deviation (≤0.007%). The sensitivity comparisons between static acquisitions for different distances from source to collimator (1, 5, 10, 20, 30cm) with energy windows of 126–154 keV and 130–158 keV showed differences of 4.4%, 5.5%, 4.2%, 5.5%, 4.5% and 5.4%, 6.3%, 6.3%, 5.8%, 5.3%, respectively. For the tomographic acquisitions, the mean differences were 7.5% and 9.8% for the energy window 126–154 keV and 130–158 keV. Comparison of simulated and experimental spatial resolutions for tomographic data showed no statistically significant differences with 95% confidence interval. Conclusions - Adequate simulation of the system basic features using GATE Monte Carlo simulation platform was achieved and validated.

Interdiffusion at Sb/Ge interfaces induced in thin multilayer films by nanosecond laser irradiation

Thin films consisting of 3 or 4 Sb and Ge alternating layers are irradiated with single nanosecond laser pulses (12 ns, 193 nm). Real time reflectivity (RTR) measurements are performed during irradiation, and Rutherford backscattering spectrometry (RBS) is used to obtain the concentration depth profiles before and after irradiation. Interdiffusion of the elements takes place at the layer interfaces within the liquid phase. The reflectivity transients allow to determine the laser energy thresholds both to induce and to saturate the process being both thresholds dependent on the multilayer configuration. It is found that the energy threshold to initiate the process is lower when Sb is at the surface while the saturation is reached at lower energy densities in those configurations with thinner layers.

Identification of a 0.4 Kb deletion region in 10q26 associated with endometrial carcinoma

We have identified an allelic deletion common region in the q26 region of chromosome 10 in endometrial carcinomas, which has been reported previously as a potential target of genetic alterations related to this neoplasia. An allelotyping analysis of 19 pairs of tumoral and non-tumoral samples was accomplished using seven microsatellite polymorphic markers mapping in the 10q26 chromosomal region. Loss of heterozygosity for one or more loci was detected in 29% of the endometrial carcinoma samples. The observed pattern of loss enabled the identification of a 3.5 Mb common deleted region located between the D10S587 and D10S186 markers. An additional result from an endometrial sample with evidence of a RER phenotype may suggest a more centromeric region of loss within the above-mentioned interval. This 401.84 Kb interval flanked by the D10S587 and D10S216 markers may be a plausible location for a putative suppressor gene involved in early stage endometrial carcinogenesis.

Faunes ichthyologiques du Néogène Supérieur d’Angola, leur âge, remarques sur le Pliocène marin en Afrique Australe

This note is concerned with fish remains from Upper Neogene beds at Farol das Lagostas (and nearby quarry of SECIL) and Baía Farta, mainly recovered by the author in 1960, 1961, 1963 and 1967. For further data see ANTUNES, 1964, pp. 213-215. All the forms identified until now (many of them for the first time) are show in «tableau I». Smaller ones are poorly represented. I. benedeni is provisorily accepted as a distinct species, though it may correspond to a dental morphotype that does exist equally in the extant I. oxyrhinchus (see text): therefore I. benedeni from Farol das Lagostas may after all represent only some dental variations that really belong in the form described as I. cf. oxyrhinchus. The presence of Aprionodon and Hypoprion could not be ascertained: Procarcharodon megalodon, Carcharodon carcharias, Isurus benedeni. Galeocerdo cuvieri, and Carcharhinus sp. I and sp. II are specially discussed. The whole fauna does not correspond either to a very shallow and coastal environment, or to deep waters far away from the coast. It clearly points out to warm waters: an acceptable model would be the fauna from the tropical Atlantic between Northern Angola and Senegal-Cape Verde. The age of this fauna was long regarded as Burdigalian. The data formerly presented (ANTUNES, 1963) that allowed us to ascribe a pliocene age to the uppermost Neogene beds of Farol das Lagostas (Neogene III, ANTUNES, 1964) are reviewed and developed in this paper. This view is corroborated by planctonic foraminifera and stratigraphical data which provide further evidence to prove the presence of miocene beds much younger than Burdigalian, and that some deposits previously correlated to this stage have instead a Plio-Pleistocene age. Fish fauna from Farol das Lagostas is very characteristic, with giant P. megalodon in association with C. carcharias (which predominates, and whose stratigraphical distribution is particularly discussed), and with other very advanced forms like the extant tiger shark, G. cuvieri, enormous I. Benedeni, Hemipristis, and Carcharhinus (whose size largely exceeds the maximum observed with miocene material). With the exception of P. megalodon (extinct) all the other forms show very close affinities, or even identity with modern species. Comparisons with very similar faunas from some South African localities that may also have a Pliocene age are also presented.

Faunes ichthyologiques du Néogène Supérieur d’Angola, leur âge, remarques sur le Pliocène marin en Afrique Australe

This note is concerned with fish remains from upper Neogene beds at Farol das Lagostas (and nearby quarry of SECIL) and Baía Farta, mainly recovered by the author in 1960, 1961, 1963 and 1967. For further data see ANTUNES, 1964, pp. 213-215. All the forms identified until now (many of them for the first time) are show in «tableau I». Smaller ones are poorly represented. I. benedeni is provisorily accepted as a distinct species, though it may correspond to a dental morphotype that does exist equally in the extant I. oxyrhinchus (see text): therefore I. benedeni from Farol das Lagostas may after all represent only some dental variations that really belong in the form described as I. cf. oxyrhinchus. The presence of Aprionodon and Hypoprion could not be ascertained: Procarcharodon megalodon, Carcharodon carcharias, Isurus benedeni. Galeocerdo cuvieri, and Carcharhinus sp. I and sp. II are specially discussed. The whole fauna does not correspond either to a very shallow and coastal environment, or to deep waters far away from the coast. It clearly points out to warm waters: an acceptable model would be the fauna from the tropical Atlantic between Northern Angola and Senegal-Cape Verde. The age of this fauna was long regarded as Burdigalian. The data formerly presented (ANTUNES, 1963) that allowed us to ascribe a pliocene age to the uppermost Neogene beds of Farol das Lagostas (Neogene III, ANTUNES, 1964) are reviewed and developed in this paper. This view is corroborated by planctonic foraminifera and stratigraphical data which provide further evidence to proove the presence of miocene beds much younger than Burdigalian, and that some deposits previously correlated to this stage have instead a Plio-Pleistocene age. Fish fauna from Farol das Lagostas is very characteristic, with giant P. megalodon in association with C. carcharias (which predominates, and whose stratigraphical distribution is particularly discussed), and with other very advanced forms like the extant tiger shark, G. cuvieri, enormous I. Benedeni, Hemipristis, and Carcharhinus (whose size largely exceeds the maximum observed with miocene material). With the exception of P. megalodon (extinct) all the other forms show very close affinities, or even identity with modern species. Comparisons with very similar faunas from some South African localities that may also have a Pliocene age are also presented.