Ataxia telangiectasia (AT) is an autosomal recessive disease characterized by neurological and immunological symptoms, radiosensitivity and cancer predisposition. The gene mutated in AT, designated the ATM gene, encodes a large protein kinase with a PI-3 kinase-related domain. In this study, we investigated the mutational spectrum of the ATM gene in a cohort of AT patients living in Germany. We amplified and sequenced all 66 exons and the flanking untranslated regions from genomic DNA of 66 unrelated AT patients. We identified 46 different ATM mutations and 26 sequence polymorphisms and variants scattered throughout the gene. A total of 34 mutations have not been described in other populations. Seven mutations occurred in more than one family, but none of these accounted for more than five alleles in our patient group. The majority of the mutations were truncating, confirming that the absence of full-length ATM protein is the most common molecular basis of AT. Transcript analyses demonstrated single exon skipping as the consequence of most splice site substitutions, but a more complex pattern was observed for two mutations. Immunoblot studies of cell lines carrying ATM missense substitutions or in-frame deletions detected residual ATM protein in four cases. One of these mutations, a valine deletion proximal to the kinase domain, resulted in ATM protein levels >20% of normal in an AT lymphoblastoid cell line. In summary, our results survey and characterize a plethora of variations in the ATM gene identified by exon scanning sequencing and indicate a high diversity of mutations giving rise to AT in a non-isolated population.

While the extravasation cascade of lymphocytes is well characterized, data on their intraepithelial positioning and morphology are scant. However, the latter process is presumably crucial for many immune functions. Integrin ␣ E (CD103)␤ 7 has previously been implicated in epithelial retention of some T cells through binding to E-cadherin. Our current data suggest that ␣ E (CD103)␤ 7 also determines shape and motility of some lymphocytes. Time-lapse microscopy showed that wild-type ␣ E (CD103)␤ 7 conferred the ability to form cell protrusions/filopodia and to move in an amoeboid fashion on E-cadherin, an activity that was abrogated by ␣ E (CD103)␤ 7 -directed antibodies or cytochalasin D. The ␣ E -dependent motility was further increased (P < .001) when point-mutated ␣ E (CD103) locked in a constitutively active conformation was expressed. Moreover, different yellow fluorescent protein-coupled ␣ E (CD103) species demonstrated that the number and length of filopodia extended toward purified E-cadherin, cocultured keratinocytes, cryostat-cut skin sections, or epidermal sheets depended on functional ␣ E (CD103). The in vivo relevance of these findings was demonstrated by wild-type dendritic epidermal T cells (DETCs), which showed significantly more dendrites and spanned larger epidermal areas as compared with DETCs of ␣ E (CD103)-deficient mice (P < .001). Thus, integrin ␣ E (CD103)␤ 7 is not only involved in epithelial retention, but also in shaping and proper intraepithelial morphogenesis of some leukocytes. IntroductionPositioning and locomotion of leukocytes within tissues provide the basis for the molecular crosstalk with other cells and are prerequisites for a functional immune system. To date, the recruitment cascade of initial endothelial adhesion, activation, firm adhesion, transmigration, and subsequent localization into the connective tissue is one of the best established concepts in leukocyte biology. 1,2 However, many effector functions of immunocytes are exerted within parenchymatous organs, mostly epithelia. It is therefore somewhat surprising that we know relatively little about locomotion and function-determining morphogenesis of lymphocytes within epithelial tissues, such as the epidermis of the skin. 3 An adhesion receptor that is thought to mediate retention of lymphocytes within epithelial tissues is integrin ␣ E (CD103)␤ 7 . 4 First described 2 decades ago as a selective marker for intestinal intraepithelial lymphocytes, 5 ␣ E (CD103)␤ 7 has been implicated in epithelial T-cell retention through binding to E-cadherin. 6,7 Indeed, ␣ E (CD103)-deficient mice exhibited a reduced number of mucosal intraepithelial T cells. 8 However, ␣ E (CD103)␤ 7 has later been found to be also expressed by some lymphocytes within other epithelia, such as the epidermis of the skin, 9 where it presumably contributes to recruitment of T cells in inflamed human skin 10 as well as dendritic epidermal T cells (DETCs) in murine skin. 11 Thymic DETC precursor cells express integrin ␣ E (CD103)␤ 7 before their migration ...

Dendritic cells (DC) are the most important antigen presenting cells and play a pivotal role in host immunity to infectious agents by acting as a bridge between the innate and adaptive immune systems. Monocyte-derived immature DCs (iDC) were infected with viable resting conidia of Aspergillus fumigatus (Af293) for 12 hours at an MOI of 5; cells were sampled every three hours. RNA was extracted from both organisms at each time point and hybridised to microarrays. iDC cell death increased at 6 h in the presence of A. fumigatus which coincided with fungal germ tube emergence; >80% of conidia were associated with iDC. Over the time course A. fumigatus differentially regulated 210 genes, FunCat analysis indicated significant up-regulation of genes involved in fermentation, drug transport, pathogenesis and response to oxidative stress. Genes related to cytotoxicity were differentially regulated but the gliotoxin biosynthesis genes were down regulated over the time course, while Aspf1 was up-regulated at 9 h and 12 h. There was an up-regulation of genes in the subtelomeric regions of the genome as the interaction progressed. The genes up-regulated by iDC in the presence of A. fumigatus indicated that they were producing a pro-inflammatory response which was consistent with previous transcriptome studies of iDC interacting with A. fumigatus germ tubes. This study shows that A. fumigatus adapts to phagocytosis by iDCs by utilising genes that allow it to survive the interaction rather than just up-regulation of specific virulence genes.

Inhibition of constitutive and induced IKKbeta-activity through treatment with KINK-1 might increase tumor susceptibility to chemotherapy.