Craig W. Bailey

T Cell Immunity in Connective Tissue Disease Patients Targets the RNA Binding Domain of the U1-70kDa Small Nuclear Ribonucleoprotein

Although the T cell dependence of autoimmune responses in connective tissue diseases has been well established, limited information exists regarding the T cell targeting of self Ags in humans. To characterize the T cell response to a connective tissue disease-associated autoantigen, this study generated T cell clones from patients using a set of peptides encompassing the entire linear sequence of the 70-kDa subunit of U1 snRNP (U1-70kDa) small nuclear ribonucleoprotein. Despite the ability of U1-70kDa to undergo multiple forms of Ag modification that have been correlated with distinct clinical disease phenotypes, a remarkably limited and consistent pattern of T cell targeting of U1-70kDa was observed. All tested T cell clones generated against U1-70kDa were specific for epitopes within the RNA binding domain (RBD) of the protein. High avidity binding of the RBD with U1-RNA was preserved with the disease-associated modified forms of U1-70kDa tested. The high avidity interaction between the U1-RBD on the polypeptide and U1-RNA may be critical in immune targeting of this region in autoimmunity. The T cell autoimmune response to U1-70kDa appears to have less diversity than is seen in the humoral response; and therefore, may be a favorable target for therapeutic intervention.

A sketch interface for mobile robots

In human to human communication, a hand-drawn route map is often sketched to show a desired navigation path. In this paper, we describe a PDA sketching interface that can be used to direct a mobile robot along a specified path. Because sketched route maps are not drawn precisely or necessarily to scale, we do not attempt to analyze precise path information, but rather qualitative route information is extracted. The paper focuses on the front-end sketch understanding and includes a description of the interactive features, such as deleting, moving, and labeling landmarks. Results of a user evaluation are also presented, in which participants report that the sketching interface was as easy as using pencil and paper by a 2:1 margin.

T Cell Epitope Mapping of the Smith Antigen Reveals That Highly Conserved Smith Antigen Motifs Are the Dominant Target of T Cell Immunity in Systemic Lupus Erythematosus

B cell and T cell immunity to the Smith Ag (Sm) is a characteristic feature of systemic lupus erythematosus (SLE). We have shown that T cell immunity against Sm can be detected in SLE patients, and that T and B cell immunity against Sm are linked in vivo. TCR usage by Sm-reactive T cells is highly restricted and characteristic of an Ag-driven immune response. Sm is a well-characterized complex Ag consisting of proteins B1, B2, D1, D2, D3, E, F, and G. A unique feature of all Sm proteins is the presence of homologous motifs, Sm motif 1 and Sm motif 2. We used limiting dilution cloning and synthetic peptide Ags to characterize the human T cell immune response against Sm in seven SLE patients. We sought to determine the precise antigenic peptides recognized, the common features of antigenic structure recognized, and the evolution of the T cell response against Sm. We found there was a highly restricted set of Sm self-peptides recognized by T cells, with three epitopes on Sm-B and two epitopes on Sm-D. We found that T cell immunity against Sm-B and Sm-D was encoded within the highly conserved Sm motif 1 and Sm motif 2, and that immunity against these epitopes appeared stable. The present study supports the concept that T cell immunity to Sm is an Ag-driven immune response directed against a highly restricted set of self-peptides, encoded within Sm motif 1 and Sm motif 2, that is shared among all Sm proteins.

Qualitative analysis of sketched route maps: translating a sketch into linguistic descriptions

In this correspondence, we introduce our work on sketch understanding, focusing here on the analysis of a sketched route map. A route map is drawn to help someone navigate along a path for the purpose of reaching a goal. A hand-sketched route map does not generally contain complete map information and is not necessarily drawn to scale, but yet it contains the correct qualitative information for route navigation. Here we propose a methodology for extracting a qualitative model of a sketched route map, based on human navigation strategies, using spatial relationships. Linguistic descriptions are generated from the sketch, both in the form of detailed descriptions at discrete path steps and also as a high-level route description. To describe the path linguistically, one must first be able to understand the path in a qualitative sense. We assert that the translation of a sketch into linguistic descriptions illustrates that the essential qualitative path knowledge has been extracted. The methodology is demonstrated using example sketches drawn on a handheld PDA.

Structural analysis of TCRalpha and beta chains from human T-Cell clones specific for small nuclear ribonucleoprotein polypeptides Sm-D, Sm-B and U1-70 kDa: TCR complementarity determining region 3 usage appears highly conserved.

Systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) are systemic autoimmune diseases that are characterized by the presence of autoantibodies reactive with U small nuclear RNP (snRNP) autoantigens. Both B and T cells are important in the pathogenesis of the disease, and T‐ and B‐cell immunity against snRNP polypeptides have been shown to be linked in vivo. Currently, several alternative hypotheses for the pathogenesis of these diseases have been proposed. These include loss of tolerance, modified self‐antigens, molecular mimicry and nondirected immune activation. To help distinguish between the various models of disease pathogenesis, we have characterized the T‐cell receptor (TCR) CDR3 from a large panel of well‐characterized human T‐cell clones and lines specific for individual snRNP polypeptides. The results presented here reveal highly restricted TCR usage across patients by the snRNP‐reactive T cells based on the deduced amino acid sequence of the CDR3 loop. These data support the hypothesis that T‐cell responses against self antigens in SLE and MCTD are antigen driven and that there are a limited number of T‐cell epitopes present on the snRNP autoantigens.

Use of random amplified polymorphic DNA analysis to compareBabesia bovis andB. bigemina isolates

Random amplified polymorphic DNA analysis provides characteristic fingerprints forBabesia bovis andB. bigemina. This genetic profile reflects similarities and minor differences between closely related regional isolates and the greater diversity representative of species from distant geographic locations.

Molecular analysis of Salmonella enteritidis isolates from the Caribbean by pulsed-field gel electrophoresis

Using pulsed-field gel electrophoresis (PFGE), between 1987 and 1996 we analyzed Salmonella enteritidis isolates from gastroenteritis cases in four Caribbean countries: Barbados, Saint Kitts and Nevis, Saint Lucia, and Trinidad and Tobago. We also determined the resistance of the isolates to 12 antimicrobial agents. Of the 129 isolates of S. enteritidis available for testing, DNA digested by XbaI revealed 13 distinctive PFGE patterns. The most prevalent XbaI PFGE patterns were group 1 (88 of 129 isolates, 68.2%) and group 2 (26 of 129, 20.2%). The patterns found among S. enteritidis isolates correlated with the geographical origin of the isolates. Of the 28 isolates from Barbados, 20 of them (71.4%) belonged to XbaI PFGE group 2, and of the 93 isolates from Trinidad and Tobago, 78 of them (83.9%) belonged to group 1. SpeI digestion of S. enteritidis genome was not as discriminatory as XbaI. Overall, of the 129 isolates, 67 of them (51.9%) exhibited resistance to one or more of the 12 antimicrobial agents that we tested. The prevalence of resistance was 53.8% for the S. enteritidis isolates tested from Trinidad and Tobago, 50.0% for those from Barbados, 28.6% for those from Saint Lucia, and 100.0% for one isolate from the island of Saint Kitts. Resistance was highest to triple sulfur (59 of 129 isolates, 45.7%), followed by furadantoin (10 of 129, 7.8%), ampicillin (7 of 129, 5.4%), and carbamycin (5 of 129, 3.9%).

Fluorescence-activated cell sorting-derived clones ofBabesia bigemina show karyotype polymorphism

Use of the fluorescence-activated cell sorter proved to be an accurate and highly efficient means for cloningBabesia parasites. These qualities were examined by separating a mixed population ofBabesia-infected bovine erythrocytes composed of two isolates with different karyotypes. Direct evidence of polymorphism was detected during comparison of the resultant clones.