T cell receptor CDR3 loop length repertoire is determined primarily by features of the V(D)J recombination reaction
Department of Pathology and Immunology, Washington University in St. Louis, San Luis, Missouri, United StatesEuropean Journal of Immunology (Impact Factor: 4.03). 07/2003; 33(6):1568-75. DOI: 10.1002/eji.200323961
The third complementarity-determining region (CDR) of the TCR alpha and beta chains forms loops that engage amino acid residues of peptides complexed with MHC. This interaction is central to the specific discrimination of antigenic-peptide-MHC complexes by the TCR. The TCRbeta chain CDR3 loop is encoded by the Dbeta gene segment and flanking portions of the Vbeta and Jbeta gene segments. The joining of these gene segments is imprecise, leading to significant variability in the TCRbeta chain CDR3 loop length and amino acid composition. In marked contrast to other pairing antigen-receptor chains, the TCR beta and alpha chain CDR3 loop size distributions are relatively narrow and closely matched. Thus, pairing of TCR alpha and beta chains with relatively similar CDR3 loop sizes may be important for generating a functional repertoire of alpha beta TCR. Here we show that the TCRbeta chain CDR3 loop size distribution is minimally impacted by TCRbeta chain or alpha beta TCR selection during thymocyte development. Rather, this distribution is determined primarily at the level of variable-region gene assembly, and is critically dependent on unique features of the V(D)J recombination reaction that ensure Dbeta gene segment utilization.
Conference Paper: A simple invariant neural network for 2-D image recognition[Show abstract] [Hide abstract]
ABSTRACT: A simple invariant neural network has been proposed. The network has invariance against scale and, rotation changes, in addition to the inherent shift of starting point on the image contour. This invariance comes from the new use of the MT-transform as a feature vector in a pre-processing stage. Thus, a complete invariance has been achieved, without any complexity in the network. Testing of the network, shows about a 100% recognition rateRadio Science Conference, 1996. NRSC '96., Thirteenth National; 04/1996
- [Show abstract] [Hide abstract]
ABSTRACT: The Food and Drug Administration (FDA) received over 90 problem reports of medical device malfunctions due to electromagnetic interference (EMI) from magnetic field emitting security devices. The FDA took action to alert users and manufacturers of medical devices and security screening devices. These malfunctions were thought to be related to the electromagnetic fields emitted from the security device and judged serious enough by the reporters (clinical users of these devices) to potentially cause patient injuries. Measurements of magnetic field emissions from security devices reveal that some security screening devices can emit magnetic fields at strengths that exceed the test levels specified in some medical device standards.Electromagnetic Compatibility, 2002. EMC 2002. IEEE International Symposium on; 09/2002
- [Show abstract] [Hide abstract]
ABSTRACT: Ag receptor variable region gene assembly is initiated through the formation of a synaptic complex which minimally includes the recombination-activating gene (RAG) 1/2 proteins and a pair of recombination signals (RSs) flanking the recombining gene segments. RSs are composed of conserved heptamer and nonamer sequences flanking relatively nonconserved spacers of 12 or 23 bp. RSs regulate variable region gene assembly within the context of the 12/23 rule which mandates that recombination only occurs between RSs of dissimilar spacer length. RSs can exert additional constraints on variable region gene assembly beyond imposing spacer length requirements. At a minimum this restriction, termed B12/23, is imposed on the Vbeta to DJbeta rearrangement step by the 5' Dbeta RS and is enforced at or before the DNA cleavage step of the V(D)J recombination reaction. In this study, the components of the 5' Dbeta RS required for enforcing the B12/23 rule are assessed on chromosomal substrates in vivo in the context of normal murine thymocyte development and on extrachromosomal substrates induced to undergo recombination in nonlymphoid cell lines. These analyses reveal that the integrity of the nonamer sequence as well as the highly conserved spacer nucleotides of the 5' Dbeta1 RS are critical for enforcing the B12/23 restriction. These findings have important implications for understanding the B12/23 restriction and the manner in which RS synaptic complexes are assembled in vivo.The Journal of Immunology 01/2004; 171(12):6604-10. DOI:10.4049/jimmunol.171.12.6604 · 4.92 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.