Introduction The recombination signal sequences (RSS) is the essential element for the immunoglobulin gene rearrangement. The RSS consists of 3 elements: heptamer (7mer), 12-bp or 23-bp spacer, and nonamer (9mer). The heptamer and nonamer are well conserved [6]. The rearrangement occurs between an RSS with 12 bp spacer sequences and an RSS with 23 bp spacer sequences (the `12/23 rule') [1]. RSSs of indispensable V gene segments should be well conserved to maintain high e#ciency of the V(D)J joining. In this work, the RSSs of the human immunoglobulin # light chain genes were investigated how the recombination and expression frequencies of the genes are influenced by the RSSs. We first conducted an extensive database search to estimate expression frequencies of the variable region gene for the # light chain (V # ) combination with the joining (J) and constant (C) region. The genes for the # light chain genes loc

Based on some features of the immune system (the selection-based mechanism compatible with Edelman's selectionist principle, self/nonself-reference and negative/positive selection) , we proposed the immune algorithm. The algorithm proceeds in three steps: diversity generation, establishment of self-tolerance, and memorizing non-self. The algorithm may be used typically to deal with the system by distributed agents where the system (the self ) as well as the environment (the non-self) are unknown or cannot be modeled or di#cult to treat even when modeled. Agent-based architecture is proposed with the application to adaptive system where the knowledge about environment is not available. Adaptive noise neutralizer is formalized and simulated for a simple plant.

Abstract: Security of wired and wireless networks is the most challengeable in today’s computer world. The aim of this study was to give brief introduction about viruses and worms, their creators and characteristics of algorithms used by viruses. Here wired and wireless network viruses are elaborated. Also viruses are compared with human immune system. On the basis of this comparison four guidelines are given to detect viruses so that more secure systems are made. While concluding this study it is found that the security is most challengeable, thus it is required to make more secure models which automatically detect viruses and prevent the system from its affect.

Mechanisms of B cell activation and

In the present article, we discuss the various ambiguous aspects of the immune system that render this complex biological network so highly flexible and able to defend the host from different external invaders. This ambiguity stems mainly from the property of the immune system to be both protective and harmful. Immunity cannot be fully protective without producing a certain degree of damage (immunopathology) to the host. The balance between protection and tissue damage is, therefore, critical for the establishment of immune homeostasis and protection. In this review, we will consider as ambiguous, various immunological tactics including: (a) the opposing functions driving immune responses, immune-regulation, and contra-regulation, as well as (b) the phenomenon of chronic immune activation as a result of a continuous cross-presentation of apoptotic T cells by dendritic cells. All these plans participate principally to maintain a state of chronic low-level inflammation during persisting infections, and ultimately to favor the species survival.

We have examined at the molecular level the CDR3 and adjacent regions in peripheral blood B lymphocytes ofnormal individuals. A total of 111 sequences (12-28 sequences from six individuals) were obtained after cloning of the polymerase chain reaction-amplified segments into plasmids or phage. The average length of the VDJ joining was 109 nucleotides, with a range from 79 to 151. Approximately 75 % of the sequences were in frame when translated into amino acids. Among the JH segments, J H4 was found most frequently (in 52.5 % of the sequences), and JH 1 and JH 2 segments the least frequently (-I % of the clones). A polymorphic JH6 gene with a one-codnn deletion accompanied by a base change was present in two of six patients. Preferential breakpoints were found for JH 2, J.3, J 4, and Jx5, although the breakpoints of JH6 were distributed more heterogenously. In-90 % of the cases, significant homology of the D regions with published D sequences was found. Preferential usage of a particular coding frame was observed in in-frame sequences utilizing DA, D21/9, and DMl segments. However, in general, all coding frames of germline D genes were used to generate CDR3s. Eight sequences that have a DN1-like D sequence with two base changes at the same positions were identified, suggesting the likely existence of a new

During the course of analyzing circular DNA in mouse thymocytes, novel recombinants were identified with immunoglobulin heavy chainjoining gene and switch region probes. These circles represent excision products of recombination between the heptamer-nonamer motif for V(D)J joining and a repetitive sequence for class switching. The molecular mechanisms that generate "hybrid circles " are discussed. Somatic DNA recombination plays a key role in activating and diversifying the Ig and TCR genes during lymphocyte development. For the V(D)J type ofjoining, recombination signal sequences (RSS's) are found adjacent to each germline V, D, or J segment, consisting of a highly conserved heptamer, CACTGTG, and nonamer, GGTTTTTGT, separated by a spacer of constant length (1). Normally, recombination occurs between one RSS containing a 12-bp spacer and a second RSS containing a 23-bp spacer; this is the socalled 12/23-bp spacer rule.

In pre-B cells, immunoglobulin ju (Igh) is associated with pre-B cell-specific proteins to form a multimeric complex that is found on the cell surface. One of these proteins is encoded by the three exon IgX-like gene 14.1, whose expression is restricted to pre-B cells and occurs from an unrearranged gene. A comparison of the 14.1 gene structure to the seven-gene human IgX locus revealed that the most 5 ' gene, IgX1, is organized in a three-exon structure very similar to the 14.1 gene. Transcription and splicing of these three-exon sequences would lead to an mRNA with an open reading frame which could encode a light (L) chain-like protein with a molecular weight of 23,045. Our analysis suggests that two transcripts may be produced from the IgX1 gene that share the same IgX1 constant region-containing third exon. One transcript would include all three 14.1-related exons and be expressed from the germline gene, and the second transcript would be produced after variablejoining (VJ) recombination has occurred to IgXJ1 and would encode a classic IgX L chain protein. The conservation of the genomic organization of the human 14.1 and IgX1 genes and the mouse homolog, X5, relative to the classic IgX L chain genes provides insight into the evolution of Ig genes. The development of B cells from stem cells to mature

When immunized with a conjugate of keyhole limpet hemocyanln (KLH) 1 with p-azophenylarsonate (Ar) groups all A/J mice respond with the production of anti-hapten antibodies, a portion of which share a cross-reactive idiotype (CRI) (1). The percentage of anti-Ar antibody molecules in an individual mouse which boars the CRI generally varies between 20-70%. Since this idiotype has not been found in a large number of other strains immunized with the same antigen, it can serve as a genetic marker for the variable (V) regions of anti-Ar antibodies (2, 3). If, before immunization, a neonatal or adult A/J mouse is first challenged with rabbit anti-ldiotypic (anti-id) antibodies directed to the CRI, the idlotype almost always fails to appear upon subsequent immunization of the recipient mouse (4, 5). Such suppression of idiotype in vivo has been confirmed in other systems (e.g., references 6-8). Despite the suppression of CRI, the immunized mice produce normal amounts of anti-Ar antibodies when challenged with KLH-Ar (5). These antibodies can, in turn, be used to elicit anti-id antibodies in rabbits (9). In contrast to the anti-Ar antibodies with CRI, the idiotypes arising in suppressed, hyperimmunized mice occur at very low frequency, or are not

Extent to which hairpin opening by the Artemis:DNA-PKcs complex can contribute to junctional diversity in V(D)J recombination