Germline sequences of V(H)7183 gene family members in C57BL/6 mice demonstrate natural selection of particular sequences during recent evolution

Identical alpha-chain T-cell receptor transcripts are present on T cells infiltrating coronary arteries of human cardiac allografts with chronic rejection

Chronic cardiac allograft rejection is characterized by graft arteriopathy and is a major obstacle of graft survival. We investigated T-cell receptor (TCR) alpha-chain transcripts of T cells infiltrating human epicardial coronary arteries from cardiac allografts with chronic rejection. The non-palindromic adaptor-polymerase chain reaction (NPA-PCR) was used to specifically amplify TCR alpha-chain transcripts from five explanted cardiac allografts with chronic rejection. The amplified products were cloned and sequenced to obtain the entire ValphaJalpha region. Immuno-histochemistry was used to identify the mononuclear cell infiltrates in the coronary arteries. All the five coronary artery specimens exhibited large populations of infiltrating mononuclear cells, which were primarily comprised of T cells and macrophages. In three specimens, high proportions ( approximately 80%) of identical alpha-chain TCR transcripts were detected. In peripheral blood mononuclear cells from a healthy individual, alpha-chain TCR transcripts were unique when compared to each other. Endomyocardial biopsies collected from one patient six months before the allograft was explanted, contained identical alpha-chain TCR transcripts to those found to be clonally expanded in the coronary arteries from this patient. These results indicate that T cells infiltrating the epicardial arteries of cardiac allografts with chronic rejection undergo proliferation and clonal expansion in response to a specific antigen, which very likely is an (allo)antigen(s).

A three-megabase yeast artificial chromosome contig spanning the C57BL mouse Igh locus

The mouse Ig H chain (Igh) complex locus is composed of >100 gene segments encoding the variable, diversity, joining, and constant portions of the Ab H chain protein. To advance the characterization of this locus and to identify all the V(H) genes, we have isolated the entire region from C57BL/6 and C57BL/10 as a yeast artificial chromosome contig. The mouse Igh locus extends approximately three megabases and contains at least 134 V(H) genes classified in 15 partially interspersed families. Two non-Igh pseudogenes (Odc-rs8 and Rpl32-rs14) were localized in the distal part of the locus. This physical yeast artificial chromosome map will provide important structure and guidance for the sequencing of this large, complex, and highly repetitive locus.

Synthesis of ligand-specific phage-display ScFv against the herbicide picloram by direct cloning from hyperimmunized mouse

Immunoglobulin genes were directly isolated from the splenocytes of a BALB/C mouse hyperimmunized with the auxinic herbicide picloram conjugated to bovine serum albumin. Variable light and heavy domain DNA were joined to produce single-chain Fv (scFv) DNA, which was cloned into phage vector fd-tet-GIIID to display multiple copies of scFv on the filamentous phage minor coat protein gIIIp. The phage-display scFv library (10(4) clones) was selected against picloram conjugated to ovalbumin. After five rounds of panning, individual clones were analyzed. ScFv with different affinities to picloram (IC(50) values ranging from 20 ppb to 10 ppm) were detected in the final enriched pool. The increased avidity of the phage vector enhanced the selection (i.e., panning) of multiple picloram-specific recombinant antibodies. Stringent selection was required to isolate the clones with the highest affinity. Nucleotide sequence analysis of six isolated clones revealed that all of the V(L) belonged to the V kappa 9A family joined to J kappa 2 segments. All of the V(H) belonged to the V(H)()7183 family and joined to two different J segments (i.e., J(H)()2 or J(H)()4). Different from the immune response to large molecular weight molecules (MW > 10,000 Da), which requires both VDJ segment rearrangement and somatic hypermutations, production of high-affinity antibodies to picloram, a small ligand having a formula weight of 241.5 Da, predominantly requires somatic hypermutations.