Tianhe Sun

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Natural killer (NK) cells are crucial in resistance to certain viral infections, but the mechanisms used to recognize infected cells remain largely unknown. Here, we show that the activating Ly49P receptor recognizes cells infected with mouse cytomegalovirus (MCMV) by a process that requires the presence of H2-D(k) and the MCMV m04 protein. Using H2(More)
Gene-targeted mice were generated with a loxP-neomycin resistance gene (neo r) cassette inserted upstream of the J ␭ 1 region and replacement of the glycine 154 codon in the C ␭ 1 gene with a serine codon. This insertion dramatically increases V ␭ 1-J ␭ 1 recombination. J ␭ 1 germ-line transcription levels in pre-B cells and thymus cells are also greatly(More)
This study is an investigation of the possible role of DNA polymerase (pol) delta with an inactivated exonuclease (exo) in somatic hypermutation (SHM). Analysis of endogenous heavy chain transcripts revealed no difference in mutation frequency and pattern between exo(-/-), exo(+/-) and exo(+/+) mice. The lack of an effect of the pol delta exo mutation on(More)
V(D)J recombination proceeds in two stages. Precise cleavage at the border of the conserved recombination signal sequences (RSSs) and the coding ends results in flush double-stranded signal ends and coding ends terminating in hairpins. In the second stage, the signal and coding ends are processed into signal and coding joints. Coding ends containing certain(More)
Surface expression of B cell antigen receptors (BCRs) containing Ig and Igalpha/Igbeta generates signals required to transit discrete developmental checkpoints. The mechanism by which BCR components collaborate to initiate signals is still unclear. The expression of Iglambda1 in SJL mice is 50-fold lower than in other strains. Here, we demonstrate by gene(More)
Gene-targeted mice were generated with a loxP-neomycin resistance gene (neo(r)) cassette inserted upstream of the Jlambda1 region and replacement of the glycine 154 codon in the Clambda1 gene with a serine codon. This insertion dramatically increases Vlambda1-Jlambda1 recombination. Jlambda1 germline transcription levels in pre-B cells and thymus cells are(More)
The presence of valine-154 instead of glycine in the constant region of lambda1 causes a severe lambda1 B cell defect in SJL and lambda1-valine knock-in mice with a compensatory increase in lambda2,3 B cells. The defect is due to low signaling by the lambda1-valine BCR. lambda1-Valine B cells deficient in the SHP-1 phosphatase survive better than lambda2,3(More)
During B and T lymphocyte development, immunoglobulin and T cell receptor genes are assembled from the germline V, (D) and J gene segments (Lewis, S.M., 1994. The mechanism of V(D)J joining: lessons from molecular, immunological and comparative analyses. Adv. Immunol. 56, 27-150). These DNA rearrangements, responsible for immune system diversity, are(More)