Ducks And Geese B Lymphocyte-stimulating Factor Study

B-cell activating factor (BAFF), belonging to the TNF family, is critical for B cell survival and maturation. cDNA of goose BAFF (gBAFF) was amplified from goose spleen by RT-PCR. The open reading frame (ORF) of gBAFF encodes a protein of 288-amino acid. The gBAFF shows 98, 92, 44 and 55% amino acid sequence identity with duck (dBAFF), chicken (cBAFF), mouse (mBAFF) and human BAFF (hBAFF), respectively. RT-PCR results showed that gBAFF mRNA is expressed in thymus and more highly expressed in the bursa of Fabricius and spleen. Recombinant soluble gBAFF (gsBAFF) expressed in Escherichia coli has molecular weight of～19 kDa. In vitro, purified gsBAFF was able to promote bursa B cells survival/proliferation in goose, duck and chicken. Furthermore, recombinant dsBAFF and csBAFF have a positive effect on goose, duck and chicken bursa B cells survival/ proliferation. These findings indicate that gBAFF plays an important role in the survival/proliferation of goose B cells and, owing to its high evolutionary conservation, functional cross-reactivity exists between chicken, duck and goose BAFF.The fragment encoding EGFP-dsBAFF, which had the linker sequence (Gly₄Ser)₂ between EGFP and dsBAFF was obtained by two rounds of PCR. The EGFP-dsBAFF was expressed in E.coli BL21 (DE3), and then the protein was pu-rified by immobilized Ni²⁺-IDA affinity chromatography. The purified fusion p-rotein retained the fluorescence activity of parental EGFP and promoted duck B lymphocyte survival in vitro.In mammals, interferon-g-inducible-lysosomal thiol reductase (GILT) has been demonstrated to play a key role in the processing and presentation of MHC class II-restricted antigen (Ag) by catalyzing disulfide bond reduction, thus unfolding native protein Ag and facilitating subsequent cleavage by proteases. cDNA of orange-spotted grouper GILT (OsgGILT) and porcine GILT(pGILT) were amplified from orange-spotted grouper and porcine spleen by RT-PCR and Rapid amplification of cDNA ends (RACE). The full-length cDNA of OsgGILT and pGILT gene is 1066 bp and 1062 bp nucleotides (nt) encoding a protein of 260 amino acids (aa) and 246aa. The result of real-time PCR showed that OsgGILT mRNA was high expressed in spleen and kidney, and pGILT was high expressed in spleen and blood. The pGILT expression is obviously up-regulated in spleen and blood after induction with LPS, these results suggest that pGILT may be involved in the immune response to LPS challenge in porcine.