Objective] To analyze the sequence difference of the SSU rDNA variable regions of Leishmania isolates from hilly foci and plain foci of China. [Methods] Specific SSU rDNA fragments from nuclear DNA of five Leishmania species and isolates were amplified by PCR. The amplified DNA fragments were cloned into pGEM R\|T Easy vector. The specific fragments were sequenced by the automated DNA sequencer. [Results] Sequence analysis showed that the amplified DNA fragments of five Leishmania species and isolates were all 392 bp in length, point mutations were located in the two unique sequence (UQ\|Ⅰ and UQ\|Ⅱ); L.d.SC10 and L.d.GS7 had two same point mutations in UQ\|Ⅱ, only L.d.GS7 had one in UQ\|Ⅰ; no insertion/deletion. [Conclusion] Sequence difference of the SSU rDNA variable region existed between Leishmania isolates from hilly foci and plain foci; The sequences of the SSU rDNA variable regions of L.d. SD2 isolate and L.infantum were identical.

OBJECTIVETo investigate the role of natural killer-22 (NK-22) cells in the synovial fluid in the proliferation of fibroblast-like synoviocytes (FLS) in patients with rheumatoid arthritis (RA) and explore the possible signal pathway involved.

METHODSNK-22 cells in the SF of RA patients were sorted by flow cytometry. NK-22 cells were cultured for two weeks and the purity was detected by flow cytometry before stimulation with 20 ng/ml phorbol 12-myristate 13-acetate and 0.5 µmol/L ionomycin for 4 h. The level of interleukin-22 (IL-22) in the culture medium supernatant was then measured with ELISA. The proliferation of FLS in the presence of the culture supernatant of NK-22 cells was assessed with MTT assay at 24, 48 and 72 h, and the effect of IL-22 antibody on FLS proliferation was also observed. Real-time PCR and Western blotting were used to detect Stat3 mRNA and p-Stat3 protein levels, respectively, in the FLS exposed to rhIL-22 and AG490.

RESULTSNK-22 cells were successfully sorted by flow cytometry with a purity exceeding 90%. The levels of IL-22 in the supernatant of NKp44(+)NK cell culture averaged 1273.42∓254.48 pg/ml. The FLS proliferated rapidly 24, 48, and 72 h after the addition of culture supernatant of NK-22 cells (P<0.05). IL-22 antibody obviously inhibited the proliferation of FLS induced by NK-22 cell culture supernatant (P<0.05). Exposure of the FLS to rhIL-22 obviously increased cellular Stat3 expression levels, which were significantly lowered by the addition of AG490 (P<0.05).

CONCLUSIONNK-22 cells in the SF of RA patients can produce high concentrations of IL-22 to promote the proliferation of FLS through the STAT3 signal pathway.

Arthritis, Rheumatoid ; metabolism ; Cell Proliferation ; Cells, Cultured ; Fibroblasts ; cytology ; Humans ; Interleukins ; metabolism ; Killer Cells, Natural ; cytology ; metabolism ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Synovial Fluid ; cytology ; Synovial Membrane ; cytology