[Immunological identification of a synthetic peptide from the paramyosin of Schistosoma japonicum].
OBJECTIVE
To identify the immunologic property of a synthetic peptide Sj97-P22 from paramyosin of Schistosoma japonicum (Sj97).


METHODS
Twenty-seven female C57BL/6 mice were divided into 3 groups each with 9 mice, Sj97-P22, control peptide and PBS groups, and each mouse was respectively immunized twice (seven days interval) with 100 microg of Sj97-P22, control peptide or PBS, emulsified with equal value of complete Freund's adjuvant. Seven to ten days after the second immunization, the mouse spleen mononuclear cells were isolated for three-color flow cytometry to detect intracellular cytokines IFN-gamma and IL-4. Then the spleen mononuclear cells were co-cultured with Sj97-P22, control peptide or PBS respectively, and the incorporation rate of 3H-thymidine, as well as the levels of IL-2, IFN-gamma and IL-4 in the cultured cell supernatant, were measured.


RESULTS
In CD4+ T cells, the percentage of IFN-gamma-producing cells in Sj97-P22 group [(8.05 +/- 0.54)%] was significantly higher than that of the control peptide group [(4.74 +/- 1.04)%] or PBS group [(6.51 +/- 0.49)%] (P<0.05), while the proportion of IL-4-producing cells was significantly lower in Sj97-P22 group [(0.60 +/- 0.11)%] than that in PBS group [(1.31 +/- 0.27)%] (P<0.05). Also, compared with control peptide or PBS stimulation, Sj97-P22 was able to effectively stimulate the proliferation with the stimulation index (3.12 +/- 1.59) and a higher secretion of IL-2 [(9.13 +/- 1.54) pg/ml] and IFN-gamma [(39.75 +/- 9.69) pg/ml] of spleen mononuclear cells in Sj97-P22-immunized mice (P<0.05). Both Sj97-P22 and control peptide were not effective stimulators to the spleen mononuclear cells from mice of PBS group.


CONCLUSIONS
It is highly possible that Sj97-P22 is a Th1-type epitope specific for C57BL/6 mice.
Tao
Fang-fang
FF
Department of Pathogen Biology, Nanjing Medical University, Nanjing 210029, China.
Wang
Hui
H
Sun
Xin-juan
XJ
Liu
Feng
F
Wang
Yong
Y
Su
Chuan
C
Wu
Hai-wei
HW
Zhang
Zhao-song
ZS
D000818:Animals; D005260:Female; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000276:immunology* / Q000378:metabolism; D012549:Schistosoma japonicum / Q000276:immunology* / Q000378:metabolism; D018417:Th1 Cells / Q000276:immunology* / Q000378:metabolism; D014335:Tropomyosin / Q000276:immunology* / Q000378:metabolism
D007376:Interleukin-2; D010455:Peptides; D014335:Tropomyosin; D015847:Interleukin-4; D007371:Interferon-gamma