title: [Dynamics of F1 antibody responses toYersinia pestisinfection inRhombomys opimus].
abstract: Objective:To observe the dynamics of antibody response in great gerbils infected withYersinia pestisin experiment.Method:A total of 211 great gerbils were captured in the southern margin of plague natural focus of Junggar Basin of the Xinjiang Uygur Autonomous Region in 2011. Among them, there were 167 great gerbils without infection ofY. pestisand 44 great gerbils infected byY.pestis.Y.pestisNo. 2504 was employed for this experimental strain, which was strong toxic strain with negativity in the reduction experiment of nitrate. 35 great gerbils without the infection ofY. pestiswere divided randomly and averagely into 7 groups including 6 experimental groups and 1 control group. Great gerbils in the 1st to 6th experimental groups were exposed first with 1 × 10(6)-1 × 10(11) CFU/ml of bacterial fluid with 10 times of gradient dilution; groin areas of great gerbils in the control group were injected subcutaneously with physiological saline; and the amount of infection was all 1 ml. 17 great gerbils infected withY. pestisand the first detection of F1-antibody titer in 1∶256-1∶4 096 were grouped according to F1-antibody titer: group 1∶4 096 (n=4), group 1∶2 048 (n=4), group 1∶1 024 (n=3), group 1∶512 (n=3) and group 1∶256 (n=3); and blood in caudal regions was collected in asepsis for the detection of F1-antibody, with a total of 5 times. 9 great gerbils which were selected from the remaining great gerbils infected withY. pestisand detected F1-antibody negative 2 times were exposed 1×10(6) CFU/ml of bacterial fluid for the second infection, with the amount of infection being 1 ml. Blood in caudal regions of great gerbils after the first and second infection were collected for the detection of plague F1-antibody on the 3rd, 5th, 7th, 15th, 30th, 60th, 90th and 120th day after infection. Declined regression models for great gerbils' antibodies were established with unary linear regression equation; declined change diagrams for the antibodies were drawn to observe the declined F1-antibody after great gerbils were exposed toY. pestis.Results:In great gerbils with the first infection ofY. pestis, antibodies were detected in the 1 × 10(6)-1 × 10(8) CFU/ml of group on the 30th, 15th and 15th day, respectively; the positive rates of antibody were 1/4, 3/4 and 4/5, respectively; the group 1×10(7) and 1× 10(8) CFU/ml reached to the highest antibody titer with 1∶256 on the 120th day; antibodies were revealed in the group 1×10(9), 1×10(10) and 1×10(11) CFU/ml from the 5th to 7th day when the seroconversion of all antibodies was observed; group 1×10(11) CFU/ml reached to the highest antibody titer on the 120th day with 1∶4 096. In the great gerbils with the second exposure toY.pestis, positive antibodies were detected on the 3rd day with the positive rate being 2/9; and the highest antibody titer with 1∶2 048 was noted on the 90th day. Unary linear regression equation of declined F1 antibody of great gerbils wasy=0.045x-0.321 (F=115.40,P<0.001), and the shortest duration for F1-antibody titer declining from 1∶4 096 to 0 was 140 d and the longest duration 200 d.Conclusion:Great gerbils infected with the high concentration ofY. pestisfluid show shorter duration in producing F1-antibody, the antibody positive rate is also higher, and the highest antibody titer can reach 1∶4 096. The great gerbils could hold the plague F1 antibodies for a long time which was about 140 to 200 days from the highest titer.
authors.affiliation: The Center for Disease Control and Prevention of Xinjiang Uygur Autonomous Region, Urumqi 830002, China.
authors.forename: W W
authors.initials: WW
authors.lastname: Meng
authors.forename: X H
authors.initials: XH
authors.lastname: Wang
authors.forename: T
authors.initials: T
authors.lastname: Luo
authors.forename: B
authors.initials: B
authors.lastname: Li
authors.forename: Q G
authors.initials: QG
authors.lastname: Wang
authors.forename: R
authors.initials: R
authors.lastname: Guo
authors.forename: X
authors.initials: X
authors.lastname: Dai
authors.forename: Y J
authors.initials: YJ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D000917:Antibody Formation; D002681:China; D005849:Gerbillinae / Q000276:immunology* / Q000382:microbiology; D010930:Plague / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D011897:Random Allocation; D013997:Time Factors; D015010:Yersinia pestis / Q000276:immunology* / Q000502:physiology
chemical_list: D000907:Antibodies, Bacterial
keywords: Gerbillinae; Plague F1 antibody; Yersinia pestis