title: [Stabilities of two kinds of Plasmodium antigen substrate slides under different storage temperatures and time].
abstract: OBJECTIVE
  To observe and compare the inspection effects of antigen substrate slides of Plasmodium cynomolgi (P. c) and Plasmodium falciparum (P. f) on the malaria antibody titer under different storage temperatures and time.
  
  
  METHODS
  The densities of Plasmodium of P. c and P. f antigen slides were counted through a microscope, and the average numbers of Plasmodium in each field of vision were calculated. The pooled serum of patients with tertian malaria and falciparum malaria were treated as antibody serum, and the dilutions were from 1:5 to 1:1 280. The two kinds of antibody slides were placed under the temperature of 4-6, 25-27, 33-35 degrees C, and two slides of each kind were selected at Day 3, 5, 7, 10 post-storage to detect the end point antibody titer of malaria by the indirect fluorescent antibody test. Meanwhile, the P. c and P. f antigen slides storing under -20 degrees C for 1 year and 2 years were placed under the aforementioned 3 temperature conditions for 3 d, and the changes of the antibody titers were compared.
  
  
  RESULTS
  The densities of Plasmodium in blood cells of P. c and P. f antigen slides were 2.00 x 10(5)/microl and 1.89x 10(5)/microl, respectively, and the average numbers of Plasmodium in each field of vision were 157 +/- 13 and 142 +/- 9, respectively. The end point titers of antibody of P. c and P. f antigen slides placed under the temperatures of 4-6, 25-27, 33-35 degrees C were all on a downward trend after storing for 5 d. The average antibody titers of the two kinds of slides under temperature of 4-6 degrees C and above were 1:440 and 1:80, respectively, and there was a significantly statistic difference between them(t = 1.940, P < 0.05). When P. c and P. f antigen slides storing under -20 degrees C for 1 year were placed under 4-6 degrees C for 3 d, the end point antibody titers were both 1:640, while for those storing under -20 degrees C for 2 years, the end point antibody titers were 1:320 and 1:160, respectively, both the differences were statistically significant (t(P. c) =11.362, P(P. c) < 0.01; t(P. f) = 38.845, P(P. f) < 0.001).
  
  
  CONCLUSIONS
  The end point antibody titers for malaria detection of P. c and P. f antigen slides decrease gradually with the raise of temperature and the prolonging of time for storage.
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Laboratory of Parasite and Vector Biology, Ministry of Health, WHO Collaborating Center for Malaria, Schistosomiasis and Filariasis, Shanghai 200025, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Fang
authors.forename: Jia-Yun
authors.initials: JY
authors.lastname: Pan
authors.forename: Xiang
authors.initials: X
authors.lastname: Zheng
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Feng
authors.forename: Wei-Kang
authors.initials: WK
authors.lastname: Jiang
mesh_terms: D000953:Antigens, Protozoan / Q000276:immunology*; D006801:Humans; D010961:Plasmodium / Q000276:immunology*; D055550:Protein Stability; D013048:Specimen Handling / Q000379:methods*; D013694:Temperament; D013997:Time Factors
chemical_list: D000953:Antigens, Protozoan