Objective:To investigate the immume mechanism and protective effect of DNA vaccine pcD flaB against pathogenic leptospira infection. Methods: DNA vaccine pcD flaB was constructed by inserting flaB into the eucaryotic expressing plasmid pcDNA3. After guinea pigs were infected with leptospira, the protective rate was observed and specific anti leptospira antibody IgG were tested by ELISA. TNF activity was tested by cell proliferation. Results:The protective rate against leptospira infection was 100%. The specific antibody IgG generated peaked at the 6th week. Activity of TNF released by macrophage of guinea pigs given DNA vaccine was higher than that not given vaccine. Conclusion:DNA vaccine pcD flaB can protect guinea pigs from leptospira challenge infection by inducing humoral immune response and increasing TNF activity.

This study was firstly conducted to detect antinuclear antibody(ANA) titer by using number influorescence density analysis assay instead of serum diluted assay. The best camera explore time was selected. Then 4,140 ANA positive sera were detected to determine the relationship between number influorescence density (detected by number camera system Spot 32 and computer analysis software ipwin32) and serum diluted titer. The consistent rates in different ANA patterns used by the two methods were compared. 4 seconds was found to be the best explore time and the relationship between number influorescence density and serum diluted titer was 29-50 vs 1:100, 51-85 vs 1:320, 86-175 vs 1:1000, 176-215 vs 1:3200, 216-237 vs 1:10,000. According to this standard we detected 3140 ANA positive sera by use of the two methods and observed a total consistency rate of 89.4%. The consistency rates of three ANA patterns including speckled, homogenous, mixture of speckled and homogenous were as high as 98.9%, 99.5%, 99.8% respectively. The lower consistency rate patterns included nucleolar (5.3%), centromere (1.8%), ribosome(12.6%) and other special patterns(0%). For practical purpose, number influorescence density analysis assay can be used in detecting the three main ANA patterns (speckled, homogeneous, mixture of speckled and homogenous) titer instead of serum diluted assay. The number influorescence density analysis assay is more objective, economical and simple than the serum diluted assay.
Antibodies, Antinuclear ; analysis ; Fluorescence ; Fluoroimmunoassay ; methods ; Software