Internalization and Colocalization of a Polyclonal Antibody Against Porphyromonas gingivalis FimA type I in Infected Cells.

Objective:  The aim of this work was to investigate the effect of a rabbit polyclonal antibody specific to FimA type I (FimI) protein internalized into infected cells.

Materials And Methods:  Rabbits were immunized with FimI protein and the serum was collected for immunoglobulin (Ig) purification. For visualization of the antibody inside the cells, it was labeled with Cy3 dye. Live was labeled with PKH67 dye. Rabbit anti-FimI Ig-Cy3 was internalized into H357 cells infected with -PKH67 by electroporation or coincubation. Location of the Ig or was observed under fluorescence microscope or confocal microscope. Percentage of -PKH67 infected cells was analyzed by flow cytometry.

Statistical Analysis:  Normality of data distribution was tested by Shapiro-Wilk test. The data failed normality test and were further analyzed by Kolmogorov-Smirnov test.

Results:  Rabbit anti- FimI Ig-Cy3 and -PKH67 were both located next to the nucleus. The rabbit anti-FimI Ig-Cy3 was able to enter H357 cells after the cells were cultured in the medium containing the labeled Ig for 16 hours. The location of the Ig was near the nucleus as found in cells electroporated with the Ig-Cy3. The percentage of -PKH67 infected cells seemed to be decreased after the infected cells internalized anti-FimI Ig by electroporation. However, it was not statistically significance.

Conclusion:  Rabbit anti- FimI Ig and was colocalized near the nucleus. And the rabbit anti-FimI Ig was able to enter H357 cells by coincubation method.