Abstract: 【Abstract】 Objective To prokaryotically express a peptide fragment of 660 - 1468 amino acids in Neisseria gonorrhoeae NGO2105 protein, and to prepare and identify its polyclonal antibody. Methods The pCold TF-NGO2105660-1468 aa recombinant plasmid was transformed into the bacterium Escherichia coli BL21（DE3） for protein expression. After the inclusion body protein was denatured and renatured, the target protein was purified. Then, BALB/c mice were immunized with the target protein to prepare a polyclonal antiserum; the antibody potency was evaluated by enzyme-linked immunosorbent assay, the specificity of the antibody against NGO2105 protein in Neisseria gonorrhoeae was analyzed by Western blot analysis, the affinity of the antiserum with Neisseria gonorrhoeae was analyzed by flow cytometry, and adhesion inhibition assay was performed to evaluate the inhibitory effect of anti-NGO2105660-1468 aa antibody on the adhesion of Neisseria gonorrhoeae to human cervical epithelial ME-180 cells. Comparisons between different groups were performed by using t test. Results The NGO2105660-1468 aa protein was expressed as the inclusion body, and the soluble target protein was obtained by denaturation, renaturation, and purification. After immunization of mice with the target protein, the antiserum titer was 5.12 × 106, and flow cytometry showed that the antibody bound well to the Neisseria gonorrhoeae NGO2105660-1468 aa. Adhesion inhibition assay showed that the anti-NGO2105660-1468 aa antibody significantly inhibited the adhesion of Neisseria gonorrhoeae to ME-180 cells, and the inhibitory effect was concentration-dependent to some extent, with the adhesion rates of Neisseria gonorrhoeae treated with 20- and 40-fold dilutions of the anti-NGO2105660-1468 aa antibody being 52.9% and 79.2% respectively, significantly lower than the adhesion rate in the untreated group (100%, t = 8.40, 5.29, P < 0.001, = 0.006, respectively） . Conclusion The NGO2105660-1468 aa protein was successfully expressed and purified, and a highly potent polyclonal antibody was prepared, which had a good affinity with Neisseria gonorrhoeae and an adhesion inhibition ability.

Key words: Neisseria gonorrhoeae, NGO2105 protein, Polyclonal antibody, Antibody affinity, Bacterial adhesion, Vaccination, Vaccines