Preparation and identification of the lipopolysaccharide binding protein mimic epitope peptide vaccine that prevents endotoxin-induced acute lung injury in mice

Abstract

The objectives of this study were to detect the immunogenicity of a lipopolysaccharide (LPS) binding protein (LBP) mimic epitope peptide vaccine and evaluate its effect on controlling excessive and uncontrolled inflammatory reactions in mice with acute lung injury. The vaccine was prepared by mixing self-made LBP mimic epitope multiple antigen peptide (MAP) and Freund adjuvants in a proper proportion. Healthy mice were inoculated with the vaccine and the dynamic changes of anti-MAP antibody were measured using ELISA. Anti-MAP antibody was prepared from the immune serum of the mice based on the standard antibody preparation program. Western blot assay was used to identify LBP specificity of anti-MAP antibody. Anti-MAP antibody bioactivity was analyzed using in vitro binding activity test. Following the vaccine inoculation, the mice were injected with LPS to induce acute lung injury. Anti-MAP antibody prepared was also used to immune the mice with LPS-induced acute lung injury. TNF-α and IL-1β contents in serum and lung tissue homogenate were measured using double antibody sandwiched ELISA at different time-points after LPS challenge. At 8 h time-point, total white blood cell counts, polymorphonuclear leucocyte count and protein content in bronchoalveolar lavage fluid were measured and pulmonary morphological changes were evaluated. The antibody titer was gradually rising, reaching to its peak at 8th week and lasting to the tenth week. The antibody possessed strong immunogenicity, high specificity and favorable biologic activity. Whole range inoculation of LBP mimic epitope peptide vaccine or anti-MAP antibody intervention partly eliminates LPS-mediated acute lung injury. In conclusion, LBP mimic epitope peptide vaccine successfully induced highly specific antibody with high bioactivity in mice. LBP mimic epitope peptide vaccine and anti-MAP antibody inhibited excessive and uncontrolled inflammatory reactions from LPS-mediated acute lung injury in mice.