IMMUNOBIOLOGICAL PROPERTIES OF BORDETELLA PERTUSSIS LIPOPOLYSACCHARIDE IN THE ACELLULAR PERTUSSIS VACCINE

Aim. Study of Bordetella pertussis lipopolysaccharide (LPS) immunobiological properties in the acellular pertussis vaccine. Materials and methods. Experimental series of acellular pertussis vaccines (APV), lyophilized LPS were used. Antibody titers against LPS in mice sera were evaluated by using EIA with peroxidase conjugate of anti-species antibodies against mice IgG. LPS activity in B. pertussis antigen complex preparations was determined in quantitative chromogenic LAL-test by end point. APV protective activity was determined in mice test during intracerebral infection by B. pertussis strain No. 18323 virulent culture. APV safety was determined in the mice body weight change test. Results. The presence of LPS in APV was shown in immune electrophoresis with purified B. pertussis LPS preparation as a control. Formalin treatment changes immunochemical properties of APV LPS that lead to the shift of precipitation bands with pertussis agglutinating sera from the start zone into cathode. The quantity of LPS in pertussis culture supernatants was on average 49050+6774 endotoxin units per ml (EU/ml). In APV preparations the quantity of LPS was on average 906+90 EU/ml, i.e. decreased by more than 50 times. An increase of antibody titers against B. pertussis LPS in mice sera after the APV immunization was shown in EIA, which gives evidence of its presence in immunogenic form in the complex preparations. The preclinical studies carried out show protective activity and specific safety of the experimental APV series. Conclusion. Formalin-neutralized APV preparation is a complex of protein antigens in association with LPS. Formalin treatment results in modification of LPS molecule that retains antigenic properties but is significantly less toxic.

Bordetella pertussis, acellular pertussis vaccine, lipopolysaccharide, immunogenicity, safety