Reducción de la toxicidad del lipopolisacárido de Neisseria meningitidis serogrupo B y estudio de su estabilidad estructural

The search of adjuvants has been one of the most important lines of the research in the development of vaccines in the last decades. One of the adjuvants under research at Finlay Institute uses lipopolysaccharide (LPS) from Neisseria meningitidis serogroup B in its composition and it is very toxic. For this reason we aim to make a structural modification of LPS from N. meningitidis serogroup B to reduce its toxicity and to study its stability for three months. A LPS purified by water and phenol extraction method was modified structurally by a controlled basic hydrolysis. The modified LPS was controlled at moment of the hydrolysis, a month and three months later. The evaluations consisted on the determination the concentrations of amine groups generated, the toxicity by Limulus Amoebocyte Lysate (LAL), the determination of the electrophoretic pattern and the constant of distribution (Kd) by chromatography of molecular exclusion as indicative parameters of structural integrity. The obtained results showed an increase of amine groups, a reduction of more than 5 000 times of the initial toxicity of native LPS and an increase of the Kd determined by chromatography. Studied parameters remained constant in the three studied months. In summary, modified structurally LPS by means of a controlled basic hydrolysis and stored in watery solution and temperatures from 2 to 8 °C remains without changes in their structure at least for three months.