IMMUNOLOGICAL PROPERTIES OF MENINGOCOCCAL LIPOPOLYSACCHARIDE FROM SEROGROUP-A, SEROGROUP-B AND SEROGROUP-C

The aim of the study was to measure and compare the oxidative burst, c hemotaxis and cytokine production of human white blood cells, stimulat ed with meningococcal lipopolysaccharides (LPS) extracted from three d ifferent serogroups (A, B and C) of Neisseria meningitidis, and to eva luate whether convalescent sera from patients with meningococcal disea se could modify cell stimulation of LPS. All three preparations of LPS from groups A, B and C were tested using the Limulus amoebocyte lysat e assay (LAL), and the KDO concentrations of the LPS extracts were mea sured. Equivalent amounts of biologically active LPS, judged by LAL, a nd LPS with the same KDO concentration were assayed. IL-1 alpha, IL-1 beta, IL-6 and TNF-alpha production was stimulated by all three LPS pr eparations. All three preparations stimulated oxidative burst in monoc ytes (MNC). Only group A LPS stimulated neutrophil chemotaxis, while n one of the three LPS stimulated superoxide production. Pooled convales cent sera from five patients with meningococcal disease suppressed the activity of neutrophils stimulated with LPS from groups B and C (p<0. 05, Mann-Whitney U-test).