On-line version ISSN 1025-0298
OCHOA, Rolando et al. ELISA Cut off Level for Quantitation of Antibodies Elicited by the Meningococcal Vaccine VA-MENGOC-BC. Vaccimonitor [online]. 2001, vol.10, n.2, pp. 8-12. ISSN 1025-0298.
The Serum Bactericidal Assay (SBA) has been used to measure the protection elicited by meningococcal vaccines. Other immunobiological assays are being improved, however simple assays as ELISA, which are useful to test many samples are necessary. The cut off levels in the ELISAs for quantitation of human IgG against the antigens in VA-MENGOC-BC vaccine, prepared from outer membrane proteins of meningococcus B and capsular polysaccharide of meningococcus C, were assessed with a panel of serum samples from infants, previously characterized by Whole-Blood Assay (WBA). The cut off levels corresponding with the greatest sensitivity and specificity were respectively 2 μg/mL and 12 μg/mL for polysaccharide C antibodies, and 1000 U/mL and 7000 U/mL for outer membrane protein antibodies. The highest coincidence was obtained with 6 μg/mL, and 2500 U/mL. Another panel of serum samples from teenagers between 14 and 18 years old was tested by ELISA and SBA against Neisseria meningitidis serogroups B and C; a good concordance was reached. A high concentration of specific antibodies persists twelve years after vaccination with VA-MENGOC-BC.
Keywords : Vaccine; Neisseria meningitidis; polysaccharide C; outer membrane proteins; ELISA.