Abstract
Introduction: Neisseria lactamica is a non pathogenic commensal bacteria commonly found in the upper respiratory tract of infants. Its carriage dynamics have been extensively studied in young children and a clear correlation has been documented between colonisation by N. lactamica and protection from meningococcal disease. This is thought to be due to common antigens resulting in a cross protective immune response. Objectives: The aim of this study was to inoculate Neisseria negative healthy adult volunteers, with live N. lactamica and monitor their specific mucosal and systemic immune response, then analyse their serum bactericidal antibody response against 6 UK prevalent meningococcal B strains. Methodology: 9 individuals were inoculated with live N. lactamica, resulting in 5 successful colonisations. Colonisation was confirmed using nasopharyngeal swabs and gargles. Saliva and blood samples were taken at 0 weeks, 2, 4, 7, and 12 weeks. Findings: Results demonstrated a specific mucosal IgA and systemic IgG immune response to colonisation by N. lactamica. The specific mucosal IgA response from baseline to 12 weeks, comparing non colonised and colonised individuals was significant, p value Z0.0159. Baseline specific IgG and peak fold rise for each individual, using a Mann Whitney test, demonstrates a value of pZ0.063 in colonised individuals. Discussion: Most interestingly colonised individuals demonstrate a greater range of SBA responses to different meningococcal strains, than the non colonised group. Within the colonised individuals 2 volunteers had a significant (greater than 4 fold rise) response to 4 different meningococcal strains. Overall, all volunteers mounted a response to at least one strain of meningococci, it is likely that individual exposure to N. lactamica is resulting in a booster response of one or more specific antigens which are found on the outer membrane of these different strains of meningococci. These results support the hypothesis that colonisation by Neisseria lactamica does result in cross protection against meningococci. MATRIX METALLOPROTEINASE DRIVEN TISSUE DESTRUCTION IN CENTRAL NERVOUS SYSTEM TUBERCULOSIS IS REGULATED BY NFjB Justin Green, Shruti Dholakia, Rachel Moores, Lucinda Rand, Paul Ekington, Jon Friedland Imperial College, London, United Kingdom
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