An attempt at an epidemiological explanation - Epib.nl

Chapter 7group B meningococci (Chapter 4), which confirms the results of previous reports." 29A vaccine based on LOS immunotypes could theoretically be restricted to L2, 13 andIA, because only these immunotypes seem capable of causing disease. lo Because themeningococcal LOS, or endotoxin, plays a key role in the induction of septic shock,l l-llan additional advantage of a vaccine based on tbe LOS moie1y is tbat tbis vaccine willprobably elicit neutralizing anti-endotoxin antibodies, which could reduce the numberof fatalities of MD I' 27The relevance of lipooligosaccharide immunotyping for the characterization of N.meningitidisIn the past, LOS immuno1yping bas been hampered by the complexi1y of themetbods involved." 29 Despite the lack of specific monoclonal antibodies (moabs)against the immuno1ypes L2 and U, we were able to develop an algorithm for easydetermination of the LOS immuno1ype of N. menillgitidis of the serogroups Band Cin a whole-cell ELISA, using a panel of 14 moabs (Chapter 4). The determination ofthe immuno1ypes L2 and U, however, is complicated and subject to error, and thedevelopment of L2 and U specific moabs is needed. For the determination ofimmunotypes among serogroup A meningococci the algorithm is less suitable,because no specific moabs against most of the regular immuno1ypes of this serogroupexist.For epidemiological purposes LOS immuno1yping is probably of limited value.Isolates of serogroup A are homogenous with regard to both the immuno1ype andserosub1ype, and studying tbe distribution of immuno1ypes will have little additionaldiscriminating power293~36 This may also apply to the serogroups Band C, wbichbarbour on ly a limited number of different immuDotypes. 28 29 37 For research all theprotective immunity to the meningococcus, however, the LOS immunotype is ofmajor importance. The LOS immunotype is considered to be a virulence determinantand plays an important role in eliciting specific immunity to the meningococcus. IS 37By using the immuno1yping method, as described in Cbapter 4, it is possible to give abetter definition of test strains for ill vitro bactericidal assays and path agenesisresearch, but further studies are needed in order to improve on LOS epitopecharacterization.Chemoprophylaxis in the prevention of secondary cases of meningococcal diseaseThe cOlltinuing controversy about chemoprophylaxis in the NetherlandsThe prescription of rifampicin to the bousehold contacts of a primary patient witbMD, as well as to the primary patient, is generally accepted practice in the UnitedStates and Great Britain" 39 The ultimate goal of this measure is to prevent secondarycases of MD. The beneficial effect of rifampicin on the prevention of secondarycases, however, has been demonstrated only in the case of meningitis caused byHaemophilus inJluenzae, but not for MD.4092