N. meningitis can be due to deficiency of this complement system:

Ref: Textbook of Microbiology by Surinder Kumar, P 262* Meningococcal disease is favoured by deficiency of the terminal complement components (C5-C9).Human genetic deficiencies of complement components and associated diseasesComplement deficiencyAssociation with diseaseC1 inhibitorHereditary angioneurotic edemaC1Systemic lupus erythematosus-like disease, frequently fatal from overwhelming infectionC2Increased susceptibility to infectionsC3Recurrent bacterial infectionsC4Systemic lupus erythematosus-like diseaseC5Recurrent infections-lupus-like diseaseC6, C7, C8Recurrent infections: Disseminated gonococcal infectionsC9Not more susceptible to disease than other individuals in the general populationFactor 1Low C3 levels with recurrent bacterial infections