Pathogenesis of Group B Streptococci and C5a
I think "neu" must be an abbreviation for "neutrophil". 

C3a and C5a are both chemotactic peptides that recruit cells to sites where complement activation is occurring. C5 is a substrate for the C5 convertases formed in one of the three complement pathways (classical, lectin, alternative). C5b, the other product of this cleavage goes on to form the membrane attack complex. 

C5a peptidase is a Streptococcal product which destroys the C5a peptide before it can recruit neutrophils and other agents of cell-mediated immunity. Streptococci also produce an inhibitor of the membrane attack complex.