However, these previous results were generally based on data obtained during early stage of infection (approximately 6–24 h), whereby, the unencapsulated K. pneumoniae strains tend to be bound by complement C3, which greatly increases their probability of being phagocytosed by macrophages and then eliminated by cell-killing effects, such as those mediated by neutrophils or complements (Alvarez et al., 2000; Cortes et al., 2002). Here, C3 is linked to infection.