realized in has disposition at some time agent_in_compromised_process artificially mutated Brucella macrophage - Brucella interaction attenuated disposition Hela cell - Brucella interaction Brucella intracellular replication Brucella virb9 mutant MUTATION: Uptake in the presence or absence of Ca2 and Mg2 did not influence the subsequent intracellular survival of wild-type Brucella, whereas the decrease in the number of surviving virB9 mutant cells was delayed in the absence of Ca2 and Mg2. Possibly two types of adhesion molecules promoted uptake of Brucella, one being Ca2 and Mg2 dependent and the other not, and that both types participate in the uptake of wild-type bacteria but only the latter type participates in the uptake of the virB9 mutant [Ref6545:Rittig et al., 2001]. Four independent mutants in virB5, virB9 or virB10 were highly attenuated in an in vitro infection model with human macrophages [Ref6467:O'Callaghan et al., 1999]. The intracellular fate of three virB mutants (virB2, virB4 and virB9) in HeLa cells by immunofluorescence was examined. The three VirB proteins are not necessary for penetration and the inhibition of phago-lysosomal fusion within non-professional phagocytes. Rather, the virB mutants are unable to reach the replicative niche and reside in a membrane -bound vacuole expressing the late endosomal marker, LAMP1, and the sec61beta protein from the ER membrane, proteins that are present in autophagic vesicles originating from the ER [Ref6546:Delrue et al., 2001]. Attenuated non-polar virB2, virB4, virB8, virB9 and virB10 Brucella mutants are capable of penetrating cells as the same rate as the virulent wild-type Brucella, transit through EEA1 -positive early compartments and then localize in LAMP1-positive compartments at early times of infection [Ref6466:Gorvel and Moreno, 2002]. See PMID:11349069, 10510235, 11437834, 12414149