Brucellosis 2003 proceedings - PHIDIAS

Poster Session
65- PHAGOCYTOSIS AND INTRACELLULAR SURVIVAL OF Brucella IN MOCL3
OVINE MACROPHAGES.
M. P. Jiménez de Bagüés 1 , M. Olivier 2 , L. Guilloteau 2 . (1) Unidad de Sanidad Animal. Servicio de
Investigación Agroalimentaria. Diputación General de Aragón. Ap 727. 50080 Zaragoza, Spain. (2)
Laboratoire de Pathologie Infectieuse et Immunologie. INRA. 37380 Nouzilly. France.
Brucella is a Gram negative pathogen which is able to penetrate and multiply
within host cells. Up to now no small ruminant cell line was available for in vitro
studies of pathogen-monocyte interaction of Brucella. An ovine blood monocyte
derived cell line named MOCL3 has been established for this purpose. In order to
determine if the cell line could be used as an in vitro model for the study of brucellose
we analysed the phagocytosis and intracellular survival of different smooth (S) and
rough (R) strains of Brucella in MOCL3 macrophages. The strains used were B. ovis
Reo 198 (R), B. melitensis 16M (S), B. melitensis R5 (R), B. melitensis B3B2 (R) and
Rev1 (vaccinal S strain), B. abortus 2308 (S), B. abortus RB51 (R), B. abortus 45/20
(R) and B19 (vaccinal S strain), B. suis 1330 (S) and B. suis manB (R). All strains
except B. ovis were internalized at a different extents in our conditions. Smooth
strains multiplied within the macrophages during the 48h period experiments while R
strains did not or multiplied slightly between 24 and 48h. Vaccinal strains like Rev 1
and B19 were less virulent than their corresponding wild types B. melitensis 16 M
and B. abortus 2308. Nitric Oxide was not detected when MOCL3 cells were
stimulated with E. coli LPS or infected with different strains of Brucella. We conclude
that the MOCL3 cell line could be a suitable tool for in vitro studying the pathogenhost
interactions in brucellosis.
66- ANALYSIS OF LONG TERM SURVIVAL OF Brucella melitensis IN OVINE
CELLS MOCL3 AND EFFECT OF OPSONIZATION ON INFECTIVITY.
Paolo Pasquali 1 , Rosanna Adone 1 , Michel Olivier 2 , Cinzia Marianelli 1 , Claudia Pistoia 1 , Paola
Petrucci 1 , Giacomo Marcon 1 , Franco Ciuchini 1 . (1) Dipartimento di Sanità Alimentare ed Animale,
Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy. (2) Laboratoire de Pathologie
Infectieuse et Immunologie. INRA. 37380 Nouzilly. France.
Brucellae are gram-negative facultative intracellular bacteria, able to infect
macrophages, within they can multiply, evading the effector mechanisms of
phagocytes. Most of the available knowledge arises from studies using murine
phagocytes. On that account the availability of an in vitro model using ovine cells
could represent a great advantage to intimately understand the interplay between
bacteria and phagocyte from animals which are natural host of the infection. Ovine
blood monocyte derived cell line, named MOCL3, were infected with Brucella
melitensis 16M, B. melitensis Rev1 at a ratio of 10 bacteria to one cell or were kept
as uninfected controls. At 24, 48, 96, 168 and 240 hours after infection, the viability of
cells and the multiplication of bacteria were monitored. Uninfected MOCL3 showed a
viability curve which reached the plateau phase after 96 hours. When macrophages
were infected with B. melitensis Rev1 we observed a similar trend, with only a
significant difference at 24h when macrophages infected resulted more viable than
the uninfected controls. Macrophages infected with the virulent B. melitensis, on the
contrary, showed a different pattern characterised by a lower viability until 48 hours
with a rapid increase around 96 hours. This trend showed a positive correlation with
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Brucellosis 2003 International Research Conference