INVESTIGADORES
GIAMBARTOLOMEI Guillermo Hernan
artículos
Título:
Brucella abortus induces apoptosis of human T lymphocytes.
Autor/es:
VELÁSQUEZ LN, DELPINO MV, IBAÑEZ AE, CORIA LM, MIRAGLIA MC, SCIAN R, CASSATARO J, GIAMBARTOLOMEI GH, BARRIONUEVO P.
Revista:
MICROBES AND INFECTION
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 14 p. 639 - 650
ISSN:
1286-4579
Resumen:
Immune evasion is essential for Brucella abortus to survive in the face of
robust adaptive CD4+ T cell response. We have previously demonstrated that B.
abortus can indirectly inhibit CD4+ T cells by down-regulating MHC-II expression
and antigen presentation on macrophages. However, whether B. abortus is able to
directly interfere with T lymphocytes is not known. We report here that B.
abortus induces apoptosis of human T lymphocytes, even though invasion of T
lymphocytes was low and non-replicative. The ability of heat-killed B. abortus
to reproduce the same phenomenon suggested that there was a bacterial structural
component involved. We demonstrated that a prototypical B. abortus outer
membrane lipoprotein (l-Omp19), but not its unlipidated form, induced T
lymphocyte apoptosis. Moreover, a synthetic lipohexapeptide that mimics the
structure of the protein lipid moiety also induced an increase in T lymphocyte
cell death, indicating that the structural component implicated in the
phenomenon could be any B. abortus lipoprotein. B. abortus-induced T lymphocyte
apoptosis was dependent on the secretion of TNF-α since pre-incubation of T
lymphocytes with anti-TNF-α mAb inhibited the apoptosis of the cells. Overall,
these results represent a new mechanism whereby B. abortus by directly
inhibiting T cell-mediated responses may evade adaptive immune responses.