Heat shock cognate protein 70 contributes to Brucella invasion into trophoblast giant cells that cause infectious abortion.
BACKGROUND
The cell tropism of Brucella abortus, a causative agent of brucellosis and facultative intracellular pathogen, in the placenta is thought to be a key event of infectious abortion, although the molecular mechanism for this is largely unknown. There is a higher degree of bacterial colonization in the placenta than in other organs and many bacteria are detected in trophoblast giant (TG) cells in the placenta. In the present study, we investigated mechanism of B. abortus invasion into TG cells.


RESULTS
We observed internalization and intracellular growth of B. abortus in cultured TG cells. A monoclonal antibody that inhibits bacterial internalization was isolated and this reacted with heat shock cognate protein 70 (Hsc70). Depletion and over expression of Hsc70 in TG cells inhibited and promoted bacterial internalization, respectively. IFN-gamma receptor was expressed in TG cells and IFN-gamma treatment enhanced the uptake of bacteria by TG cells. Administering the anti-Hsc70 antibody to pregnant mice served to prevent infectious abortion.


CONCLUSIONS
B. abortus infection of TG cells in placenta is mediated by Hsc70, and that such infection leads to infectious abortion.
Watanabe
Kenta
K
Department of Veterinary Public Health, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan. s11042@st.obihiro.ac.jp
Tachibana
Masato
M
Tanaka
Satoshi
S
Furuoka
Hidefumi
H
Horiuchi
Motohiro
M
Suzuki
Hiroshi
H
Watarai
Masahisa
M
D000031:Abortion, Septic / Q000378:metabolism / Q000382:microbiology* / Q000517:prevention & control; D000595:Amino Acid Sequence; D000818:Animals; D002003:Brucella abortus / Q000472:pathogenicity* / Q000502:physiology; D002006:Brucellosis / Q000378:metabolism* / Q000382:microbiology / Q000517:prevention & control; D002478:Cells, Cultured; D005260:Female; D050883:HSC70 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D011247:Pregnancy; D014327:Trophoblasts / Q000378:metabolism* / Q000382:microbiology; D014774:Virulence
D050883:HSC70 Heat-Shock Proteins; C494372:Hspa8 protein, mouse; D007371:Interferon-gamma