Anti-recombinant V antigen serum promotes uptake of Yersinia enterocolitica serotype 08 by macrophages.
Phagocytosis resistance even in the presence of opsonizing antibodies is a key feature of pathogenic Yersinia spp. Nevertheless, antibodies against the secreted V antigen and the outer membrane protein YadA are known to mediate protection against Y. enterocolitica serotype 08 in a mouse model with intravenous infection. To investigate the impact of anti-V antigen serum on the interaction of Y. enterocolitica and phagocytic cells, gentamicin kill assays and immunofluorescence staining were performed. In contrast to anti-YadA, the presence of V antigen-specific antibodies resulted in an increased uptake of yersiniae by macrophages. The inhibition of phagocytosis by cytochalasin D suppressed the anti-V antigen-mediated uptake. The uptake-promoting effect of anti-V antigen was more distinct for macrophages than for polymorphonuclear leukocytes. The findings of the passive immunization experiments using an orogastric infection model were in agreement with those of cell-culture experiments. In the first 3 days of infection both antisera exhibit no protective effect on the multiplication of the bacteria in the Peyer's patches. Only mice passively immunized with anti-V antigen survived lethal oral infections with Y. enterocolitica serotype 08. Taken together, the results support the assumption that V antigen might be part of the translocation apparatus and that anti-V antigen inhibits the Yop translocation. In addition, antisera against in-frame-deleted recombinant V antigen were generated. Protection experiments using these antisera suggested that the type-specific region (amino acids 225-232) of the V antigen might not be a protective epitope.
Roggenkamp
A
A
Max von Pettenkofer-Institute for Hygiene and Microbiology, Ludwig Maximilians University Munich, Germany. Rogge@m3401.mpk.med.uni-muenchen.de
Leitritz
L
L
Sing
A
A
Kempf
V A
VA
Baus
K
K
Heesemann
J
J
D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000276:immunology*; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D007116:Immunization, Passive; D017737:Macrophages, Peritoneal / Q000276:immunology / Q000382:microbiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010587:Phagocytosis; D052899:Pore Forming Cytotoxic Proteins; D011817:Rabbits; D011994:Recombinant Proteins / Q000276:immunology; D012703:Serotyping; D015009:Yersinia Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D015008:Yersinia enterocolitica / Q000276:immunology / Q000472:pathogenicity*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; C043908:LcrV protein, Yersinia; D052899:Pore Forming Cytotoxic Proteins; D011994:Recombinant Proteins