Oral bacterial lipopolysaccharide acts in mice to promote sensitisation to ovalbumin and to augment anaphylaxis via platelets.
Microbial infection is thought to modulate allergic disorders, and we previously demonstrated that not only mast cells (which release histamine), but also platelets are involved in the anaphylaxis induced in mice sensitised to ovalbumin (OVA). Here, we examined the effects of a lipopolysaccharide (LPS) from the oral bacterium Prevotella intermedia (Pi) on OVA-induced anaphylaxis. Upon intraperitoneal co-injection of Pi-LPS plus OVA into BALB/c mice, the Pi-LPS displayed a potent adjuvant effect comparable to that of alum (a standard adjuvant) in terms of its abilities to induce both anaphylactic shock and histamine-release following an antigen (OVA)-challenge. Moreover, an injection of Pi-LPS given to OVA+alum-sensitised mice shortly before an OVA-challenge augmented the shock-response. This LPS-pretreatment did not affect histamine-release, but did augment pulmonary platelet accumulation. Histamine was not by itself causal for shock-induction in sensitised mice. These results suggest that oral bacteria and/or their constituents (such as LPS) may help to sensitise the host to an antigen or exacerbate the host's allergic reactions ("aggravation effect"), probably by enhancing the platelet response to the antigen OVA.
Yoshida
Atsushi
A
Department of Molecular Regulation, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
Deng
Xue
X
Sasano
Takashi
T
Takada
Haruhiko
H
Sugawara
Shunji
S
Endo
Yasuo
Y
D000707:Anaphylaxis / Q000276:immunology* / Q000382:microbiology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000943:Antigens, Differentiation / Q000378:metabolism; D001792:Blood Platelets / Q000276:immunology* / Q000382:microbiology; D005260:Female; D006632:Histamine / Q000378:metabolism; D006636:Histamine Release / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000276:immunology*; D018713:Prevotella intermedia / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D008070:Lipopolysaccharides; D006632:Histamine; D010047:Ovalbumin