Actinobacillus actinomycetemcomitans mitogenicity for B cells can be attributed to lipopolysaccharide.
The purpose of this investigation was to determine the component(s) of whole Actinobacillus actinomycetemcomitans bacteria responsible for B cell mitogenic activity. Congenitally athymic "nude" rats were used as a source of B cells devoid of T lymphocyte activity. Spleen cells were cultured with, or without, whole formalin-killed A. actinomycetemcomitans bacteria or with purified LPS from A. actinomycetemcomitans. Dose-response curves to A. actinomycetemcomitans cells or to A. actinomycetemcomitans-LPS showed that responses were dose dependent. If optimal quantities of both A. actinomycetemcomitans and A. actinomycetemcomitans-LPS were added in combination, the proliferative responses were the same as if either was added alone, i.e., the responses were not additive. Polymyxin B at 2 micrograms/well completely abrogated the proliferative response of athymic rat splenocytes to 10(7) A. actinomycetemcomitans cells or to 1.25 micrograms A. actinomycetemcomitans-LPS/well. Therefore, the in vitro early proliferative response of B cells to A. actinomycetemcomitans can be attributed to the presence of LPS on A. actinomycetemcomitans cells. A considerable portion of the in situ lymphocytic gingival response to A. actinomycetemcomitans infection seen in periodontal disease patients may be a B cell mitogenic response to the LPS of this bacterium.
Eastcott
J W
JW
Forsyth Dental Center, Boston, Massachusetts.
Taubman
M A
MA
Smith
D J
DJ
Holt
S C
SC
D000188:Actinobacillus / Q000276:immunology*; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D008070:Lipopolysaccharides; D008213:Lymphocyte Activation; D008934:Mitogens; D010510:Periodontal Diseases / Q000276:immunology; D011112:Polymyxin B; D051381:Rats; D011923:Rats, Nude; D013154:Spleen / Q000166:cytology
D008070:Lipopolysaccharides; D008934:Mitogens; D011112:Polymyxin B