Activation of rat B lymphocytes by Actinobacillus actinomycetemcomitans

Abstract

We examined the lymphoproliferative responses of cervical lymphocytes and splenocytes of homozygous (rnu/rnu) congenitally athymic nude and normal heterozygous (rnu/+) Rowett rats to whole cells of Actinobacillus actinomycetemcomitans, a suspected periodontal disease pathogen. Previously sensitized cells from immunized only, infected only, or immunized and infected, normal rats demonstrated proliferation in response to formalinized A. actinomycetemcomitans, but cells from nude rats did not proliferate. The maximum antigenic response was observed at day 5 of culture. A. actinomycetemcomitans caused cervical lymphocytes and splenocytes from untreated naive normal and nude rats to undergo increased DNA synthesis at day 2 of culture. Highly enriched nonsensitized spleen T cells prepared on a nylon wool column did not respond to A. actinomycetemcomitans, whereas enriched nonsensitized B cells proliferated. Differences in response were probably not attributable to contributions from macrophages in the Tor B-cell populations, since macrophage percentages were approximately the same in both preparations. T-cell reconstitution of nude rats with neonatal thymus cells from rnul+ rats resulted in partial recovery of T-cell function but had no effect on the mitogenic response to A. actinomycetemcomitans. It is suggested that the antigenic responses to A. actinomycetemcomitans are dependent on T cells and that A. actinomycetemcomitans cells have mitogenic activity for B cells. The potential importance of these findings in periodontal disease is discussed.

Chemical composition and immunobiological properties of lipopolysaccharide and lipid‐associated proteoglycan from Actinobacillus actinomycetemcomitans

“…1984). Moreover, a recent study indicates that A. aetinomyeetemcomitans whole cells have mitogenic activity for rat B cells, although the active entity was not demonstrated (Yoshie et al 1985). In this study we have shown that A. aetinomyeetemcomitans LPS is a B cell mitogen (Fig.…”

Extracellular proteinaceous substances from Haemophilus actinomycetemcomitans induce mitogenic responses in murine lymphocytes

“…2), as well as LPS from H. actinomycetemcomitans ATCC 29523 (12). Yoshie et al (23) have reported that whole cells of H. actinomycetemcomitans Y4 are mitogenic for rat B lymphocytes. These results suggest that LPS of the organism may induce the infiltrate of B cells in the gingivae with established or advanced periodontal diseases.…”

Periodontal bone loss and immune characteristics after adoptive transfer of Actinobacillus‐sensitized T cells to rats

“…Endotoxin of this bacterium also has protease-sensitive bone resorptive properties (17). In addition to these direct toxic effects that could be associated with disease, Aa can stimulate a polyclonal antibody response and has a potent mito-genic activity for B lymphocytes (18,19). It has also been reported that soluble sonic extracts of Aa can suppress human peripheral blood lymphocyte responsiveness to the mitogens Con A, PHA and PWM (20).…”