Immunohistological study of lesions induced by Porphyromonas gingivalis in a murine model

Abstract

A previous study used a mouse model to demonstrate protection after challenge with Porphyromonas gingivalis ATCC 33277. In the present study, this same model was used to determine the phenotype of cells recruited into the lesions during the course of the protective immune response after immunization with this periodontal pathogen. BALB/c mice were immunized with 100 micrograms of P. gingivalis outer membrane antigens per mouse weekly for 3 weeks followed by challenge with live organisms 3 weeks after the final immunization. Hematoxylin and eosin-stained sections showed inflammatory infiltrates in all lesions from control (immunized with adjuvant only) and immunized mice. The lesions developed central necrotic cores surrounded by neutrophils, phagocytic macrophages and lymphocytes. Neutrophils were the predominant cells in the lesions 1 day after challenge with significantly more in immunized than control mice. Acid phosphatase and nonspecific esterase-positive macrophages were detected at day 4 and became the predominant cells in the healing lesions. CD4- and CD8-positive T-cells were present from day 1, and while numbers increased over time, there were no significant differences in control or immunized mice. When mice were depleted of CD4 or CD8 cells prior to immunization with P. gingivalis, fewer neutrophils were found in the lesions 1 day after challenge compared with undepleted immunized mice. Acid phosphatase and nonspecific esterase-positive macrophages were not affected by T-cell depletion. The results suggest that the P. gingivalis-induced lesion in immunized BALB/c mice is consistent with a strong innate immune response involving the recruitment of neutrophils in the first instance which may be under the control of T cells. This is followed by the infiltration of phagocytic macrophages which are involved in the healing process and do not appear to be regulated by T cells.

The Effects of Interleukin‐10 Depletion In Vivo on the Immune Response to Porphyromonas gingivalis in a Murine Model

“…Previous studies using this model showed that the induction of an immune response and subsequent healing were CD4 cell-dependent, 20,21 which supports the present findings. The induction of a Th1-like response to P. gingivalis in rats has also been reported by Katz and Michalek.…”

Immunization to Porphyromonas gingivalis enhances the local pro‐inflammatory response to subcutaneous bacterial challenge

“…The alum‐based adjuvant produced the largest increase in leukocyte numbers and its effect lasted longer than the IFA. Similarly, Gemmell et al (1997) showed an increased PMN accumulation, in an abscess model after immunization with P. gingivalis. The mechanism involved in this increased PMN recruitment is probably mediated via an increase in the accumulation of chemotactic factors including those derived from activated complement fragments.…”

Differences in mouse strain influence leukocyte and immunoglobulin phenotype response to Porphyromonas gingivalis

“…CD4 + and CD8 + T‐cell subsets, CD14 + cells (activated monocytes/macrophages and dendritic cells but not unstimulated macrophages, dendritic cells, neutrophils or blood monocytes) and CD19 + B cells (but not terminally differentiated plasma cells) were labeled using an avidin–biotin immunoperoxidase method described previously (9). Briefly, after rehydration in phosphate‐buffered saline pH 7.2, the sections were incubated with rat anti‐mouse CD4 (L3T4), CD8a (Ly‐2), CD14 or CD19 (PharMingen, San Diego, CA).…”