Lymphatic mast cell response and effect of compound 48/80 on popliteal lymph node reaction in rats following intracutaneous injection ofStaphylococcus aureus

Abstract

To investigate the significance of mast cells in the popliteal lymph node during the development of an inflammatory response, rats were inoculated with 12 x 10(7) colony-forming units of Staphylococcus aureus in the hind foot pad. Numerical changes in mast cells were then measured in the corresponding popliteal lymph node. Six days after inoculation, despite the enlargement of the responding lymph node, a marked decrease in granulated mast cell number, relative to the contralateral node, was observed in the cortical and medullary compartments. Popliteal lymph nodes from rats treated with compound 48/80 and then inoculated with S. aureus showed a higher cortical and medullary hypertrophic response and a significant increase in degranulated/weakly basophilic mast cell number in the lymph node tissue. The findings suggest that (1) Staphylococcus aureus induces a reduction in granulated mast cell number in the cortical and medullary compartments of regional lymph nodes; (2) pretreatment with compound 48/80 appears to contribute to the lymphoid cell proliferation and the hypertrophic response of lymph nodes induced by S. aureus; and (3) granulated mast cells have a regulatory role on lymphoid cell proliferation.

Interferon‐γ enhances both the anti‐bacterial and the pro‐inflammatory response of human mast cells to Staphylococcus aureus

“…In the presence of IFN‐ γ , degranulation occurred and production of LTC 4 and PGD 2 release was enhanced. This is consistent with a report that rat peritoneal MCs degranulate in response to E. coli and that rats challenged with S. aureus have a reduction in granular MCs . Additionally, mice challenged with peptidoglycan show increased histamine levels .…”

“…This is consistent with a report that rat peritoneal MCs degranulate in response to E. coli 32 and that rats challenged with S. aureus have a reduction in granular MCs. 33 Additionally, mice challenged with peptidoglycan show increased histamine levels. 7 Degranulation of MCs has also been reported to occur in response to exotoxins from S. aureus including d-toxin 5 and in response to superantigens.…”