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Sheep small intestinal mast cells/globule leucocytes: ability to divide
M Stankiewicz1, W E Jonas, W Cabaj
1AgResearch, Wallaceville Animal Research Centre, Upper Hutt, New Zealand.
Abstract:
The number of mucosal mast cells/globule leukocytes (MMC/GLs) increase in the intestinal mucosa in response to nematode parasite infections but it is not known if this accumulation is due to in situ cell division, derivation from elsewhere or some combination of both. To determine if MMC/GLs can divide, cells were obtained from immunized Romney sheep and cultured in vitro in RPMI 1640. For cultures supplemented with 10, 20 or 30% foetal lamb serum (FLS) or foetal calf serum (FCS) and without concanavalin A (Con A), cell division had ceased by day 2, but with Con A (3 micrograms ml-1) cell division continued to day 9. Better growth of cells was obtained with the higher concentrations of serum. However the use of 30% or 50% autologous serum with Con A lead to cell death but 10% serum permitted limited growth. The detrimental effect of autologous serum could be overcome by increasing the Con A concentration. It was established that an alpha-macroglobulin present in autologous serum can bind Con A. This macroglobulin appears to have a higher avidity for Con A than does the receptor(s) on the surface of MMC/GLs. Our data seem to indicate that a direct interaction of Con A with the cell surface or a receptor(s) is responsible for MMC/GLs division.
Insights
Mucosal mast cells/globule leukocytes (MMC/GLs) can divide in vitro when stimulated with concanavalin A (Con A). This suggests direct cell surface interaction drives MMC/GL proliferation, a key finding for understanding parasite-induced immune responses.
Area of Science:
- Immunology
- Cell Biology
- Parasitology
Background:
- Mucosal mast cells/globule leukocytes (MMC/GLs) increase in the intestinal mucosa during nematode parasite infections.
- The mechanisms driving this accumulation, whether local cell division or external derivation, remain unclear.
Purpose of the Study:
- To investigate the proliferative capacity of MMC/GLs in vitro.
- To determine if MMC/GLs can undergo cell division.
Main Methods:
- MMC/GLs were isolated from immunized Romney sheep and cultured in RPMI 1640.
- Cultures were supplemented with varying concentrations of fetal lamb serum (FLS), fetal calf serum (FCS), or autologous serum.
- The effect of concanavalin A (Con A) on cell division was assessed over 9 days.
Main Results:
- Cell division ceased by day 2 without Con A but continued to day 9 with Con A stimulation.
- Higher serum concentrations generally supported better cell growth.
- Autologous serum at high concentrations was detrimental, but this could be overcome by increasing Con A, suggesting alpha-macroglobulin interference.
Conclusions:
- Data indicate that MMC/GLs possess the capacity for in situ division.
- Direct interaction of Con A with cell surface receptors appears to be responsible for initiating MMC/GL proliferation.
- This finding contributes to understanding immune cell dynamics during parasitic infections.