Mast cell heterogeneity in non-human primates

Mast cells of rodents may be subdivided in terms of their properties, but the extent of such heterogeneity in man and higher animals is still unknown. The authors have compared lung (LMC) and intestinal (IMC) mast cells obtained from individual monkeys. LMC contained more histamine (HA) than IMC (6.61+/-1.3 vs. 1.6+/-0.6 pg/cell, means+/-SEM, n=3). LMC released more HA (17.7+/-2.1% vs. 9.2+/-1.0%, means+/-SEM, n=16) and also generated more LTC4 equivalents as measured by radioimmunoassay (range 13.4-41.5 vs. 3.0-4.0 ng/106 mast cells) following an anaphylactic stimulus. The majority (>90%) of LMC stained metachromatically under conditions appropriate for heparin-containing cells, whereas IMC required more forcing conditions to display metachromasia. In contrast to these quantitative and qualitative mediator differences, functional responses of LMC and IMC were similar. Thus, HA release was inhibited comparably by theophylline, isoprenaline and dibutyryl cyclic AMP, but quercetin was slightly more active on IMC. Substance P caused dose-related HA release from both cell types, although the amount released varied between individual animal, (range LMC 1.2-20.2%, IMC 1.8-23.0%, n=4). Other neuropeptides (pentagastrin) vasoactive intestinal peptide, neurotensin, somatostatin) did not release HA. They conclude that mast cell heterogeneity in higher animals may be reflected more by cytochemical rather than functional differences between mast cell classes