Purification of rat peritoneal mast cells: occupation of IgE-receptors by IgE prevents loss of the receptors
Coutts, S.M.; Nehring, R.E.; Jariwala, N.U.
Journal of Immunology 124(5): 2309-2315
1980
ISSN/ISBN: 0022-1767 PMID: 6154098 Document Number: 166593
The effect of the purification of rat peritoneal mast cells through 3 different density media (bovine serum albumin [BSA], Ficoll and Metrizamide) was examined with respect to the number and affinity of IgE-specific receptors, and the ability of the purified cells to release histamine in response to the secretagogues anti-IgE, antigen, compound 48/80 and the Ca ionophore A 23187. Purification of rat mast cells through any of the density media results in the loss of 50-80% of the IgE-receptor binding activity; receptors remaining active on the cells have the same affinity constant for IgE as do those on unpurified cells. IgE that is bound to rat mast cells before purification remains on the purified cells. Purified rat mast cells will release histamine in response to anti-IgE (without sensitization). Purified cells will not release histamine in response to antigen (ovalbumin) when the cells are passively sensitized with anti-ovalbumin after purification. Mast cells that are sensitized with anti-ovalbumin before purification will release histamine upon challenge with antigen after purification, although the method of purification affects the degree of release. IgE-specific receptors on rat mast cells apparently are shed or inactivated by sedimentation through BSA, Ficoll or Metrizamide; the loss of these receptors is prevented by occupying them with IgE. Of the 3 media described for purifying rat mast cells, Metrizamide appears to be the vehicle of choice.