In vitro studies of reversed anaphylaxis with rat cells.

Abstract

Rabbit anti-rat γ globulin (anti-RGG) was used to bring about reversed anaphylaxis in vitro using rat mesentery, peritoneal cells, or suspensions of isolated peritoneal mast cells. Histamine and 5-hydroxytryptamine were released but not slow-reacting substance. The effect of various inhibitors on the reversed anaphylactic reaction was studied quantitatively. The reaction required calcium and was inhibited by diisopropylfluorophosphate (DFP), indole or salicylaldoxime. Magnesium dependence could not be demonstrated. Succinate, caproate and large changes in the sodium chloride concentration of the containing medium had no effect. Amino-acid ester substrates of chymotrypsin released histamine in the absence of anti-RGG. Washed cells treated with a purified γ-globulin fraction of anti-RGG released histamine. The addition of fresh, but not of heated normal rabbit serum greatly potentiated this release. When washed peritoneal cells were treated with anti-RGG in the cold or at 37° in the presence of EDTA, they were gradually desensitized without histamine release. The addition of antigen to rat mesentery or peritoneal mast cells from actively sensitized rats did not produce histamine release even though the donor animals had high levels of circulating antibody and exhibited anaphylactic shock with each intravenous booster dose of alum-precipitated antigen. The finding that these tissue or cell preparations from actively sensitized rats reacted with anti-RGG indicated that either the cells did not carry γ globulin identical with the antibody in their circulation or that the antibody was biologically inert in terms of releasing histamine after interaction with antigen.