Histamine secretion in leukocyte incubates of patients with allergic hyperreactivity induced by somatostatin-14 and somatostatin-28.

Somatostatin is a potent histamine secretagogue found not only in rat mast cells but also in human leukocyte preparations. In concentrations greater than or equal to 5 mumol/l, somatostatin-14 induces histamine release, which correlates with the basophilic blood cell count, as shown in samples from allergic patients suffering from slight basophilia. Somatostatin-14 is twice as effective as somatostatin-28 on a molar basis, and acylating the tetradecapeptide with N-hydroxysuccinimidyl-p-hydroxy-phenyl-propionate decreases significantly the potency of histamine release.

Application of rat mast cell incubates as a possible short-time test for sensitizing occupational chemicals.

The direct action of sensitizing occupational chemicals (formaldehyde, phenol, phenylhydrazine, p-aminophenol) on rat mast cells was investigated by determination of histamine using HPLC separation and fluorimetric detection. It turned out that dispensed mast cells from immunized and non-immunized Wistar-rats are more sensitive than small-cut lung tissue slices. Passive cutaneous anaphylaxis was negative after a fortnight sensitizing experiment with the here described occupational chemicals.

Relationship between antigen and antibody-induced suppression of IgE antibody formation in the rat.

Formation of specific IgE antibodies as elicited in Sprague-Dawley rats against Ascaris antigen could be suppressed by intravenous administration both of antigen and of specific antiserum. The suppressive agent in the antiserum was shown to be antibodies of the IgG class, whereas a suppressive effect of cytophilic activity and of IgE antibodies could be outruled. Suppression of IgE response lasted the longer the more antibodies were transferred.