Adenylate cyclase activation in lymphoid tissues during graft-versus-host reaction

Graft-versus-host reactions were induced in adult F1 hybrid animals by injecting parental spleen cells. Adenylate cyclase activity was determined in the washed cell particles of the lymphoid tissues. During a time course study of the regional GVH reaction an increase in lymph node weight was apparent at day 2, whereas the adenylate cyclase activity increased at day 4 after the injection. Maximal lymph node hypertrophy and adenylate cyclase activation were observed 8 to 10 days after initiation of the GVH response. Adenylate cyclase stimulation by epinephrine of the GVH response. Adenylate cyclase stimulation by epinephrine and glucagon in experimental preparations was less than in the control. NaF was stimulatory only in the control preparations. Ca-2+ in concentrations up to 8 mM had no inhibitory effects on the control or experimental preparations. The pattern of responses of the experimental preparations to Zn-2+ and Cu-2+ was different than the control; however, in high concentrations both of these cations had marked inhibitory effects. An increase in the adenylate cyclase activity was also direct relationship between the adenylate cyclase activity and the cytolytic activity of spleen cells from mice undergoing systemic GVH reaction. These results can be explained on the basis of alterations in the cell membranes, and it is suggested that such changes play an important role in the pathogenesis of GVH disease.