[Action of cyclic adenosine monophosphate on the spleen antibody--forming cells of rabbits immunized with Escherichia coli]. 
Cyclic adenosine monophosphate (cAMP) parenterally injected to rabbits (immunized intraperitoneally with thymus-independent antigen of killed E. coli 0127/545) during January--April inhibited production of antibody-forming cells (AFC) in the spleen of these animals, and during May--June it increased the AFC count.  Both the stimulating and inhibitory effect of cAMP was associated with the administration of the same doses of 25--250 microgram/kg.  The nature of the cAMP effect on the production of the AFC depends on the initial immune response level.  At the maximum immune response and in the absence of the dose-effect dependence cAMP inhibited the antibody formation, but when the immunological reaction was below the maximal level and in the presence of the dose-effect relationship cAMP increased the AFC production.