In maintaining the functional activity of the immune system with the nervous and endocrine systems involved signaling molecules. Most signaling molecules are multifunctional regulatory peptides such as: neuropeptides VIP (vasoactive intestinal peptide) and CGRP (calcitonin gene related peptide), which are synthesized in the immune cells, and the expression level of which decreases with age. The purpose of research - a comparative study of the effects of peptide bioregulators (PB) on the expression of signaling molecules in cultures of spleen cells from animals of different ages. As a result of this work it was found that in organotypic cultures of young and old animals spleen was shown target action of peptide bioregulators (thymogen, dipeptide AB-0). Peptides AB-0 and timogen activate expression of macrophages (CD68) and B cells (CD20) markers in spleen of various age animals.