Evolution of ovaries during developmental immune adaptation and their behavior during immune competence. A) Primordial germ cells imprint the OSC for production of secondary germ cells (see Figure 5B vs. 5A). B) Development of rete ovarii and lymphoid tissue (LT). Uncommitted MDC and T cells (UMT) saturate rete ovarii to be converted into ovary-committed MDC and T cells (OCMT). C) Secondary germ cells originate by asymmetric division of OSC under the influence of rete-derived OCMT and hormonal signaling. The ovary commitment is also transferred into draining lymphoid tissues (arched arrows). During the perinatal period immune competence (ic) is initiated, the ovarian memory (om) is built and the rete ovarii regresses. During childhood the OCMT is available but hormonal signaling is absent until menarche. E) During the prime reproductive period (from menarche to 38+/-2 years of age) OCMT and cyclic hormonal signaling cause cyclic formation of germ cell and renewal of primordial follicles. F) After the prime reproductive period the hormonal signalling persists but follicular renewal ceases due to the lack of OCMT. Reprinted from , with permission, © Bentham Science Publishers, Ltd.