Ovarian expression of chemokines and their receptors

Recent studies suggest involvement of the immune system, including leukocytes and cytokines/chemokines, in various ovarian functions such as ovulation. Using the RT-PCR method, we examined expression of various chemokines and their receptors in normal mouse ovaries. Among seventeen examined chemokines (17 CC types and two CXC types), expressions of CC types MCP-1 and RANTES, and CXC type IP-10 were detected at high levels, while most CC types expressed at variable or low levels. Only five chemokines were not detected in the ovary. We next examined expression of chemokine receptors. CCR1 and CCR2, which are the receptors for MCP-1 and RANTES, were also expressed at constitutively high levels while others were not detectable. We further showed that a significant part of expression of both detected chemokines and receptors originated from peripheral blood leukocytes (PBL) circulating in the ovary. However, ovarian tissue was the major contributor of expression. Constitutive expression of several chemokines and their receptors suggests frequent migrations/movements of leukocytes in the ovary, which may be involved in ovarian functions other than ovulation.