OBJECTIVE: To prepare monoclonal antibody (MAb) against carboxy-terminus of E-phA4 and to analyze the immunological characteristics and significance of the antibody. METHODS: Mice were immunized with a chemically synthesized peptide that had been conjugated to KLH (keyhole limpet hemocyamin). A panel of antibodies specifically against EphA4 were obtained by hybridoma technique. The immunological properties and significance of the MAb were analyzed by immunological and immunochemistry techniques. RESULTS: A hybridoma cell line secreting anti-EphA4 MAb was established. The MAb reacted specifically with human, chicken and mouse EphA4, but did not cross-react with EphA5 and EphA7. The antibody could be used for immunochemical techniques such as ELISA, immunoprecipitation, Western blot and immunohistochemistry. CONCLUSION The anti-EphA4 MAb generated by immunizing a synthetic peptide possesses excellent immunological properties. MAb can be applied for immunological and immunohistochemical purpose and will become an important tool in the study of EphA4 and its ligand.
Animals ; Antibodies, Monoclonal ; biosynthesis ; Hybridomas ; Mice ; Mice, Inbred BALB C ; Peptide Fragments ; immunology ; Receptor, EphA4 ; immunology

BACKGROUNDIn a previous study, we demonstrated that ephrin-A2 and -A3 negatively regulate the growth of neural progenitor cells in the central nervous system. Adult mice deficient in ephrin-A2 and -A3 (A2(-/-)A3(-/-)) displayed active ongoing neurogenesis throughout the brain, and mice deficient in ephrin-A3 alone showed increased proliferation of ciliary epithelium derived retinal stem cells. This study aimed to detect that the increase in proliferation and neurogenic potential of Müller cells is influenced by the absence of ephrin-A2 and -A3.

METHODSWe assessed the retinal and Müller cell expression of ephrin-As and their receptor and neural progenitor cell markers by immunostaining and real-time PCR. We cultured purified primary Müller cells derived from wild-type and A2(-/-)A3(-/-) mice in a defined culture medium that enables trans-differentiation of Müller cells into retinal neurons. To evaluate proliferating Müller cells in vivo, we injected 5'-ethylnyl-2'-deoxiuridine (EdU) intraperitoneally to adult mice.

RESULTSExpression of ephrin-A2/A3 and their receptor EphA4 were detected in the retinas of adult mice, with EphA4 expression particularly enriched in Müller cells. Müller cells of A2(-/-)A3(-/-) mice exhibited significantly elevated expression of retinal progenitor cell markers, Pax6 and Chx10, when compared with those from wild-type mice. Moreover, a higher percentage of Müller cells of A2(-/-)A3(-/-) mice trans-differentiated and became recoverin+ and β-III-tublin+ in the culture than those from wild type mice. Strikingly, an increased number of EdU+ retinal cells was detected in the retinas of adult A2(-/-)A3(-/-) mice as compared with wild-type mice.

CONCLUSIONSEphrin-A2 and -A3 are negative regulators of the proliferative and neurogenic potentials of Müller cells. Manipulating ephrin-A signaling may thus represent a novel strategy for stimulating neuroregeneration from endogenous progenitors to participate in retinal repair in case of disease or damage.

Animals ; Cell Differentiation ; genetics ; physiology ; Ephrin-A2 ; genetics ; metabolism ; Ephrin-A3 ; genetics ; metabolism ; Fluorescent Antibody Technique ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Real-Time Polymerase Chain Reaction ; Receptor, EphA4 ; genetics ; metabolism ; Retina ; cytology ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Stem Cells ; cytology ; metabolism