Expression of GM-CSF α and β receptors in bovine COC. Confocal microscopy analysis was performed using anti-GM-CSFrα and anti-GM-CSFrβ antibodies. (A, B) Specimen incubated without the first (primary) antibody showed no signal. C, D: GM-CSFrα subunit (green). E, F: GM-CSFrβ subunit (green). Oocyte nuclei were stained using propidum iodide (red). Scale bar = 100 μm.