Effect of time and magainin on immunopositive levels of βhCG, hPL and cytokeratin 18 neo-epitope (CK18f). Isolated villous trophoblast cells grown on collagen biomatrix for 24 h (A, D, G, J, M, P), 48 h (B, E, H, K, N, Q) and 96 h (C, F, I, L, O, R) show immunopositive staining for βhCG (A-F; green), hPL (G-L; red), and cytokeratin 18 neo-epitope (CK18f; M-R; green) treated with AMA (D-F, J-L, P-R) and without AMA(A-C, G-I, M-O). The replacement of primary antibody with non-immune mouse IgG (S), non-immune rabbit and goat IgGs (T, U), as well as, pre-neutralization of primary antibodies for βhCG (V) and (hPL) (W) with specific target antigens show no immunopositive staining. Nuclei are counterstained with DAPI (blue). Bars = 20 μm.