Polyclonal antibody production. (A) Dot-blotting of the subcellular fractionation of WB trophozoites shows that surface proteins localized mainly in fractions P3 (samples e-g) and weakly in fraction P1 (samples c-e), while cytoskeleton proteins were found in P1 (samples a-c). P1, P2, and P3 corresponded to the fractions of pellet centrifuged at 1,000 × g, 20,000 × g, and 105,000 × g, respectively. (B) Antibody reactivity. Western blotting of a total WB, GS and Portland-1 Giardia lysate incubated with the pre-immune (PI) or the immune polyclonal (pAb) serum. Lane 1: standards of the indicated molecular weights. (C) Reactivity of polyclonal antibodies determined by indirect immunofluorescence in WB, GS and Portland-1 trophozoites. PI: control with pre-immune serum. Scale bar: 10 μm.