It would behave as if it was a combination of anti-Fya and anti-Fyb. The Fy3 antigen is resistant to enzyme treatment unlike Fya and Fyb which are sensitive to Papain, Trypsin and Ficin. Thus on an antibody ID panel all cells except Fy(a-b-) would react by IAT.

Antibody that does not react with Fy(a-b-) red cells yet shows reaction with proteolytic enzyme treated Fy(a+) and Fy(b+) red cells and that the antibody producer individual is typed as Fy(a-b-).

@Sanmukh: So how is that reply any different to my answer?

essentially same! Hope u r not offended!