They invited me on February 20-22, but I have another interview conflict. They were really accomodating and we are arranging a date for when I can possibly interview in late January. They seem like they will work with you on what you need.
I submitted most of my applications the weekend before December 1st and I heard back from Iowa on December 23rd. I haven't confirmed the flight information yet, and may have to decline because of other interviews. I applied to the Immunology interdisciplinary program as well.
They have a recent notification on their admission website: http://www.ohsu.edu/xd/education/schools/school-of-medicine/departments/basic-science-departments/molecular-cellular-biosciences/admissions/index.cfm
"If you are invited to interview with us in February you will be notified by January 10, 2014.
Interview dates include February 12-15 and February 19 -22."