Abstract: The present invention provides methods and systems for recovering an essentially cell-associated expression product from a host cell comprising (a) culturing said host cell under conditions that allow expression of said expression product; (b) collecting said host cell in/on a filter unit; (c) disrupting said host cell in/on the filter unit; and (d) separating said expression product from said disrupted host cell. The present invention also provides an expression product obtainable by the methods or systems, wherein the expression product is a poxvirus.

Abstract: The present invention provides a method for recovering an essentially cell-associated expression product from a host cell comprising (a) culturing said host cell under conditions that allow expression of said expression product; (b) collecting said host cell in/on a filter unit; (c) disrupting said host cell in/on the filter unit; and (d) separating said expression product from said disrupted host cell. Said host cell is preferably a vertebrate cell, more preferably an avian cell, which is preferably cultured in suspension. Furthermore, the present invention provides for the use of a filter unit characterized in that said filter unit is (i) suitable to retain a host cell which expresses an expression product; and (ii) suitable for elution of said expression product from the filter unit after cell disruption in/on said filter unit for recovering said expression product from said host cell as well as for a system for recovering an expression product from a host cell comprising said filter unit.