Designation:E2888−12StandardPracticeforProcessforInactivationofRodentRetrovirusbypH1ThisstandardisissuedunderthefixeddesignationE2888;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticeassures5log10inactivationofnon-defectiveC-typeretroviruses,whichareendogenoustomurinehybridomaandCHOcellsandarepotentiallypresentintheproductionstreamofbiopharmaceuticalprocessesthatuserodentderivedcellculture.1.2Theprocessparametersspecifiedinthispracticecon-sistentlyassure5log10inactivationofmurineretrovirusbyadjustingthepHofaprocesssolutionafterinitialaffinitycapturechromatographypurification.1.3ThispracticeisapplicabletomAb,IgGfusion,orotherrecombinantproteinsproducedfromrodentcelllines(forexample,CHOormurinehybridoma),whichdonottargetretroviralproteins.Additionally,thelowpHstepisperformedonacell-freeintermediate,postinitialcaptureusingproteinAchromatography.1.4The5log10inactivationofmurineretrovirusclaimedbyusingthispracticewillbeutilizedinconjunctionwithotherclearanceunitoperations(forexample,chromatographyandvirusretentivefiltration)toassuresufficienttotalprocessclearanceofmurineretroviruses,whichwillbesupportiveofearlyphaseregulatoryfilings.1.5ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.2.Terminology2.1DefinitionsofTermsSpecifictoThisStandard:2.1.1IgGfusionprotein—adimericproteincomprisedoftwomonomers,eachmonomerconsistingofapeptidese-quence(usuallyahumanreceptor-likeproteinorproteinfragment)fusedtothecarboxyl-terminaloftheFc-domainofahumanIgGantibody.2.1.1.1Discussion—DimerizationoccursbywayoftheFcdomain.2.1.2immunoglobulinG(IgG)—anantibodymoleculecom-posedoffourpeptidechains—twoγheavychainsandtwolightchains.2.1.2.1Discussion—EachIgGhastwoantigenbindingsites.IgGconstitutes75%ofserumimmu...
