1、Designation:E288812Standard Practice forProcess for Inactivation of Rodent Retrovirus by pH1This standard is issued under the fixed designation E2888;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number
2、in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice assures 5 log10 inactivation of non-defective C-type retroviruses,which are endogenous to murinehybridoma and CHO cells and are pote
3、ntially present in theproduction stream of biopharmaceutical processes that userodent derived cell culture.1.2 The process parameters specified in this practice con-sistently assure 5 log10 inactivation of murine retrovirus byadjusting the pH of a process solution after initial affinitycapture chrom
4、atography purification.1.3 This practice is applicable to mAb,IgG fusion,or otherrecombinant proteins produced from rodent cell lines(forexample,CHO or murine hybridoma),which do not targetretroviral proteins.Additionally,the low pH step is performedon a cell-free intermediate,post initial capture u
5、sing protein Achromatography.1.4 The 5 log10 inactivation of murine retrovirus claimedby using this practice will be utilized in conjunction with otherclearance unit operations(for example,chromatography andvirus retentive filtration)to assure sufficient total processclearance of murine retroviruses
6、,which will be supportive ofearly phase regulatory filings.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.2.Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 IgG fusion proteina dimeric protein comprised of
7、two monomers,each monomer consisting of a peptide se-quence(usually a human receptor-like protein or proteinfragment)fused to the carboxyl-terminal of the Fc-domain of ahuman IgG antibody.2.1.1.1 DiscussionDimerization occurs by way of the Fcdomain.2.1.2 immunoglobulin G(IgG)an antibody molecule com
8、-posed of four peptide chains two heavy chains and twolight chains.2.1.2.1 DiscussionEach IgG has two antigen bindingsites.IgG constitutes 75%of serum immunoglobulins inhumans.IgG molecules are synthesized and secreted by plasmaB cells.There are four IgG subclasses(IgG1,2,3,and 4)inhumans,named in o
9、rder of their abundance in serum(IgG1being the most abundant).Only human IgG1,IgG2,and IgG4show significant affinity to protein A.2.1.3 log10 reduction value(LRV)typically used to de-scribe the degree of reduction of a population,in this caserodent retrovirus,by the treatment process.2.1.3.1 Discuss
10、ionEach log reduction(10-1)represents a90%reduction in the population.So a process shown toachieve a 6-log reduction(10-6)will reduce a population froma million(106)to 1.2.1.4 monoclonal antibody(mAb)monospecific antibodieswhich have affinity for the same antigen and are made from amaster cell bank,
11、cloned from a parent cell.2.1.5 murine leukemia virus(MuLV)retroviruses namedfor their ability to cause cancer in murine(mouse)hosts.2.1.5.1 DiscussionMuLV is a member of the genus Gam-maretrovirus.MuLV is an enveloped spherical RNA viruswhich has a diameter of 80110 nm and has low chemicalresistanc
12、e.MuLV is used as a model for non-defective C-typeendogenous retrovirus or retrovirus like particles produced bymurine hybridoma and CHO cell lines.MuLV is used to assessrodent retrovirus clearance of protein purification processesthat use rodent cells for production.2.1.6 recombinant proteinproduce
13、d from the expressionof recombinant DNA within living cells.2.1.6.1 DiscussionRecombinant DNA is genetically engi-neered by inserting foreign DNA into the DNA of an appro-priate host so that the foreign DNA is replicated along with thehost DNA.2.1.7 retrovirusan RNA virus that is propagated in a hos
14、tcell using the reverse transcriptase enzyme to produce DNAfrom its RNA genome.2.1.7.1 DiscussionDNA is then incorporated into thehosts genome by an integrase enzyme.The virus is thereafterreplicated as part of the host cells DNA.Retroviruses areenveloped viruses that belong to the viral family Retr
15、oviridae.1This practice is under the jurisdiction of ASTM Committee E55 on Manufac-ture of Pharmaceutical and Biopharmaceutical Products and is the direct responsi-bility of Subcommittee E55.04 on General Biopharmaceutical Standards.Current edition approved Aug.1,2012.Published September 2012.DOI:10
16、.1520/E2888-12.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 2.1.8 modular validationa modular clearance study is onethat demonstrates virus removal or inactivation at individualsteps during the purification process(column chromatography,filtration,heat treatment,solvent/detergent treatment,low pHtreatment,etc.).2.1.8.1 DiscussionEach module,or unit operation,in thepurification scheme may be studied independently of the othermodules
