Virus Cultivation

Primary, Human Diploid, and Continuous Culture Cell Lines for Virus Isolation and Proliferation and Virus-based Vaccines

The advent of cell culture techniques has fundamentally changed virus isolation and proliferation in the lab setting. Cell-based production systems offer a convenient and cost-effective approach for the isolation, detection, and identification of viruses. Greater process control contributes to a more reliable and well-characterized product, with faster and shorter production cycles than that of animal- and egg-based production systems.

Cell-based production systems for virus culture and vaccine production are important for:

• Virus detection/identification: Cell cultures provide a suitable environment for detection and identification of many human viral pathogens, affording important microscopic examinations for evidence of viral proliferation. Accurate identification of virus is important to ensure timely and appropriate treatments, and can facilitate the detection of mixed viral infections.
• Host-pathogen interaction research: Innovations in cell biology have allowed deeper and more complex insights into host-pathogen interactions for the study of pathogenesis. In vitro cell culture systems can facilitate experimental access for investigation of the mode and etiological factors of viral infection.
• Viral structure and replication: Genetic material and replication methods vary considerably among different types of viruses. Cell culture systems can facilitate virus growth and elucidate development and interactions with host cells at every stage of replication.
• Vaccine production: Cell-based vaccine production systems offer a flexible and cost-effective approach for meeting vaccine output needs. Manufacturers can supply vaccines more quickly and in greater quantities to alleviate vaccine supply shortages during outbreaks when traditional egg-based production systems may fall short. Virus-based vaccines produced in mammalian cells may also offer better protection against viral infections, as they more closely replicate viruses in circulation than vaccines produced in chicken eggs.

Cell culture systems used for virus propagation may employ primary cells, semi-continuous cell lines, and continuous cell lines:

Primary cell lines	Human diploid cells (Semi-continuous cell lines)	Continuous cell lines
Derived from animal tissues. May be passaged once or twice to generate secondary cultures, but grow only for limited time. Secondary cultures (subculture of the primary culture) are similar to primary cultures in both morphology and viral susceptibility Used both for virus isolation (clinical samples) and vaccine production	Derived from fetal tissues, and can be subcultured for ~50 passages Similar to primary cultures in viral susceptibility Used for vaccine production and isolation of fastidious viruses	Cancer or other immortalized cells, which multiply rapidly and may be cultured indefinitely May become heteroploid on serial passage Narrower range of viral susceptibility than primary or diploid cultures Easy to adapt viruses for propagation Used for production of serologic antigens, and a source of cells for neutralizing antibody assays

Cell Line	Origin	Infectious Agents
A549	human lung carcinoma	Adenovirus,1 HSV,2 influenza,3 measles,4 mumps,4 parainfluenza,5 poliovirus,6 respiratory syncytial virus (RSV),6 rotavirus,7 Varicella zoster virus (VZV),8 metapneumovirus (MPV)9
BHK 21 (clone 13)	Syrian hamster kidney	Human adenovirus D,10 reovirus 3,11 vesicular stomatitis virus (Indiana strain),12 Dengue,13 influenza,13 rabies,13 foot and mouth,14 rubella,15
CV-1	African green monkey kidney fibroblast	RSV,16, measles,16, HSV,17, VZV,18
HeLa	human cervix adenocarcinoma	Poliovirus type I,19 adenovirus type 3,20 CMV,21 echovirus,22 HSV23 poliovirus,24 rhinovirus,25 vesicular stomatitis (Indiana Strain) virus,26 VZV27
LLCMK2	Rhesus monkey kidney	Poliovirus type 1,17 enterovirus,28 rhinovirus,29 poxvirus groups30
McCoy	Mouse fibroblast	HSV32
MDCK	Madin-Darby canine kidney	Influenza A,31 influenza B, some types of adenovirus,33 reoviruses34
MRC-5	human fetal lung	CMV,35 HSV,36 adenovirus,37 influenza,38 mumps,39 echovirus,40 poliovirus,41 rhinovirus,42 RSV,43 VZV,27
NCI-H292	Human lung, mucoepidermoid carcinoma	Vaccinia virus,44 HSV,45 adenovirus,46 measles virus,47 reoviruses,48 BK polyomavirus,49 RSV,50 some strains of influenza A,51 most enteroviruses,52 and rhinoviruses53
Vero	African green monkey kidney	Coxsackie B,54 HSV,55 measles,56 mumps,57 poliovirus type 3,58 rotavirus,59 rubella,60
Vero76	African green monkey kidney	Coxsackie B,61 HSV,62 West Nile virus,63
Wi 38	Human fetal lung	Adenovirus,64 CMV,65 echovirus,66 HSV,67 mumps,68 influenza,69 rhinovirus,70 RSV,71 VZV,72

References

1. Hodzic J, Sie D, Vermeulen A, van Beusechem VW. 2017. Functional Screening Identifies Human miRNAs that Modulate Adenovirus Propagation in Prostate Cancer Cells. Human Gene Therapy. 28(9):766-780. https://doi.org/10.1089/hum.2016.143

2. Wang Y, Zhou B, Lu J, Chen Q, Ti H, Huang W, Li J, Yang Z, Jiang Z, Wang X. 2017. Inhibition of influenza virus via a sesquiterpene fraction isolated from Laggera pterodonta by targeting the NF-?B and p38 pathways. BMC Complement Altern Med. 17(1): https://doi.org/10.1186/s12906-016-1528-8

3. Holzberg M, Boergeling Y, Schräder T, Ludwig S, Ehrhardt C. Vemurafenib Limits Influenza A Virus Propagation by Targeting Multiple Signaling Pathways. Front. Microbiol.. 8 https://doi.org/10.3389/fmicb.2017.02426

4. Franz S, Rennert P, Woznik M, Grützke J, Lüdde A, Arriero Pais EM, Finsterbusch T, Geyer H, Mankertz A, Friedrich N. 2017. Mumps Virus SH Protein Inhibits NF-?B Activation by Interacting with Tumor Necrosis Factor Receptor 1, Interleukin-1 Receptor 1, and Toll-Like Receptor 3 Complexes. J Virol. 91(18): https://doi.org/10.1128/jvi.01037-17

5. Dirr L, El-Deeb IM, Chavas LMG, Guillon P, Itzstein Mv. 2017. The impact of the butterfly effect on human parainfluenza virus haemagglutinin-neuraminidase inhibitor design. Sci Rep. 7(1): https://doi.org/10.1038/s41598-017-04656-y

6. McCaskill JL, Ressel S, Alber A, Redford J, Power UF, Schwarze J, Dutia BM, Buck AH. 2017. Broad-Spectrum Inhibition of Respiratory Virus Infection by MicroRNA Mimics Targeting p38 MAPK Signaling. Molecular Therapy - Nucleic Acids. 7256-266. https://doi.org/10.1016/j.omtn.2017.03.008

7. Mackowiak M, Leifels M, Hamza IA, Jurzik L, Wingender J. 2018. Distribution of Escherichia coli, coliphages and enteric viruses in water, epilithic biofilms and sediments of an urban river in Germany. Science of The Total Environment. 626650-659. https://doi.org/10.1016/j.scitotenv.2018.01.114

8. Aiba N, Shiraki A, Yajima M, Oyama Y, Yoshida Y, Ohno A, Yamada H, Takemoto M, Daikoku T, Shiraki K. 2017. Interaction of Immunoglobulin with Cytomegalovirus-Infected Cells. Viral Immunology. 30(7):500-507. https://doi.org/10.1089/vim.2016.0151

9. Li Y, Lund C, Nervik I, Loevenich S, Døllner H, Anthonsen MW, Johnsen IB. 2018. Characterization of signaling pathways regulating the expression of pro-inflammatory long form thymic stromal lymphopoietin upon human metapneumovirus infection. Sci Rep. 8(1): https://doi.org/10.1038/s41598-018-19225-0

10. Okeke M, Okoli A, Diaz D, Offor C, Oludotun T, Tryland M, Bøhn T, Moens U. Hazard Characterization of Modified Vaccinia Virus Ankara Vector: What Are the Knowledge Gaps?. Viruses. 9(11):318. https://doi.org/10.3390/v9110318

11. Pudupakam RS, Raghunath S, Pudupakam M, Daggupati S. 2017. Genetic characterization of the non-structural protein-3 gene of bluetongue virus serotype-2 isolate from India. Vet World. 10(3):348-352. https://doi.org/10.14202/vetworld.2017.348-352

12. Kleinlützum D, Hanauer JDS, Muik A, Hanschmann K, Kays S, Ayala-Breton C, Peng K, Mühlebach MD, Abel T, Buchholz CJ. Enhancing the Oncolytic Activity of CD133-Targeted Measles Virus: Receptor Extension or Chimerism with Vesicular Stomatitis Virus Are Most Effective. Front. Oncol.. 7 https://doi.org/10.3389/fonc.2017.00127

13. Nikolay A, Castilho LR, Reichl U, Genzel Y. 2018. Propagation of Brazilian Zika virus strains in static and suspension cultures using Vero and BHK cells. Vaccine. 36(22):3140-3145. https://doi.org/10.1016/j.vaccine.2017.03.018

14. Kamal SA, El-Rahman Hassan RA. Advanced Virological And Clinicopathological Studies On Cattle Suffering From Foot And Mouth Disease Virus. JI. 1(1):33-47. https://doi.org/10.14302/issn.2577-137x.ji-17-1736

15. Prescott J, Feldmann H, Safronetz D. 2017. Amending Koch's postulates for viral disease: When ?growth in pure culture? leads to a loss of virulence. Antiviral Research. 1371-5. https://doi.org/10.1016/j.antiviral.2016.11.002

16. Hampton CM, Strauss JD, Ke Z, Dillard RS, Hammonds JE, Alonas E, Desai TM, Marin M, Storms RE, Leon F, et al. 2017. Correlated fluorescence microscopy and cryo-electron tomography of virus-infected or transfected mammalian cells. Nat Protoc. 12(1):150-167. https://doi.org/10.1038/nprot.2016.168

17. Dotti S, Lombardo T, Villa R, Cacciamali A, Zanotti C, Andreani NA, Cinotti S, Ferrari M. Transformation and Tumorigenicity Testing of Simian Cell Lines and Evaluation of Poliovirus Replication. PLoS ONE. 12(1):e0169391. https://doi.org/10.1371/journal.pone.0169391

18. Yang K, Dang X, Baines JD. 2017. A Domain of Herpes Simplex Virus pUL33 Required To Release Monomeric Viral Genomes from Cleaved Concatemeric DNA. J Virol. 91(20): https://doi.org/10.1128/jvi.00854-17

19. Gromeier M, Nair SK. 2018. Recombinant Poliovirus for Cancer Immunotherapy. Annu. Rev. Med.. 69(1):289-299. https://doi.org/10.1146/annurev-med-050715-104655

20. Weigert M, Binks A, Dowson S, Leung EYL, Athineos D, Yu X, Mullin M, Walton JB, Orange C, Ennis D, et al. 2017. RIPK3 promotes adenovirus type 5 activity. Cell Death Dis. 8(12): https://doi.org/10.1038/s41419-017-0110-8

21. Khadivjam B, Stegen C, Hogue-Racine M, El Bilali N, Döhner K, Sodeik B, Lippé R. 2017. The ATP-Dependent RNA Helicase DDX3X Modulates Herpes Simplex Virus 1 Gene Expression. J Virol. 91(8): https://doi.org/10.1128/jvi.02411-16

22. Aguilera ER, Erickson AK, Jesudhasan PR, Robinson CM, Pfeiffer JK. 2017. Plaques Formed by Mutagenized Viral Populations Have Elevated Coinfection Frequencies. mBio. 8(2): https://doi.org/10.1128/mbio.02020-16

23. Ibáñez FJ, Farías MA, Retamal-Díaz A, Espinoza JA, Kalergis AM, González PA. Pharmacological Induction of Heme Oxygenase-1 Impairs Nuclear Accumulation of Herpes Simplex Virus Capsids upon Infection. Front. Microbiol.. 8 https://doi.org/10.3389/fmicb.2017.02108

24. Acevedo A, Woodman A, Arnold JJ, Yeh MT, Evans D, Cameron CE, Andino R. Genetic recombination of poliovirus facilitates subversion of host barriers to infection. https://doi.org/10.1101/273060

25. Ganjian H, Zietz C, Mechtcheriakova D, Blaas D, Fuchs R. ICAM-1 Binding Rhinoviruses Enter HeLa Cells via Multiple Pathways and Travel to Distinct Intracellular Compartments for Uncoating. Viruses. 9(4):68. https://doi.org/10.3390/v9040068

26. Pan W, Song D, He W, Lu H, Lan Y, Li H, Gao F, Zhao K. 2017. EIF3i affects vesicular stomatitis virus growth by interacting with matrix protein. Veterinary Microbiology. 21259-66. https://doi.org/10.1016/j.vetmic.2017.10.021

27. Sadaoka T, Schwartz CL, Rajbhandari L, Venkatesan A, Cohen JI. 2017. Human Embryonic Stem Cell-Derived Neurons Are Highly Permissive for Varicella-Zoster Virus Lytic Infection. J Virol. 92(1): https://doi.org/10.1128/jvi.01108-17

28. Betancourt WQ, Abd-Elmaksoud S, Gerba CP. 2018. Efficiency of Reovirus Concentration from Water with Positively Charged Filters. Food Environ Virol. 10(2):209-211. https://doi.org/10.1007/s12560-017-9332-2

29. Sato K, Watanabe O, Ohmiya S, Chiba F, Suzuki A, Okamoto M, Younghuang J, Hata A, Nonaka H, Kitaoka S, et al. 2017. Efficient isolation of human metapneumovirus using MNT-1, a human malignant melanoma cell line with early and distinct cytopathic effects. Microbiol Immunol. 61(11):497-506. https://doi.org/10.1111/1348-0421.12542

30. Parker S, Crump R, Hartzler H, Buller R. Evaluation of Taterapox Virus in Small Animals. Viruses. 9(8):203. https://doi.org/10.3390/v9080203

31. Petyaev IM, Zigangirova NA, Morgunova EY, Kyle NH, Fedina ED, Bashmakov YK. 2017. Resveratrol Inhibits Propagation ofChlamydia trachomatisin McCoy Cells. BioMed Research International. 20171-7. https://doi.org/10.1155/2017/4064071

32. Danaher RJ, Fouts DE, Chan AP, Choi Y, DePew J, McCorrison JM, Nelson KE, Wang C, Miller CS. 2017. HSV-1 clinical isolates with unique in vivo and in vitro phenotypes and insight into genomic differences. J. Neurovirol.. 23(2):171-185. https://doi.org/10.1007/s13365-016-0485-9

33. Glatthaar-Saalmüller B, Mair KH, Saalmüller A. 2017. Antiviral activity of aspirin against RNA viruses of the respiratory tract-an in vitro study. Influenza Other Respi Viruses. 11(1):85-92. https://doi.org/10.1111/irv.12421

34. Shah Mahmud R, Müller C, Romanova Y, Mostafa A, Ulyanova V, Pleschka S, Ilinskaya O. 2017. Ribonuclease fromBacillusActs as an Antiviral Agent against Negative- and Positive-Sense Single Stranded Human Respiratory RNA Viruses. BioMed Research International. 20171-11. https://doi.org/10.1155/2017/5279065

35. Hobom U, Brune W, Messerle M, Hahn G, Koszinowski UH. 2000. Fast Screening Procedures for Random Transposon Libraries of Cloned Herpesvirus Genomes: Mutational Analysis of Human Cytomegalovirus Envelope Glycoprotein Genes. J. Virol.. 74(17):7720-7729. https://doi.org/10.1128/jvi.74.17.7720-7729.2000

36. Didcock L, Young DF, Goodbourn S, Randall RE. 1999. Sendai Virus and Simian Virus 5 Block Activation of Interferon-Responsive Genes: Importance for Virus Pathogenesis. J. Virol.. 73(4):3125-3133. https://doi.org/10.1128/jvi.73.4.3125-3133.1999

37. Gugala Z, Olmsted-Davis EA, Gannon FH, Lindsey RW, Davis AR. 2003. Osteoinduction by ex vivo adenovirus-mediated BMP2 delivery is independent of cell type. Gene Ther. 10(16):1289-1296. https://doi.org/10.1038/sj.gt.3302006

38. Cheng P, Ng L, Chiang L, Lin C. 2006. ANTIVIRAL EFFECTS OF SAIKOSAPONINS ON HUMAN CORONAVIRUS 229E IN VITRO. Clin Exp Pharmacol Physiol. 33(7):612-616. https://doi.org/10.1111/j.1440-1681.2006.04415.x

39. Wilson MR, Suan D, Duggins A, Schubert RD, Khan LM, Sample HA, Zorn KC, Rodrigues Hoffman A, Blick A, Shingde M, et al. 2017. A novel cause of chronic viral meningoencephalitis: Cache Valley virus. Ann Neurol.. 82(1):105-114. https://doi.org/10.1002/ana.24982

40. Atieh T, El Ayoubi MD, Aubry F, Priet S, de Lamballerie X, Nougairède A. Haiku: New paradigm for the reverse genetics of emerging RNA viruses. PLoS ONE. 13(2):e0193069. https://doi.org/10.1371/journal.pone.0193069

41. Lewandowska DW, Zagordi O, Geissberger F, Kufner V, Schmutz S, Böni J, Metzner KJ, Trkola A, Huber M. 2017. Optimization and validation of sample preparation for metagenomic sequencing of viruses in clinical samples. Microbiome. 5(1): https://doi.org/10.1186/s40168-017-0317-z

42. Jenny RA, Hirst C, Lim SM, Goulburn AL, Micallef SJ, Labonne T, Kicic A, Ling K, Stick SM, Ng ES, et al. 2015. Productive Infection of Human Embryonic Stem Cell-Derived NKX2.1+Respiratory Progenitors With Human Rhinovirus. 4(6):603-614. https://doi.org/10.5966/sctm.2014-0274

43. Jerome KR. Lennette's Laboratory Diagnosis of Viral Infections. https://doi.org/10.3109/9781420084962

44. Pereira L. Therapeutic and Nutritional Uses of Algae. https://doi.org/10.1201/9781315152844

45. Mu J, Hirayama M, Sato Y, Morimoto K, Hori K. A Novel High-Mannose Specific Lectin from the Green Alga Halimeda renschii Exhibits a Potent Anti-Influenza Virus Activity through High-Affinity Binding to the Viral Hemagglutinin. Marine Drugs. 15(8):255. https://doi.org/10.3390/md15080255

46. Costello MJ, Smernoff NT, Yungbluth M. 1993. Laboratory Diagnosis of Viral Respiratory Tract Infections. Lab Med. 24(3):150-157. https://doi.org/10.1093/labmed/24.3.150

47. Currier MG, Lee S, Stobart CC, Hotard AL, Villenave R, Meng J, Pretto CD, Shields MD, Nguyen MT, Todd SO, et al. EGFR Interacts with the Fusion Protein of Respiratory Syncytial Virus Strain 2-20 and Mediates Infection and Mucin Expression. PLoS Pathog. 12(5):e1005622. https://doi.org/10.1371/journal.ppat.1005622

48. Tan B, Wu L, Yang X, Li B, Zhang W, Lei Y, Li Y, Yang G, Chen J, Chen G, et al. 2016. Isolation and characterization of adenoviruses infecting endangered golden snub-nosed monkeys (Rhinopithecus roxellana). Virol J. 13(1): https://doi.org/10.1186/s12985-016-0648-6

49. Yang T, Li S, Zhang X, Pang X, Lin Q, Cao J. 2015. Resveratrol, sirtuins, and viruses. Rev. Med. Virol.. 25(6):431-445. https://doi.org/10.1002/rmv.1858

50. Gagliardi TB, Criado MF, Proença-Módena JL, Saranzo AM, Iwamoto MA, de Paula FE, Cardoso RS, Delcaro LS, Silva ML, Câmara AA, et al. 2017. Syncytia Induction by Clinical Isolates of Human Respiratory Syncytial Virus A. Intervirology. 60(1-2):56-60. https://doi.org/10.1159/000480014

51. Amatore D, Sgarbanti R, Aquilano K, Baldelli S, Limongi D, Civitelli L, Nencioni L, Garaci E, Ciriolo MR, Palamara AT. 2015. Influenza virus replication in lung epithelial cells depends on redox?sensitive pathways activated by NOX4 ?derived ROS. Cell Microbiol. 17(1):131-145. https://doi.org/10.1111/cmi.12343

52. Castells E, George VG, Hierholzer JC. 1990. NCI-H292 as an alternative cell line for the isolation and propagation of the human paramyxoviruses. Archives of Virology. 115(3-4):277-288. https://doi.org/10.1007/bf01310536

53. Bianco A, Sethi S, Allen J, Knight R, Spiteri M. 1998. Th2 cytokines exert a dominant influence on epithelial cell expression of the major group human rhinovirus receptor, ICAM-1. 12(3):619-626. https://doi.org/10.1183/09031936.98.12030619

54. Mall AS, Habte H, Mthembu Y, Peacocke J, de Beer C. 2017. Mucus and Mucins: do they have a role in the inhibition of the human immunodeficiency virus?. Virol J. 14(1): https://doi.org/10.1186/s12985-017-0855-9

55. Elion GB, Furman PA, Fyfe JA, Miranda Pd, Beauchamp L, Schaeffer HJ. 1977. Selectivity of action of an antiherpetic agent, 9-(2-hydroxyethoxymethyl)guanine. Proceedings of the National Academy of Sciences. 74(12):5716-5720. https://doi.org/10.1073/pnas.74.12.5716

56. Rima BK, Davidson WB, Martin SJ. 1977. The Role of Defective Interfering Particles in Persistent Infection of Vero Cells by Measles Virus. Journal of General Virology. 35(1):89-97. https://doi.org/10.1099/0022-1317-35-1-89

57. Gouma S, ten Hulscher HI, Schurink-van ?t Klooster TM, de Melker HE, Boland GJ, Kaaijk P, van Els CA, Koopmans MP, van Binnendijk RS. 2016. Mumps-specific cross-neutralization by MMR vaccine-induced antibodies predicts protection against mumps virus infection. Vaccine. 34(35):4166-4171. https://doi.org/10.1016/j.vaccine.2016.06.063

58. Sanders BP, Oakes IdlR, van Hoek V, Liu Y, Marissen W, Minor PD, Wimmer E, Schuitemaker H, Custers JH, Macadam A, et al. 2015. Production of high titer attenuated poliovirus strains on the serum-free PER.C6® cell culture platform for the generation of safe and affordable next generation IPV. Vaccine. 33(48):6611-6616. https://doi.org/10.1016/j.vaccine.2015.10.091

59. Kang JY, Lee DK, Ha NJ, Shin HS. 2015. Antiviral effects of Lactobacillus ruminis SPM0211 and Bifidobacterium longum SPM1205 and SPM1206 on rotavirus-infected Caco-2 cells and a neonatal mouse model. J Microbiol.. 53(11):796-803. https://doi.org/10.1007/s12275-015-5302-2

60. Mangala Prasad V, Klose T, Rossmann MG. Assembly, maturation and three-dimensional helical structure of the teratogenic rubella virus. PLoS Pathog. 13(6):e1006377. https://doi.org/10.1371/journal.ppat.1006377

61. Venturi G, Zammarchi L, Fortuna C, Remoli ME, Benedetti E, Fiorentini C, Trotta M, Rizzo C, Mantella A, Rezza G, et al. 2016. An autochthonous case of Zika due to possible sexual transmission, Florence, Italy, 2014. 21(8): https://doi.org/10.2807/1560-7917.es.2016.21.8.30148

62. Criscuolo E, Clementi N, Mancini N, Burioni R, Miduri M, Castelli M, Clementi M. 2018. Synergy evaluation of anti-Herpes Simplex Virus type 1 and 2 compounds acting on different steps of virus life cycle. Antiviral Research. 15171-77. https://doi.org/10.1016/j.antiviral.2018.01.009

63. Richard AS, Shim B, Kwon Y, Zhang R, Otsuka Y, Schmitt K, Berri F, Diamond MS, Choe H. 2017. AXL-dependent infection of human fetal endothelial cells distinguishes Zika virus from other pathogenic flaviviruses. Proc Natl Acad Sci USA. 114(8):2024-2029. https://doi.org/10.1073/pnas.1620558114

64. Kim YY, Jee HJ, Um J, Kim YM, Bae SS, Yun J. 2017. Cooperation between p21 and Akt is required for p53-dependent cellular senescence. Aging Cell. 16(5):1094-1103. https://doi.org/10.1111/acel.12639

65. Plotkin S. 2015. The history of vaccination against cytomegalovirus. Med Microbiol Immunol. 204(3):247-254. https://doi.org/10.1007/s00430-015-0388-z

66. Mintz L, Drew WL. 1980. Relation of Culture Site to the Recovery of Nonpolio Enteroviruses. 74(3):324-326. https://doi.org/10.1093/ajcp/74.3.324

67. Baker DA, Kleger B, Plotkin SA. 1979. A Comparison of Herpes Simplex Virus (HSV) Typing Using Direct Fluorescent Antibody (DFA) and Chick Embryo Plaque (CEP) Assays. Lab Med. 10(9):559-561. https://doi.org/10.1093/labmed/10.9.559

68. Perelygina L, Plotkin S, Russo P, Hautala T, Bonilla F, Ochs HD, Joshi A, Routes J, Patel K, Wehr C, et al. 2016. Rubella persistence in epidermal keratinocytes and granuloma M2 macrophages in patients with primary immunodeficiencies. Journal of Allergy and Clinical Immunology. 138(5):1436-1439.e11. https://doi.org/10.1016/j.jaci.2016.06.030

69. Sousa FH, Casanova V, Findlay F, Stevens C, Svoboda P, Pohl J, Proudfoot L, Barlow PG. 2017. Cathelicidins display conserved direct antiviral activity towards rhinovirus. Peptides. 9576-83. https://doi.org/10.1016/j.peptides.2017.07.013

70. Shariff S, Shelfoon C, Holden NS, Traves SL, Wiehler S, Kooi C, Proud D, Leigh R. 2017. Human Rhinovirus Infection of Epithelial Cells Modulates Airway Smooth Muscle Migration. Am J Respir Cell Mol Biol. 56(6):796-803. https://doi.org/10.1165/rcmb.2016-0252oc

71. Corry J, Johnson SM, Cornwell J, Peeples ME. 2016. Preventing Cleavage of the Respiratory Syncytial Virus Attachment Protein in Vero Cells Rescues the Infectivity of Progeny Virus for Primary Human Airway Cultures. J. Virol.. 90(3):1311-1320. https://doi.org/10.1128/jvi.02351-15

72. Zahoor MA, Khurshid M, Qureshi R, Naz A, Shahid M. 2016. Cell culture-based viral vaccines: current status and future prospects. Future Virology. 11(7):549-562. https://doi.org/10.2217/fvl-2016-0006