Our previous in vitro comparative study on a feline coronavirus (FCoV) pair, differing only in the intactness of their ORF3abc regions, showed that the truncated ORF3abc plays an important role in the efficient macrophage/monocyte tropism of type II feline infectious peritonitis virus (FIPV). In the present study, we describe a challenge experiment with the same recombinant FCoVs in order to gain data on the in vivo characteristics on these viruses. While parent virus FIPV DF-2 developed feline infectious peritonitis in all the infected cats, its recombinant virus PBFIPV-DF-2, differing only in seven nucleotides, proved to be surprisingly low virulent, although caused an acute febrile episode similarly to the original FIPV DF-2. PBFIPV-DF-2 infection induced significantly lower virus neutralization titers than its parent virus, and lacked the second phase of viremia and development of fatal course of the disease. The recombinant PBFIPV-DF-2-R3i with completed ORF3abc gained biological properties that differentiate between the feline enteric coronavirus (FECV) and FIPV biotypes such as intensive replication in the gut, absence of viremia and weak or no serological response. Using reverse genetic approaches our study is the first experimental proof that ORF3abc is indeed responsible for the restriction of FECV replication to the intestine in vivo.
References
[1]
Horzinek MC, Osterhaus AD (1979) Feline infectious peritonitis: a worldwide serosurvey. Am J Vet Res 40: 1487–1492.
[2]
Pedersen NC, Boyle JF, Floyd K, Fudge A, Barker J (1981) An enteric coronavirus infection of cats and its relationship to feline infectious peritonitis. Am J Vet Res 42: 368–377.
[3]
Herrewegh AA, Mahler M, Hedrich HJ, Haagmans BL, Egberink HF, et al. (1997) Persistence and evolution of feline coronavirus in a closed cat-breeding colony. Virology 234: 349–363. doi: 10.1006/viro.1997.8663
[4]
Addie D, Jarrett O (1992) A study of naturally occurring feline coronavirus infections in kittens. Vet Rec 130: 133–137. doi: 10.1136/vr.130.7.133
[5]
de Groot-Mijnes JD, van Dun JM, van der Most RG, de Groot RJ (2005) Natural history of a recurrent feline coronavirus infection and the role of cellular immunity in survival and disease. J Virol 79: 1036–1044. doi: 10.1128/jvi.79.2.1036-1044.2005
[6]
Haijema BJ, Rottier PJM, de Groot RJ (2007) Feline coronaviruses: a tale of two-faced types. Coronaviruses. In: Thiel V, editor. Molecular and Cellular Biology. Norfolk. 183–203.
[7]
Addie D, Belák S, Boucraut-Baralon C, Egberink H, Frymus T, et al. (2009) Feline infectious peritonitis. ABCD guidelines on prevention and management. J Feline Med Surg 11: 594–604. doi: 10.1016/j.jfms.2009.05.008
[8]
Pedersen NC (2009) A review of feline infectious peritonitis virus infection: 1963–2008. J Feline Med Surg 11: 225–258. doi: 10.1016/j.jfms.2008.09.008
[9]
Vennema H, Poland A, Foley J, Pedersen NC (1998) Feline infectious peritonitis viruses arise by mutation from endemic feline enteric coronaviruses. Virology 243: 150–157. doi: 10.1006/viro.1998.9045
[10]
Rottier PJ, Nakamura K, Schellen P, Volders H, Haijema BJ (2005) Acquisition of macrophage tropism during the pathogenesis of feline infectious peritonitis is determined by mutations in the feline coronavirus spike protein. J Virol 79: 14122–14130. doi: 10.1128/jvi.79.22.14122-14130.2005
Kennedy M, Boedeker N, Gibbs P, Kania S (2001) Deletions in the 7a ORF of feline coronavirus associated with an epidemic of feline infectious peritonitis. Vet Microbiol 81: 227–234. doi: 10.1016/s0378-1135(01)00354-6
[13]
Dedeurwaerder A, Desmarets LM, Olyslaegers DA, Vermeulen BL, Dewerchin HL, et al. (2012) The role of accessory proteins in the replication of feline infectious peritonitis virus in peripheral blood monocytes. Vet Microbiol 162: 447–455. doi: 10.1016/j.vetmic.2012.10.032
[14]
Chang HW, de Groot RJ, Egberink HF, Rottier PJ (2010) Feline infectious peritonitis; insights into feline coronavirus pathobiogenesis and epidemiology based on genetic analysis of the viral 3c gene. J Gen Virol 91: 415–420. doi: 10.1099/vir.0.016485-0
[15]
Chang HW, Egberink HF, Rottier PJ (2011) Sequence analysis of feline coronaviruses and the circulating virulent/avirulent theory. Emerg Infect Dis 17: 744–746. doi: 10.3201/eid1704.102027
[16]
Pedersen NC, Liu H, Dodd KA, Pesavento PA (2009) Significance of coronavirus mutants in feces and diseased tissues of cats suffering from feline infectious peritonitis. Viruses 1: 166–184. doi: 10.3390/v1020166
[17]
Bálint A, Farsang A, Zádori Z, Hornyák A, Dencs？ L, et al. (2012) Molecular characterization of feline infectious peritonitis virus strain DF-2 and studies on the role of ORF3abc in viral cell tropism. J Virol 86: 6258–6267. doi: 10.1128/jvi.00189-12
[18]
Haijema BJ, Volders H, Rottier PJ (2004) Live, attenuated coronavirus vaccines through the directed deletion of group-specific genes provide protection against feline infectious peritonitis. J Virol 78: 3863–3871. doi: 10.1128/jvi.78.8.3863-3871.2004
[19]
Scott VL, Burgess SC, Shack LA, Lockett NN, Coats KS (2008) Expression of CD134 and CXCR4 mRNA in term placentas from FIV-infected and control cats. Vet Immunol Immunopathol 123: 90–96. doi: 10.1016/j.vetimm.2008.01.014
[20]
Shiba N, Maeda K, Kato H, Mochizuki M, Iwata H (2007) Differentiation of feline coronavirus type I and II infections by virus neutralization test. Vet Microbiol 124: 348–352. doi: 10.1016/j.vetmic.2007.04.031
[21]
Dewerchin HL, Cornelissen E, Nauwynck HJ (2005) Replication of feline coronaviruses in peripheral blood monocytes. Arch Virol 150: 2483–2500. doi: 10.1007/s00705-005-0598-6
[22]
Meli M, Kipar A, Müller C, Jenal K, G？nczi E, et al. (2004) High viral loads despite absence of clinical and pathological findings in cats experimentally infected with feline coronavirus (FCoV) type I and in naturally FCoV-infected cats. J Feline Med Surg 6: 69–81. doi: 10.1016/j.jfms.2003.08.007
[23]
Vogel L, Van der Lubben M, te Lintelo EG, Bekker CP, Geerts T, et al. (2010) Pathogenic characteristics of persistent feline enteric coronavirus infection in cats. Vet Res 41: 71. doi: 10.1051/vetres/2010043
[24]
Pedersen NC, Liu H, Scarlett J, Leutenegger CM, Golovko L, et al. (2012) Feline infectious peritonitis: role of the feline coronavirus 3c gene in intestinal tropism and pathogenicity based upon isolates from resident and adopted shelter cats. Virus Res 165: 17–28. doi: 10.1016/j.virusres.2011.12.020
[25]
Hoskins JD, Taylor HW, Lomax TL (1994) Challenge trial of an intranasal feline infectious peritonitis vaccine. Feline Pract 22: 9–13.
[26]
Ziebuhr J, Snijder EJ, Gorbalenya AE (2000) Virus-encoded proteinases and proteolytic processing in the Nidovirales. J Gen Virol 81: 853–879.
[27]
Huang C, Lokugamage KG, Rozovics JM, Narayanan K, Semler BL, et al. (2011) SARS coronavirus nsp1 protein induces template-dependent endonucleolytic cleavage of mRNAs: viral mRNAs are resistant to nsp1-induced RNA cleavage. PLoS Pathog 7: e1002433. doi: 10.1371/journal.ppat.1002433
[28]
Cornillez-Ty CT, Liao L, Yates JR 3rd, Kuhn P, Buchmeier MJ (2009) Severe acute respiratory syndrome coronavirus nonstructural protein 2 interacts with a host protein complex involved in mitochondrial biogenesis and intracellular signaling. J Virol 83: 10314–10318. doi: 10.1128/jvi.00842-09
[29]
Cruz JL, Sola I, Becares M, Alberca B, Plana J, et al. (2011) Coronavirus gene 7 counteracts host defenses and modulates virus virulence. PLoS Pathog 7: e1002090. doi: 10.1371/journal.ppat.1002090
[30]
Herrewegh AA, Vennema H, Horzinek MC, Rottier PJ, de Groot RJ (1995) The molecular genetics of feline coronaviruses: comparative sequence analysis of the ORF7a/7b transcription unit of different biotypes. Virology 212: 622–631. doi: 10.1006/viro.1995.1520
[31]
Lin CN, Su BL, Huang HP, Lee JJ, Hsieh MW, et al. (2008) Field strain feline coronaviruses with small deletions in ORF7b associated with both enteric infection and feline infectious peritonitis. J Feline Med Surg 11: 413–419. doi: 10.1016/j.jfms.2008.09.004
[32]
Tekes G, Spies D, Bank-Wolf B, Thiel V, Thiel HJ (2012) A reverse genetics approach to study feline infectious peritonitis. J Virol 86: 6994–6998. doi: 10.1128/jvi.00023-12
[33]
Simons FA, Vennema H, Rofina JE, Pol JM, Horzinek MC, et al. (2004) A mRNA PCR for the diagnosis of feline infectious peritonitis. J Virol Meth 124: 111–116. doi: 10.1016/j.jviromet.2004.11.012
[34]
Gunn-Moore DA, Gruffydd-Jones TJ, Harbour DA (1998) Detection of feline coronaviruses by culture and reverse transcriptase-polymerase chain reaction of blood samples from healthy cats and cats with clinical feline infectious peritonitis. Vet Microbiol 62: 193–205. doi: 10.1016/s0378-1135(98)00210-7
[35]
Pedersen NC, Allen CE, Lyons LA (2008) Pathogenesis of feline enteric coronavirus infection. J Feline Med Surg 10: 529–541. doi: 10.1016/j.jfms.2008.02.006
[36]
Poland AM, Vennema H, Foley JE, Pedersen NC (1996) Two related strains of feline infectious peritonitis virus isolated from immunocompromised cats infected with a feline enteric coronavirus. J Clin Microbiol 34: 3180–3184.
[37]
Pedersen NC, Sato R, Foley JE, Poland AM (2004) Common virus infections in cats, before and after being placed in shelters, with emphasis on feline enteric coronavirus. J Feline Med Surg 6: 83–88. doi: 10.1016/j.jfms.2003.08.008
[38]
Kipar A, Meli ML, Baptiste KE, Bowker LJ, Lutz H (2010) Sites of feline coronavirus persistence in healthy cats. J Gen Virol 91: 1698–1707. doi: 10.1099/vir.0.020214-0
[39]
Herrewegh AA, Smeenk I, Horzinek MC, Rottier PJ, de Groot RJ (1998) Feline coronavirus type II strains 79–1683 and 79–1146 originate from a double recombination between feline coronavirus type I and canine coronavirus. J Virol 72: 4508–4514.
[40]
Decaro N, Martella V, Ricci D, Elia G, Desario C, et al. (2005) Genotype-specific fluorogenic RT-PCR assays for the detection and quantitation of canine coronavirus type I and type II RNA in faecal samplesof dogs, J Virol Meth. 130: 72–78. doi: 10.1016/j.jviromet.2005.06.005
