Abstract
The contribution of cell-mediated immunity to protective immunity against virulent transmissible gastroenteritis virus (TGEV) infection conferred by primary porcine respiratry coronavirus (PRCV) or TGEV exposure was assessed in pigs that were challenged with TGEV 24 days after a primary oronasal inoculation with PRCV or TGEV when 11 days old. PRCV exposure induced partial protection against TGEV challenge in suckling pigs based upon a decreased number of diarrhea cases (42% vs. 90% in age-matched control pigs), limited virus shedding in feces, and increases in virus-neutralizing serum antibody titers; in contrast, all 11-day-old pigs inoculated with TGEV were completely protected after challenge. Weaned pigs were also studied to eliminate any possibility that lactogenic immunity from contact PRCV-exposed sows contributed to protection against TGEV. Once weaned, none of the PRCV-exposed or age-matched control pigs had diarrhea after TGEV challenge; moreover, both groups exhibited less rectal virus shedding than suckling pigs. Vigorous lymphocyte proliferative responses (> 96 000 counts per minute (cpm)) were detected in mononuclear cells prepared from mesenteric (MLN) and bronchial (BLN) lymph nodes of TGEV-primed pigs. Analyses of these responses indicate that virus-specific cell-mediated immune responses correlated with protection against rectal and nasal virus shedding after TGEV challenge. Primary inoculation of 11-day-old pigs with PRCV induced moderate, transient virus-specific lymphocyte proliferation (> 47 000 cpm) in MLN from both suckling and weaned pigs after TGEV challenge. Substantial BLN proliferative responses (> 80 000 cpm) correlated with failure to detect TGEV in nasal secretions from these pigs. Virus-specific lymphocyte proliferation in spleens was delayed in onset and of lower magnitude than that observed in MLN and BLN. Virulent TGEV exposure resulted in increased percentages of T cell subsets, especially in the lamina propria and MLN, mucosaassociated lymphoid tissues in proximity to the primary replication site of TGEV in the small intestine. Our results confirm that PRCV infection primes anti-viral immune responses and, thus, contributes to partial immunity against virulent TGEV challenge.
Keywords: Transmissible gastroenteritis virus, Porcine respiratory coronavirus, Cellular immunity, Lymphocyte proliferation, Lymphocyte subsets, T lymphocytes
References
- Akbar A.N., Salmon M., Janossy G. The synergy between naive and memory T cells during activation. Immunol. Today. 1991;12:184–188. doi: 10.1016/0167-5699(91)90050-4. [DOI] [PubMed] [Google Scholar]
- Bailey M., Stevens K., Bland P.W., Stokes C.R. A monoclonal antibody recognising an epitope associated with pig interleukin-2 receptors. J. Immunol. Methods. 1992;153:85–91. doi: 10.1016/0022-1759(92)90309-h. [DOI] [PubMed] [Google Scholar]
- Bernard S., Bottreau E., Aynaud J.M., Have P., Szymansky J. Natural infection with the porcine respiratory coronavirus induces protective lactogenic immunity against transmissible gastroenteritis virus. Vet. Microbiol. 1989;21:1–8. doi: 10.1016/0378-1135(89)90013-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Binns R.M. Organisation of the lymphoreticular system and lymphocyte markers in the pig. Vet. Immunol. Immunopathol. 1982;3:95–146. doi: 10.1016/0165-2427(82)90033-2. [DOI] [PubMed] [Google Scholar]
- Binns R.M., Duncan I.A., Powis S.J., Hutchings A., Butcher G.W. Subsets of null and γδ T-cell receptor+ T lymphocytes in the blood of young pigs identified by specific monoclonal antibodies. Immunology. 1992;77:219–227. [PMC free article] [PubMed] [Google Scholar]
- Bohl E.H., Kumagai T. Vol. 69. 1965. The use of cell cultures for the study of TGE virus of swine; pp. 343–350. (Proc. US Livest. Sanit. Assoc.). [Google Scholar]
- Bohl E.H., Gupta R.K.P., Olquin M.V.F., Saif L.J. Antibody responses in serum, colostrum and milk of swine after infection or vaccination with transmissible gastroenteritis virus. Infect. Immun. 1972;6:289–301. doi: 10.1128/iai.6.3.289-301.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brim T.A., VanCott J.L., Lunney J.K., Saif L.J. Lymphocyte proliferative responses of pigs inoculated with transmissible gastroenteritis virus or porcine respiratory coronavirus. Am. J. Vet. Res. 1994;55:494–501. [PubMed] [Google Scholar]
- Brown I., Cartwright S. New porcine coronavirus? Vet. Rec. 1986;119:282–283. doi: 10.1136/vr.119.11.282. [DOI] [PubMed] [Google Scholar]
- Callebaut P., Correa I., Pensaert M., Jimenez G., Enjuanes L. Antigenic differentiation between transmissible gastroenteritis virus of swine and a related porcine respiratory coronavirus. J. Gen. Virol. 1988;69:1725–1730. doi: 10.1099/0022-1317-69-7-1725. [DOI] [PubMed] [Google Scholar]
- Callebaut P., Cox E., Pensaert M., van Deun K. Induction of milk IgA antibodies by porcine respiratory coronavirus infection. In: Cavanagh D., Brown T.D.K., editors. Coronaviruses and Their Diseases. Plenum Press; New York: 1990. pp. 421–428. [DOI] [PubMed] [Google Scholar]
- Cox E., Hooyberghs J., Pensaert M.B. Sites of replication of a porcine respiratory coronavirus related to transmissible gastroenteritis virus. Res. Vet. Sci. 1990;48:165–169. doi: 10.1016/S0034-5288(18)30984-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cox E., Pensaert M.B., Callebaut P. Intestinal protection against challenge with transmissible gastroenteritis virus of pigs immune after infection with the porcine respiratory coronavirus. Vaccine. 1993;11:267–272. doi: 10.1016/0264-410X(93)90028-V. [DOI] [PMC free article] [PubMed] [Google Scholar]
- De Diego M., Laviada M.D., Enjuanes L., Escribano J.M. Epitope specificity of protective lactogenic immunity against swine transmissible gastroenteritis virus. J. Virol. 1992;66:6502–6508. doi: 10.1128/jvi.66.11.6502-6508.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dunkley M.L., Husband A.J. Distribution and functional characteristics of antigen-specific helper T cells arising after Peyer's patch immunization. Immunology. 1987;61:475–482. [PMC free article] [PubMed] [Google Scholar]
- Furuuchi S., Shimizu Y., Kumagai T. Multiplication of low and high cell culture passaged strains of transmissible gastroenteritis virus in organs of newborn piglets. Vet. Microbiol. 1978/1979;3:169–178. [Google Scholar]
- Garwes D.J., Stewart F., Cartwright S.F., Brown I. Differentiation of porcine coronavirus from transmissible gastroenteritis virus. Vet. Rec. 1988;122:86–87. doi: 10.1136/vr.122.4.86. [DOI] [PubMed] [Google Scholar]
- Hall G.A., Byrne T.F. Effects of age and diet on small intestinal structure and function in gnotobiotic piglets. Res. Vet. Sci. 1989;47:387–392. [PubMed] [Google Scholar]
- Hein W.R., Mackay C.R. Prominence of γδ T cells in the ruminant immune system. Immunol. Today. 1991;12:30–34. doi: 10.1016/0167-5699(91)90109-7. [DOI] [PubMed] [Google Scholar]
- Hill H., Biwer J., Wood R., Wesley R. Porcine respiratory coronavirus isolated from two U.S. swine herds. Proceedings of the 21st Annual Meeting of the American Association of Swine Practitioners; 4–6 March, Denver, CO; 1990. pp. 333–335. [Google Scholar]
- Hirt W., Saalmuller A., Reddehase M.J. Distinct γδ T cell receptors define two subsets of circulating porcine CD2−CD4−CD8− T lymphocytes. Eur. J. Immunol. 1990;20:265–269. doi: 10.1002/eji.1830200206. [DOI] [PubMed] [Google Scholar]
- Kemeny L.J., Wiltsey V.L., Riley J.L. Upper respiratory infection of lactating sows with transmissible gastroenteritis virus following contact exposure to infected piglets. Cornell Vet. 1975;65:352–362. [PubMed] [Google Scholar]
- Kimpen J.L.L., Rich G.A., Mohar C.K., Ogra P.L. Mucosal T cell distribution during infection with respiratory syncytial virus. J. Med. Virol. 1992;36:172–179. doi: 10.1002/jmv.1890360305. [DOI] [PubMed] [Google Scholar]
- London S.D., Cebra-Thomas J.A., Rubin D.H., Cebra J.J. CD8 lymphocyte subpopulations in Peyer's patches induced by reovirus serotype I infection. J. Immunol. 1990;144:3187–3194. [PubMed] [Google Scholar]
- Lunney J.K., Urban J.F., Jr., Johnson L.A. Protective immunity to Ascaris suum: analysis of swine peripheral blood cell subsets using monoclonal antibodies and flow cytometry. Vet. Parasitol. 1986;20:117–131. doi: 10.1016/0304-4017(86)90096-8. [DOI] [PubMed] [Google Scholar]
- Lunney J.K. Characterization of swine leukocyte differentiation antigens. Immunol. Today. 1993;14:147–148. doi: 10.1016/0167-5699(93)90227-C. [DOI] [PubMed] [Google Scholar]
- Mestecky J., McGhee J.R. Immunoglobulin A (IgA): molecular and cellular interactions involved in IgA biosynthesis and immune response. Adv. Immunol. 1987;40:153–245. doi: 10.1016/s0065-2776(08)60240-0. [DOI] [PubMed] [Google Scholar]
- Moon H.W., Norman J.O., Lambert G. Age dependent resistance to TGE of swine. I. Clinical signs and some mucosal dimensions in the small intestine. Can. J. Comp. Med. 1973;37:157–166. [PMC free article] [PubMed] [Google Scholar]
- O'Toole D., Brown I., Bridges A., Cartwright S.F. Pathogenicity of experimental infection with ‘pneumotropic/’ porcine coronovirus. Res. Vet. Sci. 1989;47:23–29. doi: 10.1016/S0034-5288(18)31226-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Paton D.J., Brown I.H. Sows infected in pregnancy with porcine respiratory coronavirus show no evidence of protecting their sucking piglets against transmissible gastroenteritis. Vet. Res. Commun. 1990;14:329–337. doi: 10.1007/BF00350714. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Paul P.S., Mengeling W.L., Malstrom C.E., van Deusen R.A. Production and characterization of monoclonal antibodies to porcine immunoglobulin gamma, alpha, and light chains. Am. J. Vet. Res. 1989;50:471–479. [PubMed] [Google Scholar]
- Pensaert M., Callebaut P., Vergote J. Isolation of a porcine respiratory, non-enteric coronavirus related to transmissible gastroenteritis. Vet. Q. 1986;8:257–261. doi: 10.1080/01652176.1986.9694050. [DOI] [PubMed] [Google Scholar]
- Pescovitz M.D., Lunney J.K., Sachs D.H. Murine anti-swine T4 and T8 monoclonal antibodies; distribution and effects on proliferative and cytotoxic T cells. J. Immunol. 1985;134:37–44. [PubMed] [Google Scholar]
- Pescovitz M.D., Sakopoulos A.G., Gaddy J.A., Hussman R.J., Zuckermann F.A. Porcine peripheral blood CD4+CD8+ dual expressing T-cells. Vet. Immunol. Immunopathol. 1994;43:53–62. doi: 10.1016/0165-2427(94)90120-1. [DOI] [PubMed] [Google Scholar]
- Rothkotter H.J., Pabst R. Lymphocyte subsets in jejunal and ileal Peyer's pathches of normal and gnotobiotic minipigs. Immunology. 1989;67:103–108. [PMC free article] [PubMed] [Google Scholar]
- Rothkotter H.J., Ulbrich H., Pabst R. The postnatal development of gut lamina propria lymphocytes: number, proliferation, and T and B cell subsets in conventional and germ-free pigs. Pediatr. Res. 1991;29:237–242. doi: 10.1203/00006450-199103000-00004. [DOI] [PubMed] [Google Scholar]
- Saalmuller A., Reddehase M.J., Buhring J.J., Jonjic S., Koszinowski U.H. Simultaneous expression of CD4 and CD8 antigens by a substantial proportion of resting porcine T lymphocytes. Eur. J. Immunol. 1987;17:1297–1301. doi: 10.1002/eji.1830170912. [DOI] [PubMed] [Google Scholar]
- Saalmuller A., Hirt W., Reddehase M.J. Phenotypic discrimination between thymic and extrathymic CD4−CD8− and CD4+CD8+ porcine T lymphocytes. Eur. J. Immunol. 1989;19:2011–2016. doi: 10.1002/eji.1830191107. [DOI] [PubMed] [Google Scholar]
- Saalmuller A., Hirt W., Reddehase M.J. Porcine γδ T lymphocyte subsets differing in their propensity to home to lymphoid tissue. Eur. J. Immunol. 1990;20:2343–2346. doi: 10.1002/eji.1830201026. [DOI] [PubMed] [Google Scholar]
- Saif L.J., Wesley R.D. Transmissible gastroenteritis. In: Leman A.D., Straw B.E., Mengeling W.L., D'Allaire S., Taylor D.J., editors. Diseases of Swine. 7th edn. Iowa State University Press; Ames: 1992. pp. 362–386. [Google Scholar]
- Saif L.J., Bohl E.H., Kohler E.M., Hughes J.H. Immune electron microscopy of transmissible gastroenteritis virus and rotavirus (reovirus-like agent) of swine. Am. J. Vet. Res. 1977;38:13–20. [PubMed] [Google Scholar]
- Sanders M.E., Makgoba M.W., Shaw S. Human naive and memory T cells: reinterpretation of helperinducer and suppressor-inducer subsets. Immunol. Today. 1988;9:195–199. doi: 10.1016/0167-5699(88)91212-1. [DOI] [PubMed] [Google Scholar]
- Simkins R.A., Weilnau P.A., Bias J., Saif L.J. Antigenic variation among transmissible gastroenteritis virus (TGEV) and porcine respiratory coronavirus strains detected with monoclonal antibodies to the S protein of TGEV. Am. J. Vet. Res. 1992;53:1253–1258. [PubMed] [Google Scholar]
- VanCott J.L., Brim T.A., Simkins R.A., Saif L.J. Isotype-specific antibody-secreting cells to transmissible gastroenteritis virus and porcine respiratory coronavirus in gut- and bronchus-associated lymphoid tissues of suckling pigs. J. Immunol. 1993;150:3990–4000. [PubMed] [Google Scholar]
- VanCott J.L., Brim T.A., Lunney J.K., Saif L.J. Contribution of antibody-secreting cells induced in mucosal lymphoid tissues of pigs inoculated with respiratory or enteric strains of coronavirus to immunity against enteric coronavirus challenge. J. Immunol. 1994;152:3980–3990. [PubMed] [Google Scholar]
- Van Nieuwstadt A.P., Boonstra J. Comparison of the antibody response to transmissible gastroenteritis virus and porcine respiratory coronavirus, using monoclonal antibodies to antigenic sites A and X of the S glycoprotein. Am. J. Vet. Res. 1992;53:184–190. [PubMed] [Google Scholar]
- Van Nieuwstadt A.P., Zetstra T., Boonstra J. Infection with porcine respiratory coronavirus does not fully protect pigs against intestinal transmissible gastroenteritis virus. Vet. Rec. 1989;125:58–60. doi: 10.1136/vr.125.3.58. [DOI] [PubMed] [Google Scholar]
- Welch S.K.W., Saif L.J., Ram S. Cell-mediated immune responses of suckling pigs inoculated with attenuated or virulent transmissible gastroenteritis virus. Am. J. Vet. Res. 1988;49:1228–1234. [PubMed] [Google Scholar]
- Wesley R.D., Woods R.D. Active and passive immunity to transmissible gastroenteritis virus induced by porcine respiratory coronavirus. Proceedings II of the 12th Congress of the International Pig Veterinary Society; 17–20 August 1992, The Hague, The Netherlands; 1992. p. 95. [Google Scholar]
- Wesley R.D., Woods R.D., Hill H.T., Biwer J.D. Evidence for a porcine respiratory coronavirus, antigenically similar to transmissible gastroenteritis virus, in the United States. J. Vet. Diagn. Invest. 1990;2:312–317. doi: 10.1177/104063879000200411. [DOI] [PubMed] [Google Scholar]
- Wilson A.D., Stokes C.R., Bourne F.J. Responses of intraepithelial lymphocytes to T-cell mitogens: a comparison between murine and porcine responses. Immunology. 1986;58:621–625. [PMC free article] [PubMed] [Google Scholar]
- Zeitz M., Quinn T.C., Graeff A.S., James S.P. Mucosal T cells provide helper function but do not proliferate when stimulated by specific antigen in lymphogranuloma venereum proctitis in nonhuman primates. Gastroenterology. 1988;94:353–366. doi: 10.1016/0016-5085(88)90422-2. [DOI] [PubMed] [Google Scholar]