Vet. Res. 34 (2003) 389-404
DOI: 10.1051/vetres:2003013

Humoral and cell-mediated immune responses of d/d histocompatible pigs against classical swine fever (CSF) virus

Laurence Piriou^a, Sylvie Chevallier^a, Evelyne Hutet^a, Bernard Charley^b, Marie-Frédérique Le Potiera^a and Emmanuel Albina<sup>c

a</sup>  Agence Française de Sécurité Sanitaire des Aliments, Unité de Virologie et Immunologie Porcines, BP 53, 22440 Ploufragan, France
^b  Institut National de la Recherche Agronomique, Virologie et Immunologie Moléculaires, 78352 Jouy-en-Josas, France
^c  Centre de Coopération Internationale en Recherche Agronomique pour le Dééveloppement, Programme Santé animale, TA 30/G, Campus International de Baillarguet, 34398 Montpellier, France

(Received 12 November 2002; accepted 10 February 2003)

Abstract
A better understanding of cell-mediated immune responses to classical swine fever virus (CSFV) is essential for the future development of improved vaccines. We analyzed the generation of cell-mediated and humoral immune responses in d/d histocompatible pigs following CSFV infection or vaccination. Viral infection induced high T cell responses with high primary and secondary CTL activity correlated with high IFN- production, whereas vaccination with a live vaccine followed by infection mainly induced neutralizing antibody but low cell-mediated responses. Moreover, high IgG1 response was associated with high IFN-g response following infection whereas a weak IFN- response was related to a good IgG2 response but a low IgG1 production. These data could reflect Th1/Th2-like balance of immune responses depending upon immunization protocols, which has not yet been described in the pig. T-cell responses to CSFV were evidenced by CSFV-specific CD25 upregulation on CD4 ^-CD8 ⁺, but not on CD4 ⁺CD8 ^- cells, which further illustrated the importance of CTL responses after infection. Our results indicated that generation of cell-mediated immune responses was much higher following intranasal/oral CSFV infection than after intramuscular vaccination, which implies that the capacity of new CSFV vaccines to induce higher T-cell responses should be considered.

Key words: immunity / cytotoxicity / CSFV / d/ d histocompatible pig

Correspondence and reprints: Marie-Frédérique Le Potiera Tel.: (33) 02 96 01 62 90; fax: (33) 02 96 01 62 94;
    e-mail: mf.lepotier@ploufragan.afssa.fr

© INRA, EDP Sciences 2003