title: Long-term treatment of pigs with low doses of monoclonal antibodies against porcine CD4 and CD8 antigens.
abstract: In vivo depletion of lymphocyte subsets allows investigation of the role of specific subsets in protective immunity. In the present study we evaluated the effects of long-term, low-dose treatment with murine monoclonal antibodies (mAbs) against porcine CD4 and CD8 surface antigens on lymphocyte subsets in pigs. Four-week-old pigs were treated by intramuscular injections of hybridoma cell culture supernatants containing anti-CD mAbs twice a week for a period of 5 weeks. The immunomodulatory effects of the treatments were assessed by flow cytometry (FCM) analysis of peripheral blood lymphocytes. Treatment with the anti-CD4 mAb almost completely eliminated the CD4(+) T-cell subset from the circulation after 2 weeks of therapy. This depletion persisted until the end of the experimental period 5 weeks after initiated therapy. Treatment with the anti-CD8 mAb was less effective, reducing the CD8(+) T-cell subset in peripheral blood by approximately 50% of the initial level after 3 weeks of therapy. Further, the anti-CD8 mAb-treated pigs showed a parallel increase in the CD4(+) T-cell subset from day 7. Two-colour FCM analysis indicated that a shift in phenotype from single-positive CD4(+)/CD8(-) to double-positive CD4(+)/CD8(+) T-cells might have occurred in these pigs. In the present experiment we demonstrated specific modulation of the peripheral blood T-lymphocyte population in pigs with continuous low-dose injections of specific mAb. The ability to modulate individual T-cell subsets should provide a method to elucidate their functionality in protection against infectious disease.
authors.affiliation: Danish Institute for Food and Veterinary Research, Kalvehave, Denmark.
authors.forename: Louise
authors.initials: L
authors.lastname: Lohse
authors.forename: Jens
authors.initials: J
authors.lastname: Nielsen
authors.forename: Lis
authors.initials: L
authors.lastname: Eriksen
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D015704:CD4 Antigens / Q000032:analysis / Q000276:immunology; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D016827:CD8 Antigens / Q000032:analysis / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D007273:Injections, Intramuscular; D008212:Lymphocyte Depletion / Q000379:methods*; D013552:Swine / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D016827:CD8 Antigens