Long-term treatment of pigs with low doses of monoclonal antibodies against porcine CD4 and CD8 antigens
Abstract:Lohse L, Nielsen J, Eriksen L. Long-term treatment of pigs with low doses of monoclonal antibodies against porcine CD4 and CD8 antigens. APMIS 2006;114:23–31.
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.