THE CYTOKINE RESPONSE OF AFFERENT LYMPH FOLLOWING ORF VIRUS REINFECTION OF SHEEP

The in vivo dynamics of differentiated cells and interleukin (IL)-1 be ta, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF) an d interferon (IFN)-gamma titres in afferent lymph were compared follow ing orf virus reinfection and inactivated virus injection of previousl y infected sheep. The biphasic lymphoblast and cytokine response in th e lymph to virus reinfection is consistent with a response initially t o orf virus as recall antigen followed by a response to viral replicat ion. CD4 T cells increased in output over other cell types in the lymp h in both groups. A rapid immune/inflammatory response was detected in lymph plasma as an increase in cytokine titres within 24 h of virus r einfection or injection. Lymph cells producing IL-I beta and IL-8 appe ared prior to those producing GM-CSF in both groups. In spite of varia tions in the concentration of individual cytokines in lymph following reinfection, both the size of the orf lesion and the time to resolve w ere similar in all cases.