Sheep were immunized against Visna/Maedi virus (VMV) gag and/or env genes via the nasopharynxassociated lymphoid tissue (NALT) and lung using polyethylenimine (PEI)–DNA complexes and modified vaccinia Ankara, and challenged with live virus via the lung. env immunization enhanced humoral responses prior to but not after VMV challenge. Systemic T cell proliferative and cytotoxic responseswere generally low, with the responses following single gag gene immunization being significantly depressed after challenge. A transient reduction in provirus load in the blood early after challenge was observed following env immunization, whilst the gag gene either alone or in combination with env resulted in significantly elevated provirus loads in lung. However, despite this, a significant reduction in lesion score was observed in animals immunized with the single gag gene at post-mortem. Inclusion of IFN- in the immunization mixture in general had no significant effects. The results thus showed that protective effects against VMV-induced lesions can be induced following respiratory immunization with the single gag gene, though this was accompanied by an increased pulmonary provirus load.
Mucosal immunization against ovine lentivirus using PEI-DNA complexes and modified vaccinia Ankara encoding the gag and/or env genes
MAZZEI, MAURIZIO;BANDECCHI, PATRIZIA;TOLARI, FRANCESCO;
2008-01-01
Abstract
Sheep were immunized against Visna/Maedi virus (VMV) gag and/or env genes via the nasopharynxassociated lymphoid tissue (NALT) and lung using polyethylenimine (PEI)–DNA complexes and modified vaccinia Ankara, and challenged with live virus via the lung. env immunization enhanced humoral responses prior to but not after VMV challenge. Systemic T cell proliferative and cytotoxic responseswere generally low, with the responses following single gag gene immunization being significantly depressed after challenge. A transient reduction in provirus load in the blood early after challenge was observed following env immunization, whilst the gag gene either alone or in combination with env resulted in significantly elevated provirus loads in lung. However, despite this, a significant reduction in lesion score was observed in animals immunized with the single gag gene at post-mortem. Inclusion of IFN- in the immunization mixture in general had no significant effects. The results thus showed that protective effects against VMV-induced lesions can be induced following respiratory immunization with the single gag gene, though this was accompanied by an increased pulmonary provirus load.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
