CHARACTERIZATION OF THE PRIMARY LOCAL AND SYSTEMIC IMMUNE-RESPONSE INGNOTOBIOTIC LAMBS AGAINST ROTAVIRUS INFECTION

This study characterised the primary immune response in gnotobiotic la mbs after infection with a lamb rotavirus (RV). Lambs were infected an d killed over a 7 week period together with controls. RV-ELISA and neu tralising antibodies were determined in serum, nasal secretions, and i ntestinal scrapings. RV-antibody secreting cells (ASC) were enumerated in blood. Lymphocyte proliferations were determined in blood and gut- associated lymphoid tissues and cytokine expression was analysed in je junal Peyer's patches (JPPs) and mesenteric lymph nodes (MLNs). Infect ed lambs cleared the virus by 8-9 days after infection without showing any clinical signs. The first indication of a specific immune respons e to RV was an increased expression of IL-4 mRNA in the JPPs in the in fected group compared to the control group 3 days after infection. Rot avirus-specific IgA ASC in blood and IgA antibodies in serum and nasal secretions were detected from 7 days after infection followed at 10 d ays after infection by RV-specific IgG ASC and antibodies. Rotavirus-s pecific IgA antibodies were not detected in intestinal scrapings in th e first 10 days after infection, but were detected by 52 days after in fection. No RV-specific neutralising antibodies were seen in the intes tine during the course of the experiment. (C) 1998 Elsevier Science B. V. All rights reserved.