Systematic and intestinal antibody-secreting cell responses and correlates of protective immunity to human rotavirus in a gnotobiotic pig model of disease

Abstract

Neonatal gnotobiotic pigs orally inoculated with virulent (intestinal-suspension) Wa strain human rotavirus (which mimics human natural infection) developed diarrhea, and most pigs which recovered (87% protection rate) were immune to disease upon homologous virulent virus challenge at postinoculation day (PID) 21. Pigs inoculated with cell culture-attenuated Wa rotavirus (which mimics live oral vaccines) developed subclinical infections and seroconverted but were only partially protected against challenge (33% protection rate). Isotypespecific antibody-secreting cells (ASC) were enumerated at selected PID in intestinal (duodenal and ileal lamina propria and mesenteric lymph node [MLN]) and systemic (spleen and blood) lymphoid tissues by using enzyme-linked immunospot assays. At challenge (PID 21), the numbers of virus-specific immunoglobulin A (IgA) ASC, but not IgG ASC, in intestines and blood were significantly greater in virulent-Wa rotavirusinoculated pigs than in attenuated-Wa rotavirus-inoculated pigs and were correlated (correlation coefficients: for duodenum and ileum, 0.9; for MLN, 0.8; for blood, 0.6) with the degree of protection induced. After challenge, the numbers of IgA and IgG virus-specific ASC and serum-neutralizing antibodies increased significantly in the attenuated-Wa rotavirus-inoculated pigs but not in the virulent-Wa rotavirus-inoculated pigs (except in the spleen and except for IgA ASC in the duodenum). The transient appearance of IgA ASC in the blood mirrored the IgA ASC responses in the gut, albeit at a lower level, suggesting that IgA ASC in the blood of humans could serve as an indicator for IgA ASC responses in the intestine after rotavirus infection. To our knowledge, this is the first report to study and identify intestinal IgA ASC as a correlate of protective active immunity in an animal model of human-rotavirus-induced disease. . † Approved as Ohio Agricultural Research and Development Center manuscript 179-95. 3076 YUAN ET AL. J. VIROL. 3080 YUAN ET AL. J. VIROL.

Modulation by colostrum-acquired maternal antibodies of systemic and mucosal antibody responses to rotavirus in calves experimentally challenged with bovine rotavirus

“…Intestinal tissues were initially digested with dithiotreithol (GIBCO, BRL, Grand Island, NY, USA) and collagenase type II (Sigma Chemical Co., St Louis, MO, USA). MNC suspensions were obtained by centrifugation through 30% Percoll (Amersham Pharmacia Biotech, Upsala, Sweden) followed by 43 and 70% density gradients of Percoll as previously described for pig tissues (Yuan et al, 1996).…”

“…An ELISPOT assay for quantification of anti-BRV IgM, IgA, IgG1 and IgG2 ASC was used to evaluate effector B-cell responses in the inoculated calves. The assay was adapted from that conducted in pigs Yuan et al, 1996). Briefly, IND BRV infected MA-104 cells in 96-well plates were fixed with 70% acetone, air dried, and stored at À20 8C until used.…”

“…However, the magnitude and distribution of antibody secreting cells (ASC) involved in the development of systemic and mucosal antibody-mediated immunity in the presence of passive maternal Abs, have not been evaluated in cattle. Studies conducted in mice and CD gnotobiotic pigs indicate that after rotavirus infection, anti-RV ASC are mainly located in the intestinal lamina propria and mesenteric lymph nodes, with very few ASC present in spleen and blood (Blutt et al, 2002;Hodgins et al, 1999;Yuan et al, 1996). Additionally, studies of passive protection in gnotobiotic and conventional pigs show that high titers of passive circulating or colostrally acquired maternal antibodies confer high protection rates against rotavirus infection and disease Ward et al, 1996).…”

The porcine innate immune system: An update

“…As of the writing of this review, over 500 papers have been published using gnotobiotic piglets. Gnotobiotic pigs allow researchers to study many enteric diseases which affect humans and pigs such as rotavirus (Yuan et al, 1996), Cryptosporidium parvum (Widmer et al, 2000), disseminated candidiasis (Andrutis et al, 2000), entero-hemorragic E. coli (Brady et al, 2011), S. Typhimurium (Martins et al, 2013a,b;Meurens et al, 2009) and acute gastritis from Shigella dysenteriae Type I (Jeong et al, 2010). The gastro-intestinal tract of germ-free piglets colonized with human fecal microbiome better approximate the human gastro-intestinal tract than the mouse gastro-intestinal tract (Che et al, 2009;Zhang et al, 2013b).…”

Evidence for a common mucosal immune system in the pig

“…Gnotobiotic pigs have altered intestinal structure (reduced villous length and increased crypt depth) and proinflammatory cytokine gene expression relative to conventionally reared piglets (Shirkey et al, 2006). These piglets show signs of clinical disease and pathology to Human Rotavirus (HRV) making them a valuable animal model in which to study the mucosal and systemic immune responses to rotavirus (Azevedo et al, 2010;Gonzalez et al, 2004;Iosef et al, 2002;Saif et al, 2003;Ward et al, 1996;Yuan et al, 2005Yuan et al, , 1998Yuan et al, , 1996.…”