Development of nasal, fecal and serum isotype-specific antibodies in calves challenged with bovine coronavirus or rotavirus

Abstract

Unsuckled specific pathogen free calves were inoculated at 3-4 weeks of age, either intranasally (IN) or orally (O) with bovine coronavirus or O plus IN (O/IN) or O with bovine rotavirus. Shedding of virus in nasal or fecal samples, and virus-infected nasal epithelial cells were detected using immunofluorescent staining (IF), ELISA or immune electron microscopy (IEM). Isotype-specific antibody titers in sera, nasal and fecal samples were determined by ELISA. Calves inoculated with coronavirus shed virus in feces and virus was detected in nasal epithelial cells. Nasal shedding persisted longer in IN-inoculated calves than in O-inoculated calves and longer than fecal shedding in both IN and O-inoculated calves. Diarrhea occurred in all calves, but there were no signs of respiratory disease. Calves inoculated with rotavirus had similar patterns of diarrhea and fecal shedding, but generally of shorter duration than in coronavirus-inoculated calves. No nasal shedding of rotavirus was detected. Peak IgM antibody responses, in most calves, were detected in fecal and nasal speciments at 7-10 days post-exposure (DPE), preceeding peak IgA responses which occurred at 10-14 DPE. The nasal antibody responses occurred in all virus-inoculated calves even in the absence of nasal shedding of virus in rotavirus-inoculated calves. Calves inoculated with coronavirus had higher titers of IgM and IgA antibodies in fecal and nasal samples than rotavirus-inoculated calves. In most inoculated calves, maximal titers of IgM or IgA antibodies correlated with the cessation of fecal or nasal virus shedding. A similar sequence of appearance of IgM and IgA antibodies occurred in serum, but IgA antibodies persisted for a shorter period than in fecal or nasal samples. Serum IgG1 antibody responses generally preceeded IgG2 responses and were predominant in most calves after 14-21 DPE.

Capture ELISA systems for the detection of bovine coronavirus-specific IgA and IgM antibodies in milk and serum

“…It is evident that the IgA response to BCV was detectable for a much longer period of time than the IgM response in all 10 cattle in this study. Serum IgA responses in calves experimentally infected with BCV (Saif, 1987) were much shorter than in our study, as expected from the detection in indirect ELISA. In our study, in contrast to other ®eld studies (Heckert et al, 1991c), we were able to ®nd seronegative cattle that became naturally infected, which facilitates the evaluation.…”

“…BCV-speci®c IgA and IgM were detected by indirect ELISAs in serum and mucosal secretions from calves (Saif, 1987;Heckert et al, 1991a, b, c). In an indirect system, however, where antigen is bound to the solid phase, detection and quanti®cation of speci®c antibodies in classes that occur at low levels, like IgA in serum, will be hampered by inter-isotype competition for binding sites mainly with IgG (Chantler and Diment, 1981;Zaane and Ijzerman, 1984).…”

Bovine Coronavirus Associated Syndromes

“…Infection is primarily via feco-oral and to a lesser extent, respiratory (aerosol) routes. 20,23, [41][42][43] Bovine enteropathogenic coronavirus is shed in mucosal secretions from the upper respiratory tract and excretions from the gastrointestinal tract. [43][44][45] Bovine coronavirus is ubiquitous in the cattle population and persists in adults as subclinical infections.…”

Rotaviruses: Immunological Determinants of Protection Against Infection and Disease

“…The humoral immune response, using animals infected with homologous host rotavirus strains, has been the primary focus of a number of studies. Studies of calves, rabbits, and pigs orally inoculated with cell culture-adapted strains (Conner et al, 1991;Corthier and Vannier, 1983;Saif, 1987;Saif et al, 1992;Vonderfecht and Osburn, 1982) and mice with murine strains poorly adapted to growth in cell culture (Sheridan et al, 1983) have produced important information on the site of rotavirus-specific antibody-bearing cells (i.e., B cells and plasma cells) and the isotype and neutralization capacity of these antibodies. Within 10 days of infection, rotavirus-specific binding and neutralizing antibodies of all isotypes are detected both in the serum and in small intestinal fluids; in both sites the appearance of rotavirusspecific IgM precedes the appearance of virus-specific IgA and IgG.…”