Epitope specificity of protective lactogenic immunity against swine transmissible gastroenteritis virus

Abstract

The epitope specificity of the protective immune response against swine transmissible gastroenteritis (TGE) has been investigated by using circulating and secretory antibodies. This study was carried out with sows vaccinated with TGEV or the antigenically related porcine respiratory coronavirus (PRCV). TGEV vaccination of sows resulted in greater lactogenic protection of suckling piglets against TGEV challenge and a higher secretory immune response than PRCV vaccination did. These differences in the immune response were conditioned by the route of antigen presentation as a result of the different tropism of each virus. Epitopes on S protein, and in particular those contained in its antigenic site A, were more immunogenic than epitopes on N and M proteins in both groups of vaccinated sows, as determined by a competitive radioimmunoassay. Minor differences in antibody response against the previously defined antigenic subsites Aa, Ab, and Ac were also detected, with subsite Ab being the most antigenic in both TGEVand PRCV-immune sows. These findings suggest that antigenic site A on S protein, involved in virus neutralization, is the immunodominant site in pregnant sows that confer lactogenic protection. They also validate, in experiments with secretory antibodies, the antigenic maps made with murine monoclonal antibodies. Therefore, this antigenic site should be considered for vaccine or diagnostic development.

Monoclonal antibodies to SARS-associated coronavirus (SARS-CoV): Identification of neutralizing and antibodies reactive to S, N, M and E viral proteins

“…The ability to detect specific proteins has proven useful for assessing protein-specific antibody responses and for developing diagnostic assays. On the basis of results from studies of other coronavirus infections in animals (Daniel and Talbot, 1990;De Diego et al, 1992;Ignjatovic and Galli, 1993;Kusters et al, 1989;Saif, 1993) and on the serum antibody response of patients with SARS (Che et al, 2003), the antibody response to SARS-CoV appears to be dominated by anti-N protein and anti-S protein antibodies. Thus, mAbs reactive to N or S proteins can be used in antibody capture assays and provide a key reagent for high-quality IgM and IgA antibody assays.…”

Immunization of pregnant gilts with PRCV induces lactogenic immunity for protection of nursing piglets from challenge with TGEV

“…Studies to measure the level of passive protection induced in sows with European PRCV isolates have yielded variable results. In studies by Paton andBrown (1990) andby De Diego et al (1992), seronegative sows were experimentally infected with either a low or high dose of PRCV, respectively. In both instances, following two oronasal exposures to PRCV, the serum and colostrum VN titers were approximately I 0-fold less than we report here following infection with the U.S. PRCV.…”

“…Since then the virus has spread by contact and by aerosol throughout much of Europe (S~tnchez et al, 1992;Cox et al, 1993). TGEV challenge studies for piglets nursing sows immunized with PRCV suggest widely varying results (Bernard et al, 1989;Paton and Brown, 1990;De Diego et al, 1992). However, field observations indicate that the incidence of TGEV has declined in European countries concomitantly with the spread of PRCV.…”

Cooperation between transmissible gastroenteritis coronavirus (TGEV) structural proteins in the in vitro induction of virus-specific antibodies

“…Protection can be provided by antibodies, without a requirement for cytotoxic responses. Newborn animals can be protected by artificial lactogenic immunity using IgG and sIgA immunoglobulin fractions from immune colostrum or serum (De Diego et al, 1992;Stone et al, 1977;Wesley et al, 1988). Therefore, it is of interest to identify immunogenic structures formed by viral components which elicit strong antibody immune responses.…”