Homotypic and heterotypic serum and milk antibody to rotavirus in normal, infected and vaccinated horses

Abstract

The homotypic and heterotypic antibody response to rotavirus was determined in three pony mares and their foals. The normal concentrations of anti-rotavirus antibodies in mares' milk and mares' and foals' serum over the first 10 weeks post-partum were measured using IgA, IgG and rotavirus serotype-specific enzyme linked immunosorbent assays. Experimental infection of the foals with serotype 3 equine rotavirus produced a rapid, serotype-specific response which peaked 10 days after infection and a slower heterotypic response which peaked 32 days later. In contrast, vaccination of the mares with an inactivated, adjuvanted serotype 6 bovine rotavirus produced a heterotypic response similar to that of the homotypic response in both serum and milk, although the predominant response in serum was IgG, while in milk it was IgA. These results suggest that non serotype-restricted passive protection of foals against rotavirus may be achieved by parenteral vaccination of mares.

Antibody response in vaccinated pregnant mares to recent G3BP[12] and G14P[12] equine rotaviruses

“…In contrast, the geometric mean antibody titers to the G14P[12] viruses were lower than that to the homologous virus, although they were 3.0- to 3.5-fold increased after vaccination. Browning et al have reported that mares immunized with a single-type (G6) inactivated bovine rotavirus vaccine develop antibodies in the serum and milk not only to the G6 type but also to the G2 and the G3 type [26]. Such a heterotypic response has been also reported in adult cows [27,28].…”

Equine rotaviruses—Current understanding and continuing challenges

“…An ideal rotavirus vaccine would provide heterotypic immunity against a wide variety of rotavirus serotypes. Experimental studies on specific pathogen free foals infected with G3 rotavirus at 10 weeks of age found that although a serotype specific antibody response was detectable at day 6 after infection, a heterotypic response peaked later, at 32 days after infection (Browning et al, 1991b). This suggests that, while heterotypic immunity is possible with a monovalent vaccine, it is likely to be delayed in onset compared to homotypic immunity.…”

“…Currently, there is a multivalent vaccine available that aims to induce heterotypic immunity, however, of all the G genotypes in group A rotaviruses, the two G types most prevalent in horses, G3 and G14, are also the most genetically similar (Browning et al, 1991d), which raises questions about the benefit of using a multivalent vaccine in horses. Furthermore, studies on vaccination of dams with monovalent inactivated rotavirus vaccines have shown that the response generated is typically panserotypic, generating neutralising antibodies against rotavirus serotypes that are unlikely to have infected the dam previously (Browning et al, 1991b;.…”