IBDV immune-complex vaccines are considered to be an intelligent tool in the prevention of Gumboro disease. These vaccines do not just offer the efficacy of a live virus (without being neutralized by maternally derived antibodies), but their onset of immunity is adapted to the protective needs of each individual chick, which avoids the feared immunity gap that can happen when other types of vaccines are used¹.

Immune-complex vaccines against IBDV are formulated on the basis of adding specific IBDV antibodies (IgY) that coat the vaccine virus. From the first immune-complex vaccines developed in the 1990s until now, all available commercial immune-complex vaccines have used specific IgY extracted from the serum of hyperimmunized animals as coating antibodies (Figure 1).

A newly formulated immune-complex vaccine has now appeared on the market (GUMBOHATCH®) which uses specific IBDV IgY extracted from eggs instead of the now familiar IgY from serum.

But what are the main advantages behind this new formulation?

A new procedure for extracting the IgY from eggs has been developed in order to improve the consistency and capacity for production of the highest quality antibodies.

The extraction of antibodies from egg yolks has many advantages compared to extraction from the serum. Since the antibodies are extracted from the yolks of laid eggs, the method of antibody production is non-invasive. Besides, through appropriate immunization strategies, the concentration of antibodies in the egg yolk can be maintained at optimal levels over time.

This process, therefore, prevents the animals from bleeding and stress whilst it allows the harvest of large amounts of antibodies.

The possibility of obtaining large quantities of IgY through extraction from eggs has changed the way of formulating immune-complex vaccines, giving the possibility of adding high proportions of IgY to ensure a complete coating of all the virus particles.

REFERENCES:

¹Gelb et al. 2016. Avian Diseases 60 (3), 603-612.

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