One of the major causes of sickness, death, and economic loss in the cattle industry is Mannheimia haemolytica, which causes bovine pasteurellosis, or shipping fever. Noninvasive delivery of a vaccine using transgenic plants expressing immunogens would reduce labor costs and trauma to livestock. An early step toward developing an edible vaccine is to determine whether an injected version of an antigen (usually a derivative of the pathogen) is capable of stimulating the development of antibodies in a test organism. The following table assesses the ability of a transgenic portion of a toxin (Lkt) of M. haemolytica to stimulate development of specific antibodies in rabbits. Immunogen Injected Antibody Production in Serum Lkt50*—saline extract + Lkt50*—column extract + Mock injection - *Lkt50 is a smaller derivative of Lkt that lacks all hydrophobic regions. indicates at least 50 percent neutralization of toxicity of Lkt; indicates no neutralization activity. Source: Modified from Lee et al. (2001). Infect. and Immunity 69:5786–5793. With regards to development of a usable edible vaccine, what work remains to be done?

Key Concepts

Transgenic Plants

Transgenic plants are genetically modified organisms that have had a foreign gene inserted into their genome. This technology allows for the expression of specific proteins, such as immunogens, which can be used in vaccine development. In the context of edible vaccines, transgenic plants can produce antigens that stimulate an immune response when consumed, potentially simplifying vaccine delivery and reducing costs.

Antibody Production

Antibody production is a crucial aspect of the immune response, where B cells produce antibodies in response to antigens. The presence of specific antibodies in serum indicates that the immune system has recognized and responded to a pathogen or its derivative. In the context of the question, assessing whether the injected antigen stimulates antibody production in test organisms is essential for evaluating the effectiveness of potential vaccines.

Edible Vaccines

Edible vaccines are a novel approach to immunization that involves delivering antigens through food, typically produced in transgenic plants. This method aims to elicit an immune response without the need for injections, making vaccination more accessible and less traumatic for livestock. However, challenges remain in ensuring that these vaccines are effective, stable, and capable of inducing a strong immune response in the target organisms.