Chapter 22, Problem 4PDQ

One of the major causes of sickness, death, and economic loss in the cattle industry is Mannheimia haemolytiea, which causes bovine pasteurellosis, or shipping fever. Non invasive 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. haemolytiea to stimulate development of specific antibodies in rabbits.

* 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.

1. (a) What general conclusion can you draw from the data?
2. (b) With regards to development of a usable edible vaccine, what work remains to be done?