Diarrhea is the third most common cause of diseases in the world. Enterotoxigenic E. coli (ETEC) is responsible for over a quarter of reported cases of diarrheal diseases. ETEC produces two toxins that are capable of inducing diarrhea in humans, heat-labile (LT) and heat-stable enterotoxins (ST). It is seen in developing countries that infections with ETEC that produce ST cause the most severe forms of diarrhea. ETEC causes 280-400 million cases of diarrhea annually and is responsible for 380,000 deaths. Having an effective vaccine against this diarrheal disease is currently a high priority.This study describes the kinetics of the immune response to a recently developed vaccine that is comprised of ST attached to the carrier bovine serum albumin. The vaccine was administered to ten rabbits. This study showed that the vaccine was able to induce significant immune response to ST in eight of the rabbits tested, and a positive neutralization of ST in seven of the ten rabbits. Binding capability was shown to increase over time. After achieving the peak, neutralization capacity, however, was not shown to increase over time at a statistically significant level. A model was constructed to predict neutralization capacity from binding data. In this study seven of ten rabbits mounted an immune response that was able to neutralize 10,000 mouse units or more, as opposed to previous studies that have only showed maximal neutralization upwards of 5,000 mouse units.
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