Question - GAVI is very interested in funding projects that provide novel delivery mechanisms for vaccines. Dr. Bimmel has always wanted to find a way to make a vaccine for S. pneumoniae that targets all of the serotypes! This may be her opportunity! Her goal is one vaccine that would be completely protective against all strains of S. pneumoniae. She has an idea to make an edible vaccine that would contain the antigen derived from S. pneumoniae. Dr. Bimmel decides to try using yogurt as the delivery mechanism! She wants to clone a gene from S. pneumoniae that encodes an antigen and to express this gene in a microorganism that would grow in yogurt. Eating the yogurt would serve as the vaccine delivery. Consider the various molecules expressed by S. pneumoniae.

1. What is/are the immunogenic compounds of the current pneumococcal vaccines?

2. Choose one molecule that would be an appropriate choice to serve as the antigen for Dr. Bimmel's vaccine preparation. What molecule have you chosen? What is the gene or genes needed to make that product?

3. Explain how your choice would allow an immunized person protection from all strains of S. pneumoniae.

4. If your answer to (1) is not the same as (2) explain why that is. Describe any advantages your choice from (2) has over (1).