A group of researchers have isolated a new pathogenic bacterium Q from lungs and lymph nodes of cystic fibrosis patients that produces an unusual polysaccharide capsule, called QPS. They can see QPS on the surfaces of the bacteria in electron micrographs from fresh isolates (i.e., bacteria just obtained from patients). In addition to the capsule, bacterium Q produces a protease, called QP, which the researchers believe is responsible for degrading host sIgA.
A. The researchers propose that QPS and QP might make good targets for vaccine development against bacterium Q. What led the researchers to propose this?
B. What potential problems could the researchers have in using QPS as a vaccine?
C. How are QP antigens presented to immune cells?
D. The researchers found that the QPS vaccine does not elicit a long-lasting immune response. How does QPS elicit an immune response? What vaccine strategy could be used to generate longlasting immunity targeting QPS?
E. The researchers believe that they can develop an oral vaccine that will be effective against lung infections with bacterium Q using QP as a vaccine component. What specific experimental evidence supports their rationale for using this proposed approach?
F. If QP were used as a vaccine, what immune response would be primarily responsible for controlling lung infection caused by bacterium Q?