Fig. 2.

Intranasal immunization with MPs elicits production of pneumococcal-specific IgG to noncapsular antigens. Mice were immunized intranasally with MPs from strain T4. Using ELISA, pneumococcal-specific IgG was detected in wells coated with (A) WT T4 or (B) T4R (isogenic mutant in the capsule of T4 bacteria). The low responder mice in the MP+Adjuvant and MP groups are those that did not survive after serotype 1 challenge. These mice are highlighted in the graphs within red borders. Each dot represents one mouse. Error bars represent the standard error of the mean (SEM). *P < 0.05; **P < 0.01; ***P < 0.001.