Pneumonia caused by Streptococcus pneumoniae (Sp) remains a leading cause of serious
illness and death worldwide. Immunization with conjugated pneumococcal vaccine has
lowered the colonization rate and consequently invasive diseases by inducing serotype-
specific antibodies. However, many of the current pneumonia cases result from infection by
serotype strains not included in the vaccine. In this study, we asked if cross-protection
against lung infection by heterologous strains can be induced, and investigated the …