Fig. 1
Detection of type 2 capsular polysaccharides in S. pneumoniae. Preparations of S. pneumoniae R6 WT and S. pneumoniae D39 WT, or from D39Δcps2C and its complemented D39cps2C-rpsL version with no antiserum (control) and with type 2 antisera were viewed under oil immersion using a Nikon Eclipse TE300 microscope and a 100× objective. A positive Quellung reaction is observed when the cells appear swollen in the presence of antisera, which is indicative of the presence of type 2 capsular polysaccharides. The presence and absence of the capsule is indicated by a ‘+’ and a ‘-’, respectively. Sensitivity and resistance to pneumophages (SOCP and Dp-1) is indicated by a ‘+’ and a ‘-’, respectively