IMMUNOCHEMICAL LOCALIZATION OF CAMP FACTOR (PROTEIN-B) IN STREPTOCOCCUS-AGALACTIAE

Biochemical and immunochemical investigations were used in order to st udy the quantitative and qualitative localization of CAMP factor (prot ein B) in the cell fractions of Streptococcus agalactiae during the lo garithmic growth phase. The dynamic quantitative distribution of CAMP factor activity showed that higher concentrations of CAMP factor were found in the cytoplasm than in the cell envelopes. A maximal intracell ular accumulation of CAMP factor activity was observed in the late log phase. Immunoblotting analysis using specific anti-CAMP-IgG showed th at CAMP factor could be detected in the different cell fractions of S. agalactiae. During the early log phase, CAMP factor was present as a single 25 kD protein band in the cytoplasm, while it was found togethe r with its 26 and 24 kD satellite proteins in the cytoplasmic membrane and the cell wail as well as in all the cell fractions in the mid- an d late log phases. Intracellular CAMP factor exhibited the same antige nic and amphiphilic behaviour as the extracellular species. Additional ly, a newly discovered amphiphilic protein of similar to 54 kD which e xhibited similar antigenicity with the CAMP factor was present in all the cell fractions. immunoelectron microscopic examinations using ferr itin-labelled antibodies revealed that CAMP factor was mainly found in the cytoplasm, whereas it was associated to a minor extent with the c ell envelopes. Interestingly, an accumulation of CAMP factor was also localized either at the sites of cross-wall initiation or at the cell surfaces where the cell wall became autolysed.