Klebsiella pneumoniae 35 and 36 kDa porins are common antigens in different serotypes and induce opsonizing antibodies

Background. Klebsiella pneumoniae is a major cause of neonatal sepsis and nosocomial infections in Mexico. Antibiotic therapy is the first choice for treatment hut the increase in multiple resistance strains has forced scientists to look for alternative treatments. such as immunotherapy. In this work, we propose that pol ins could be a common antigen among four different capsular serotypes of Klebsiella pneumoniae for the production of immune sera with opsonizing capacity. Methods. The 35 and 36 kDa porins from four different serotypes of the bacteria were isolated by the Nikaido method followed by purification in Sephacryl column chromatography. The 36 kDa of serotype K8 was further purified by electroelution. The 35 and 36 kDa porins were used to obtain rabbit polyclonal antibodies (PolyAb) to the four serotypes and the 36 kDa from KS for the production of monoclonal antibodies (MoAb). Antigenic reactivity of PolyAb and MoAb were analyzed by ELISA and WB and their opsonizing capacity for human PMN was measured by chemiluminescence (CL) using capsulated and noncapsulated bacteria. Results. Porins from the four strains showed electrophoretic homology and cross reaction by ELISA and WE. CL assays indicated that PolyAb opsonized heterologous strains and that MoAb perform this in the absence of capsule. Conclusions. K. pneumoniae 35 and 36 kDa porins are common antigens for the four se retypes studied and induce opsonizing antibodies. (C) 2000 IMSS. Published by Elsevier Science Inc.