Differential expression of Pmp10 in cell culture infected with Chlamydia pneumoniae CWL029

The complete genome of Chlamydia pneumoniae contains a total of 21 genes en coding polymorphic membrane proteins (Pmp). From this large Pmp family thre e genes, pmp8, pmp10 and pmp11. were cloned and antibodies against recombin ant full-length Pmp proteins were produced. Indirect immunofluorescence mic roscopy of HEp-2 cells infected with C pneumoniae CWL029 was performed with the Pmp antibodies in combination with a Chlamydia-specific anti-lipopolys accharide (LPS) antibody, This double staining technique clearly showed tha t expression of Pmp10 was differential. Additional double staining with mon oclonal antibodies to the surface of C pneumoniae elementary bodies and the anti-LPS antibody resulted in identification of seven monoclonal antibodie s that reacted identically to the Pmp10 antibody indicating that Pmp10 is a n immunodominant protein. Finally, the molecular mechanism responsible for differential expression is suggested to be variation in the guanine residue s in the polyG tract of pmp10. (C) 2001 Federation of European Microbiologi cal Societies. Published by Elsevier Science B.V. All rights reserved.