Serological cross-reactivity between different Chlamydia-like organisms

Abstract

The serological cross-reactivity between different recently described Chlamydia-related organisms was determined. Mouse sera exhibited a strong reactivity against autologous antigen and closely related heterologous antigen but no cross-reactivity with distantly related species. These results are important to better interpret serological studies and assess the pathogenic role of these obligate intracellular bacteria.

FIG. 1.

(A) Congruence of the phylogenetic tree based on the 16S rRNA encoding gene (left panel) and the phyletic tree based on the SDI (right panel). Both trees were built by using the neighbor-joining method and were outrooted with Waddlia chondrophila. The 16S rRNA sequences were downloaded from GenBank. The accession numbers are as follows: Waddlia chondrophila, AF042496; Rhabdochlamydia crassificans, AY928092; Simkania negevensis, U68460; Neochlamydia hartmannellae, AF177275; Protochlamydia amoebophila, BX908798; Parachlamydia acanthamoebae strain Hall's coccus, AF366365; and Parachlamydia acanthamoebae strain BN9, Y07556. (B) Western blot pattern of each Chlamydia-like organisms. Each serum elicited in mice (two sera raised against each bacteria) was tested against its autologous antigen. All sera were tested at a 1/64 dilution. Lanes: A and B, Parachlamydia acanthamoebae strain BN9; C and D, Parachlamydia acanthamoebae strain Hall's coccus; E and F, Protochlamydia amoebophila; G and H, Neochlamydia hartmannellae; I and J, Waddlia chondrophila; K and L, Simkania negevensis; M and N, Rhabdochlamydia crassificans. The molecular sizes reported on the left of the figure were determined by using the Kaleidoscope prestained marker (Bio-Rad).