Coccoid like forms (CLF) of Helicobacter pylori. Enzyme activity and antigenicity.

In this study we attempted to transform "helical" forms of Helicobacter pylori to "coccoid like forms" (CLF) by induction with the following substances in vitro: bismuth subcitrate, bismuth subsalicylate, ampicillin, amoxicillin, erythromycin, ursodeoxycholic acid and glycochenodeoxycholic acid. Some liquid cultures were incubated for 24 days to induce CLF by aging. Changes in the protein pattern, urease enzyme activity and in the serological response against specific antigens were investigated. In all strains a significant but strain-variable rate of CLF was detected by induction of the tested substances. Beta-lactams and erythromycin generated a population of nearly 100% CLF, including many "spheroblasts". Relative induction rates by these substances were in the following order: beta-lactams and erythromycin > bismuth subcitrate > bismuth subsalicylate > bile acids. Strain variable reaction also was true for both inhibition of urease activity and influence on immunological response. Urease activity was lost in CLF induced by aging and was inhibited by bismuth salts. CLF induced by aging showed a loss of reactivity bands in the immunoblot. They always lost a 160 kD band and depending on the strain, 115 kD, 108 kD, 100 kD and 95 kD bands. Immunological response to the 120 kD band was reduced. Ultrastructural studies showed great degenerative changes of the cell wall in CLF induced by antibiotics but only few in CLF induced by bismuth salts and bile acids.