Increasing effect of high dose of PG-1 peptide on the infectivity of different animal species of Chlamydia.

The modification of infectivity of different animal chlamydial species after their in vitro treatment with 10 and 80 µg/ml of PG-1 peptide, was studied. PG-1 at 10 µg/ml concentration had neither inhibitory nor increasing effects on the infectivity of all Chlamydia tested, whereas the incubation of 80 µg/ml of PG-1 with C. suis and Cp. pecorum isolates resulted in a twofold increase in the number of inclusions; a five- to tenfold increase in chlamydial infectivity was observed when Cp. psittaci and Cp. abortus strains were tested with the concentration of 80 µg/ml of PG-1 peptide. On the contrary, C. muridarum strain and Cp.felis isolates did not show any increase in the number of inclusions when incubated with PG-1 at a 80 µg/ml concentration. The different effect of PG-1 on the animals strains of chlamydiae could be due to the unique characteristics in the membrane structure of each strain.