Purification on renografin density gradients of Chlamydia trachomatis grown in the yolk sac of eggs.

Chlamydia trachomatis grown in the yolk sac of embryonated eggs was purified by centrifugation on continuous isopycnic Renografin density gradients. A band of chlamydial particles with a buoyant density of 1.20 contained 70% of the starting particles, and electron microscopy revealed the virtual absence of contaminating egg material. Centrifugation on Renografin gradients caused only a moderate decrease in infectivity. For large-scale purification, infected yolk sac was centrifuged through Renografin solutions, resulting in greater than 60% recovery of starting chlamydial particles, but less than 1% recovery of the dry weight and protein.