[Method of obtaining concentrated and purified chlamydial suspensions]

A method was worked out to obtain concentrated and purified chlamydial suspensions. Used were differential centrifugation and super-centrifugation, gel filtration on sepharose, and ultracentrifugation on saccharose substrate. The new method was successfully employed in electron microscopic, immunologic, and immunofluorescence investigations. As a result of its use in electron microscopy studies were carried out on the morphology of the purified chlamydial particles in ultra thin sections and negatively contrasting preparations. Immunologic studies led to the production of high-titer hyperimmune sera from guinea pigs. Such native sera were successfully used to obtain high-titer fluorescent sera.