Sexually transmitted diseases

Chlamydiae represent a unique group of gram-negative organisms sharing a characteristic intracellular lifestyle. In common with other gram-negative bacteria their surface components, i.e. outer membrane constituents, play a major role in their interaction with their surroundings. Surface antigens appear to modulate the critical events of attachment, uptake, infectivity, toxicity and the host immune responses that contribute to immunity and pathogenesis. The classes of molecules which make up the chlamydial cell envelope are generally similar to those found in other gram-negative bacteria, namely phospholipid, lipid, lipopolysaccharide and protein.