Morphology and immunotyping of AC-43 strain of Chlamydia pneumoniae isolated from a Japanese child]

A strain of Chlamydia pneumoniae (C. pneumoniae) which had been isolated from a Japanese child (AC-43) was examined morphologically and serologically using micro-immunofluorescent (micro-IF) test. Inclusions of AC-43 were stained by an indirect immunofluorescent method using C. pneumoniae specific monoclonal antibody. They were dense round inclusions which had been reported as a characteristic figure for C. pneumoniae. An elementary body (EB) of AC-43 was pear-shaped by electron micrograph, which was the same as previous reports for C. pneumoniae. We produced monoclonal antibodies using purified EB of AC-43 as antigen. Culture fluids of these clones reacted with C. pneumoniae antigens, but did not react with C. trachomatis or C. psittaci antigens by micro-IF tests. There was no difference in morphological and serological findings among standard strains and Japanese isolate of C. pneumoniae.