ISOLATION OF TRACHOMA AND INCLUSION CONJUNCTIVITIS VIRUSES IN THE UNITED STATES*

Demonstration of complement-fixation titres against the speciesspecific trachoma antigen in sera of trachoma patients

Semi-purified elementary body suspensions, prepared or preserved in three different ways, have been compared as to their species-specific CF-activity as revealed both against Bedsonia-negative sera of trachoma patients (of known stage), and against psittacosis-positive sera of men and animals.

Two of these antigens (the SPG-formol-antigen and the SPG-glycerol-antigen) revealed a positive species-specific CF-reaction in 61–100% of the Bedsonia-negative serum samples obtained from trachoma patients, with titres ranging from 1/2 to 1/128.

Various parameters (as percentage proportion of positive reactors, CF-titre, duration of the disease, clinical stage of trachoma, etc.) have been analysed for correlation, and the results obtained with the different antigens are compared with one another.

The most useful of the three antigens, showing a good species-specific CF-reactivity and no anticomplementary activity, was found to be the ‘SPG-formolantigen’. However because of its group-specific reactivity, for detection of species-specific trachoma antibodies in routine, it could be used only with Bedsonia-negative samples of sera. Because of the thermolability of its species-specific component, the SPG-formol-antigen proved to be liable to deterioration.

We have pleasure in thanking to Dr F. B. Gordon for help in procuring bibliography and the viable strain of trachoma virus. We wish to express our thanks also to Mrs R. Šepetavic and to Miss M. Krečo for their technical assistance.

Long-term clinical, microbiological, and immunological observations of a volunteer repeatedly infected with Chlamydia trachomatis

A blind volunteer was inoculated in one eye with an isolate of Chlamydia trachomatis in 1961 and followed for 20 years. During this time, many observations were made of his clinical responses to the first inoculation and several subsequent inoculations with the same and other strains, chlamydial shedding, and antibody and cell-mediated immune responses. Evidence is presented that partial resistance to chlamydial eye infection developed during repeated infections and that antibodies, cell-mediated immune reactions, and specific antigen in conjunctival cells persisted for many years after the last infection. The antibody response was directed mainly against the original infecting immunotype, regardless of whether the response was restimulated by infection with the same immunotype or with other immunotypes. The lymphocyte stimulation response appeared to be species specific.

Survival of chlamydiae after cooling to -196 degrees C

Factors influencing the survival of chlamydiae after freezing were reexamined. From the data presented, it is suggested that preservation of laboratory-grown chlamydiae is best achieved through the use of sucrose as the cryoprotective agent, in the presence of 10% serum. Dimethyl sulfoxide and glycerol are more toxic. The period of exposure to sucrose before freezing must be kept as short as possible and be at 4 degrees C rather than at room temperature. The rate of cooling during freezing in sucrose is not important; however, cooling at a rate slower than 1 degrees C/min should be avoided. Since chlamydial survival is increased by rapid thawing, the volume of the sample should be kept to a minimum. Thawed suspensions should be inoculated onto cell monolayers without delay. The application of these methods may increase the proportion of stored clinical specimens in which chlamydiae can be found.