Lavelle Hanna

Inhibition of TRIC agents by virus-induced interferon.

The causative agents of trachoma and inclusion conjunctivitis (TRIC) have been called viruses in the past. However, TRIC agents possess several characteristics which clearly separate them from typical viruses. They possess a bacteria-like cell wall containing muramic acid; they contain both DNA and RNA; they elaborate enzymes involved in decarboxylation of carbohydrates and in folic acid synthesis; they are inhibited by antibacterial drugs; and at least some stages in the development of TRIC agents involve binary fission(l). Thus it appears that TRIC agents are more closely related to obligate intracellular bacteria or rickettsiae than to true viruses. Up to the present time, interferons have been known to act only on true viruses. It was, therefore, of interest to determine whether virus-induced interferons would inhibit the replication of the more complex TRIC agents. Early in this work we were made aware of a publication by Mordhorst and Reinecke(2) in which it was claimed that interferon had no effect on TRIC agents, We wish to report here experiments which establish the inhibition of a TRIC agent by virus-induced mouse interferon in L cells. Materials and methods. Interferon. Mouse interferon for these experiments was prepared by infecting strain L 929 cells, obtained from Dr. J. Youngner, with Newcastle disease virus (NDV) (E4 Herts strain) at a multiplicity of 1.5 pfu/cell (plaque forming units) as measured on chick embryo fibroblasts. The L cells were grown in one liter Blake bottles in a 5% CO2 incubator at 37°C, using a growth medium of 10% calf serum in Eagles Minimum Essential Medium (MEM) containing penicillin, streptomycin and myco-statin. Following infection, the cells were maintained on serum free MEM + antibiotics. Supernatants were collected 24 hours after infection.

Elementary-Body Virus isolated from Clinical Trachoma in California.

From an adult white resident of California with clinically typical early trachoma a virus was isolated by growth in embryonated eggs. Morphologically and serologically the virus belongs in the psittacosis-lymphogranuloma group. When it is instilled into monkey eyes it produces acute follicular conjunctivitis with typical inclusion bodies.

Antibodies to APC Virus Type 8 in Epidemic Keratoconjunctivitis.

Summary The sera from patients with epidemic keratoconjunctivitis (EKC) in Japan, Italy, Switzerland, and North America regularly contain neutralizing antibodies to APC virus type 8, whereas such antibodies are absent from the general population in these areas. Paired sera from patients with EKC show a significant rise in neutralizing antibodies to APC virus type 8. These antibodies persist for only a limited period after the onset of the disease. The constant association of clinical EKC and antibodies to APC virus type 8 suggests that this agent (or antigenically related virus) may play a role in the etiology of this disease.

Trachoma Viruses Isolated in United States.∗ 1. Growth in Embryonated Eggs

Summary From 6 active trachoma cases in the United States strains of“trachoma virus”have been isolated. Conjunctival scrapings suspended in broth-saline containing 1-10 μg/ml streptomycin were inoculated into yolk sac of embryonated eggs. From 1 to 6 blind passages were required for establishment of strains which subsequently reached titers of 106.3-107.4 egg LD50/ml. The essential nature of ill-defined egg“quality”for isolation of“trachoma viruses”is discussed. The isolated agents produced unequivocal eye infections in M. Cynomolgus and in a human volunteer.

Characteristics of Interferon Induced in vitro and in vivo by a TRIC Agent.

Summary A TRIG agent (LB-1), a member of the psittacosis-LGV-trachoma group, can induce the production in vivo and in vitro of a material with antiviral activity similar to virus-induced interferon. The interferon induced in cell culture by LB-1 had a molecular weight of about 50,000 and hence appeared to differ significantly from virus-induced interferon prepared in cell culture or in vivo. Addendum: The peak of TRIC-induced interferon production in serum of mice is late (6-13 hours), similar to that of virus(3), brucella(3), or statalon(lO), but distinct from the early (2 hour) peak appearing after endotoxin(4).

Trachoma viruses isolated in the United States. 4. Infectivity and immunogenicity for monkeys.

Summary Three strains of trachoma virus and one strain of inclusion conjunctivitis virus isolated in the United States gave reproducible disease upon inoculation into eyes of rhesus or cynomolgus monkeys. Among several clinical criteria follicle scores were most suitable for quantitation of eye disease, and microscopic demonstration of inclusions in conjunctival scrapings served as additional criterion of infection. Significant differences were demonstrated in the infectivity of 2 strains for the monkey eye. Repeated eye infection failed to modify the response to re-infection. Repeated parenteral administration of live virus in large quantities significantly diminished disease from subsequent challenge infection but failed to induce solid immunity.

CONTROLLED TREATMENT TRIALS OF TRACHOMA IN AMERICAN INDIAN CHILDREN

Abstract The effect of topical applications of tetracycline and the administration by mouth of sulphafurazole (sulfisoxazole) was compared, in a double-blind trial, with that of placebos in a group of American Indian children with chronic trachoma. In this population, bacterial conjunctivitis is uncommon and trachoma seldom leads to blindness. During the trials and for 6 months thereafter, the children lived in a boarding-school under good hygienic conditions. In both groups—the children who received treatment and those who were given placebos—the incidence of signs of active trachoma diminished greatly during the 7 months of observation. Judged by the number of positive findings of immunofluorescence of conjunctival smears, however, the persistence of the aetiological agent remained unchanged. Eye-drops of 1% tetracycline hydrochloride in oil three times daily for 6 weeks, or a suspension of sulphafurazole 4 g. daily for 3 weeks by mouth was not demonstrably superior to the administration of placebo. The good environment seemed to be the overriding beneficial influence. In any 1 year, only 10% of the general school population (many of whom had scars of old trachoma) showed signs of trachomatous activity. Some of the reported benefits of chemotherapy in areas of endemic trachoma may be attributable to control of bacterial superinfection. Additional trials are urgently needed to define the potential usefulness of chemotherapy in the control of trachoma.

Trachoma Viruses Isolated in the United States. VIII. Separation of TRIG Viruses from Related Agents by Immunofluorescence.

Summary Yolk sacs infected with trachoma, inclusion conjunctivitis, lymphogranuloma venereum, psittacosis 6BC or meningopneumonitis were extracted repeatedly with fluorocarbon. The resulting suspension of elementary bodies contained little egg material. The particles were distinct, and reacted with strain-specific rabbit antisera as measured by indirect fluorescence. The homologous antiserum usually yielded the highest titer; heterologous antisera showed equal, intermediate or no reaction; antisera to normal yolk sac were negative. Psittacosis 6BC and meningopneumonitis could be separated easily from TRIG agents. LGV, an IC isolate, and BOUR, a trachoma isolate, showed much cross-reaction, but BOUR could be differentiated regularly from another trachoma isolate (ASGH).

TRIC Agents Isolated in the United States. X. Immunofluorescence in the Diagnosis of TRIC Agent Infection in Man.

Summary Conjunctival scrapings from volunteers experimentally infected with TRIC agents and from patients with spontaneous eye disease were examined by immunofluorescence. Brightly fluorescing inclusions were demonstrated with hyperimmune TRIC anti-sera. The findings were compared with those obtained by Giemsa stain, iodine stain or isolation of the infectious agent in embryonated eggs. Immunofluorescence appears to offer an improved method for laboratory diagnosis of TRIC infections.

Virus Isolated from Inclusion Conjunctivitis of Newborn (Inclusion Blennorrhea)

An infant developed acute conjunctivitis 7 days after birth. Smears of the mucopurulent discharge contained many typical elementary-body inclusions. From conjunctival scrapings a virus resembling trachoma was grown in eggs. When instilled into monkey eyes, it produced an acute conjuctivitis resembling the human disease. Nine other patients with inclusion conjunctivitis of similar intensity failed to yield viruses.