Antigenic relationships among thermophilic actinomycetes

Improved medium for recovery and enumeration of the farmer's lung organism, Saccharomonospora viridis

A new medium, which we propose to call R8, was developed for the isolation and enumeration of the thermophilic actinomycete, Saccharomonospora viridis. This organism has been implicated in a range of hypersensitivity pneumonitides, including farmer's lung, but is generally isolated in small numbers from contaminated environments. Recovery of S. viridis from moldy hay and mushroom compost on R8 medium was compared with recovery on conventional media. S. viridis was isolated from both substrates but in highest numbers and most consistently on the R8 medium. The selectivity of this medium was best observed when the sedimentation chamber method was used for hay samples. Here S. viridis accounted for up to 80% of the total number of actinomycetes recovered on R8 and could not be recovered on rifampin selective medium under the same conditions. R8 was also found to be an efficient recovery medium for a range of thermophilic actinomycetes from mushroom compost and for another allergenic species, Faenia rectivirgula, from moldy hay. Contamination of isolation plates by thermophilic bacilli was reduced on R8 compared with the activity on half-strength tryptone soy agar, supplemented with 0.2% casein hydrolysate, and this, together with specific improvements in S. viridis growth, accounts for the selective effect. It is possible that the occurrence of S. viridis and its role as a causative agent of hypersensitivity pnuemonitis have been underestimated by the use of suboptimal recovery protocols. It is hoped that use of R8 in conjunction with dilution plate techniques will generate information on the ecology of S. viridis and contribute to health risk assessment studies.

Enzyme-linked immunosorbent-assay (ELISA) for IgG in bagasse workers' sera: comparison with counter-immunoelectrophoresis

An enzyme-linked immunosorbent-assay (ELISA) for the detection of antibodies against Thermoactinomyces sacchari associated with bagassosis has been described and compared with the counter-immunoelectrophoresis (CIE) assay in forty-five bagasse workers; twenty-six of whom had symptoms consistent with bagassosis, and ten who were normal blood-bank donors. The ELISA was more sensitive than CIE in detecting antibodies against the double dialysis antigen used. There was a significantly (P less than 0.05) greater number of ELISA-positive individuals (82%) than those who were precipitin positive (60%). Results of the ELISA also gave a significantly better correlation (P less than 0.05) with the clinical diagnosis (88%) than did the precipitin test results (58%). The ELISA was useful in quantitating antibodies in the sera. The symptomatic group of bagasse workers did not have significantly higher titres in the ELISA than the group of exposed but asymptomatic subjects. We conclude that the ELISA is a sensitive and specific test, which is readily available and widely applicable for the detection of immunization in bagasse workers.

Circulating IgG antibodies against fungal and actinomycete antigens in the sera of farmer's lung patients from different countries

Sixty-nine farmer's lung patients and 28 normal controls from four countries (Finland, Switzerland, Canada and the United States) were investigated for antibody levels against 13 antigens commonly used for the screening panel for hypersensitivity pneumonitis. Of these antigens, eight were from the Medical College of Wisconsin (United States) and five were from the University of Kuopio (Finland). IgG antibodies against these antigens were studied in 97 sera using a sensitive biotin-avidin-linked enzyme immunoassay. The results indicate that the mean antibody titer against Micropolyspora faeni was highest in the United States (U.S.) followed by Finland. Both Finnish and U.S. antigens reacted almost identically against various groups of patients, although the degree of reactivity varied considerably. Higher antibody levels against Thermoactinomyces vulgaris were detected in Finnish patients than patients from other countries while patients from all four countries showed elevated levels of antibodies against T. candidus. This study demonstrates that antigens from identical species, irrespective of geographic origin, reacted similarly. However, variability between antigens of the same species was still considerably significant. Since the microbiological flora of moldy hay varies widely in different regions, the microbial species associated with the disease at a given geographical area has to be determined before selecting antigens for serological studies. The antigens currently used in various laboratories are crude preparations and need to be purified and standardized for dependable results. Until such antigens are available, all antigenic preparations used in the immunological evaluation of patients should be immunochemically characterized for their reproducibility and reliability although the ultimate goal should be to obtain standardized pure antigens for dependable immunodiagnosis of farmer's lung.

Candida albicans group A-specific soluble antigens demonstrated by quantitative immunoelectrophoresis

Soluble cytoplasmic extracts of Candida albicans groups A and B were prepared and compared by quantitative immunoelectrophoresis experiments performed with a commercial anti-C. albicans group A immune serum. Although crossed immunoelectrophoresis, tandem crossed immunoelectrophoresis, and line immunoelectrophoresis revealed many cross-reactions between the two groups, some components seemed to be specific to group A. However, the complexity of the extracts studied did not allow us to demonstrate specific constituents with these methods. Crossed-line immunoelectrophoresis with and without absorption of antibodies in situ was then used, and four specific antigens unique to group A cytoplasmic extract were demonstrated, one of which appeared to be quantitatively important. The value of various quantitative immunoelectrophoretic methods applied to complex antigenic preparations is discussed.