The Presence of mycotoxin-associated fungal spores isolated from the indoor air of the damp domestic environment and cytotoxic to human cell lines

One hundred and fifty-two fungal isolates from the air spores of 503 damp,
mouldy dwellings in Glasgow and Edinburgh, Scotland, were screened for
cytotoxicity against the human embryonic diploid fibroblast lung cell line,
MRC-5 (ATTC No. CCL171). At least 37% of the isolates, principally of the
genus Penicillium, showed toxicity to the cells when subjected to the MTT
[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay following a water extraction procedure. When spores of 23 of the isolates were subjected to extraction with the organic solvent dimethyl sulphoxide, an additional level of cytotoxicity was observed separate from the water extraction methods. Many mycotoxins are known to be sparingly soluble in water. When some
of these isolate extracts were exposed to human Chang liver cells (ATCC No.
CCL13) and to human normal sternal bone marrow cells, (Detroit 98, ATCC
No. CCL18), some additional cytotoxicity was observed. A comparison was
also made, in some cases, between results obtained in the MTT and neutral
red assays. Organisms exhibiting the greatest cytotoxicity included Penicillium viridicatum, P. expansum, P. chrysogenum, P. commune and Aspergillus
fumigatus.