Biosafety in the laboratory - VIB

onment in a safety cabinet. Yeasts are airborne and able to survive in the air for long
periods of time. In this way they can contaminate all kinds of other cultures. In addition,
sensitised people might suffer from allergic reactions after having been exposed to yeast
or its spores. For this reason, yeast is often manipulated in a separate laboratory.
Waste
All waste consisting of or containing genetically modified yeasts should be inactivated or
decontaminated.
Note
As was the case for E. coli, the organism will move one level up in both risk class and the
corresponding measures to be taken when a gene that produces a hazardous substance,
such as a toxin, is cloned into the yeast.
Working with genetically modified cell lines
Classification
Classifying animal or human cell lines is not that simple. The determining factor is the
cells’ ability to produce hazardous biological agents, notably viruses. First of all a distinction
should be made between primary cells and “established cell lines”. Primary cells
should at least be classified as L2 organisms. When established cell lines are involved, it
should be determined whether they might produce virus particles, taking into account any
viral sequences that might be present in the vector being used in combination with the
cell line. Some examples:
Cell line Viral Vector (by way Classification* Classification Comments
sequences of example only) rule**
in cell line
Primary Not known Not relevant L2 - Classification at a
mouse cells
lower level only
upon proof that no
hazardous biological
agents are produced
NIH-3T3 None SV40ori vector L1 4, e or j Zero risk of virus
particle formation
HELA E6E7 genes SV40ori vector L1 4, e or j Combination of viral
from HPV
sequences in cell
line and vector will
not result in the
formation of virus
particles
Working with commonly used laboratory organisms 39