Table 1.

Comparison of different VLP expression systems for viruses.

	Mammalian	Insect	Plant	Yeast	Bacteria	Cell-free
VLP type	Non-enveloped and enveloped	Non-enveloped and enveloped	Non-enveloped and enveloped	Mostly Non-enveloped	Non-enveloped	Non-enveloped
Cost	++++	+++	++	+	+	++++
PTMs	++++	+++	++	+	None	+
Contamination	Mammalian virus	Baculovirus and nodavirus	None	None	Endotoxins	None

Note: greater number of “+” = a higher level; PTM, post-translational modification.