Structural variability of the external glycoprotein of simian immunodeficiency virus propagated in cell cultures

We examined the structural variability of the external glycoprotein (gp130) of a cloned simian immunodeficiency virus (SIV) in culture. Cloned SIVmac142 was either permanently propagated in HUT-78 cells or sequentially passaged in MT-2 cells. After 12, 24 and 60 passages of permanent or lytic cell-culture systems, virus was harvested, gp130 was isolated and peptide mapped. Comparison of gp130 peptide maps of SIVmac142 by computer graphic analysis revealed a variation in relative spot intensity of up to 20%. No major variability of gp130 was observed in SIVmac142 propagated in HUT-78 cells (i.e. without cytopathic effect induction) in up to 60 passages. However, in MT-2 cells, which are lysed by this virus, gp130 exhibited significant variability and displayed six additional fragments in peptide maps after 24 passages. Peptide map of SIVmac142 gp130 obtained after 60 passages in MT-2 cells was comparable to that after 24 passages. Alterations in the intensity of certain spots indicated changes in the composition of the replicating virus population.