Reversible interference with TCGF activity by virus particles.

Several types of virus particles including retroviruses and herpes viruses can impede the ability of human peripheral blood lymphocytes to respond to mitogenic stimuli. This is true even in the case of viruses that have been inactivated by u.v. light, indicating that the mechanisms involved are infection independent, at least in part. The observed inhibition could be shown to correlate with a reduced level of production of TCGF activity in the virus co-incubated cultures. In addition, these same viruses are apparently able to complex directly with TCGF activity and to render it biologically inactive. This was shown by allowing known quantities of virus to interact with TCGF activity for different periods of time, followed by centrifugation of any virus-TCGF complexes. This interference is reversible, however, and the dissociation of these virus-TCGF complexes by mild detergent, followed by viral centrifugation, yields TCGF activity in the supernatant.