[Use of reconstructed Sendai virus envelopes for the microinjection of proteins into monolayer cells].

It has been shown that biological microinjection, that is, fusion of protein-charged human erythrocytes with monolayer cells may be achieved by means of reconstructed Sendai virus consisting of envelope structures but devoid of nucleoid. Sendai virion envelopes reconstructed by dialysis possessed no infectivity, interferon-inducing, or interfering activities. The use of 125I-IgG demonstrated that erythrocytes are loaded with protein by 35%-40% and that each of the monolayer L929 cells is fused on the average with 4 loaded erythrocytes.

[Effect of modulation of the production of interferon by L-929 cells treated with theophylline].

The specific inhibitor of cAMP phosphodiesterase theophylline has been shown to evoke in L929 cells 2.3-fold induction of 2-5A-synthetase activity and 3.5-fold superinduction of the same enzyme activity while acting in combination with actinomycin D.

[Modulation of the induction of interferon formation by calcium chloride].

The results of the study confirm earlier reports on the stimulating effect of calcium ions on production of interferon induced by poly(I) X poly(C) and on translation of messenger RNA for interferon. Neutralization of the inhibiting activity of interferon production suppressor present in the cytoplasm of normal cells has first been demonstrated which broadens our concepts on the mechanism of action of calcium ions.

Differential effects of pure human alpha and gamma interferons on fibroblast cell growth and the cell cycle.

Pure human alpha and recombinant gamma interferons had differential effects on two strains of fetal lung fibroblasts in vitro. Alpha interferon had little effect on long-term cell growth, whereas gamma interferons, both glycosylated and non-glycosylated, were cytotoxic. However, when synchronized cells were studied, alpha interferon prolonged both G1 and S + G2 phases of the cell cycle, whereas gamma interferon only affected the G1 phase.