Background:
Changes in biomolecules under the influence of chemical and physical factors on cells, tissues, and whole organisms are investigated.

Material and methods:
In vitro-incubated bovine embryonic cells were inoculated with low titers (high dilutions of viral suspensions) of vaccine avipoxviral strains. Mouse embryonic fibroblasts were co-cultivated with mouse malignant myeloma cells (P3-X63-Ag8) transfected by recombinant DNA plasmid or preincubated in culture fluid from prior incubation of the same cells. Sub-populations of virus-inoculated, co-cultivated, and preincubated cell cultures were frozen in the presence of the cryoprotectant dimethylsulfoxide (DMSO), subsequently thawed, and re-incubated. Newly formed cell monolayers were inoculated with extracellular and intracellular forms of each viral strain, both before and after exposure to DMSO and drastic temperature changes. Extracellular forms were derived from the cultural fluids of inoculated cell cultures, while intracellular forms were obtained from suspensions of mechanically scraped virus-inoculated cells.

Results:
Exchange of nucleotide (DNA and/or RNA) fragments between cellular and viral genomes, as well as between genomes of separate cells, was suggested. These changes were explained by activated fusion induced by the organic detergent (DMSO) combined with drastic temperature changes. Such processes could provide vectors for gene-engineering manipulations and the development of molecular (DNA-based, RNA-based, and/or protein-based) antiviral and antimalignant vaccines. Production of immune molecules by nonimmune cell types under appropriate conditions, such as the presence of immunomodulators, was also proposed.

Conclusions:
The results suggest the possibility of nucleotide (DNA and/or RNA) fragment exchange between separate cells, as well as between cells and virions. Nonimmune cells demonstrated the capacity to produce immune molecules under appropriate conditions.