Abstract: The invention concerns a process for preparing a pharmaceutical composition of thymus factors which displays immunomodulating and anti-inflammatory properties and is stable during storage. The process comprises the extraction of a homogenized thymus tissue and subsequent repeated ultrafiltration via a filter membrane having an exclusion volume of 30 kD. The resultant first ultrafiltrate is then subjected to a second ultrafiltration process on a membrane having an exclusion volume of 3 kD, the retentate being used. A composition prepared in this way, in contrast to the first ultrafiltrate obtained on leukocyte cultures stimulated by phytohaemagglutinin, displays a great increase in the production of anti-inflammatory IL-10 and a reduction in the formation of inflammation-promoting IL-2 and IFN-gamma.

Abstract: This invention provides a process for checking the removal rate of pyrogenic substances, in particular viruses, from organic material. The material to be purified is passed through an ultrafilter or an ultrafiltration unit whose virus-removal rate has already been determined by passing viruses of the Leviviridae family or other comparable small bacteriophages through the filter or filtration unit, the virus titer is determined before and after the filtration operation and the virus removal rate thus calculated. Before or after determining the virus-removal rate, a given pressure is applied to the filter or filtration unit in a gas pressure-hold test, and the decrease in the pressure over a given period is measured. After filtration of the biological material, the rate of virus removal by the filter is checked by repeating the pressure-hold test.

Abstract: To deplete viruses in organic material, the material to be purified is conveyed through an ultrafilter or an ultrafiltration unit the depletion rate of which is previously determined. The filter or filtration unit is charged with viruses of the family Leviviridae and the viral count is determined before and after filtration and used to derive the depletion rate. The virus depletion can be monitored during the process by following the depletion of a marker.