Effects of fetal versus postnatal sera upon adipose tissue stromal-vascular cells in primary culture

Summary This experiment was conducted to determine if serum factors are responsible for differences in cellularity of prenatal and postnatal pig adipose tissue as determined by in vitro measurement of cellular proliferation and enzyme-histochemical metabolic development. Cellular proliferation of stromal-vascular cells derived from rat inguinal adipose tissue was measured by [³H]-thymidine incorporation. Coverslip cultures were used for analysis of histochemical differentiation. Cells were incubated in media containing 10% fetal bovine, fetal pig, mature pig, or various combinations of these sera. Fetal bovine serum promoted more [³H]-thymidine incorporation than fetal or postnatal pig sera. Fetal pig sera also stimulated more [³H]-thymidine incorporation than mature pig sera. Sera from adult pigs promoted differentiation and lipid filling of adipocytes. Fetal pig sera stimulated histochemical expression of enzymes, but did not induce lipid filling. Fetal bovine serum produced histochemically undifferentiated cells. Addition of fetal bovine serum to media containing mature pig sera reduced lipid accumulation and histochemical reactivity of cells. This effect of fetal serum was thus due to specific inhibition of lipid deposition and not substrate restriction. These experiments demonstrated that serum factors have a major influence on morphological development of fetal and postnatal adipose tissue.     

So-called antireceptor sera

Experiments in delayed type hypersensitivity transfer were carried out with the aim of studying the ability of rabbit antisera against peritoneal exudate cells of rats sensitized with bovine gamma globulin or rabbit kidney tissue antigen to block peritoneal exudate cells of guinea pigs. In the serological test the antisera prepared against the cells of sensitized rats and tentatively named "receptor antisera", reacted not only with the cells of these rats, respectively, but also with guinea pig cells. In hypersensitivity transfer experiments in guinea pigs receptor antisera showed a blocking effect on the transferred cells, making them incapable of transferring hypersensitivity, i. e. rabbit antisera against rat peritoneal exudate cells reacted with guinea pig cells. This interaction was specific: the blocking effect was manifested only when guinea pigs whose cells were used in the transfer were sensitized with the same antigen as the rats against whose cells the receptor antisera had been prepared. The control antisera, taken for the treatment of the transferred cells in the same doses as the receptor antisera, had no blocking effect on the cells.     

Evaluation of the antimicrobial potential of immune sera

The inhibiting activity of blood sera obtained from 20 volunteers immunized with the multi-component vaccine "PYOPOL", 25 nonimmune donors and 7 lots of human antistaphylococcal immunoglobulin with respect to Staphylococcus aureus, Escherichia coli, Proteus vulgaris and Pseudomonas aeruginosa has been studied in the liquid nutrient medium with the use an automated microbiological analyzer. The sera of donors immunized with the vaccine "PYOPOL" have been found to possess high antimicrobial activity, comparable with the definite concentration of the antiseptic agent "Myramistin". The proposed method may be recommended for the evaluation of the bacteriostatic activity of different immuno- biological preparations.