Comparison of the PK(15)- and WEHI 164 (clone 13)-based bioassays for detection of porcine tumor necrosis factor.

OBJECTIVE

To determine relative sensitivities of the PK(15)- and WEHI 164(13)-based bioassays for detection of tumor necrosis factor alpha (TNF).

SAMPLE POPULATION

Recombinant human, murine, and porcine INF, and serum from pigs given endotoxin IV.

PROCEDURE

Two cell lines were used as targets for recombinant human, murine, and porcine TNF cytotoxicity bioassays. Pigs were given sublethal doses of endotoxin to obtain serum samples containing high activity of porcine TNF. Serum TNF activity was tested, using both cell lines. Viable cells were detected by addition of dimethylthiazol diphenyltetrazolium bromide after 18 to 20 hours' incubation with samples containing TNF.

RESULTS

The 2 cell lines tested had different sensitivities to human, murine, and porcine TNF. Compared with WEHI 164(13) cells, PK(15) cells were 50 times less sensitive to murine TNF and 15 times less sensitive to human TNF. However, PK(15) cells were 4 times more sensitive to recombinant porcine TNF and 15 times more sensitive to porcine serum containing TNF.

CONCLUSIONS

The PK(15) cell line was more sensitive to porcine TNF-mediated lysis than was the WEHI 164(13) cell line. The PK(15)-based TNF bioassay will be especially useful for study of infectious disease processes in swine, particularly where low activity of TNF exists.