Objective  To investigate the optimal condition for the detection of anti-non-galactose (Gal) xenoantigen and antibody in human serum.

  Methods  Peripheral blood mononuclear cell (PBMC) obtained from Wuzhishan miniature pig models with α-1, 3-galactosyltransferase gene knockout (GTKO) were used as target cells, mixed and incubated with healthy human serum of different concentrations (4.8%, 16.7% and 100%) for 0.5, 1.0, 2.0, 3.0 and 6.0 h, respectively. The abilities of PBMC to bind with IgM and IgG were detected by flow cytometry.

  Results  At the serum concentration of 16.7%, the ability of non-Gal IgM to bind with PBMC was significantly enhanced from 0.5 h to 3.0 h incubation (P < 0.01), whereas no statistical significance was noted in terms of IgG (P > 0.05). Increasing serum concentration could also enhance the ability of non-Gal IgM to bind with PBMC. At the serum concentration of 100% and incubation for 3 h, the ability of IgM to bind with PBMC was the highest among all groups (P < 0.01). At the serum concentration of 100% and incubation for 6 h, the ability of IgG to bind with PBMC was significantly enhanced (P < 0.05). Prolonging incubation time and increasing serum concentration did not affect the activity of PBMCs.

  Conclusions  The optimal condition for detection of anti-non-Gal xenoantigen and antibody is determined. A quantity of 1×10⁵ PBMC from pig should be incubated with 100% human serum for 3 h for detection of IgM level, or incubated with 100% human serum for 6 h for measurement of IgG level. This optimized condition contributes to screening the donor pigs which lowly express non-Gal antigen.