T-dependent antigen response (TDAR) tests: meta-analysis of results generated across multiple laboratories

The primary T-cell-dependent antibody response (TDAR) to antigens is widely used as a functional test in immunotoxicology. TDAR assays can be performed using different antigens, e.g., sheep red blood cells (SRBC) and keyhole limpet hemocyanin (KLH) are presently utilized by different laboratories. The purpose of this study was to apply meta-analysis to compare data from several laboratories using these antigens, in two strains of rats, by multiple routes of immunization and with different primary TDAR assay formats. Although limitations imposed by the scale of the data set and the need to convert some data to an ordinal scale to allow comparisons restrict the scope and strength of the conclusions that can be drawn, the results of this study have shown that the two antigens in different assay formats give comparable results. Similarly, both antigens and assays formats showed the same pattern of response to strong immunotoxicants. These results indicate that standardizing the choice of antigen in TDAR assays may not be critical in the evaluation of potential immunotoxicity.