Comparison of Cross-Reactivities between Albumins of Various Species at the Level of Antibody and Helper T Cells--Studies in Mice

A study was made in LAF1 mice of the cross-reactivity between bovine serum albumin (BSA) and albumins from a wide variety of species with respect to their interaction with anti-BSA and reactivity with BSA-sensitized helper T cells. Inhibition studies and direct binding of 125I-albumins to anti-BSA were used to determine humoral cross-reactivity. Challenge by various trinitrophenyl- (TNP)-albumins of BSA-immune helper cells and TNP-keyhole limpet hemocyanin immune spleen cells in an adoptive anti-TNP plaque-forming cell response was used as a measure of cross-reactivity at the T cell level. In most cases, cross-reactivities at both the humoral and T cell levels correlated fairly well. Goat and sheep albumin were highly cross-reactive, guinea pig, dog, and rabbit albumin gave medium-range reactivity, and rat and chicken albumin were essentially negative. Two major exceptions were observed both in the direction of greater T cell reactivity (pig albumin) and in the direction of greater humoral reactivity (horse albumin). The results do not permit any definite conclusion as to the nature of the T cell receptor. They suggest, however, that such receptors may have discriminatory capabilities comparable to those of immunoglobulin.