Influence of MHC background on the antibody response to detergent enzymes in the mouse intranasal test

The mouse intranasal test (MINT) was developed to assess the immunogenic potential of detergent enzymes. The BDF1 mouse (H-2(b/d)), a cross of C57Bl/6 (H-2(b)) x DBA/2 (H-2(d)) has been used for most of the development work. Preliminary data in the CB6F1(H-2(d/b)), a cross of Balb/c (H-2(d)) x C57Bl/6 showed that this strain was similar to the BDF1 in its response to enzymes. These data also showed that the parental strains responded differently to the enzymes. To understand better the influence the major histocompatibility complex (MHC) background has on immune responses to enzymes, 3 different enzymes were tested in 4 inbred strains (C57Bl/6, DBA/2, Balb/c, and C57Bl/10), 2 hybrid strains (BDF1 and CB6F1), and 2 congenic strains (Balb.B10 and B10.D2). BDF1 mice rank enzymes the same as the guinea pig, which in turn correlates with sensitization in occupationally exposed humans. The ranking is based upon the dose of enzyme needed to give one-half maximal IgG1 antibody response (ED(50)) where Termamyl is more potent than Alcalase, which is equipotent to Savinase. The H-2(d) strains ranked the enzymes the same as the BDF1 but generated ED(50)s for the proteases that were one order of magnitude greater than the BDF1 ED(50)s. The response to Termamyl was the same in the two F1 strains and the H-2(d) strains. The H-2(b) strains did not rank the enzymes the same as BDF1 but the ED(50)s for the proteases were similar to the ED(50)s in the F1 strains. The response to Termamyl in the H-2(b) strains was lower than the response in the F1 and H-2(d) strains. Initial data show that the inbred strains will make enzyme-specific IgE antibody to high doses of enzyme with DBA/2 > Balb/c > C57Bl/6 in terms of the robustness of the response. The IgG1 responses in the congenic strains were similar to the responses in the H-2 matched strains. In addition, the antibody response to enzymes was consistent regardless of the source of BDF1 mice. The responses to these enzymes are clearly MHC linked with a role for Class II I-E molecules indicated. The current data strongly support the use of the F1 hybrid as an appropriate strain for evaluating allergic responses to enzymes.