Anti-idiotype to monoclonal anti-swine SLA antibody detects a common idiotype shared by mouse anti-SLA sera and elicits an anti-SLA activity.

Heterologous anti-idiotypic reagents have been prepared against a BALB/c anti-swine MHC (SLAd) monoclonal antibody (74-11-10) in order to test for possible interspecies idiotypic cross-reactions of anti-MHC antibodies. Using these reagents to examine xenoantisera produced in BALB/c mice immunized with swine SLAdd peripheral blood lymphocytes, all animals tested were found to express detectable levels of the 74-11-10 idiotype (Id). The Id could also be detected in one out of five BALB/c mice immunized with swine SLAcc PBL. Swine anti-SLAdd alloantibodies were also tested, but failed to show detectable levels of the 74-11-10 Id. The in vivo administration of anti-idiotypic reagents to BALB/c mice induced detectable levels of 74-11-10 Id positive antibodies that bound specifically to SLAdd PBL. Similar treatment of SLAgg swine (recombinant swine expressing the class I MHC molecules of c) with anti-idiotypic antibodies failed to induce anti-SLAd antibody activity. These results thus indicate that 74-11-10 represents a shared idiotype of BALB/c anti-SLAdd antibodies. The presence of 74-11-10 Id in one mouse immunized with SLAcc PBL suggests that the failure of pigs to express the 74-11-10 Id following treatment with anti-idiotypic antibodies may be the result of tolerance rather than absence of the relevant variable region gene(s).