Aberrancy in immunogenicity and cell-surface expression of H-2 antigens on erythrocytes(1)
The response of mice to H-2 antigens on red blood cells (RBC) was induced independent of T-cell activity and seemed to involve direct presentation of H-2 antigens to B lymphocytes by RBC. T cell-independent immunoglobulin M (IgM) antibody responses to spleen H-2 antigens demonstrable by either a plaque-forming cell (PFC) assay or a hemagglutination test suggested that H-2D antigens were dominant over H-2K antigens. The order of magnitude of both immunogenicity and cell-surface expression on RBC is H-2Dd>>H-2Db>H-2Ka, H-2Kb. Furthermore, H-2d public antigens and H-2Ld antigens were neither immunogenic nor easily demonstrable on RBC. These findings contrasted with poor immunogenicity for PFC response and proportionally strong expression of H-2 antigens on lymphoid cells.
Alloantisera were produced in mice by injecting 10^6-10^7 allogeneic spleen cells or tumor cells intraperitoneally more than four times at intervals of 20-30 days, followed by bleeding at 7-10 days after the injection. All the RBC with H-2a and H-2u haplotypes which code for H-2Dd pri-
vate antigen H-2.4 were highly active in PFC response. In contrast, the RBC of other haplotypes not bearing the H-2.4 antigen were poorly immunogenic, even though they should bear public antigens shared by H-2a including H-2Ld(H-2.64,65) antigen. The results suggested that the H-2Dd private antigen is strongly immunodominant.
The order of magnitude of expression on lymphoid cells measured by 125I-labeled protein A radioimmunoassay using highly specific anti-H-2 sera was Db>Kd=Kk=Kb=Dq>Dd>Kq>Dk. The magnitude of expression on RBC is Dd>>Db>Kd,Kb,Ld.