Cell-mediated cytotoxicity to non-MHC alloantigens on mouse epidermal cells. IV. An alloantigen shared with B cells but not T cells

Recognition of an Igh-linked histocompatibility antigen, H-40, on B-cell tumors by cytotoxic T lymphocytes

This article reviews our data on H-40, a histocompatibility antigen controlled by a locus linked to Igh structural genes but telomeric to Tsu. The antigen is detected by rejection of H-40+ tumor cells in vivo and by the activity of H-2 restricted anti-H-40 cytotoxic T lymphocytes in vitro. H-40 is expressed on lipopolysaccharide stimulated B cells and B cell tumors that express surface(s) IgM and not on sIgM- tumors or other neoplastic cells. Its expression on the sIgM,D+ BALB/c (Igha, H-40a) derived leukemia, BCL1, prevents its transplantability across the Ig heavy chain (and H-40) barrier into C.B-20 (Ighb, H-40b) mice; whereas, BALB/c tumors that do not express H-40 can be transplanted into this allotype-congenic recipient. Although irradiated C.B-20 animals are susceptible to the BCL1 tumor, adoptive transfer of a mixture of Lyt-2+ and Lyt-2- effector cells (anti-H-40) from C.B-20 animals that have previously rejected BCL1 protect such recipients. However, the same effector cells will not protect irradiated BALB/c or (BALB/c X C.B-20)F1 recipients from this tumor. Since normal BALB/c sIg+ cells express H-40, either the effector cells are diverted from interacting with and destroying the tumor, or recognition of H-40 on non-tumor cells elicits a suppressor mechanism.

H-40, an antigen controlled by an Igh linked gene and recognized by cytotoxic T lymphocytes. I. Genetic analysis of H-40 and distribution of its product on B cell tumors

C.B-20 ( Ighb ) mice challenged with BALB/c ( Igha ) spleen cells (or vice-versa) generate cytotoxic T lymphocytes (CTL) that recognize an antigen, H-40, controlled by an Igh-linked gene. The gene maps to the Igh-C region end of the Igh complex, telomeric to Tsu in the region of Pre-1. At least three alleles, a, b, and c, can be defined. Using a cold target competition assay, no polymorphism of the a allele was detected. Both surface Igh-5a positive and negative spleen cells from (C.B-20 X BALB/c)F1 animals express the a allele of the antigen, indicating that this gene is not allelically excluded. Recognition of the target antigen by CTL is restricted by the D-end of H-2d. The tissue distribution of H-40 was explored using both bulk-cultured and cloned CTL. The antigen is expressed on surface immunoglobulin positive (sIg+) cells and correlates with the expression of sIgM. This was determined by analysis of several B lymphomas as well as of other tumors that varied in their extent of expression of sIg. Four subclones of BCL1 were analyzed. Two of the subclones are sIg+ and express H-40, while two other subclones are sIg- and H-40-. Thus, these data define an Igh-linked gene, separate from immunoglobulin structural loci, that controls an antigen expressed on sIg+ cells. Possible mechanisms to account for this finding are discussed.

Cell-mediated cytotoxicity to non-MHC alloantigens on mouse epidermal cells. VI. Influence of the MHC on the tissue specificity of cytotoxic T-lymphocyte responses

Mice of the C3H/He and A non-H-2 backgrounds are disparate from mice of the B10 background for the tissue-restricted, non-H-2 alloantigen of epidermal cells (EC), Epa-1, that is expressed by EC but not by lymphocytes (LC), as well as for a number of other alloantigens of the B10 background that are expressed by both EC and LC, generically referred to as "lymphocyte/epidermal alloantigens" (LEA). In this study, we compared the ability of various H-2 congenic strains on the C3H or A backgrounds to mount cytotoxic T-lymphocyte (CTL) responses to EC from H-2 compatible mice of the B10 background. High responses to Epa-1 were detected only in the H-2a and H-2k haplotypes; H-2b, H-2o1, H-2s, H-2t1, and H-2t2 haplotypes were nonresponders to Epa-1. High responses to LEA were detected in H-2a, H-2b, H-2s, H-2t1, and H-2t2 haplotypes; H-2k and H-2o1 were nonresponsive to LEA. Analysis of the H-2K, I and D region alleles of responders indicates that H-2Kk is essential for anti-Epa CTL responses, whereas Dd, Db or Ks were all permissive for strong anti-LEA responses. The ability to mount a given CTL response was not associated with differences in I-region alleles. These results are discussed in terms of K/D region products serving as Ir-gene products for CTL and in determining the apparent tissue-specificity of CTL.