Expression of murine Lm-1 locus. Lm-1 determinants on lymphocytes and macrophages, and effects of Lm-1 incompatibility on bone marrow grafts.

Abstract

The Lm-1 locus controls the expression of one or more cell surface alloantigens recognized by cytotoxic T lymphocytes (CTL). ~ Earlier studies showed Lm-1 is Igh-linked and located five map units telomeric to Pre-I on chromosome 12 (1). Two Lm-1 alleles (Lm-1 a and Lm-1 b) were identified, and lipopolysaccharide (LPS) blasts from 46 strains derived from crosses between Lm-I a and Lm-1 b mice were typed. 37 of these strains were known to have genetic recombinations in the telomeric region of chromosome 12. None of the recombinations divided the Lm-1 locus; i.e., all strains typed unambiguously as either Lm-I a or Lm-I b. Accordingly, if Lm-I were to consist of more than one gene, such genes would have to be closely linked.Two other laboratories (2, 3) have identified Igh-linked loci for cell surface alloantigens recognized by CTL. Forman et al. (2) have defined a locus telomeric to Igh and Tsu that codes for an antigen (H-40) that is expressed only on surface Ig-positive B cells. The antigen described by Rolink et ai. (3), H(C.), is also encoded by a locus teiomeric to Igh, but is expressed on both B and T lymphocytes.All of the above findings clearly demonstrate that the telomeric end of mouse chromosome 12 codes for cell surface determinants that are immunogenic for T cells. What is not clear, however, is the number of such antigens, their distribution and relationship to each other, and their possible role in cell differentiation and interaction.To elucidate further the nature of Lm-1 and its product(s), we tested different cell types for expression of Lm-1 determinants. We show here that Lm-1 determinants (a) are expressed on T and B cell blasts, some pre-B cell lines, and macrophages, but not on fibroblasts, normal (unstimulated) thymocytes, and cloned lines of two thymic T cell lymphomas; (b) are differentially expressed on

Linkage between the porcine genes encoding immunoglobulin heavy‐chain allotypes and some serum α‐protease inhibitors: a conserved linkage in pig, mouse and human

“…First there are three genes (Tind, Tsu and Tthy) encoding T-cell specific antigens which are apparently involved with suppression or ,augmentation of the immune response (Owen et al 1982;Roderick & Davisson 1984). Secondly, a lymphocyte alloantigen locus (Ly-7) and a cell-surface alloantigen locus (Lm-1) are located near the Pi gene cluster (O'Toole et al 1984(O'Toole et al , 1985. It is possible that the porcine homologues of these murine genes will also be found to be located in the ZGH-PI region of pigs.…”