T cell receptor repertoire in BALB/c mice varies according to tissue type, sex, age, and hydrocortisone treatment.

Diversity in T cell recognition of antigens is determined by diverse usage of T cell receptor (TCR) repertoire. TCR repertoire analysis provides fundamental information for understanding T cell immune responses in the pathogenesis of various diseases. In the present study, we examined the TCR repertoire in various tissues in normal BALB/c mice. The TCR alpha chain variable region repertoires were consistent among the spleen, lymph nodes, and the thymus. The TCR beta chain variable region (TCRBV) repertoires were consistent between the spleen and lymph nodes, but different in the thymus. The TCR repertoires also differed in the lungs and the intestinal tract. The TCR repertoires were consistent between male and female mice, except for TCRBV15-1. TCR repertoire was almost similar in 3- and 7-week-old mice, except for TCRBV1-1, 8-3, and 14-1. The present findings suggest that the TCR repertoire of mice varies according to tissue type, sex and age. Additional analysis of the TCR repertoire, i.e., the effect of hydrocortisone (HC), was carried out. After the HC treatment, although the thymic T cells decreased to one-tenth, only a small fraction of CD4(+)CD8(+) T cells survived the treatment. Furthermore, the percentages of thymic T cells bearing TCRBV3-1, 5-1, 5-2, and 16-1 substantially decreased, but the percentage of cells bearing TCRBV12-1 did not decrease. The present findings suggest that the HC susceptibility of immature thymic T cells is different between TCR families.

Identification of pathogenic T cells in patients with beryllium-induced lung disease.

Chronic beryllium disease (CBD) is caused by beryllium exposure and is characterized by granulomatous inflammation with accumulation of CD4+ T cells in the lung. We analyzed TCR beta-chain and alpha-chain genes expressed by these CD4+ T cells. In the lungs of individual patients, as well as among four of five CBD patients studied, different oligoclonal expansions within the Vbeta3 subset were found to express homologous or even identical CDR3 amino acid sequences. These related expansions were specific for CBD patients, were compartmentalized to lung, and persisted at high frequency in patients with active disease. Limiting dilution cloning and analysis of coexpressed TCR alpha-chain genes confirmed that these TCRs were selectively expanded by a common Ag involving beryllium. Overall, homologous TCR beta- and alpha-chains showed identical V regions and invariant charged residues within the CDR3 but considerable variability in TCRJ usage. Remarkably, CBD patients expressing nearly identical TCRs did not share common HLA-DRB1 or DQ alleles. These results implicate particular CD4+ cells in the pathogenesis of CBD and provide insight into how beryllium is recognized in human disease.

Block of T lymphocyte differentiation by activation of the cAMP-dependent signal transduction pathway.

Differentiation of T lymphocytes is a complex and finely tuned process. Here we show that treatment of mouse fetal thymus organ cultures with agents activating the cAMP-dependent signalling pathway results in the block of thymocyte differentiation. This is due to severe impairment of maturation beyond the CD4-/CD8- stage. In addition, rearrangements at the TCR alpha gene locus, but not at the TCR beta locus, are completely inhibited. The cAMP effect is reversible and is restricted to TCR alpha beta+ cells. cAMP acts both by triggering apoptosis and by inducing cell-cycle block in thymocytes. Thus, activation of the cAMP pathway provides a mechanism to modulate thymic function for hormones and ligands whose receptors are coupled to adenylate cyclase.

Growth and differentiation of a human T-cell leukemia cell line, CCRF-CEM, grafted in mice.

The growth of human CCRF-CEM T-cell lymphoblastic leukemia was studied in mice immune deprived by different techniques, and in CD-nu/nu athymic mice. Female CBA/CaJ mice were immune deprived by infant thymectomy, priming with 1-beta-D-arabinofuranosylcytosine (200 mg/kg) 48 h prior to total body irradiation (925 cGy) designated theta ara-C gamma; or after thymectomy the mice received 925 cGy total body irradiation with marrow reconstitution (4 x 10(6) nucleated cells), designated theta gamma BM. Only in mice immune deprived by theta gamma BM, subsequently given a single dose of cyclophosphamide (100 mg/kg) 18-24 h before transplantation of CCRF-CEM, was there progressive reproducible engraftment and tumor growth. For mice immune deprived in this manner the tumor engraftment rate was 100 and 80% of tumors achieved greater than or equal to 1 cm3 within 46 days. In immune-deprived CBA/CaJ mice, but not CD-nu/nu athymic mice, tumor transplanted to the s.c. site metastasized to paraaortic and axillary nodes. Metastatic spread to lymph nodes was confirmed by immunophenotyping and by karyotyping. In contrast to the CCRF-CEM cells in culture, which expressed cytoplasmic CD3 (T3) but not surface CD3, both s.c. and metastatic CCRF-CEM line was exposed to phorbol-12-myristate 13-acetate in vitro to mimic the apparent differentiation which occurred in the xenografted cells, and a similar expression of surface CD3 after treatment was seen. This surface expression of CD3 was accompanied by production of mRNA for the T-cell receptor alpha chain and surface expression of the T-cell receptor. Identical T-cell receptor beta and gamma chain gene rearrangements were found for the CCRF-CEM line in vitro and the xenografted cells in vivo, demonstrating that only one clone was present and that differences in immunophenotyping were not the result of clonal selection. These results suggest that host (mouse) hematopoietic factors could affect human leukemic cell differentiation.