Expression and function of HLA-DQ8 (DQA1*0301/DQB1*0302) genes in transgenic mice.

Transgenic mice expressing HLA-DQA1*0301 and HLA-DQB1*0302 genes (DQ8) were produced. The transgenes were then transferred into mouse (Ab degrees) class II negative mice: the only class II molecules expressed in these animals were therefore coded by the HLA-DQ8 genes. Good expression of HLA-DQ molecules was found. Both CD4+ T cells and DQ8-specific T-cell receptor V beta expressing cells were positively selected in these mice. The HLA-DQ8 molecules expressed in these animals can present various foreign and self antigens and induce T-cell proliferation in vitro. These mice will be invaluable in future studies of the structure and function of HLA-DQ8 genes.

Staphylococcus periprostatic abscess: an unusual cause of acute urinary retention.

Prostatic abscess has occasionally been known to present with urinary retention. We report an unusual case of a Staphylococcus aureus periprostatic abscess causing acute urinary retention. Diagnosis was made by transrectal sonogram and computed tomography scan, and the patient was treated successfully with intravenous antibiotics, perineal exploration, and drainage.

HLA-DQ beta chain can present mouse endogenous provirus MTV-9 product and clonally delete Tcr V beta 5+ and V beta 11+ T cells in transgenic mice.

The elusive Mls gene(s) are mouse mammary tumor virus genes. The endogenous cotolerogen involved in the clonal deletion of Tcr V beta 5.1, 5.2, and 11 in H-2E+ mouse strains has been narrowed down to MTV-9. We demonstrate that similar to H-2E alpha molecules, human DQw6 beta chain mediated clonal deletion of Tcr V beta 5.1, 5.2, and 11 also requires the MTV-9 gene product. This shows that human class II molecules can present mouse retroviral antigen. Further, backcross analysis involving [B10.M(DQb) x DBA/1] suggest a second cotolerogen in the B10.M background in the clonal deletion of V beta 5-bearing T cells.

Integration site-dependent expression of a transgene reveals specialized features of cells associated with neuromuscular junctions.

After skeletal muscle is denervated, fibroblasts near neuromuscular junctions proliferate more than fibroblasts distant from synaptic sites, and they accumulate adhesive molecules such as tenascin (Gatchalian, C. L., M. Schachner, and J. R. Sanes. 1989. J. Cell Biol. 108:1873-1890). This response could reflect signals that arise perisynaptically after denervation, preexisting differences between perisynaptic and extrasynaptic fibroblasts, or both. Here, we describe a line of transgenic mice in which patterns of transgene expression provide direct evidence for differences between perisynaptic and extrasynaptic fibroblasts in normal muscle. Transgenic mice were generated using regulatory elements from a major histocompatibility complex (MHC) class I gene linked to the Escherichia coli beta-galactosidase (lacZ) gene. Expression of lacZ was detected histochemically. In each of eight lines, lacZ was detected in different subsets of cells, none of which included lymphocytes. In contrast, endogenous MHC is expressed in most tissues and at high levels in lymphocytes. Thus, the MHC gene sequences appeared inactive in the transgene, and lacZ expression was apparently controlled by genomic regulatory elements that were specific for the insertion site. In one line, cells close to the neuromuscular junction were lacZ positive in embryonic and young postnatal mice. Electron microscopy identified these cells as fibroblasts and Schwann cells associated with motor nerve terminals, as well as endoneurial fibroblasts, perineurial cells, and Schwann cells in the distal branches of motor nerves. No intramuscular cells greater than 200 microns from synaptic sites were lacZ positive. These results indicate that there are molecular differences between perisynaptic and extrasynaptic fibroblasts even in normal muscle and that diverse perisynaptic cell types share a specific pattern of gene expression.

Human HLA-DQ beta chain presents minor lymphocyte stimulating locus gene products and clonally deletes TCR V beta 6+, V beta 8.1+ T cells in single transgenic mice.

Minor lymphocyte stimulating locus (Mls) gene products in association with mouse major histocompatibility complex (MHC) class II molecules are known to determine the repertoire of T-cell receptor (TCR) in mature T cells. In order to test whether human class II molecules can present mouse Mls, HLA-DQ beta transgenic mice were generated. The expression and function of the DQ beta transgene were studied in the progeny of one selected founder which was H-2f and H-2E negative. In these mice, DQ beta molecules pairing with mouse A alpha chain and invariant chain are expressed on the cell surface in a tissue-specific manner. When the DQ beta gene was bred into the Mls-1a strain DBA/1 (H-2q), T cells bearing V beta 6 and V beta 8.1 TCR were clonally deleted in the thymus of DQ beta+ transgenics but not in DQ beta-negative full sibs. Thus, the data presented here clearly demonstrate that the human MHC DQ beta chain can present Mls in the clonal deletion of T cells. Our results also suggest the requirement for an interaction between CD4 and class II molecules (alpha chain) for clonal deletion of T cells to occur.

Thymic deletion of V beta 11+, V beta 5+ T cells in H-2E negative, HLA-DQ beta+ single transgenic mice.

DQw6b transgenic mice have been generated by microinjecting a linearized cosmid clone containing 34-kb DQb genomic DNA, isolated from HLA-homozygous B cell line AKIBA (DR2, Dw12, DQw6), into embryos of (CBA x B10.M)F2 or (SWR x SJL)F2. Among 85 mice screened, eight mice were transgene-positive. The transgene in seven of eight founders was germline-transmitted. FACS analysis and immunohistochemical studies with DQ beta-specific mAb demonstrated that DQ beta molecules in association with mouse A alpha f molecules are expressed on peripheral mononuclear cells, spleen cells, and in thymic medulla. More interestingly, V beta 11-, V beta 5.1-, and V beta 5.2-bearing T cells, but not V beta 8.2-bearing T cells, were clonally deleted in the H-2E-negative but DQ beta+ progeny of two selected founders (260-23 and 258-10). The deletion was found to take place intrathymically during the transition stage from immature to mature thymocyte development. We postulate that although human DQ genes are more homologous to mouse H-2A genes, A alpha f/DQ beta hybrid molecules may possess the same self-peptide- (or superantigen)-presenting epitope as E alpha/E beta molecules critical for deletion of V beta 11-, V beta 5.1-, and V beta 5.2-bearing T cells in thymus. Our results also confirm the previous findings that accessory molecules on thymocytes such as CD4 may be involved in thymic selection, and further suggest that an interaction of mousE CD4 and mouse A alpha chain is required for the clonal deletion.

Expression and function of mutant Ia antigen in transgenic mice.

Cell surface expression of Ia antigens requires the assembly of alpha and beta heterodimers. We have produced a double transgenic mouse with a wild form Ak alpha gene and a mutant Ak beta (Ak beta MB) gene with d-allele substitution at positions 63 and 65-67. Initial studies indicated that the Ak alpha and Ak beta MB transgenes are not expressed on the surface of lymphoid cells of the transgenic mice. However, when spleen cells were stimulated with LPS prior to FACS analyses, Ak/Ak MB assembly and subsequent surface expression was induced. The tail skins from transgenic founder mice were rejected by the parental mice indicating a role for the mutant antigen on the allograft. In addition, the Ak transgenic mice on H-2q/q background can partially delete V beta 6+ T cells, suggesting the presence of the transgene product in the thymus.

Susceptibility of HLA-B27 transgenic mice to Yersinia enterocolitica infection.

The majority of patients with reactive arthritis have the major histocompatibility complex class I gene HLA-B27. The development of arthritis in these patients often occurs following infection with one of several enteric bacteria, including Yersinia enterocolitica. In this study, transgenic mice expressing HLA-B27 and their negative full sibs were infected intravenously with Yersinia enterocolitica 0:8 WA in an attempt to develop an experimental model of reactive arthritis. To date, no reactive arthritis has been observed; however, a significantly higher incidence of paralysis was observed in the HLA-B27+ transgenic mice. Injection of 10(5) organisms induced hind limb paralysis in 8 out of 30 of the HLA-B27 transgenic mice (27%) and in only 1 of the 24 negative siblings (4%). Paralysis occurred in 14 out of 30 HLA-B27+ mice (47%) at a dose of 10(4) organisms. Only 2 of the 25 negative siblings (8%) were affected at this dose. Paraspinal abscesses were found in all of the paralyzed animals. At the 10(4) dose most of the HLA-B27+ mice (70%) succumbed to the disease within 4 weeks, while the mortality in their B27- full sibs was less than 10%. Thus, HLA-B27 transgenic mice have higher mortality and morbidity from infection with Y. enterocolitica 0:8 WA than corresponding HLA-B27- littermates.

Expression of I-A alpha k and allelic restriction on A alpha/A beta pairing in transgenic mice.

Cell surface expression of class 11 major histocompatibility complex encoded (1a) molecules depends on association of the component alpha and beta chain into a stable heterodimer. Studies on cell lines transfected with MHC class II genes have revealed important limitations on the assembly of haplotype-mismatched A alpha:A beta complex. In order to study alpha:beta chain pairing restrictions in vivo a number of lines of transgenic mice carrying the A alpha k gene were generated. The transgene was studied in the context of H-2b, H-2s, H-2q, H-2u, H-2f and H-2v haplotypes. Initial FACS analysis of spleen and peripheral blood cells showed no A alpha kappa expression. Spleen cells stimulated with LPS and analysed by FACS showed A alpha k expression in three different H-2b strains as well as H-2u, but not in others. These data indicate that A alpha k can associate with A beta b and A alpha k, but not with A beta s, A beta q, A beta f, A beta v.

Identification of I-E alpha genes in H-2 recombinant mouse strains by F1 complementation.

Nine recombinant H-2 mouse strains with crossovers in the I region between I-E-negative haplotypes f,q and I-E-positive haplotypes p,k were examined for I-E expression by microcytotoxicity dye exclusion assay. These recombinants were found to be negative for I-E expression. There are two possible genotypes in these recombinant mouse strains that could result in lack of I-E expression. Recombinants with crossovers between the E alpha gene and the S region would have both nonexpressed I-E alpha and beta genes (E beta fE alpha f, E beta qE alpha q) and recombinants with crossovers between the E beta and E alpha genes would have a nonexpressed E beta gene (E beta f or E alpha q) and a functional E alpha gene (E alpha k or E alpha p). To distinguish between these possible genotypes these recombinants were crossed to B10.A(4R), which carries a functional E alpha k gene but is I-E-negative due to a nonexpressed E alpha b gene. F1 mice were examined for transcomplementing I-E molecules by immunoprecipitation of 3H-leucine-radiolabeled detergent lysates of spleen cells with a monoclonal I-E antibody (14-4-4). Detection of a transcomplementing I-E molecule was confirmed by immunoprecipitation with a monoclonal antibody (H9-14.8) specific for the I-Ek beta polypeptide chain derived from B10.A(4R) and by tryptic peptide map comparisons. Five recombinant mouse strains were able to complement with B10.A(4R) in F1 mice to generate a transcomplementing I-E molecule, and thus have an expressed I-E alpha gene (E alpha k or E alpha p). Four recombinants did not complement with B10.A(4R) in the F1 expression of I-E molecules, and thus have nonexpressed I-E alpha genes (E alpha f or E alpha q).

Mapping of a second recombination hot spot within the I-E region of the mouse H-2 gene complex.

The crossover points of nine intra-I region recombinant mouse strains were determined by restriction fragment analysis. The recombinants were examined for the presence of k and p haplotype specific DNA restriction endonuclease sites. These restriction sites were a Sac I site between the E beta and E beta 2 genes, a Hpa I site within the E beta 2 gene, and a Rsa I site approximately 1 kb to the right of the E alpha gene. Seven of the recombinants were found to have crossovers between the Hpa I and the Rsa I site. This analysis suggests that a recombination hot spot exists within this segment. This segment is approximately 12-14 kb, and contains the E alpha gene and the intervening sequence between the E beta 2 and E alpha genes.

Proximity of the Mep-1 gene to H-2D on chromosome 17 in mice.

The Mep-1 gene on chromosome 17 in mice controls the activity of meprin, a kidney brush border metalloendopeptidase. Most inbred mouse strains of the k haplotype (e.g., CBA, C3H, AKR) are markedly deficient in meprin activity; these mice carry the Mep-1b allele. Mouse strains in which meprin activity levels are normal are designated Mep-1a. Studies using congenic and recombinant strains mapped the Mep-1 gene telomeric to H-2D near the Tla gene. To further study the relationship between the major histocompatibility complex and Mep-1, a linkage study was conducted. Mep-1a F1 hybrids [C3H.A (KkDd) X C3H.OH (KdDk)] were backcrossed with Mep-1b C3H.OH (KdDk) parents. The progeny were assayed for H-2D markers, Pgk-2 isozymes, and meprin activity. Recombination between H-2D and Mep-1 occurred in 6 out of 284 mice, a crossover frequency of 2.1%. Mep-1 is therefore 2.1 crossover units telomeric to H-2D and approximately 0.6 crossover units from Tla. The Mep-1 locus provides a new genetic marker for the future mapping of this important area of the mouse genome.

The pattern of non-diabetic peripheral vascular disease in South India.

One hundred and twelve South Indian males with non-diabetic peripheral vascular disease of the lower limb were classified clinically into three groups according to the level of obstruction (aorto-iliac, 26 patients; femoropopliteal, 46 patients; distal, 40 patients). Arteriography was done in 65 patients and serum lipid estimations in 69. In the aorto-iliac group the mean age was 45 years (+/- 11.6 s.d.); 23 per cent had hypertension, 28 per cent polycythaemia and 55 per cent hyperlipidaemia. Aortography suggested atheroma in most. In the femoropopliteal group the mean age was 39 years (+/- 12.8); 22 per cent had hypertension, 11 per cent polycythaemia and 21 per cent hyperlipidaemia. Arteriography showed lesions typical of atheroma in many and was consistent with thrombo-angiitis obliterans in some. In the distal group the mean age was 37 years (+/- 9.8); 8 per cent had hypertension, 20 per cent polycythaemia, 25 per cent hyperlipidaemia and 20 per cent had distal arterial disease of the upper limb. Arteriography was consistent with thrombo-angiitis obliterans in most cases. Atheroma seemed to be implicated in 96 per cent of the aorto-iliac group and in 64 per cent of the femoropopliteal group.