Male-specific antigen: modification of potency by the H-2 locus in mice.

Skin grafts from C57BL/10 (B10) male mice survive significantly longer than do B10.BR male skin grafts on (B10 x X B10.BR)F(1) females. This indicates that the H-2 locus influences the potency of the male-specific antigen in mice.

Genetic control of susceptibility to experimental allergic encephalomyelitis in rats.

Rats of the inbred strains Lewis and DA are highly susceptible to the induction of experimental allergic encephalomyelitis (EAE) while Brown Norway rats are resistant to this disease. Evidence has been obtained which suggests that a single dominant gene is associated with susceptibility to EAE. The locus controlling EAE susceptibility is closely linked to the Ag-B histocompatibility locus but is not identical to it.

A monoclonal antibody specific for the Yc subunit of rat liver glutathione S-transferase B.

A monoclonal antibody against rat liver glutathione S-transferase B, which consists of subunits Ya (Mr 27,000) and Yc (Mr 29,500), was produced in a mouse hybridoma system. The monoclonal antibody, BE6Yc1, was of the immunoglobulin G1 class and specifically recognized glutathione S-transferase B showing no cross-reactivity against the dimeric form of Ya, ligandin, in enzyme-linked immunosorbent assay. A glutathione S-transferase B-BE6Yc1 monoclonal antibody complex was identified from the zymogram pattern on starch gel electrophoresis. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis of rat liver glutathione S-transferase B, followed by Western blotting with BE6Yc1 antibody, a single polypeptide with a molecular weight of 29,500, identical to the Yc subunit of rat liver glutathione S-transferase B, was identified. The antibody showed no cross-reactivity with the Ya subunit with a molecular weight of 27,000 of either glutathione S-transferase B or ligandin. These results show that there are at least two distinct epitopes in the Ya and the Yc subunit. The monoclonal antibody did not block the catalytic activity of glutathione S-transferase B toward cumene hydroperoxide and possibly also 1-chloro-2,4-dinitrobenzene. Quantitative differences in expression of the Yc subunit of glutathione S-transferases were demonstrated in extracts of various normal tissues with the BE6Yc1 antibody by Western blot analysis. The Yc subunit was found to be present at much lower levels in kidney, small intestine, spleen, and lung than in liver and testis.

Characterization of a monoclonal antibody to ligandin.

A monoclonal antibody has been produced in the mouse system using purified rat liver ligandin as antigen. The antibody is of the immunoglobulin M class and appears to be specific for the Ya subunit of lowest molecular weight which comprises the isoenzymes of glutathione S-transferases in rat liver. Of the series of glutathione S-transferases, the antibody cross-reacted with purified ligandin (YaYa) and, in ion-exchange separations of isoenzymes, gave positive Western blots with fractions containing glutathione S-transferases B and a combination of D and E. Interactions of the immunoglobulin M antibody and the antigen were demonstrated using 125I-ligandin (YaYa) and physical separations in gel filtration experiments. The antibody did not inhibit the glutathione S-transferase activity of ligandin (YaYa) but rather increased the catalytic activity in a dose-dependent fashion up to a molar ratio of antiligandin:ligandin of 24.

The genetic divergence of sublines as assessed by histocompatibility testing.

The degree of genetic divergence which has occurred between a number of inbred strains of mice and between two sublines of inbred rats was assessed by determining the fate of inter-subline skin grafts. Sublines which had been separated for 29 and 42 generations possessed no detectable incompatibility, while three combinations of sublines judged to have been maintained apart for from 123 to 129 generations showed slight degrees of histoincompatibility. One pair of sublines which had been separated for 119 generations demonstrated a marked degree of incompatibility, and an F(2) test suggested that mutations had occurred at four or five histocompatibility loci.

Expression in organ culture of agouti locus genes of the mouse.

CLEFFMANN (1963) reported that pigment cells of the lethal yellow (A-y/a) genotype change to black immediately upon cultivation, and continue to produce black pigment unless sulfhydryl reagents are added to the culture medium. We have attempted to repeat this observation and have not been able to do so. We also have been unable to indue the synthesis of yellow pigment by adding glutathione to cultures of agouti (A/A) skin. We therefore suggest that hypotheses which attempt to explain the action of agouti locus genes on the basis of effects of sulfhydryl compounds be considered with caution.

Monoclonal antibodies to the glucocorticoid receptor.

One thousand-fold purified unactivated rat liver glucocorticoid receptor was obtained by affinity chromatography followed by gel filtration. Splenic lymphocytes of immunized mice were fused with a nonproducer SP2 myeloma cell line to obtain hybridomas secreting antibodies against receptor. Hybridoma lines, injected into mice, developed ascites tumors which provide substantial amounts of monoclonal antibodies. A monoclonal antibody was purified from ascites fluids by chromatography on an anti-mouse IgG column. The antibody was shown to react physically with the glucocorticoid receptor.

Association between alleles of the transforming growth factor-alpha locus and the occurrence of cleft lip.

DNA samples from 100 patients with cleft lip with or without cleft palate (CL/P) were compared with those of 98 unaffected control individuals with respect to transforming growth factor alpha (TGFA) genotypes. Among the Caucasians in this population (83 CL/P, 84 controls), there was a significant difference in the restriction fragment length polymorphisms (RFLPs) observed after digestion with TaqI (chi 2 = 4.68, P = 0.03). The frequency of the C2 allele in the Caucasian CL/P population was 0.169, whereas that in the control group was 0.089. When the data for Caucasians, African-Americans, and Asians were examined jointly, the chi 2 value for the pooled sample was 5.08 (P = 0.02). This confirms the hypothesis of Ardinger et al. [1989, Am J Hum Genet, 45:348-353] that TFGA itself or a closely linked gene contributes to the development of CL/P in humans.

Nongenetic determinants of human serum esterases.

A panel of 1151 unselected individuals was screened by starch gel electrophoresis for serum esterase variants. Two types of variants were observed which were shown by family studies not to be genetically determined. No consistent disease process was correlated with the occurrence of these variants. Suggestive evidence has been obtained to support the hypothesis that these variant proteins were produced by the action of exogenous neuraminidase on the individuals' normal C, esterases. A third type of variant enzyme was observed in 1 patient. This enzyme was shown to be a substantially larger molecule than the C, esterase and it is suggested that this protein may be a polymer of the C, esterase.

Dence for a gene in rats affecting lymphocyte responsiveness to PHA.

A gene controlling high responsiveness of lymphocytes to in vitro stimulation by PHA was transferred from the Lewis strain of rats to the BN background by ten generations of backcrossing. The high-responder phenotype was initially defined on the basis of incorporation of(3)H-thymidine, but we show that this trait also involves higher levels of mitotic activity than are observed with low responder lymphocytes. This gene is not closely linked to any histocompatibility locus which could be detected by skin grafting, and it does not appear to affect the proportion of T lymphocytes.

Genetic control of resistance to clinical EAE accompanied by histological symptoms.

The susceptibility of rats to experimental allergic encephalomyelitis (EAE) induced by myelin basic protein (MBP) was studied in a variety of genetic crosses. Rats were evaluated according to weight loss, neurological symptoms, and histological criteria. The results demonstrate that three different types of genes are involved in susceptibility. An RT1-linked gene is necessary but not sufficient for full expression of EAE induced by MBP in complete Freund's adjuvant (CFA). Additional genes are required for the occurrence of histological EAE, but a full-blown inflammatory reaction is not sufficient for the expression of clinical EAE. A third type of gene, which can be demonstrated in appropriate crosses, is required for the consistent expression of clinical symptoms. Dominant genes for resistance to clinical symptoms were transferred to the Lewis (LEW) background from the BN.B1 strain through two generations of backcrossing. Thus, there are genetically controlled mechanisms involved in the neurological expression of EAE which are independent of the inflammatory reaction as observed in central nervous system (CNS) histology.

Palate teratogenicity and embryotoxicity of cyclosporin A in mice.

Mice of the A/J and B10.A/SgSnJ strains were treated with 50 mg of cyclosporin A (CsA) per kg of body weight on day 12 of gestation. There were significantly more fetal resorptions in both the A/J and B10.A strain when treated with CsA than in controls treated with olive oil. A low frequency (7.6%) of isolated cleft palates were induced in the A/J strain, which was significantly greater than that observed in A/J mice treated with olive oil alone. No cleft palates were induced in B10.A, which suggests that any increase in susceptibility that was observed could not be attributed to H-2 linked genes.