Genetics of the anti-dextran B512 and the autoanti-idiotypic response: Codominant expression in F1 hybrids and dichotomy of response and allotype-linked idiotype

The IgM plaque-forming response to the alpha 1–6 epitope of dextran B512 is linked to the Ig-1 heavy chain allotypes j and b characteristic of CBA and C57BL strains, respectively, and the response typically induces the formation of autoanti-idiotypic antibodies that can distinguish between anti-dextran antibodies of CBA and C57BL origin. Nevertheless, some substrains of Balb/c mice (allotype a) and some Bailey recombinant stains give a PFC response although they do not possess allotypes j or b. The anti-dextran antibodies in these strains lack the idiotypes characteristic of either CBA and C57BL antibodies to dextran, but they possess their own particular idiotype. F₁ hybrids between two responder strains possessing different idiotypes on their antibodies against dextran, produce both idiotypes and two different autoanti-idiotypic antibodies. CBA(Ig-1^b) mice were high responders to dextran and possessed the idiotype of C57BL, whereas C57BL/6(Ig-1^a) mice were low responders. The V_H recombinant strains BAB.14 and CB-8KN that possess the Ig-1^b allotype of C57BL, but have some of theV _H genes from Balb/c and the rest from C57BL/6 were high responders to dextran, but did not possess the C57BL idiotype, suggesting that the genes determining the response against dextran and the idiotype may have different locations in the heavy chain locus.     

Genetic variation in the activity of the histidine catabolic enzymes between inbred strains of mice: A structural locus for a cytosol histidine aminotransferase isozyme (Hat-1)

Variation in activity of the main histidine catabolic enzymes (histidase, urocanase, and aminotransferase) has been surveyed using inbred strains of mice (C57BL, DBA, Peru, SM, and SWR). Some variation was found in the activity of all enzymes, but only in the case of cytosolic histidine aminotransferase was it greater than twofold (SM 3.3-fold greater than C57BL). The divergent strains for the activity of this enzyme were crossed and the F ₁ 's were backcrossed; the segregation analysis indicated a single locus with additively acting alleles (designated Hat-1: a allele SM, b allele C57BL). Cytosolic histidine aminotransferase differed in heat stability between SM and C57BL, indicating that Hat-1 is a structural locus. The conflict in the biochemical literature (Morris et al., 1973; Noguchi et al., 1976a, b) over the number and subcellular distribution of the histidine aminotransferase isozymes is partly resolved by the acquisition of a variant at the Hat-1 locus. Hat-1 affects the cytosolic form but not the mitochondrial form of the enzyme. Purification and analysis of the isozymes of histidine aminotransferase from livers of C57BL and SM mice will further clarify the situation.     

Cleft palate susceptibility linked to histocompatibility-2 (H-2) in the mouse

Data have been obtained indicating that cortisone-induced cleft palate in the mouse is linked to theH-2 ^a complex. Cortisone (2.5 mg) was administered to pregnant females on days 11 through 14 of pregnancy. On day 17 of pregnancy, the fetuses were inspected for cleft palates. Sham experiments were done by injecting sterile saline instead of cortisone. The inbred strains, A/J and C57BL/6, and the congenic strains C57BL/10ScSn and B10.A were tested for susceptibility to cleft palate. The clefting frequency was also observed in hybrids of the congenic strains. The A/J and B10.A strains showed a characteristic high susceptibility to cleft palate (i.e., 99% and 81% incidence of cleft palate, respectively) after teratogenic treatment. The C57BL/6 and C57BL/ 10ScSn demonstrated a significant resistance to the teratogen (i.e., 25% and 21 % incidence of clefting, respectively). The teratogenic treatment of congenic hybrids indicated that maternal influences significantly affected the incidence of cleft palate formation. The maternal influence appeared to depend upon the specificH-2 haplotype of the mother.     

Use of fluorescence microspectral method for studying bone marrow EGFP+ cell transplantation in 5-fluorouracil-treated mice

In this paper the experimental results of bone marrow transplantation from C57BL/6-Tg(ACTB-EGFP)1Osb/J transgenic mice into C57BL/6 mice subjected to 5-fluorouracil treatment are represented. It has been shown that EGFP⁺ cell engraftment in bone marrow, spleen and thymus of host mice after 5-Fu treatment significantly increased. More long-term engraftment was recorded after transplantation between closely related donors and 5-fluorouracil treatment hosts. We have also obtained data on differences in the dynamics of EGFP⁺ cell engraftment in host investigated organs. To assess the effect of the donor’s bone marrow cells on the host immune system, functional activity of the synthetic apparatus (synthetic activity) of cells in bone marrow, spleen, thymus and blood have been investigated with fluorescence microspectral method. The results obtained allow of improving techniques for bone marrow transplantation without host irradiation in order to minimize the adverse effects.     

Relationship among H-2 type,serum testosterone level,and kidney β-glucuronidase activity in the mouse

C57BL/Kl, DBA/2/Kl, and backcross male mice have been analyzed for H-2 type, serum testosterone level, and kidney β-glucuronidase activity. No associations or correlations were found among these three parameters in the backcross material.     

H-2 restriction of cytolysis after immunization of minorH congenic pairs of mice

Mice of three congenic resistant lines differing from C57BL/10 at theH-3, H-13, H-7, andH-8 minor histocompatibility loci were used to immunize, and were immunized with, C57BL/10. Cytotoxic cells which were capable of causing rapid lysis of cells from the immunizing strain were generated at least one-way in all combinations tested. In order for a target to be susceptible to cytolysis, it had to carry both the sameH-2 ^b haplotype and the same differential minor histocompatibility alleles as the immunizing strain. That is, B10.C(47N) (H-2 ^b ,H-7 ^b ) anti-C57BL/10 (H-2 ^b ,H-7 ^a ) cytotoxic cells lysed C57BL/10 targets but not B10.BR (H-2 ^k ,H-7 ^a ) targets, nor BALB.B (H-2 ^b ,H-7 ^b ) targets. Crossreactions in the cytotoxic assay suggest that theH-3, H-13 congenic pair —B10.LP and C57BL/10 —may differ in at least two more minor histocompatibility loci which have not yet been defined. Although 6 x 10⁶6 C57BL/10 lymphoid cells primed B10.D2(57N) (H-8 ^b ) mice for a secondary in vitro cytotoxic response, a tenfold higher dose apparently made them tolerant. It is concluded that all minor histocompatibility differences can generate cytotoxic T cells which show specificity both for the minor and major histocompatibility alleles.     

Genetic regulation of the expression of catalase activity in murine red blood cells

The specific activity (k′₁) and concentration of red blood cell catalase from four inbred strains of mice (BALB/c, C57BL, C57BL/6, and NBL) were measured to determine the mechanisms responsible for interstrain variations in enzyme activity. The specific activities of RBC catalase in NBL and the C57BL sublines are equal (2.5×10⁷ m ^?1 sec^?1), while that of BALB/c (4.0×10⁷ m ^?1 sec^?1) is 67% greater. The relative concentration of catalase is approximately 30% lower in NBL erythrocytes compared to the other three strains. The activity of BALB/c RBC catalase is due to a high k′₁ coupled with a high intracellular concentration; RBC catalase activity in the C57BL sublines is the result of a low k′₁ and high concentration. A low k′₁ and a low concentration are responsible for the low catalase activity levels found in NBL erythrocytes.     

Serum prealbumin in inbred strains of Mus musculus

Separation of blood serum prealbumin from ten strains of inbred mice was accomplished using acrylamide electrophoresis. Nine of these strains demonstrated the same five prealbumin bands; however, the C57BL/6JWg strain showed a sixth band. The use of appropriate crosses of C57BL/6JWg and DBA/2fWg showed this unique band to be the product of a single autosomal dominant gene. We have named the gene for this prealbumin band Pre-1 and have shown a map distance between Pre-1 and b of 2.25 cM. Only one of the five prealbumins present in all strains of mice tested showed nonspecific esterase activity.     

The immune response of inbred mouse strains to DNP-BGG

The immune response of six inbred mouse strains (SJL, A, C57BL/6, CBA, BALB/c, and DBA/1) to DNP₅₆BGG was tested under three separate immunization schedules: 1 Μg DNP-BGG in 1 mg Al(OH)₃ adjuvant, 50 Μg DNP-BGG in 1 mg A1(OH)₃ adjuvant, and 1 Μg DNP-BGG in complete Freund's adjuvant. Individual serum samples were titered using a modified Farr assay. It was found that the first schedule allowed classification of the mice into responder (SJL, A) and nonresponder (C57BL/6, CBA, BALB/ c, DBA/1) strains. The second schedule produced quantitative as well as qualitative differences among the strains and allowed classification of the mice into higher-responder (SJL, A), intermediate-responder (C57BL/6, CBA, BALB/c), and low-responder (DBA/1) categories. When complete Freund's adjuvant was used in the third schedule, the differences among strains became insignificant. The sera from each strain were pooled and assayed for relative antibody affinity and IgM content. Both of these parameters were dependent largely on the dose of antigen and type of adjuvant used, rather than on the particular mouse strain being studied. The mechanism of adjuvant action, and possible cell interactions in the genetic control of the immune response, are discussed.     

G-CSF displays restricted ability to promote Sca-1+ cardiac stem cell proliferation in vitro

Granulocyte colony-stimulating factor (G-CSF) is a controversial chemical in cardiac cell therapy. Myocardial homing of mobilized bone marrow-derived cells is thought to play a critical role in observed G-CSF-induced cardiac repair; meanwhile, the activation of proliferative potential of cardiac stem cells (CSCs) residing in the heart is a significant challenge. The present study aims to investigate whether G-CSF receptor is expressed in adult resident Sca-1⁺ CSCs and determine the effect of G-CSF treatment on the proliferation of CSCs. For cardiac cells isolation, 12-week-old male C57BL/6 mice were anesthetized in a chamber containing 2.5 % isoflurane in oxygen, euthanized by CO₂ inhalation and then sacrificed by cervical dislocation. Magnetic-activated cell sorting was employed to acquire highly purified Sca-1⁺ CSCs. We found that G-CSF receptor was expressed in adult resident Sca-1⁺ CSCs by immunofluorescence staining and Western blotting. Exposure of Sca-1⁺ cells to G-CSF in the culture medium for 72 h induced time-dependent but self-limiting cell cycle acceleration with a restricted effect on the CSC proliferation. As a result, it has provided a new insight to focus on the association between cardiac G-CSF therapy and adult resident stem cell activation. It may suggest gaining a deeper insight into the mechanisms of the interaction between CSCs and G-CSF to develop a synergistic strategy based on resident stem cell and G-CSF therapy for heart disease.     

Immune response of mice to the Thy-1.1 antigen: Effect of theIr-5 alleles studied in 129/J and B10.129 (6M) mice

The primary immune response to the Thy-1.1 antigen was measured by a plaque assay that detected cells producing antibodies lytic for AKR thymocytes. B10.129(6M) mice carrying theH-2 complex of an intermediate responder (129) on a low-responder (B10) background, were low responders. Studies employing different F₁ hybrids and segregating generations of 129/J and 6M mice indicated that differences in responsiveness of those two strains depend on alleles at a single locus, loosely linked to theH-2 complex. These results lend further support to the previously advanced concept that the expression of theIr-Thy-1 allcles controlling the response to the Thy-1.1 antigen is influenced by the alleles at theIr-5 locus. In addition, studies employing F₁ hybrids produced through matings of 129/J, 6M, C3H.B10 and C57BL/6J mice to a panel of inbred strains suggested that in regard to the responsiveness to the Thy-1.1 antigen, 129/J and 6M mice are phenotypically, and presumably genotypically, similar to C3H.B10 and C57BL/6J mice, respectively.     

Genetics of histocompatibility in mice

Twenty-five new congenic lines with distinctive BALB/cBy-strain histocompatibility alleles introduced onto the C57BL/6By-strain background by a regimen of backcrossing and tailskin grafting have been established. Twenty-one of the histocompatibility loci represented by these lines are new, while four duplicate theH-1, H-2, H-7, andH-8 loci identified by Snell.     

Genetic relationship between β-galactosidase and β-fucosidase in the mouse

Evidence for the identity of β-galactosidase and β-fucosidase enzymes in the house mouse was obtained by examination of the enzyme activities in animals from different crosses between C57BL/Kl mice with high galactosidase and fucosidase activities and DBA/2/Kl mice with low activities. There is a strong correlation between the activities of these two enzymes in different tissues of F₂ animals. A comparison of the fractionation properties of β-galactosidase and β-fucosidase showed that the two activities had a parallel distribution and identical thermostability. These data suggest that the same enzyme catalyzes the hydrolysis of both substrates.     

Pleiotropic and other genetic effects influencing the activities of brain and liver enzymes in congenic lines of C57BL/6J mice with defined electrophoretic variant markers

A single genetic factor may affect the realization of several enzymes. To investigate the extent of pattern pleiotropy in the mouse, the activities of 28 enzymes in livers and brains from an inbred stock of C57BL/6J Nctr and five F₁ stocks heterozygous for known electrophoretic variants were measured. Five congenic backcross stocks of C57BL/6J, each homozygous for one or more electrophoretic markers, were mated with C57BL/6J Nctr to construct the heterozygous variant F₁ stocks. One of the five F₁ stocks had no enzyme activities significantly different from those of C57BL/6J Nctr, while two had one enzyme, one had four enzymes, and another had six enzymes with activities that were significantly different from those of C57BL/6J Nctr. The latter two F₁ stocks with multiple activity differences were those having the largest proportion of their genome of donor origin. Two of the F₁ stocks were different from each other for one enzyme, and two were different for another enzyme. These differences and the relationship of these enzyme activities to the variant genes suggest that several genetic factors may affect an enzyme's realization.     

Polymorphism of DNA Repair Gene xrcc1 and Lung Cancer Risk

The current large-scale meta-analysis was performed to reach a reliable conclusion on the association between X-ray repair cross-complementing 1 (xrcc1) rs1799782 and the development of lung cancer. Studies that investigated the association between rs1799782 and lung cancer risk were identified by searching PubMed. We calculated odds ratio (OR) with corresponding 95 % confidence interval (CI) for Trp/Trp vs Arg/Arg, Trp/Trp + Arg/Trp vs Arg/Arg, and Trp/Trp vs Arg/Trp + Arg/Arg contrast models. Combining all 25 studies, we yielded three summary ORs: 1.07 (95 % CI 0.92–1.23) for Trp/Trp vs Arg/Arg, 0.93 (95 % CI 0.87–1.00) for Trp/Trp + Arg/Trp vs Arg/Arg, and 1.08 (95 % CI 0.94–1.25) for Trp/Trp vs Arg/Trp + Arg/Arg, suggesting rs1799782 was not associated with overall risk of lung cancer. Strikingly, a significantly deceased risk was found among Caucasian populations (Trp/Trp + Arg/Trp vs Arg/Arg, OR = 0.86, 95 % CI 0.76–0.97). This study confirms that xrcc1 rs1799782 may lower the risk of lung cancer among Caucasians.     

Apparent Reduction of ADAM10 in Scrapie-Infected Cultured Cells and in the Brains of Scrapie-Infected Rodents

It has been described that A disintegrin and metalloproteinase (ADAM10) may involve in the physiopathology of prion diseases, but the direct molecular basis still remains unsolved. In this study, we confirmed that ADAM10 was able to cleave recombinant human prion protein in vitro. Using immunoprecipitation tests (IP) and immunofluorescent assays (IFA), reliable molecular interaction between the native cellular form of PrP (PrP^C) and ADAM10 was observed not only in various cultured neuronal cell lines but also in brain homogenates of healthy hamsters and mice. Only mature ADAM10 (after removal of its prodomain) molecules showed the binding activity with the native PrP^C. Remarkably more prion protein (PrP)-ADAM10 complexes were detected in the membrane fraction of cultured cells. In the scrapie-infected SMB cell model, the endogenous ADAM10 levels, especially the mature ADAM10, were significantly decreased in the fraction of cell membrane. IP and IFA tests of prion-infected SMB-S15 cells confirmed no detectable PrP-ADAM10 complex in the cellular lysates and PrP-ADAM10 co-localization on the cell surface. Furthermore, we demonstrated that the levels of ADAM10 in the brain homogenates of scrapie agent 263K-infected hamsters and agent ME7-infected mice were also almost diminished at the terminal stage, showing time-dependent decreases during the incubation period. Our data here provide the solid molecular basis for the endoproteolysis of ADAM10 on PrP molecules and interaction between ADAM10 and PrP^C. Obvious loss of ADAM10 during prion infection in vitro and in vivo highlights that ADAM10 may play essential pathophysiological roles in prion replication and accumulation.     

The amino-terminal sequence ofStreptomyces griseus carboxypeptidase

The amino-terminal sequence of carboxypeptidase fromStreptomyces griseus was determined using a new protocol for automatic Edman degradation that reduced background noise. The sequence of the first 48 residues is: Asp-Phe-Pro-Pro-Ala-Asp-Ser-Arg-Tyr-His-Asn-Tyr-Ala-Glu-Met-Asn-Ala-Ala-Ile-Asp-Ala-Arg-Ile-Ala-Ala-Asn-Pro-Ser-Ile-Met-Ser-Lys-Arg-Val-Ile-Gly-Lys-Thr-Tyr-Gln-Gly-(Arg)-Asp-Val-Ile-Ala-Val-Lys, which is homologous to that of other zinc-containing carboxypeptidase from vertebrate and invertebrate sources.     

On the existence of two GABA pools associated with newly synthesized GABA and with newly taken up GABA in nerve terminals

[¹⁴C]Glutamic acid and [³H]GABA were injected into the lateral ventricle of mouse and then [¹⁴C]GABA and [³H]GABA in synaptosomes isolated from the animals were analysed. The [¹⁴C]GABA was interpreted to be newly synthesized GABA from [¹⁴C]glutamic acid while the [³H]GABA to be newly taken up GABA. We have obtained the following results: (1) when the animals were pretreated with aminooxyacetic acid and thus the GABA content in synaptosomes increased to about 2 times of the control level, only the [³H]GABA was enhanced to 3 times of the control level without any change of [¹⁴C]GABA, (2) the release of [¹⁴C]GABA from synaptosomes by high K⁺ depolarization was 1.5 times greater than that of [³H]GABA, (3) the releases of both [¹⁴C]GABA and [³H]GABA were increased in the presence of cold GABA,l-2,4-diaminobutyric acid or γ-amino-β-hydroxybutyric acid, but only slightly increased in the presence of β-alanine. These results would suggest that newly synthesized GABA and newly taken up GABA localized individually in different pools, which might localize either in different nerve terminals or separately in the same nerve terminal.