Expression of murine killer immunoglobulin-like receptor KIRL1 on CD1d-independent NK1.1<Superscript>+</Superscript> T cells

Three mouse killer immunoglobulin-like receptors (KIRs), namely, KIR3DL1, KIRL1, and KIRL2, have recently been identified in C56BL/6 (B6) mice. However, only two Kir genes are found in the B6 mouse genome sequence data base. To clarify this discrepancy, we cloned Kir cDNAs from multiple strains of mice. Sequencing of the cDNA clones showed that the Kir3dl1 gene is found in C3H/HeJ and CBA/J but not in B6 mice. Analysis of the single nucleotide polymorphism data base suggested that Kir3dl1 is the C3H/HeJ and CBA/J allele of Kirl1. We generated mAb to the recombinant KIRL1 protein to investigate its expression pattern. The anti-KIRL1 mAb bound to NK1.1⁺ T cells but only very weakly or at undetectable levels to other lymphocytes including natural killer (NK) cells and conventional T cells. Among NK1.1⁺ T cells, conventional NK T cells stained with CD1d tetramer did not significantly bind anti-KIRL1 mAb, whereas CD1d-tetramer-negative subset was KIRL1-positive. Furthermore, the expression of KIRL1 is readily detected on NK1.1⁺ T cells from β₂-microglobulin-deficient B6 mice. Thus, KIRL1 is predominantly expressed on CD1d-independent NK1.1⁺ T cells.     

Participation of NK1.1+ T Cells in the Rejection of lpr αβT Cells When Bone Marrow Cells of Ipr Mice Are Transplanted into B6 Mice

When C57BL/6 (B6) mice were irradiated (9 Gy) and received bone marrow (BM) cells of B6-lpr/lpr mouse origin (i.e., lpr→B6), all mice died within 6 days. In the irradiated B6 mice, radioresistant CD3^? IL-2Rβ⁺ NK cells and IL-2Rβ CD3^int cells (i.e., CD3^int cells of extrathymic origin) remained, especially in the liver. There were two subsets, NK1.1⁺ and NK1.1^?, among the IL-2Rβ⁺ CD3^int cells. However, the NK1.1⁺ subset (i.e., NK1.1⁺ T cells) was much more radioresistant, and the majority of CD3^int cells belonged to this subset in irradiated mice. The expansion of lymphocytes from injected BM cells did not occur in the irradiated B6 mice. However, such expansion did take place in irradiated B6-lpr/lpr mice injected with both BM cells of B6-lpr/lpr and B6 origin. As a result, the mice subjected to BM cells survived. Irradiated B6 mice were treated in vivo with anti-NK1.1 mAb or anti-asialoGM₁ antibody to eliminate NK cells alone or both NK cells and NK1.1⁺ T cells. When irradiated B6 mice were pretreated with anti-NK1.1 mAb, the mice could survive. These results suggest that intact NK1.1⁺ T cells of extrathymic origin may recognize abnormal BM cells with the lpr gene and inhibit the expansion of lymphocytes, including abnormal double-negative CD4^?8^? cells, in B6-lpr/lpr mice. To inhibit the expansion of lymphocytes, mechanisms other than Fas ligand/Fas molecules on extrathymic T cells may be responsible.     

Age-Associated Increase of CD5+ B Cells in the Liver of Autoimmune (NZB × NZW) F1 Mice

The liver has been demonstrated to be a major site for extrathymic differentiation of T cells. In this study, an identification of CD5⁺ B cells, which are responsible for the onset of autoimmune disease by virtue of autoantibody production, was performed in autoimmune (NZB × NZW) F₁ mice. An age-associated increase of CD5⁺ B cells was demonstrated in the liver of these mice. Although CD5⁺ B cells (i.e., CD5⁺IgM⁺ and CD5⁺B220⁺) constituted a minor population of hepatic mononuclear cells (MNC) (<5%) when mice were young (8 weeks), a large population of CD5⁺ B cells (10 to 30% of whole MNC) was identified in the liver of mice aged 25 to 30 weeks after the onset of disease. Such age-dependent increase of CD5⁺ B cells was not observed in any other strains including NZB, NZW, C3H/He and BALB/c mice. The phenotype of hepatic CD5⁺ B cells was the same as that of CD5⁺ B cells in the peritoneal cavity and spleen, showing dull-CD5, bright-IgM and dull-B220. High levels of CD5⁺ B cells were observed in the peritoneal cavity and liver, but not in the spleen nor in any other lymphoid organs in mice aged 30 weeks. Radioimmunoassay of autoantibodies in the 5-day culture supernatants demonstrated that hepatic MNC were unable to produce any amounts of IgM- and IgG-autoantibodies against double-stranded DNA and single-stranded DNA, despite the increased proportion of CD5⁺ B cells. On the other hand, peritoneal exudate cells produced only IgM-, but not IgG-, autoantibodies, whereas splenic cells were able to produce both IgM- and IgG-autoantibodies. These results suggest that the liver might support the generation of the most primitive CD5⁺ B cells in these mice and that such generation increases as a function of age, probably resulting in the onset of autoimmune disease.     

129/SvJ mice have mutated CD23 and hyper IgE

CD23, the low affinity IgE receptor, is hypothesized to function as a negative regulator of IgE production. Upon discovering reduced CD23 surface levels in 129/SvJ inbred mice, we sought to further investigate 129/SvJ CD23 and to examine its influence on IgE levels. Five amino acid substitutions were found in 129/SvJ CD23. Identical mutations were also observed in CD23 from New Zealand Black and 129P1/ReJ mice. 129/SvJ B cells proliferated more rapidly than those from BALB/c after stimulation with IL-4 and CD40 ligand trimer. However, in vitro IgE levels in supernatants from stimulated 129/SvJ B cells were significantly reduced. Contrary to the in vitro findings, the 129/SvJ CD23 mutations correlated with a hyper IgE phenotype in vivo and 129/SvJ were able to clear Nippostrongylus brasiliensis infection more rapidly than either BALB/c or C57BL/6. Overall, this study further suggests that CD23 is an important regulatory factor for IgE production.     

Separation of T and B lymphocytes from various mouse strains by density gradient electrophoresis

T and B mouse spleen lymphocytes were separated by density gradient electrophoresis on the basis of their surface charge. In all strains examined, the T lymphocytes were found in the high mobility fractions and the B in the low. The T and B cells were separated completely in most fractions, with some overlapping in the middle. Significant differences were found in the electrophoretic distribution profiles between the strains: C57BL/6j, C57BL/10j, (BALB/cXC57BL/6j)F₁, and all the following: B₆·C-H-2^d/cBy (congenic to C57BL/6j), BALB/c, CBA/H/T6j, C57BL/10Sn, and C3H. The C57BL/6j and the (BALB/cXC57BL/6j)F₁ cells appear more heterogeneous as far as electrophoretic mobility is concerned. Almost all the other strains give two major peaks. Moreover, the high mobility areas are less populated in the C57BL/6j and the (BALB/cXC57BL/6j)F₁ animals than in all the others. The above differences were found consistently when cells prepared by different methods were electrophoresed. It is concluded that the surface charge of lymphocytes may be genetically determined. Possible dependency on the H-2 complex or non-H-2 areas is discussed.     

Interleukin-15 expression affects homeostasis and function of B cells through NK cell-derived interferon-γ

Interleukin-15 (IL-15) is a cytokine important for the development, maturation, and function of many cells of the immune system including NK, NKT, γδT, and CD8⁺ T cells. The relationship between IL-15 and B lymphocytes however, is not well characterized and is the focus of our study. Previous in vitro reports have shown that IL-15 increases proliferation of B lymphocytes and increases antibody secretion however, this relationship remains inadequately defined in vivo. The focus of this study was to examine the role of IL-15 in B cell homeostasis and function in vivo using mice that either over express IL-15 (IL-15tg mice) or are deficient in IL-15 (IL-15^−/− mice) production. Here we report significant differences between the B cell populations of IL-15^−/−, C57BL/6, and IL-15tg mice. In fact, increased expression of IL-15 resulted in a significant decrease in the percentage and absolute number of CD19⁺ cells. In vitro B cell co-cultures implicate interferon-gamma (IFN-γ) as the factor responsible for inhibiting B cell proliferation. We also show that IL-15 expression affects B cell function, as B cells from IL-15 transgenic mice produce greater amounts of IgG and IgA than IL-15 knockout mice in vitro. Interestingly, despite significant differences in B cell numbers in these strains, there were no significant differences in total antibody titers in serum and vaginal washes of these mice. Results from our in vivo and in vitro experiments suggest that altered expression of IL-15 affects B cell homeostasis through the induction of NK cell-derived IFN-γ.     

Uncoupling of Natural IgE Production and CD23 Surface Expression Levels

CD23, the low affinity receptor for immunoglobulin E (IgE), has been proposed to play a critical role in the regulation of IgE production, based on altered IgE levels in CD23-deficient mice and transgenic mouse models, as well as in mouse strains with mutations in the CD23 gene, e.g. 129 substrains. Here, we have investigated a mouse line termed LxT1 that expresses reduced CD23 surface levels on B cells, and its influence on natural IgE production. Extensive phenotypic analysis showed that CD23 surface expression was reduced in LxT1 compared to the control, without affecting B cell development in general. This CD23^low surface level in LxT1 mice is not as a result of reduced CD23 mRNA expression levels or intracellular accumulation, but linked to a recessive locus, a 129-derived region spanning 28 Mb on chromosome 8, which includes the CD23 gene. Sequence analysis confirmed five mutations within the CD23 coding region in LxT1 mice, the same as those present in New Zealand Black (NZB) and 129 mice. However, this CD23^low phenotype was not observed in all 129 substrains despite carrying these same CD23 mutations in the coding region. Moreover, serum IgE levels in LxT1 mice are as low as those in the C57BL/6 (B6) strain, and much lower than those in 129 substrains. These data indicate that the CD23 surface level and serum IgE level are uncoupled and that neither is directly regulated by the mutations within the CD23 coding region. This study suggests that caution should be taken when interpreting the immunological data derived from mice with different genetic background, especially if the gene of interest is thought to influence CD23 surface expression or serum IgE level.     

DonorIgh-linked genetic control of allotype-specific antibody response

Immunogenicity of allogeneic immunoglobulins in mice were studied, measuring the allotype-specific antibody activity by agglutination of allogeneic antibody-coated red blood cells. It was found that the serum from C.B-20 mice (Igh ^b , BALB/c-congenic) was uniquely immunogenic in BALB/c mice for allotype antibody response. Whereas the C57BL/6 (Igh ^b ) serum was immunogenic only when heat aggregated and/or combined with adjuvant, the ultracentrifugation-deaggregated C.B-20 serum was definitely immunogenic when administered in a moderate dose (100 μl/mouse). Even more surprising was the fast that very low doses (0.01–0.1 μl) of soluble C.B-20 serum, but not C57BL/6 serum, down regulated the allotype-specific response effectively. Genetic analysis on congenic mice suggested that the immunogenicity is controlled by donorIgh orIgh-V(Id-C.B) inasmuch as the serum from BALB/c-congenic C.B-20 (Igh-V ^b C ^b ), but not BALB/c-congenic BAB/14 (Igh-V ^a C ^b ), mice was active in BALB/c mice in soluble form. Further studies showed that the Id-C.B was dominantly expressed on the immunoglobulins of (BALB/c×C.B-20)F₁ and (C56BL/6×C.B-20)F₁ strains, and was originally derived from the C57BL/Ka strain. The major determinant for the antibody production was encoded inIgh-C, but not inIgh-V. It is suggested thatId-C.B controls the allotype-specific antibody response in an unusual manner, possibly acting as a unique determinant activating helper T cells.     

Genetic control of mitogen-induced B-cell hyperproliferation in SM/J mice

Previous studies have shown that B cells from SM/J mice exhibit hyperproliferative responsiveness to several bacterial-derived B-cell mitogens. This hyperresponse trait was found to be under autosomal, polygenic control by non-H-2 genes. We have now estimated the number of genes involved by statistical analysis of the proliferative responses of splenocytes from SM/J and low-responder C57BL/6J strains, and progeny from the (B6 × SM)F₁, F₂ and (F₁ × B6) crosses. The number of loci involved was ascertained using two different statistical approaches. An estimate of two loci was determined using chi-squared statistics. The second approach, based on an additive model in the natural log scale, also pointed to a lower bound of two genes. We conclude that the hyperresponse to B-cell mitogens in SM/J mice is determined by two autosomal genes which are not linked to the H-2 major histocompatibility complex.Abbreviations used in this paper LPS a bacterial lipopolysaccharide - AVIS a mitogenic preparation from Actinomyces viscosus - B6 C57BL/6J mice - ¹²⁵IUdR ¹²⁵Iodo-deoxyuridine     

Identifying tumor stem-like cells in mouse melanoma cell lines by analyzing the characteristics of side population cells

Increasingly more evidence shows that TSCs possess the characteristics of stem-like cells. However, a link between stem cells and TSCs remains to be shown. We have sorted SP cells and non-SP cells from the B16F10 cell lines by FACS, and then studied their cellular biological characteristics by using a SFCM culture method, proliferative assay in vitro, clone formation assays in soft agar and normal media, tumorigenic assays in C57BL/6 mice, and resistance to chemotherapy assay in vitro, the quantitative detecting expression of ABCG2 and their CD phenotype analysis by a FCM. We detected 0.96% SP cells in the B16F10 cells and found that they had obvious differences in characteristics from non-SP cells. They possessed a marked capacity for self-renewal in soft agar and culture medium, strong tumorigenic potential in C57BL/6 mice, apparent resistance to vinblastin in vitro, upregulated ABCG2 expression, and a high expression of CD44⁺CD133⁺CD24⁺ phenotypes. We conclude that there were a few of SP cells that had the characteristics of tumor stem-like cells which may provide a useful tool and a readily accessible source for further study when specific TSCs markers are unknown.     

Genetic control of the target structures recognized in hybrid resistance

Hybrid resistance of lethally irradiated (C57BL/6 × DBA/2)F₁ and (C57BL/10 × C3H)F₁ hybrid mice to the engraftment of parental C57BL/6 or C57BL/10 bone marrow cells is controlled by the H-2-linked Hh-1 locus. This resistance can be specifically blocked or inhibited by the injection of irradiated spleen cells from lethally irradiated, marrow reconstituted donor mice of certain strains. By testing the ability of regenerating spleen cells from various donor strains to block the resistance, we studied the genetic requirements for the expression of putative cell-surface structures recognized in hybrid resistance to H-2^b marrow cells. Strains of mice bearing informative intra-H-2 or H-2/ Qa-Tla recombinant haplotypes provided evidence that the Hh-1 locus is located telomeric to the H-2S region complement loci and centromeric to the H-2D region class I locus in the H-2 ^b chromosome. Two mutations that affect the class I H-2D ^b gene have no effect on Hh-1 ^b gene expression. The H-2D region of the H-2 ^S haplotype contains an allele of the Hh-1 locus indistinguishable from that of the H-2D ^b region, as judged by the phenotypes of relevant strains and F₁ hybrids. Collectively these data indicate that the Hh-1 locus is distinct from the class I H-2D (L) locus in the H-2 ^b or H-2 ^s genome, and favor the view that the expression or recognition of the relevant determinants is not associated with class I gene products.Abbreviations used in this paper BM(C) bone marrow (cells) - CML cell-mediated lympholysis - CTL cytotoxic T lymphocytes - FBS fetal bovine serum - HBSS Hanks' balanced salt solution - SC spleen cells from irradiated, bone marrow-reconstituted mice Address correspondence to: Dr. I. Najamura, Department of Pathology, School of Medicine, State University of New York at Buffalo, Buffalo, NY 14214, USA     

口服维生素D对实验性脑疟小鼠树突状细胞的影响

维生素D（VD）为固醇类衍生物,除发挥抗佝偻病作用,还具有一定的免疫调节功能。主要研究VD对实验性脑疟小鼠树突状细胞的影响。结果显示,与对照组相比,在伯氏疟原虫（P.bANKA）感染前给予VD,可降低C57BL/6小鼠发生脑型疟疾的风险,存活时间明显延长。VD预处理后,脾脏中髓样树突状细胞（CD11c⁺CD11b⁺）和浆样树突状细胞（CD11c⁺B220⁺）百分率明显降低,CD11c⁺MHCII⁺细胞、CD11c⁺TLR4⁺细胞和CD11c⁺TLR9⁺细胞的百分含量也显著减少。由此提示,预防性口服VD可抑制感染小鼠树突状细胞的数量和功能,对脑型疟疾的发生具有一定预防作用,为新型抗疟药物的研发提供参考。     

Accelerated Progression of a Murine Retrovirus-Induced Immunodeficiency Syndrome In Fas Mutant C57BL/6/lpr/lpr Mice

We reported previously that CD4⁺ T cells and B cells in mice with retrovirus-induced murine acquired immunodeficiency syndrome (MAIDS) caused by LP-BM5 murine leukemia virus (MuLV) mixtures increased the expression of Fas antigen (Fas) during progression of the disease. However, the contribution of the Fas/Fas ligand (Fas L) system to the pathogenesis of MAIDS remained unknown. Here, we examined the susceptibility of C57BL/6 (B6) lpr/lpr mice, which has been reported to be defective for the expression of Fas, to MAIDS. We found that the Thy 1.2^? CD4 T cells and IgK dull B220⁺ cells, which are characteristic of MAIDS, increased after the inoculation of LP-BM5 MuLV in B6 lpr/lpr mice. B22⁺ TCR αβ T cells, unique to lupus prone mice, also increased in the B6 lpr/lpr mice after infection. CD4⁺ B220⁺ TCR αβ T cells increased profoundly among the B220⁺ TCR αβ T cells from LP-BM5 MuLV-infected B6 lpr/lpr mice, while the B220⁺ TCR αβ T cells observed in non-infected B6 lpr/lpr mice were largely of the CD4^? CD8^? phenotype. A DNA PCR analysis of the LP-BM5 MuLV-infected B6 lpr/lpr mice revealed the genome integration of defective LP-BM5 virus, further confirming that MAIDS is inducible to B6 lpr/lpr mice. LP-BM5 MuLV-infected lpr/lpr mice died within 3 months, while MAIDS-infected B6 +/+ mice usually died within 5 to 6 months, and B6 lpr/lpr mice not infected with LP-BM5 MuLV lived more than 6 months. Taken together, these results suggest that MAIDS is inducible independently with functional Fas expression and the possibility of accelerated progression of murine AIDS and lpr-associated autoimmune disease in B6 lpr/lpr mice infected with LP-BM5 MuLV.     

Xid-defective male (CBA/N x C57BL/6)F1 accessory cells present bovine insulin to long-term cultured F1-restricted T-cells

The reactivity of H-2^b-restricted murine T cells towards bovine insulin was reported to depend on the expression of Ia.W39, a private specificity of I-A^b, on antigen-presenting cells. Cells of male (CBA/N x B6)F₁ mice carrying the mutation xid on the X chromosome lack Ia.W39 on the cell surface. These cells are unable to present bovine insulin to primed T cells derived from female (CBA/N x B6)F₁ mice. We show here that spleen cells of male (CBA/N x B6)F₁ hybrids served perfectly as accessory cells for the insulin-dependent induction of a proliferative response of long-term cultured T cells with (B10 x B10.BR)F₁ genotype, restricted to recognizing insulin in the context of F₁-unique I-A determinants. The epitope on the insulin molecule essential for stimulation was determined to depend on the glutamic acid residue in position 4 of the A chain of insulin. This contrasts with the H-2^b-restricted response of B6 mice to bovine insulin, which appears to be directed at the A chain loop determinant (amino acids A8 and A10). These data suggest that distinct I-A^b-encoded structures, the expression of which is regulated independently, may serve as components of restriction elements for H-2^b and (H-2^b x H-2^k)F₁ restricted T cells, which are specific for different epitopes of bovine insulin.     

Isolation of Mouse Peritoneal Cavity Cells

The peritoneal cavity is a membrane-bound and fluid-filled abdominal cavity of mammals, which contains the liver, spleen, most of the gastro-intestinal tract and other viscera. It harbors a number of immune cells including macrophages, B cells and T cells. The presence of a high number of naïve macrophages in the peritoneal cavity makes it a preferred site for the collection of naïve tissue resident macrophages (1). The peritoneal cavity is also important to the study of B cells because of the presence of a unique peritoneal cavity-resident B cell subset known as B1 cells in addition to conventional B2 cells. B1 cells are subdivided into B1a and B1b cells, which can be distinguished by the surface expression of CD11b and CD5. B1 cells are an important source of natural IgM providing early protection from a variety of pathogens (2-4). These cells are autoreactive in nature (5), but how they are controlled to prevent autoimmunity is still not understood completely. On the contrary, CD5⁺ B1a cells possess some regulatory properties by virtue of their IL-10 producing capacity (6). Therefore, peritoneal cavity B1 cells are an interesting cell population to study because of their diverse function and many unaddressed questions associated with their development and regulation. The isolation of peritoneal cavity resident immune cells is tricky because of the lack of a defined structure inside the peritoneal cavity. Our protocol will describe a procedure for obtaining viable immune cells from the peritoneal cavity of mice, which then can be used for phenotypic analysis by flow cytometry and for different biochemical and immunological assays.     

Development of peritoneal macrophage along a dendritic cell lineage in response to uptake of oligomannose-coated liposomes

In this study, we investigate the potential of peritoneal macrophages to differentiate into dendritic cell (DCs) in response to preferential uptake of oligomannose-coated liposomes (OMLs). About 30% of peritoneal cells (PECs) preferentially took up OMLs that were administered into the peritoneal cavity. The OML-ingesting cells expressed CD11b and F4/80, but lacked CD11c expression, indicating that the OML-ingesting PECs with a CD11b^highCD11c⁻ phenotype are resident peritoneal macrophages. During in vitro cultivation, CD11c⁺ cells arose among the PECs with ingested OMLs. CD11c⁺ cells also developed among enriched peritoneal CD11b^highCD11⁻ cells from OML-treated mice, and the resulting CD11c⁺ cells expressed co-stimulatory molecules and MHC class II. In addition, OML-ingesting CD11b^highCD11c⁺ cells were found in spleen after the enriched peritoneal macrophages with ingested OMLs were transplanted in the peritoneal cavity of mice. These results show that a fraction of peritoneal macrophages can differentiate into mature DCs following uptake of OMLs.     

Melanoma cell expression of CD200 inhibits tumor formation and lung metastasis via inhibition of myeloid cell functions

CD200 is a cell surface glycoprotein that functions through engaging CD200 receptor on cells of the myeloid lineage and inhibits their functions. Expression of CD200 has been implicated in a variety of human cancer cells including melanoma cells and has been thought to play a protumor role. To investigate the role of cancer cell expression of CD200 in tumor formation and metastasis, we generated CD200-positive and CD200-negative B16 melanoma cells. Subcutaneous injection of CD200-positive B16 melanoma cells inhibited tumor formation and growth in C57BL/6 mice but not in Rag1^−/−C57BL/6 mice. However, i.v. injection of CD200-positive B16 melanoma cells dramatically inhibited tumor foci formation in the lungs of both C57BL/6 and Rag1^−/−C57BL6 mice. Flow cytometry analysis revealed higher expression of CD200R in Gr1⁺ myeloid cells in the lung than in peripheral myeloid cells. Depletion of Gr1⁺ cells or stimulation of CD200R with an agonistic antibody in vivo dramatically inhibited tumor foci formation in the lungs. In addition, treatment with tumor antigen specific CD4 or CD8 T cells or their combination yielded a survival advantage for CD200 positive tumor bearing mice over mice bearing CD200-negative tumors. Taken together, we have revealed a novel role for CD200-CD200R interaction in inhibiting tumor formation and metastasis. Targeting CD200R may represent a novel approach for cancer immunotherapy.     

Prenatal TCDD causes persistent modulation of the postnatal immune response, and exacerbates inflammatory disease, in 36-week-old lupus-like autoimmune SNF1 mice

BACKGROUND: Prenatal exposure to the persistent environmental pollutant and model Ah receptor agonist, 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD), has been shown to permanently suppress postnatal cell‐mediated immunity. More recently, skewing of select adult T and B cell responses toward enhanced inflammation has also been described in C57BL/6 mice after prenatal TCDD. This raises questions about adverse postnatal immune consequences of prenatal TCDD in animals genetically predisposed to inappropriate inflammatory responses. METHODS: Lupus‐prone SNF₁ mice were exposed to 0, 40, or 80 µg/kg TCDD on gestation day (gd) 12 and examined at 36 weeks‐of‐age for immunomodulatory effects that correlated with worsened lupus pathology. RESULTS: Bone marrow pro‐ and large pre‐B cells were decreased by prenatal TCDD, in both adult male and female mice, as were pre‐ and immature B cells. Splenic CD23⁻CD1^hi and CD19⁺CD5⁺ B cells were increased in males, as were B220^hi B cells in females, further suggesting persistent disruption of B cell lymphopoiesis by prenatal TCDD. Female mice displayed decreased IL‐10 production by ConA‐activated splenocytes, while males underproduced IL‐4. Autoreactive CD4⁺Vβ17a⁺ spleen T cells were increased in both sexes by 80 µg/kg TCDD. Male mice but not females showed increased anti‐ds DNA and cardiolipin autoantibody levels. CONCLUSIONS: Prenatal TCDD augmented the hallmark indicators of SLE progression in the lupus‐prone SNF₁ mice, including renal immune complex deposition, glomerulonephritis, and mesangial proliferation. Prenatal TCDD therefore caused persistent modulation of the postnatal immune response, and exacerbated inflammatory disease, in lupus‐like autoimmune SNF₁ mice. Birth Defects Res (Part B) 92:82–94, 2011. © 2011 Wiley‐Liss, Inc.     

High-resolution genetic mapping of the saccharin preference locus (Sac) and the putative sweet taste receptor (T1R1) gene (Gpr70) to mouse distal Chromosome 4

The Sac (saccharin preference) locus affecting mouse behavioral and neural responsiveness to sweeteners has been mapped to distal Chr 4. A putative sweet taste receptor, T1R1, has been recently cloned, and the gene encoding it, Gpr70, has also been mapped to mouse distal Chr 4. To assess Gpr70 as a candidate gene for Sac, we compared the Gpr70 sequences of C57BL/6ByJ and 129P3/J mouse strains with different alleles of Sac. Using Gpr70 sequence variation between the C57BL/6ByJ and 129P3/J strains, we conducted a high-resolution analysis of the chromosomal localization of the Gpr70 and Sac loci in the F₂ hybrids and 129.B6-Sac partially congenic mice originating from these two strains. The Gpr70 gene maps proximal to Sac, which demonstrates that they are different loci. Received: 24 April 2000 / Accepted: 14 September 2000     

Natural resistance of irradiated 129-strain mice to bone marrow allografts: Genetic control by theH-2K region

A major genetic determinant of natural resistance to bone marrow allografts, designated asHh-3, was mapped to theH-2K region. This gene may code for or regulate the expression of cell surface structures selectively expressed on donor hemopoietic cells and recognized by naturally occurring cytotoxic effectors. Resistance was observed as failure of donor cell growth in the spleen of irradiated 129-strain (H-2 ^bc ) recipients of H-2^k bone marrow cells. The mapping was accomplished by substituting donor cells bearingk alleles throughout theH-2 complex with cells of recombinant mouse lines bearingk alleles at definedH-2 regions. The host antigraft reaction underlying resistance was abrogated by pretreating 129-strain mice with either rabbit antimouse lymphocyte serum or the antimacrophage agent silica. Grafting of H-2K^k cells into mice ancestrally unrelated to 129 but sharing theH-2 ^bc or the similarH-2 ^b haplotype, and intoH-2 ^b/k ,H-2 ^k/bc , andH-2 ^k/d F₁ hybrids revealed that resistance was unique to 129 mice, since mice of the other strains, including F₁ hybrids, were susceptible to the grafts. Thus,Hh-3 incompatibility was a necessary but insufficient condition for the manifestation of allogeneic resistance; other genetic factors not associated withH-2 conferred responder status to 129-strain mice and nonresponder status to D1.LP, B10.129(6M), B10, B6, and possibly to F₁ hybrid mice. The possible relationships between allogeneic resistance to H-2^k marrow grafts, hybrid resistance to H-2^k lymphomas, and F₁ hybrid antiparental H-2^k cytotoxicity induced in vitro are discussed.