PubMed Health⌕ Search

Biomedical subjects

P Nguyen

Publications and source records attributed to P Nguyen.

At least 37 records · Page 2Linked to original sources
PubMed2001

Geldanamycin abrogates ErbB2 association with proteasome-resistant beta-catenin in melanoma cells, increases beta-catenin-E-cadherin association, and decreases beta-catenin-sensitive transcription.

Beta-catenin undergoes both serine and tyrosine phosphorylation. Serine phosphorylation in the amino terminus targets beta-catenin for proteasome degradation, whereas tyrosine phosphorylation in the COOH terminus influences interaction with E-cadherin. We examined the tyrosine phosphorylation status of beta-catenin in melanoma cells expressing proteasome-resistant beta-catenin, as well as the effects that perturbation of beta-catenin tyrosine phosphorylation had on its association with E-cadherin and on its transcriptional activity. Beta-catenin is tyrosine phosphorylated in three melanoma cell lines and associates with both the ErbB2 receptor tyrosine kinase and the LAR receptor tyrosine phosphatase. Geldanamycin, a drug which destabilizes ErbB2, caused rapid cellular depletion of the kinase and loss of its association with beta-catenin without perturbing either LAR or beta-catenin levels or LAR/beta-catenin association. Geldanamycin also stimulated tyrosine dephosphorylation of beta-catenin and increased beta-catenin/E-cadherin association, resulting in substantially decreased cell motility. Geldanamycin also decreased the nuclear beta-catenin level and inhibited beta-catenin-driven transcription, as assessed using two different beta-catenin-sensitive reporters and the endogenous cyclin D1 gene. These findings were confirmed by transient transfection of two beta-catenin point mutants, Tyr-654Phe and Tyr-654Glu, which, respectively, mimic the dephosphorylated and phosphorylated states of Tyr-654, a tyrosine residue contained within the beta-catenin-ErbB2-binding domain. These data demonstrate that the functional activity of proteasome-resistant beta-catenin is regulated further by geldanamycin-sensitive tyrosine phosphorylation in melanoma cells.

Antibiotics, Antineoplastic↗
PubMed2001

Use of L-[(15)N] glutamic acid and homoglutathione to determine both glutathione synthesis and concentration by gas chromatography-mass spectrometry (GCMS).

A method for simultaneous measurement of both glutathione enrichment and concentration in a biological sample using gas chromatography mass spectrometry is described. The method is based on the preparation of N,S-ethoxycarbonylmethyl ester derivatives of glutathione, and the use of homoglutathione (glutamyl-cysteinyl--alanine) as an internal standard. A procedure for determination of glutamate concentration and enrichment is also reported. Both methods have within-day and day-to-day inter-assay coefficients of variation less than 5%, and recoveries of known added amounts of glutathione and glutamate are close to 100%. Taken together, these methods allowed determination of glutathione concentration and fractional synthesis rate in red blood cells using L-[(15)N] glutamic acid infusion. This approach was applied in vivo to investigate the effects of a 72 h fast, compared with a control overnight fast, on erythrocyte glutathione in a single dog. The 72 h fast was associated with a 39% decline in erythrocyte glutathione level, (2.9 +/- 0.4 versus 4.7 +/- 0.5 mmol l(-1), fasting versus control) with no change in glutathione fractional synthesis (67.4 versus 71.3% d(-1), fasting versus control).

Animals↗
PubMed2001

Identification of quantitative trait loci controlling activation of TRBV4 CD8+ T cells during murine gamma-herpesvirus-induced infectious mononucleosis.

The murine gamma-herpesvirus, MHV-68, shares important biological and genetic features with the human gamma-herpesvirus, Epstein-Barr virus. Following intranasal infection, mice develop an infectious mononucleosis-like syndrome accompanied by increased numbers of activated CD8+ T cells in the blood. A consistent feature of the CD8+ T-cell activation is a marked increase in the frequency of cells expressing a TRBV4+ T-cell receptor. Previous studies suggested that the magnitude of TRBV4 expansion varied significantly among mouse strains, and was influenced by both MHC and non-MHC genes. Detailed analysis of strains with high (C57BL/6) or low (DBA/2) TRBV4 CD8+ T-cell expansion showed that differences in the degree of expansion were not a consequence of variation in genetic susceptibility to the viral infection. Rather, the magnitude of the TRBV4 CD8+ T-cell expansion correlated with differences in expression of the unidentified stimulatory ligand on activated, latently infected B cells. In the present study, analysis of TRBV4 expansion in C57BL/6, DBA/2, B6D2 F1 mice, BXD recombinant inbred strains, and the progeny of C57BL/6xDBA/2 F1 hybrids backcrossed to C57BL/6 demonstrated strong cumulative dominance of the low DBA/2 trait and moderately high heritability (h2 approximately 0.5). Two quantitative trait loci (QTLs) strongly associated with variance in TRBV4 expansion were identified using simple and composite mapping procedures. The first QTL is located on Chromosome (Chr) 17, near or proximal to H2. The second QTL is located on Chr 6 in a region spanning the Tcrb and Cd8a loci.

Animals↗
PubMed2001

Leptin, body fat content and energy expenditure in intact and gonadectomized adult cats: a preliminary study.

The present study was conducted to assess the body composition, leptin, and energy expenditure changes following gonadectomy in cats. Twenty-one females (12 intact and nine spayed) and 21 males (11 intact and 10 castrated) were used. Body weight was recorded. Serum plasma leptin was measured by radioimmunoassay and body composition and energy expenditure were assessed after injection of doubly labelled water. These results confirmed the gain in body weight and body fat following neutering and demonstrated a strong linear relationship between body fat and serum level of leptin. Energy expenditure decreased in castrated cats in comparison with intact ones. This study underlined the effect of gonadectomy as a major factor of obesity in cats and showed that the increase in circulating leptin reflected the amount of body fat. The present results provide further evidence that the regimen of gonadectomized cats should be carefully controlled to avoid excessive weight gain.

Adipose Tissue↗
PubMed2001

Effects of dietary protein restriction and amino acids deficiency on protein metabolism in dogs.

Although stable isotope methods have been used to revisit the protein and amino acid requirements of humans in the last two decades, estimates of the minimum protein requirement of the dog have mainly been based on nitrogen balance studies. The aim of this study was: (i) to assess dog protein metabolism using the (13)C-leucine method, and (ii) to test the effects of protein deprivation and amino acid deficiency on protein metabolism. Eight dogs were fed three consecutive diets: (i) a normoprotein regimen [control; 63 g crude protein (CP)/Mcal metabolizable energy (ME)]; (ii) a protein-restricted diet (PR; 32 g CP/Mcal ME); and (iii) a protein-restricted diet that was, in addition, deficient in lysine and tryptophan (D-PR; 31 g CP/Mcal ME). The energy supply was similar for the three diets. The dogs were adapted to each diet for 2 weeks. After a 24 h fasting period, a 3 h infusion of (13)C-bicarbonate was performed, followed by a 3 h continuous infusion of L-[1-(13)C]leucine. Blood and breath samples were collected before and during the last hour of each isotope infusion for determination of plasma (13)C-alpha-ketoisocaproate and breath (13)CO(2) enrichments by mass spectrometry. Rates of protein breakdown, oxidation, and synthesis were calculated from leucine appearance into plasma, oxidation, and non- oxidative disposal, respectively, and expressed in g N/kg body weight (BW)0.75 per day, assuming body protein contains 0.08 g leucine per g protein. Protein breakdown was 3.71 +/- 0.17, 3.29 +/- 0.16 and 2.73 +/- 0.18 (mean +/- SEM) for control, PR, and D-PR, respectively (p < 0.01 D-PR versus control, and p < 0.05 D-PR versus PR). Protein synthesis was 3.08 +/- 0.13, 2.77 +/- 0.13, and 2.15 +/- 0.18 for control, PR and D-PR, respectively (p < 0.001 D-PR versus control, and p < 0.05 D-PR versus PR). Protein oxidation was 0.63 +/- 0.05, 0.53 +/- 0.05 and 0.58 +/- 0.05 for control, PR and D-PR, respectively (p=NS). These data suggest that: (i) the (13)C-leucine method can be used to assess large variations of protein turnover in dogs; (ii) dogs have the capacity to adapt their protein turnover to the level and to the quality of their protein supplies; and (iii) the dog nitrogen requirement for maintenance may be between 0.41 and 0.55 g N/kg BW(0.75) per day.

Adaptation, Physiological↗
PubMed2001

Gastrointestinal transit of solid radiopaque markers in large and giant breed growing dogs.

Observations on food tolerance in dogs have shown that some breeds, especially the giant breeds, have a greater digestive sensitivity. One of the consequences common in these breeds is a higher faecal water content and a poor faecal quality. This could be explained, at least in part, by limited digestive capacity and function in giant breed dogs. In this report, the gastric emptying that represents one parameter of the digestive function was studied in large and giant breed dogs during their growth. Six Great Danes (GD) and six Giant Schnauzers (GS) were fed small radiopaque markers mixed with a test diet at 12, 22 and 36 weeks of age. Abdominal radiographs were made every 30 min for a period of 4 h and then hourly until 12 h. At 12 weeks of age, the gastric emptying pattern was similar in both breeds. However, from 22 weeks of age, the gastric emptying of the GD was significantly more rapid than that of GS. The gastric emptying of small markers tended to slow down in growing dogs, especially in GS. A significant positive correlation between the gastric emptying time of 50% of markers and the body weight was found. These results show that GD have a lower gastric retention time of foods, which could lead to a poor digestion and an altered absorption of nutrients. These could explained why digestive function and sensitivity could be different in dogs from different sizes and breeds.

Age Factors↗
PubMed2001

The ChromaGen contact lens system: colour vision test results and subjective responses.

The ChromaGen lens system is designed to enhance colour perception in colour vision deficiency (CVD). To investigate its efficacy, 14 CVD subjects were prescribed ChromaGen contact lenses. Colour vision tests (Ishihara, Farnsworth Munsell D-15, Farnsworth Lantern) were administered at baseline, lens dispensing, and after a 2-week lens-wearing trial during which subjective responses were recorded daily using visual analogue scales. ChromaGen lenses significantly reduced ishihara error rates (p < 0.001; ANOVA), particularly for deutan subjects. There was also a significant reduction in errors (p < 0.005) on the D-15 test. Conversely, lens wear had no significant effect on Farnsworth Lantern test performance. Subjectively, subjects reported enhanced colour perception, but poor vision in dim light. Judgement of distance and motion were only slightly affected. We conclude that ChromaGen lenses may enhance subjective colour experience and assist in certain colour-related tasks, but are not indicated as an aid for CVD in occupations with colour vision-related restrictions.

Adolescent↗
PubMed2001

Protein restriction and dexamethasone as a model of protein hypercatabolism in dogs: effect of glutamine on leucine turnover.

To determine (1) whether protein restriction, combined with glucocorticosteroid treatment, can be used as a hypercatabolic model and (2) if so, whether glutamine attenuates protein wasting in this model, the effects of protein restriction, dexamethasone, and glutamine on leucine metabolism were assessed in dogs. A control group (n = 8) received a maintenance diet; another group (n = 8) received a protein-restricted diet either (1) alone; (2) along with a 7-day corticoid treatment; or (3) along with a 7-day corticoid treatment and a 7-hour intravenous (IV) glutamine infusion. The last day of each regimen, dogs underwent an IV isotope infusion in the fasting state, with a 3-hour NaH(13)CO3 infusion to assess CO2 production, and immediately thereafter, a 3-hour (13)C-leucine infusion to assess leucine appearance rate (Ra), oxidation (Ox), and nonoxidative leucine disposal (NOLD), expressed as micromol x kg(-1) x h(-1). Protein restriction was associated with a 24% decline in leucine Ra (223 +/- 16 v 298 +/- 17; P <.01), an index of whole body proteolysis, and a 29% decline in NOLD (180 +/- 15 v 223 +/- 13; P <.01), an index of whole body protein synthesis. In the protein-restricted group, dexamethasone treatment was associated with a 32% increase in Ra, (295 +/- 28 v 223 +/- 16; P <.05), a 186% increase in Ox (120 +/- 14 v 43 +/- 4; P <.001), with no change in NOLD, when compared with the protein-restricted alone. After protein restriction + dexamethasone, glutamine infusion induced a 40% increase in plasma glutamine (1,090 +/- 70 v 780 +/- 29 micromol x L(-1); P <.01), but failed to alter Ra, Ox, or NOLD. These results suggest that (1) in dogs, protein restriction combined with a 7-day course of dexamethasone results in alterations in leucine kinetics similar to those observed in stress-induced protein wasting in humans, and (2) in that model, a 7-hour IV glutamine infusion in the fasting state does not significantly attenuate protein wasting.

Animals↗
PubMed2001

Prevalence and predictors of skin disease in the Women's Interagency HIV Study (WIHS).

OBJECTIVE: We attempted to determine the prevalence and predictors of skin disease in a cohort of women with and at risk for HIV infection. METHODS: We analyzed baseline data from a multicenter longitudinal study of HIV infection in women. RESULTS: A total of 2018 HIV-infected women and 557 HIV-uninfected women were included in this analysis. Skin abnormalities were reported more frequently among HIV-infected than uninfected women (63% vs 44%, respectively; odds ratio [OR] 2.10; 95% confidence interval [95% CI], 1.74-2.54). Infected women were also more likely to have more than 2 skin diagnoses (OR, 3.27; 95% CI, 1.31-8.16). Folliculitis, seborrheic dermatitis, herpes zoster, and onychomycosis were more common among HIV-infected women (P < .05). Independent predictors of abnormal findings on skin examination in the infected women were African American race (OR, 1.38; 95% CI, 1.07-1.77), injection drug use (OR, 2.74; 95% CI, 2.11-3.57), CD4(+) count less than 50 (OR, 1.68; 95% CI, 1.17-2.42), and high viral loads (100,000-499,999 = OR, 1.77; 95% CI, 1.32-2.37; > 499,999 = OR, 2.15; 95% CI, 1.42-3.27). CONCLUSION: HIV infection was associated with a greater number of skin abnormalities and with specific dermatologic diagnoses. Skin abnormalities were also more common among women with CD4(+) cell depletion or higher viral load.

Adolescent↗
PubMed2001

A randomized double-blind clinical trial of the effect of chondroitin sulfate and glucosamine hydrochloride on temporomandibular joint disorders: a pilot study.

Previous studies have shown chondroitin sulfate and glucosamine hydrochloride have beneficial effects on symptoms of osteoarthritis of the knee. Our aim was to study the effect of a daily dose of 1500 mg of glucosamine hydrochloride (GH) and 1200 mg of chondroitin sulfate (CS) taken for twelve weeks on subjects diagnosed with capsulitis, disk displacement, disk dislocation, or painful osteoarthritis of the temporomandibular joint (TMJ). Forty-five subjects were enrolled in the study and were randomly assigned to either an active medication group or a placebo group. Eleven subjects were lost from the study for various reasons, resulting in fourteen subjects remaining in the active medication group and twenty subjects remaining in the placebo group. Subjects taking CS-GH had improvements in their pain as measured by one index of the McGill Pain Questionnaire, in TMJ tenderness, in TMJ sounds, and in the number of daily over-the-counter medications needed. Subjects taking the placebo medication had improvements in their pains as measured by the visual analog scale and by four indices of the McGill Pain Questionnaire. Additional studies are required to evaluate the clinical effectiveness of CS-GH and to determine the exact mechanism by which CS-GH affects the articular cartilage of synovial joints.

Adult↗
PubMed2001

Factors controlling levels of CD8+ T-cell lymphocytosis associated with murine gamma-herpesvirus infection.

Intranasal infection of mice with murine gamma-herpesvirus 68 (MHV-68) elicits a striking CD8+ T-cell lymphocytosis following the establishment of latency, which includes a marked increased frequency of Vbeta4+ CD8+ T cells. The Vbeta4+ CD8+ T cells do not recognize a conventional viral peptide, but are stimulated by an uncharacterized ligand expressed on latently infected, activated B cells. The selective expansion of Vbeta4+ CD8+ T cells after MHV-68 infection is observed in all mouse strains examined, although the fold-increase varies widely, ranging from less than twofold to greater than 10-fold. The factors controlling the variation are currently undefined. In the current study, CD8+ T cell activation and Vbeta4+ CD8+ T-cell frequencies were analyzed in 18 inbred strains of mice. The data show that the magnitude of the Vbeta4+ CD8+ T-cell response correlates with the degree of CD8+ T cell-activation, and that both major histocompatibility complex (MHC) and non-MHC genes contribute to the magnitude of the activation. Furthermore, the magnitude of the response does not reflect major differences in susceptibility to viral infection and/or corresponding differences in the acute response. Rather the degree of Vbeta4+ CD8+ T cell activation may be determined by differences in levels of expression of the stimulatory ligand at the peak of latency.

Animals↗
PubMed2001

Potentiation of estrogen receptor activation function 1 (AF-1) by Src/JNK through a serine 118-independent pathway.

Estrogen receptor (ER) is activated either by ligand or by signals from tyrosine kinase-linked cell surface receptors. We investigated whether the nonreceptor Src tyrosine kinase could affect ER activity. Expression of constitutively active Src or stimulation of the endogenous Src/JNK pathway enhances transcriptional activation by the estrogen-ER complex and strongly stimulates the otherwise weak activation by the unliganded ER and the tamoxifen-ER complex. Src affects ER activation function 1 (AF-1), and not ER AF-2, and does so through its tyrosine kinase activity. This effect of Src is mediated partly through a Raf/mitogen-activated ERK kinase/extracellular signal-regulated kinase (Raf/MEK/ERK) signaling cascade and partly through a MEKK/JNKK/JNK cascade. Although, as previously shown, Src action through activated ERK stimulates AF-1 by phosphorylation at S118, Src action through activated JNK neither leads to phosphorylation of S118 nor requires S118 for its action. We therefore suggest that the Src/JNK pathway enhances AF-1 activity by modification of ER AF-1-associated proteins. Src potentiates activation functions in CREB-binding protein (CBP) and glucocorticoid receptor interacting protein 1 (GRIP1), and we discuss the possibility that the Src/JNK pathway enhances the activity of these coactivators, which are known to mediate AF-1 action.

CREB-Binding Protein↗
PubMed2000

The enamel protein amelogenin binds to the N-acetyl-D-glucosamine-mimicking peptide motif of cytokeratins.

Amelogenins bind to GlcNAc of the dentine-enamel matrix proteins (Ravindranath, R. M. H., Moradian-Oldak, J., Fincham, A. G. (1999) J. Biol. Chem. 274, 2464-2471). The hypothesis that amelogenins may interact with the peptides that mimic GlcNAc is tested. GlcNAc-mimicking peptide (SFGSGFGGGY) but not its variants with single amino acid substitution at serine, tyrosine, or phenylalanine residues inhibited hemagglutination of amelogenins and the terminal tyrosine-rich amelogenin polypeptide (TRAP). The binding affinity of SFGSGFGGGY to amelogenins was confirmed by dosimetric binding of amelogenins or TRAP with [(3)H]peptide, specific binding in varying concentrations of the peptide, Scatchard plot analysis, and competitive inhibition with the unlabeled peptide. The ability of the peptide or GlcNAc to stoichiometrically inhibit TRAP binding of [(14)C]GlcNAc or [(3)H]peptide indicated that both the peptide and GlcNAc compete for a single binding site. Using different fragments of amelogenins, we have identified the peptide-binding motif in amelogenin to be the same as the GlcNAc-binding "amelogenin trityrosyl motif peptide." The GlcNAc-mimicking peptide failed to bind to the amelogenin trityrosyl motif peptide when the tyrosyl residues were substituted with phenylalanine or when the third proline was replaced with threonine, as in some cases of human X-linked amelogenesis imperfecta. This study documents that molecular mimicry may play a role in stability and organization of amelogenin during amelogenesis.

Acetylglucosamine↗
PubMed2000

An antiestrogen-responsive estrogen receptor-alpha mutant (D351Y) shows weak AF-2 activity in the presence of tamoxifen.

Antiestrogens, including tamoxifen and raloxifene, block estrogen receptor (ER) action by blocking the interactions of an estrogen-dependent activation function (AF-2) with p160 coactivators. Although tamoxifen does show some agonist activity in the presence of ERalpha, this stems from a distinct constitutive activation function (AF-1) that lies within the ERalpha N terminus. Previous studies identified a naturally occurring mutation (D351Y) that allows ERalpha to perceive tamoxifen and raloxifene as estrogens. Here, we examine the contributions of ERalpha activation functions to the D351Y phenotype. We find that the AF-2 function of ERalpha D351Y lacks detectable tamoxifen-dependent activity when tested in isolation but does synergize with AF-1 to allow enhanced tamoxifen response. Weak tamoxifen-dependent interactions between the ERalpha D351Y AF-2 function and GRIP1, a representative p160, can be detected in glutathione S-transferase binding assays and mammalian two-hybrid assays. Furthermore, tamoxifen-dependent AF-2 activity can be detected in the presence of ERalpha D351Y and high levels of overexpressed GRIP1. We therefore propose that the D351Y mutation allows weak tamoxifen-dependent AF-2 activity but that this activity is only detectable when AF-1 is strong, and AF-1 and AF-2 synergize, or when p160s are overexpressed. We discuss the possible structural basis of this effect.

Estrogen Receptor Modulators↗
PubMed2000

Effect of Staphylococcus enterotoxin B on the concurrent CD8(+) T cell response to influenza virus infection.

Bacterial superantigens have potent in vivo effects. Respiratory viral infections are often associated with secondary bacterial infections, raising the likelihood of exposure to bacterial superantigens after the initiation of the anti-viral immune response. In this study, the general and V beta-specific effects of exposure to Staphylococcal enterotoxin B (SEB) during influenza virus infection on both the ongoing acute and the subsequent recall CD8(+) T cell responses were analyzed, using the well-characterized murine influenza model system and tetrameric MHC/peptide reagents to directly identify virus-specific T cells. The results show that although superantigen exposure during the primary viral infection caused delayed viral clearance, there was remarkably little effect of SEB on the magnitude or TCR repertoire of the ongoing cytolytic T cell response or on the recall response elicited by secondary viral infection. Thus, despite the well-characterized immunomodulatory effects of SEB, there was surprisingly little interference with concurrent anti-viral immunity.

Acute Disease↗
PubMed2000

Human blood monocytes interact with type I collagen through alpha x beta 2 integrin (CD11c-CD18, gp150-95).

Human blood monocytes are attracted into connective tissues during early steps of inflammation and wound healing, and locally interact with resident cells and extracellular matrix proteins. We studied the effects of type I collagen on monocyte adhesion and superoxide anion production, using human monocytes elutriated from peripheral blood and type I collagen obtained from rat tail tendon. Both acid-soluble and pepsin-digested type I collagens promoted the adhesion of monocytes, whereas only acid-soluble collagen with intact telopeptides induced the production of superoxide. Adhesion and activation of monocytes on acid-soluble type I collagen depended on the presence of divalent cations. mAbs directed against integrin subunits CD11c and CD18 specifically inhibited adhesion and activation of monocytes on type I collagen. Protein membrane extracts obtained from monocytes were submitted to affinity chromatography on collagen I-Sepharose 4B, and analyzed by Western blotting using specific anti-integrin subunit Abs. In the case of both acid-soluble and pepsin-digested collagens, two bands were revealed with mAbs against CD11c and CD18 integrin subunits. Our results demonstrate that monocytes interact with type I collagen through CD11c-CD18 (alpha x beta 2) integrins, which promote their adhesion and activation. For monocyte activation, specific domains of the type I collagen telopeptides are necessary. Interactions between monocytes and collagen are most likely involved in the cascade of events that characterize the initial phases of inflammation.

Acids↗
PubMed2000

Ly49I NK cell receptor transgene inhibition of rejection of H2b mouse bone marrow transplants.

The Ly49 family of genes encode NK cell receptors that bind class I MHC Ags and transmit negative signals if the cytoplasmic domains have immunoregulatory tyrosine-based inhibitory motifs (ITIMs). 5E6 mAbs recognize Ly49C and Ly49I receptors and depletion of 5E6+ NK cells prevents rejection of allogeneic or parental-strain H2d bone marrow cell (BMC) grafts. To determine the function of the Ly49I gene in the rejection of BMC grafts, we transfected fertilized eggs of FVB mice with a vector containing DNA for B6 strain Ly49I (Ly49IB6). Ly49IB6 is ITIM+ and is recognized by 5E6 as well as Ly49I-specific 8H7 mAbs. Normal FVB H2q mice reject H2b but not H2d BMC allografts, and the rejection of H2b BMC was inhibited partially by anti-NK1.1 and completely by anti-asialo GM1, but not by anti-CD8, Abs. In FVB mice, NK1.1 is expressed on only 60% NK cells. FVB. Ly49IB6 hosts failed to reject H2d or H2b BMC, but did reject class I-deficient TAP-1-/- BMC, indicating that NK cells were functional. Nondepleting doses of anti-Ly49I Abs reversed the acceptance of H2b BMC by FVB.Ly49IB6 mice. FVB.Ly49IB6+/- mice were crossed and back-crossed with 129 mice-H2b, 5E6-, poor responders to H2d BMC grafts. While transgene-negative H2b/q F1 or first-generation back-crossed mice rejected H2b marrow grafts (hybrid resistance), transgene-positive mice did not. Thus B6 strain Ly49I receptors transmit inhibitory signals from H2b MHC class I molecules. Moreover, Ly49IB6 has no positive influence on the rejection of H2d allografts.

Animals↗