Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Chimerism”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,585 records · Page 88Linked to original sources
PubMed2002

A chimeric mouse model of Gaucher disease.

BACKGROUND: There is a major need for a mouse model of Gaucher disease, but the glucocerebrosidase knockout mouse is not viable; it dies shortly before or immediately after birth, apparently because of involvement of the central nervous system and/or skin. The most common form of Gaucher disease, type I, has a phenotype that is limited to the monocyte-macrophage system. MATERIALS AND METHODS: We have created a chimeric mouse by infusing hematopoietic stem cells from fetuses that are homozygous for the glucocerebrosidase knockout into irradiated mice. RESULTS: The chimeric mice manifested a severe deficiency of glucocerebrosidase activity in peripheral blood cells and spleen indicating a lack of cell-cell correction. Levels of glucocerebroside in spleen and liver are increased, and infusing the mice with exogenous glucocerebroside/albumin particles produced a marked increase in the amount of glucocerebroside stored in liver and spleen. Morphologically identifiable Gaucher cells were not present. CONCLUSIONS: The chimeric model reflects the increased glycolipid storage in the reticuloendothelial system that is characteristic of Gaucher disease, and could be useful as a model for studying treatment of Gaucher disease.

Animals↗
PubMed2002

[Construction of specifically targeted chimeric hepatitis E virus DNA vaccine and its efficacy assessment].

OBJECTIVE: To design chimeric DNA vaccine targeted to antigen-presenting cells (APCs) with enhanced efficacy to induce immunization. METHODS: The plasmid containing the gene encoding cytotoxic T-lymphocyte antigen 4 (CTLA4), a surface molecule on T cells, was directly fused to the gene fragment HEVE2 coding for hepatitis E virus antigen by molecular engineering technology. The plasmid containing HEVE2 gene fragment alone was also constructed to serve as control and transfection of COS-7 cells with the 2 resultant plasmids was performed respectively, followed by assay of the expressions of CTLA4- HEVE2 fusion protein and HEVE2 protein in COS-7 cells by way of Western blotting. BALB/c mice were injected intracutaneously with the DNA vaccine (100 microgram) for 3 times at 2-week intervals, and the titer of anti-HEVE2 total IgG and IgG subclasses were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: The mammalian expression plasmids of CTLA4-HEVE2 fusion protein or HEVE2 protein alone were cloned. The culture supernants of COS-7 cells transfected with the plasmids showed the production of CTLA4-HEVE2 and HEVE2 proteins, which were secreted in the form of dimers. Mice immunized with pCTLA2-HEVE2 produced high levels of specific anti-HEVE2 total IgG titers with IgG2a, IgG2b and IgG1 subclasses predominant in the serum, approximately 50- to 100-fold higher than those in mice immunized with pHEVE2, whose serum contained predominantly IgG1. CONCLUSION: CTLA4-HEVE2 chimeric vaccine stimulates strong immune responses in mice, making it possible for further exploration into chimeric DNA vaccines that target the antigen to APCs.

Animals↗
PubMed2002

Quantitative analysis of chimerism after allogeneic peripheral blood stem cell transplantation.

BACKGROUND: For peripheral blood stem cell transplantation (PSCT), several engraftment analysis methods have been performed including detection of restriction fragment length polymorphisms and amplification of polymorphic genetic loci. To facilitate monitoring of the engraftment, a quantitative, non-isotopic method using a short tandem repeat (STR) marker has been set up in our laboratory. METHODS: DNAs from pretransplant recipients and donors were amplified with the AmpFISTR Profiler Plus kit that contains 9 STR markers. The fluorescent polymerase chain reaction products were then fractionated on polyacrylamide gels in an ABI PRISM 377 DNA sequencer. Results were analyzed using GeneScan 2.1 software. We selected the best markers as informative alleles which can distinguish donor from recipient. For quantitative analysis of the engraftment, we prepared a mixed chimeric sample by mixing pretransplant recipient and donor DNAs in different ratios to produce a standard curve. After amplifying the posttransplant recipient DNA, we were able to detect the extent of engraftment by interpolating the percent peak area of the informative alleles from this standard curve. RESULTS: We retrospectively analyzed 10 patients who had received allogeneic PSCT. Two of them showed some degree of mixed chimerism indicating leukemic relapse. In case one, 38.7% of the recipient DNA was first detected in the third month after PSCT. In case two, 6.5% of the recipient DNA was first detected in the tenth month after PSCT. CONCLUSION: In summary, this method provides an accurate, quantitative, and early assessment of mixed chimerism in posttransplant patients. Such information may be useful to guide implementation of additional treatment to circumvent graft failure or relapse in the future.

Adolescent↗
PubMed2003

A chimeric mouse model established by allogenic in utero transplantation.

In utero stem cells transplantation is a promising approach to the prenatal treatment of diseases. In order to investigate the fate of the stem cells after in utero transplantation, we have established a chimeric mouse model with the method of in utero transplantation. Mononuclear cells (including stem cells/progenitor cells) derived from male mouse bone marrow were injected into fetal mouse peritoneal cavity during the pre-immune period. The donor cells in the circulatory blood of female recipients were identified by fluorescence in situ hybridization (FISH), and the Y-chromosome specific DNA was detected by PCR as well as real-time quantitative PCR after the recipient mice were born. The results showed that a total of 4 female recipient mice were chimeric in their peripheral blood. Significantly, the donor cells in three chimeric mice persisted up to six months.

Animals↗
PubMed2003

[Expression of human-mouse chimeric antibody ch-BD1 and its affinity to human bladder cancer in vitro and in vivo].

OBJECTIVE: To investigate the expression of human-mouse chimeric antibody ch-BD1 against human bladder cancer and its affinity to human bladder cancer in vitro and in vivo. METHODS: Three kinds of mutated fragments of dihydrofolate reductase (DHFR) gene were created by techniques of molecular biology to decrease the transcriptional activities and then cloned into pDHL-BD1 so as to construct the vectors pWSD1-BD1, pWSD2-BD1, and pWSD3-BD1 expressing the human-mouse chimeric antibody ch-BD1 against human bladder cancer with decreased expression of DHFR gene. These vectors and pDHL-BD1 were transfected into Chinese hamster ovary cell (CHO)/DHFR- cell respectively. 72 hours later Northern blotting was used to examine their DHFR gene expression. Methotrexate (MTX) of increasing concentrations was added into the culture of transfected CHO/DHFR-cells. The ch-BD1 levels in the supernatants were measured. Purified ch-BD1 was labeled by (99m)TcO(4)(-) and added into the serially diluted solutions of human bladder cancer EJ cells to examine their radioactivities and calculate their affinity constants. EJ cells were injected into the roots of hind limb of 3 Balb/C mice. Four weeks later, (99m)TcO(4)(-)-labeled antibody ch-BD1 were injected into the rats' caudal veins. Radioimmunoimaging was conducted to examine the distribution of the antibody. RESULTS: The sequence of DHFR gene expression levels from strong to weak in the constructed vectors was as follows: pDHL-BD1 > pWS1-BD1 > pWS3-BD1 > pWS2-BD1. When the concentration of MTX was 10(-6) mol/L the expression level of ch-BD1 was significantly correlated to the expression level of DHFR gene, the lower the baseline expression level of DHFR gene the higher the expression level of ch-BD1. After the serially diluted EJ cells were co-incubated with the (99m)TcO(4)(-)-labeled antibody ch-BD1 the immunoactivity ratio of ch-BD1 was 76%, and that of murine monoclonal antibody was 81%; the affinity constant of ch-BD1 was 3.56 x 10(9) M(-1), and that of murine monoclonal antibody BD1 was 1.22 x 10(9) M(-1). 6 hours after injection of the (99m)TcO(4)(-)-labeled antibody ch-BD1 into the mice body it was mainly distributed in the tumor, 22 hours later, it was specifically distributed in tumor, and 24 hours later it was still concentrated here. CONCLUSION: Decrease of the baseline expression level of DHFR gene effectively increases the amplification of MTX to exogenous gene. The human-mouse chimeric antibody ch-BD1 shows an ideal affinity activity to human bladder cancer in vivo and in vitro and has a certain clinical prospect.

Animals↗
PubMed2003

Enhancement of mucosal immune responses by chimeric influenza HA/SHIV virus-like particles.

To enhance mucosal immune responses using simian-human immunodeficiency virus-like particles (SHIV VLPs) as a mucosal HIV vaccine, we have produced phenotypically mixed, chimeric influenza HA/SHIV 89.6 VLPs and used them to immunize C57B/6J mice intranasally. Systemic and mucosal antibody responses, as well as cytotoxic T cell (CTL) responses, were compared in groups immunized with SHIV 89.6 VLPs or HA/SHIV 89.6 VLPs. Intranasal immunizations were given using VLPs either with or without the addition of the mucosal adjuvant cholera toxin. Total serum IgG, IgG1 and IgG2a, and IgA in saliva, vaginal lavage, lung wash, and fecal extracts were evaluated by enzyme-linked immunosorbent assay (ELISA). The level of serum IgG production to HIV Env was highest in the group immunized with chimeric HA/SHIV 89.6 VLPs. Similarly, mucosal IgA production was also enhanced in the mucosal HA/SHIV 89.6 VLP-immunized group. Analysis of the IgG1/IgG2a ratio indicated that a Th1-oriented immune response resulted from these VLP immunizations. High levels of serum IgG and mucosal IgA against influenza virus were also detected in mice immunized with HA/SHIV VLPs. HA/SHIV 89.6 VLP-immunized mice also showed significantly higher CTL responses than those observed in SHIV 89.6 VLP-immunized mice. Furthermore, a Major Histocompatibility Complex (MHC)-class-I-restricted T cell activation ELISPOT assay showed elevated interferon-gamma, interleukin-2, and interleukin-12 production in HA/SHIV 89.6 VLP-immunized mice, indicating that phenotypically mixed HA/SHIV 89.6 VLPs can enhance both humoral and cellular immune responses at multiple mucosal sites. Therefore, chimeric HA-containing VLPs represent a potential approach for mucosal immunization for prevention of HIV infection.

Animals↗
PubMed2003

Mixed hematopoietic chimerism for preventing graft-versus-host disease in mice receiving rat bone marrow transplantation.

OBJECTIVE: To find a method for preventing graft-versus-host disease (GVHD) in BALB/c mice receiving rat bone marrow transplantation. METHODS: Firstly 12 SD rats were conditioned with 5.0 Gy sublethal total body irradiation(TBI), followed by infusion of 8 x 10(7) bone marrow cells from 28 BALB/c mice within 4 h and intraperitoneal administration of 100 mg/kg cyclophosphamide (Cy) 2 d later, for the purpose of inducing chimeric SD rats with specific immunological tolerance. Secondly, 24 BALB/c mice were exposed to 9.0 Gy lethal TBI and divided randomly into 3 equal groups designated respectively as groups A, B and C. Mice in group A were injected with 4 x 10(7) bone marrow cells from 4 normal rats, and mice in group B were injected with 4 x 10(7) bone marrow cells and 2 x 10(7) spleen cells from 4 normal rats, while those in group C were given 4 x 10(7) bone marrow cells and 2 x 10(7) spleen cells from 6 chimeric rats. The mice were then observed for 150 d for GVHD. RESULTS: In the second procedure, 2 mice in group A failed to survive due to infection and radiation injury respectively, and none of the rest mice presented signs of GVHD. The mice in group B all developed GVHD of varied degrees with symptoms as wasting, diarrhea, fur loss, arched body posture, and even bloody stool, and all died within 5 to 15 d with an average survival of 10.0 d (95% confidence interval 8,12). Pathological examination of the liver and intestinal tissues revealed inflammatory lymphocyte infiltration and necrosis. The majority of the mice in group C, in contrast, survived for more than 150 d with only two died on the postoperative days 18 and 31 respectively. The survival time of group B was significantly shorter than that of the other two groups. CONCLUSION: Donor/recipient chimerism may help prevent GVHD in xenogeneic bone marrow transplantation.

Animals↗
PubMed1992

Enhanced RNase H activity with methylphosphonodiester/phosphodiester chimeric antisense oligodeoxynucleotides.

Chimeric oligodeoxynucleotides, comprised of internal phosphodiester and terminal methylphosphonodiester sections, possess many beneficial characteristics as antisense effectors. We have investigated the effects of progressive replacement of phosphodiester by methylphosphonodiester linkages on hybrid stability with complementary RNA and DNA. The melting temperatures (Tms) of oligodeoxynucleotide/RNA heteroduplexes were found to decrease dramatically with increasing methylphosphonate substitution. In contrast, a smaller reduction in Tm was observed for comparable DNA heteroduplexes. This disparate reduction in hybrid stability was found with both the G + C-rich human c-myc and A + T-rich human c-Ha-ras sequences used, suggesting that methylphosphonate oligodeoxynucleotide analogues generally hybridize with less affinity to RNA than DNA. RNase H assays were employed to determine if the noted decreases in Tm impaired the ability of chimeric oligodeoxynucleotides to direct the degradation of RNA. Contrary to expectation, increasing methylphosphonate substitution gave rise to increasing rates of RNA degradation for both the c-myc and c-Ha-ras series. The present results suggest that chimeric oligodeoxynucleotide analogues may be of considerable utility as antisense agents in systems where RNase H is thought to make a major contribution to inhibition of gene expression.

Amino Acid Sequence↗
PubMedDate not supplied

Chimeric enkephalin-cystatins: opioid binding and structure-activity relationships of inhibitory domains.

A chimeric inhibitor of cysteine proteinases, YGGFLQVVAGK.amide, was synthesized for use in examining SAR of its cystatin and opioid domains. Analogs were prepared by solid-phase syntheses and evaluated for inhibition of rat brain cathepsin L (E.C. 3.4.22.15) and papain (E.C.3.4.22.2), or binding to rat brain opioid receptors using tritiated DSLET (delta), DAGO (mu) and U69593 (kappa) in competitive binding assays. Cystatin consensus analogs QVVAGK- or N-Ac.QVVK.amide were weakly active as inhibitors, but were enhanced 10-fold to 20-fold with N-terminal L-, FL-, GFL-, GGFL-, or YGGFL, yielding Ki 3 microM and 26 microM for cathepsin L and papain, respectively. YGGFL itself was inactive, but expressed inhibition with N-terminal Q-, QV-, QVV-, etc. Highest activity was found with YGGFLQVK.amide (Ki, 2 microM). N-Dns analogs differentially increased inhibition for papain, whereas an N-Ac-cyclic peptide, N-Ac-CKYGGFLQVVKC.amide, was 2-fold to 10-fold less potent than the two-domain inhibitor. Chimeric peptides containing YGGFL were equipotent as delta-ligands (Ki, 1.7-3.7 nM), but were 2-fold to 10-fold more potent as mu ligands (3.7-11 nM) versus YGGFL itself (37 nM). Two analogs with -QVVAK- and -QVK.amide expressed kappa-binding properties. These data demonstrate the feasibility of using chimeric peptides as probes for exploring enzyme catalysis, and the potential for targeting inhibitors to endosomal or lysosomal compartments via receptor-mediated uptake in cells.

Amino Acid Sequence↗
PubMed1992

The catalytic functions of chimeric reverse transcriptases of human immunodeficiency viruses type 1 and type 2.

The reverse transcriptases (RTs) from human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2, respectively) are relatively highly related yet there are several significant differences in their catalytic activities. In an attempt to relate these functional dissimilarities to the differences in amino acid sequences, we have employed a novel approach of constructing chimeric molecules composed of complementary amino acid sequences derived from the two HIV RTs. These recombinant proteins were analyzed for their enzymatic activities and for their sensitivity to tetrahydroimidazo[4,5,1-jk][1,4]benzodiazepin-2[1H]-one and thione (TIBO), which selectively inhibits only HIV-1 RT. The active chimeric RTs were used to map the TIBO binding site on the HIV-1 RT molecules and to localize the putative sequences responsible for the high RNase H activity of HIV-1 RT relative to that of HIV-2 RT. The results suggest that TIBO interacts with amino acid residues located around residue 200 within the DNA polymerase domain of HIV-1 RT which shows a relatively low similarity to HIV-2 RT. The difference in the RNase H activity maps to a position in the DNA polymerase domain rather than to the RNase H domain. Out of the 12 chimeric RTs generated, four were either fully active or hyperactive, three others lost most of their catalytic activities, and the rest were totally inactive. The pattern of catalytic activities of these hybrid proteins can be explained by a model for the initial folding of HIV RTs, which entails the formation of three distinct and independently folded regions. Each region can be formed by amino acid sequences derived exclusively from either HIV-1 RT or HIV-2 RT.

Amino Acid Sequence↗
PubMed1992

[Chimerism monitoring by VNTRs polymorphism analysis in a patient who received allogenic bone marrow transplantation].

A 39-year-old female diagnosed as acute myelogenous leukemia received allogenic bone marrow transplantation (BMT) pre-conditioned with busulfan and cyclophosphamide regimen from her HLA identical sibling. To distinguish donor and recipient cells, we analyzed variable numbers of tandem repeats (VNTRs) polymorphisms using a YNH-24 probe by Southern blot hybridization. VNTRs polymorphism analysis documented the engraftment of donor cells, relapse of recipient cells, and mixed hematopoietic chimerism. Assessment of the chimerism state is important for determining the prognosis of patients undergoing BMT, and VNTRs polymorphisms analysis is very useful for identifying the chimerism state.

Adult↗
PubMed2003

A Phase I trial of 90Y-anti-carcinoembryonic antigen chimeric T84.66 radioimmunotherapy with 5-fluorouracil in patients with metastatic colorectal cancer.

PURPOSE: Targeted systemic radiation therapy using radiolabeled antibodies results in tumor doses sufficient to produce significant objective responses in the radiosensitive hematological malignancies. Although comparable doses to tumor are achieved with radioimmunotherapy (RIT) in solid tumors, results have been modest primarily because of their relative lack of radiosensitivity. For solid tumors, as with external beam radiotherapy, RIT should have a more important clinical role if combined with other systemic, potentially radiation-enhancing chemotherapy agents and if used as consolidative therapy in the minimal tumor burden setting. The primary objective of this trial was to evaluate the feasibility and toxicities of systemic 90Y-chimeric T84.66 (cT84.66) anti-carcinoembryonic antigen RIT in combination with continuous infusion 5-fluorouracil (5-FU). EXPERIMENTAL DESIGN: Patients with chemotherapy-refractory metastatic colorectal cancer were entered. The study was designed for each patient to receive 90Y-cT84.66 anti-carcinoembryonic antigen at 16.6 mCi/m2 as an i.v. bolus infusion combined with 5-FU delivered as a 5-day continuous infusion initiated 4 h before antibody infusion. Cohorts of patients were entered at 5-FU dose levels of 700, 800, 900, and 1000 mg/m2/day. Upon reaching the highest planned dose level of 5-FU, a final cohort received 90Y-cT84.66 at 20.6 mCi/m2 and 5-FU at 1000 mg/m2/day. For all patients, Ca-diethylenetriaminepentaacetic acid at 125 mg/m2 every 12 h was administered for the first 72 h after 90Y-cT84.66. Patients were eligible to receive up to three cycles of 90Y-cT84.66/5-FU every 6 weeks. RESULTS: Twenty-one patients were treated on this study. All had been heavily pretreated with 19 having previously received 5-FU and 16 having failed two to four chemotherapy regimens. A maximum-tolerated dose of 16.6 mCi/m2 90Y-cT84.66 combined with 1000 mg/m2/day 5-FU was reached. These dose levels are comparable with maximum-tolerated dose levels of each agent alone. Thirteen patients received one cycle and 8 patients two cycles of therapy. Hematopoietic toxicity was dose-limiting and reversible. RIT did not appear to increase nonhematopoietic toxicities associated with 5-FU. Two of 19 patients assayed developed a human anti-chimeric antibody immune response after the first cycle of therapy, which is significantly less than that observed in a previous trial evaluating 90Y-cT84.66 alone. No objective responses were observed. However, 11 patients with progressive disease entering the study demonstrated radiological stable disease of 3-8 months duration and 1 patient demonstrated a mixed response. CONCLUSIONS: Results from this trial are encouraging and demonstrate the feasibility and possible advantages of combining continuous infusion 5-FU with 90Y-cT84.66 RIT. The addition of 5-FU does not appear to significantly enhance hematological toxicities of the radiolabeled antibody. In addition, 5-FU reduces the development of human anti-chimeric antibody response, permitting multicycle therapy in a larger number of patients. Future efforts should continue to focus on integrating radiation therapy delivered by radiolabeled antibodies into established 5-FU regimens.

Antibodies, Monoclonal↗
PubMed2003

[Construction and Identification of DNA vaccine containing chimeric gene gag-gp120 of HIV-1].

AIM: To construct DNA vaccine expression plasmid containing the chimeric gene gag-gp120 of HIV-1. METHODS: The recombinant eukaryotic expression vector pVAXGE was constructed via inserting the chimeric gene gag-gp120 into the vector pVAX1. Hela cells had been transfected by recombinant plasmid via liposome. After 72 h, the transfected cells was detected by RT-PCR and analyzed by Dot-ELISA. RESULTS: The transcript products of target gene could be amplified from the cells transfected by recombinant plasmid. Dot-ELISA detection showed that the target gene was expressed in Hela cells. CONCLUSION: The DNA vaccine plasmid expressing chimeric gene gag-gp120 was successfully constructed, which lays the foundation for preparing DNA vaccine against HIV-1.

Genetic Vectors↗
PubMed2003

One-step purification of chimeric green fluorescent protein providing metal-binding avidity and protease recognition sequence.

Gene fusion technique was successfully applied as a potential approach to create a metal-binding site to assist one-step purification of green fluorescent protein (GFP). The chimeric GFP carrying hexapolyhistidine (H6GFPuv) was purified to homogeneous protein via the Immobilized Metal Affinity Chromatography charged with zinc ions. Removal of metal tagger could readily be performed by using enterokinase enzyme. Engineering of the hexahistidine and enterokinase cleavage sites (DDDDK) onto the chimeric protein did not significantly affect the fluorescent property and the binding avidity to Burkholderia pseudomallei protease of a chimeric protease-binding GFP (H6PBGFPuv). This concludes that engineering of repetitive histidine regions onto interested target protein along with the enterokinase cleavage sites will ease the complication of protein purification.

Binding Sites↗
PubMed2004

[The immune response in mice inoculated with HIV-1 gag-gp120 chimeric gene DNA vaccine and IL-18 plasmid].

AIM: To explore the immune response in mice inoculated with HIV-1 chimeric gene gag-gp120 DNA vaccine and IL-18 plasmid. METHODS: BALB/c mice were injected i.m with eukaryotic expression plasmid pVAXIL18 containing IL-18 gene and DNA vaccine plasmid pVAXGE containing HIV-1 gag-gp120 chimeric gene. The specific killing activities of spleen CTL and the titers of serum antibodies of the immunized mice were detected. RESULTS: The specific killing activities of spleen CTL and the titers of serum antibodies in the co-inoculation group were significantly higher than those in the single inoculation group(P<0.05), the vector control group (P<0.01) and PBS control group (P<0.01). CONCLUSION: The specific cellular and humoral immunity in mice can be induced by co-inoculating HIV-1 gag-gp120 chimeric gene DNA vaccine and IL-18 plasmid indicating that IL-18 augments immune response as immunoadjuvant.

Adjuvants, Immunologic↗
PubMed1992

Comparison of GK1.5 and chimeric rat/mouse GK1.5 anti-CD4 antibodies for prolongation of skin allograft survival and suppression of alloantibody production in mice.

GK1.5 is a rat mAb that recognizes the mouse CD4 Ag. It has been shown to deplete CD4+ cells in vivo and to be immunosuppressive. To evaluate the effect of the C region of this antibody in achieving cell depletion, chimeric antibodies, each having the rat GK1.5 V regions and one of the four mouse IgG C region isotypes, were compared with the native rat antibody. The chimeric antibodies and the native antibody were tested for their ability to mediate in vitro C-dependent cytotoxicity, in vivo cell depletion, and prolongation of allogeneic skin graft survival and suppression of alloantibody production. In vitro C-dependent cytotoxicity assays revealed that rat IgG2b and the chimeric antibodies containing mouse IgG2a, mouse IgG2b, and mouse IgG3 were effective in lysing CD4+ lymphocytes whereas mouse IgG1 was ineffective. In vivo studies of CD4+ cell depletion showed that mouse IgG2a, rat IgG2b, and mouse IgG2b were effective isotypes, mouse IgG1 was less effective, and mouse IgG3 did not deplete CD4+ cells. A correlation was found between the ability of an isotype to deplete CD4+ cells in vivo and its ability to prolong the survival of skin allografts and to suppress alloantibody production. The nondepleting mouse IgG3 was ineffective in these assays. Overall the most effective mouse isotype was IgG2a which was as effective as rat IgG2b. These results indicate 1) that syngeneic isotypes of mAb can cause cell depletion and consequently the prolongation of allograft rejection and suppression of alloantibody production; 2) that not all isotypes are equally effective; and 3) that the ability of a given isotype to deplete cells in vivo does not correlate with its ability to mediate C-dependent lysis in vitro. Our results are consistent with the hypothesis that in vivo depletion of cells is mediated by opsonization and binding through the FcR.

Animals↗
PubMed2004

[Diagnostic significance and clinical application of specific chimeric genes in soft tissue sarcomas by RT-PCR using paraffin-embedded tissues: a study of 103 specimens].

OBJECTIVE: To investigate the expression of the chimeric genes resulting from the specific chromosomal translocations in soft tissue sarcomas (STS) and its diagnostic significance for STS. METHODS: The variety of fusion transcripts were detected in 103 cases of STS, including 30 cases of synovial sarcoma (SS), 15 cases of rhabdomyosarcoma (RMS), 25 cases of Ewing's sarcoma/peripheral primitive neuroectodermal tumors (ES/pPNET), 12 cases of dermatofibrosarcoma protuberans (DFSP), 14 cases of aveolar soft part sarcoma (ASPS), 3 cases of leiomyosarcoma (LMS), 2 cases of malignant fibrous histocytoma (MFH), and 2 cases of fibrosarcoma (FS); and 20 cases of control tumors by reverse transcription-polymerase chain reaction (RT-PCR) using formalin fixed, paraffin embedded specimens. RESULTS: Of the 34 cases of SS 28 (93.3%) expressed SSX-SYT chimeric transcripts (14 were positive for SYT-SSX1, 9 for SYT-SSX2). Four of the six cases of alveolar RMS had a PAX3/PAX7-FKHR fusion transcript. None of the 9 cases of embryonic and polymorphic RMS expressed PAX3/PAX7-FKHR. Of the 25 cases of ES/pPNET, 19 were positive for EWS-FLI1 fusion transcript and 1 for EWS-ERG fusion transcript. COL1A1-PDGFB fusion transcript was expressed in 8 of the 12 cases (66.7%) of DFSP. Of the fourteen cases of ASPS, ten expressed ASPL-TFE3 fusion transcript. None of the 3 cases of LMS, 2 cases of MFH, 2 cases of FS, and 20 control cases contained any of the fusion transcript. CONCLUSION: Chimeric gene transcript resulting from specific chromosomal translocations is a reliable index for the molecular diagnosis of STS and RT-PCR assay for detection of specific fusion gene provides a useful tool for confirmation of the diagnosis of STS in diagnostically difficult cases and in retrospective studies.

Artificial Gene Fusion↗
PubMed2005

Characterization of the functional domains of human foamy virus integrase using chimeric integrases.

Retroviral integrases insert viral DNA into target DNA. In this process they recognize their own DNA specifically via functional domains. In order to analyze these functional domains, we constructed six chimeric integrases by swapping domains between HIV-1 and HFV integrases, and two point mutants of HFV integrase. Chimeric integrases with the central domain of HIV-1 integrase had strand transfer and disintegration activities, in agreement with the idea that the central domain determines viral DNA specificity and has catalytic activity. On the other hand, chimeric integrases with the central domain of HFV integrase did not have any enzymatic activity apart from FFH that had weak disintegration activity, suggesting that the central domain of HFV integrase was defective catalytically or structurally. However, these inactive chimeras were efficiently complemented by the point mutants (D164A and E200A) of HFV integrase, indicating that the central domain of HFV integrase possesses potential enzymatic activity but is not able to recognize viral or target DNA without the help of its homologous N-terminal and C-terminal domains.

Amino Acid Sequence↗