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 361 records · Page 20Linked to original sources
PubMed2002

Detection of chimeric genes in Ewing's sarcoma and its clinical applications.

Ewing's sarcoma (ES), most commonly an undifferentiated tumor of bone, belongs to the enigmatic diagnostic category of small round cell tumors (SRCT) of childhood. The consistent presence of the translocation t (11; 22) in the vast majority of tumors provides evidence for a common histogenesis in ES and its family of tumors (ESFT), and also provides a unique diagnostic characteristic to discriminate this tumor family from SRCT. Molecular analysis of this translocation has revealed that it forms a chimeric gene between EWS on chromosome 22 and FLI-1 on chromosome 11. Similarly, the variant t (21; 22), t (7; 22), t (17; 22), and t (2; 22) rearrangements also form chimeric genes between regions of EWS and the ETS gene family (ERG, ETV1, E1AF, and FEV). Detection of these specific chimeric genes would provide a method for diagnosis of ESFT. We have developed a procedure for simultaneous detection of the chimeric genes by reverse transcription polymerase chain reaction (RT-PCR) with a mixture of primers. We conclude that the detecting those chimeric genes by this method can be easy and useful for diagnosis of ESFT. Moreover, by defining the specific chimeric gene it is possible to detect the tumor cell contamination in autologous blood stem cell transplantation.

Bone Neoplasms↗
PubMed2004

Expression and visualization of a human interferon-beta-enhanced green fluorescent protein chimeric molecule in cultured cells.

We have constructed a recombinant cDNA encoding the chimeric protein between human IFN-beta (HuIFN-beta) and enhanced green fluorescent protein (EGFP) to elucidate the intracellular localization of IFN-beta. Transient expression of the chimeric molecule, HuIFN-beta-EGFP, in L cells demonstrated that the chimeric molecule secreted from the cells had an intact biological activity as far as antiviral effect was concerned. Immunostaining of the transfected cells using anti-HuIFN-beta antibody demonstrated that green-fluorescence was co-localized with the IFN signal and its profile was similar to IFN signals in the cells transfected with HuIFN-beta expressing plasmid DNA. These results indicate that the HuIFN-beta-EGFP chimeric gene was expressed as a chimeric protein and the chimera was transported via the regular secretory pathway in the cells. In other cell types, the fluorescence derived from the chimeric protein was also seen on cytoplasmic vesicular structures. These results suggest that HuIFN-beta-EGFP will be a useful tool to investigate the intracellular trafficking processes of HuIFN-beta in a variety of cell types.

Animals↗
PubMed2005

Chimerism: a strategy to expand the utility and applications of peptides.

The modular nature of peptides can be exploited in the synthesis of chimeric sequences that combine diverse motifs in a single molecule. A theoretical consideration of the classification of peptides further expounds the multigeneric nature of peptide chimeras. Strategies for chimeric peptide syntheses include the chemical cross-linking of monomers and tandem combination by conventional SPPS. Additional details of chimeric peptide synthesis are also provided elsewhere in this volume. This chapter also explores some of the more common applications of chimeric peptides with particular emphasis on the molecular pharmacology of sequences that include address motifs for G protein-coupled receptors. Specific details of the biological properties of chimeras containing mastoparan, an amphiphilic tetradecapeptide component of wasp venom, further illustrate the novel and often unpredictable biological actions of chimeric constructs. These and numerous additional studies confirm that chimerism is an established strategy for the synthesis of molecular probes and bioactive agents.

Amino Acid Sequence↗
PubMed2004

Regeneration of heart muscle tissue: quantification of chimeric cardiomyocytes and endothelial cells following transplantation.

Persuasive evidence has been recently provided that adult bone marrow (BM) cells exert greater plasticity than previously assumed. This review is focused on the quantification of mixed chimerism (mCh) in the hearts (cardiomyocytes and endothelial cells) of patients after orthotopic heart to heart transplantation (HHT) in comparison to full (unmanipulated) allogeneic BM and peripheral blood stem cell (PBSC) transplants. Following a sex-mismatched transplantation constellation heart muscle tissue obtained at autopsy was examined. Evaluation of mCh was most often performed by immunophenotyping combined with fluorescence in-situ hybridization (FISH) applying x- and y-chromosome-specific DNA probes. When comparing our data with the results of former studies that were regularly based on the detection of the y-chromosome alone, the quantity of chimeric cardiomyocytes after HHT ranged from 0% to 9%. On the other hand, after full BM transplantats (chimeric) cardiomyocytes of donor-type origin appeared at an incidence between 0.23% to 6.4%. These disturbing inconsistencies were assumed to be related to methodology: the restriction to the y-chromosome, disregard of the plane of section (detection sensitivity ranging between 35% and 67%) and state of tissue preservation (cadaver hearts). Therefore, when strictly applying dual color FISH and limiting the recognition of chimeric cardiomyocytes and endothelial cells to the presence of two distinctive signals detection sensitivity was significantly enhanced. Contrasting a total congruence with the genotyping in control specimens of normal cadaver hearts, a striking disparity in the extent of mCh was found depending on the different modes of transplantation. After allografting with PBSC a considerably low incidence (1.6%) of chimeric cardiomyocytes was determined contrasting with 5.3% of donor-derived cells after full BM transplants. Following HHT host-type endothelial cells (16.2%) of the intramural and subepicardial vessel walls were more often encountered than following BM and PBSC allografting. These findings are in keeping with the assumption of a sprouting and migration of vascular structures into the donor heart from the site of surgical aligment and injury between retained host and donor atrial walls. When considering the other methods of transplantation (BM, PBSC) the data on chimeric endothelial cells support the hypothesis of a common hemangioblast. Concerning the cardiomyocytes it seems most reasonable to assume that primitive mesenchymal stem cells of the BM play a pivotal role in the development of mCh. This phenomenon is more extensively expressed than previously expected and may be related to an enforced repair of the damaged myocardium during the post-transplant period as the sequel of myeloablative (cardiotoxic) conditioning.

Animals↗
PubMed1999

Development of HIV/AIDS vaccine using chimeric gag-env virus-like particles.

We attempted to develop a candidate HIV/AIDS vaccine, by using unprocessed HIV-2 gag pr45 precursor protein. We found that a 45 kDa unprocessed HIV-2 gag precursor protein (pr45), with a deletion of a portion of the viral protease, assembles as virus-like particles (VLP). We mapped the functional domain of HIV-2 gag VLP formation in order to find the minimum length of gag protein to form VLP. A series of deletion mutants was constructed by sequentially removing the C-terminal region of HIV-2 gag precursor protein and expressed truncated genes in Spodoptera frugiperda (SF) cells by infecting recombinant baculoviruses. We found that deletion of up to 143 amino acids at the C-terminus of HIV-2 gag, leaving 376 amino acids at the N-terminus of the protein, did not affect VLP formation. There is a proline-rich region at the amino acid positions 373 to 377 of HIV-2 gag, and replacement of these proline residues by site-directed mutagenesis completely abolished VLP assembly. Our data demonstrate that the C-terminal p12 region of HIV-2 gag precursor protein, and zinc finger domains, are dispensable for gag VLP assembly, but the presence of at least one of the three prolines at amino acid positions 373, 375 or 377 of HIV-2NIH-Z is required for VLP formation. Animals immunized with these gag particles produced high titer antibodies and Western blot analyses showed that anti-gag pr45 rabbit sera react with p17, p24 and p55 gag proteins of HIV-1. We then constructed chimeric gag genes, which carry the hypervariable V3 region of HIV-1 gp120, because the V3 loop is known to interact with chemokine receptor as a coreceptor, and known to induce the major neutralizing antibodies and stimulate the cytoxic T lymphocyte responses in humans and mice. We expressed chimeric fusion protein of HIV-2 gag with 3 tandem copies of consensus V3 domain that were derived from 245 different isolates of HIV-1. In addition, we also constructed and expressed chimeric fusion protein that contains HIV-2 gag with V3 domains of HIV-1IIIB, HIV-1MN, HIV-1SF2 and HIV-1RF. The chimeric gag-env particles had a spherical morphology, and the size was slightly larger than that of a gag particle. Immunoprecipitation and Western blot analyses show that these chimeric proteins were recognized by HIV-1 positive human sera and antisera raised against V3 peptides, as well as by rabbit anti-gp120 serum. We obtained virus neutralizing antibodies in rabbits by immunizing these gag-env VLPs. In addition, we found that gag-env chimeric VLPs induce a strong CTL activity against V3 peptide-treated target cells. Our results indicate that V3 peptides from all major clades of HIV-1 carried by HIV-2 gag can be used as a potential HIV/AIDS vaccine.

AIDS Vaccines↗
PubMedDate not supplied

Chimeric restriction enzymes: what is next?

Chimeric restriction enzymes are a novel class of engineered nucleases in which the non-specific DNA cleavage domain of Fokl (a type IIS restriction endonuclease) is fused to other DNA-binding motifs. The latter include the three common eukaryotic DNA-binding motifs, namely the helix-turn-helix motif, the zinc finger motif and the basic helix-loop-helix protein containing a leucine zipper motif. Such chimeric nucleases have been shown to make specific cuts in vitro very close to the expected recognition sequences. The most important chimeric nucleases are those based on zinc finger DNA-binding proteins because of their modular structure. Recently, one such chimeric nuclease, Zif-QQR-F(N) was shown to find and cleave its target in vivo. This was tested by microinjection of DNA substrates and the enzyme into frog oocytes (Carroll et al., 1999). The injected enzyme made site-specific double-strand breaks in the targets even after assembly of the DNA into chromatin. In addition, this cleavage activated the target molecules for efficient homologous recombination. Since the recognition specificity of zinc fingers can be manipulated experimentally, chimeric nucleases could be engineered so as to target a specific site within a genome. The availability of such engineered chimeric restriction enzymes should make it feasible to do genome engineering, also commonly referred to as gene therapy.

DNA Restriction Enzymes↗
PubMed1989

Neuropsychological factors associated with perceptual biases for emotional chimeric faces.

Mechanisms underlying hemispace biases for free-field judgments of emotional intensity in chimeric faces were explored. The Levy et al. chimeric faces task (1983b) was examined in relationship to relevant neuropsychological measures (emotional, imaginal, ocular). Forty-four normal adults were administered a test battery including measures of chimeric face perception, lateral eye movements to nonemotional and emotional instructions, image generation, and ocular dominance ("eyedness"). Overall, subjects showed a significant left-sided bias for judging chimeric faces and for producing lateral eye movements to emotional instructions. Asymmetries for chimeric face perception were significantly correlated with asymmetries for the location of self-generated images in space. When task modalities were examined, there was a specific relationship between chimeric face perception and tactile processing on the other neuropsychological measures.

Adult↗
PubMedDate not supplied

Use of regression analysis and flow cytometry for determining levels of mixed semiallogeneic immune chimerism.

It has been shown that tolerance or specific immunologic nonresponsiveness in various lymphohemopoietic transplant models can be associated with the development of mixed lymphoid chimerism. As a specific example, composite tissue (limb) allografts were studied as a model for vascularized bone marrow transplantation (VBMT) and it was demonstrated that development of stable cellular immune chimerism is associated with long-term allograft survival. Recently, studies were initiated using a new parental to hybrid VBMT model, but the detection of donor cells is complicated, due to the fact that they share one parental allotypic determinant. Therefore, regression analysis with a flow cytometric immunofluorescent staining assay was evaluated for the assessment of cellular lymphoid chimerism in donor parental to hybrid (P-->F1) lymphohemopoietic transplant models. Standard curves consisting of known mixed populations of parental donor (Lewis, LEW) and hybrid host F1 (Lew x BN, LBN) lymphocytes were established. Standard curves were analyzed by linear regression statistics and excellent coefficients of determination (r > .881) were obtained for all standard curves. A highly statistically significant (p < .016) linear relationship between level of donor cell chimerism (independent variable) and percent stained (dependent variable) was determined. The technique was then evaluated using the parental to hybrid VBMT model. Levels of donor LEW lymphoid chimerism in all VBMT LBN recipients were successfully assessed by regression analysis and inverse prediction using distinct recipient allodeterminant markers. In conclusion, this technique was proven to be reliable and accurate for the detection of of chimerism in parental to F1 lymphohemopoietic allograft models.

Animals↗
PubMed2001

Apoptosis-inducing human-origin Fcepsilon-Bak chimeric proteins for targeted elimination of mast cells and basophils: a new approach for allergy treatment.

During the past few years, many chimeric proteins have been developed to specifically target and kill cells expressing specific surface molecules. Generally these molecules carry a bacterial or plant toxin to destroy the unwanted cells. The major obstacle regarding these molecules in their clinical application is the immunogenicity and nonspecific toxicity associated with bacterial or plant toxins. We lately reported a new approach for construction of chimeric proteins: we successfully replaced bacterial or plant toxins with human apoptosis-inducing proteins. The resulting chimeras were shown to specifically induce apoptosis in the target cells. Taking advantage of the human apoptosis inducing proteins Bak and Bax as novel killing components, we have now constructed new chimeric proteins targeted against the human FcepsilonRI, expressed mainly on mast cells and basophils. These cells are the main effectors of the allergic response. Treatment of the target cells with the new chimeric proteins, termed Fcepsilon-Bak/Bax, had a dramatic effect on cell survival, causing apoptosis. The effect was specific to cells expressing the FcepsilonRI of both human and, very unexpectedly, also of mouse origin. Moreover, interaction of the chimeric proteins with the mast cells did not cause degranulation. Fcepsilon-Bak/Bax are new chimeric proteins of human origin and, as such, are expected to be both less immunogenic and less toxic and, thus, may be specific and efficient reagents for the treatment of allergic diseases.

Animals↗
PubMed2004

Does HLA-dependent chimerism underlie the pathogenesis of juvenile dermatomyositis?

Juvenile dermatomyositis (JDM) is a multisystem autoimmune disease that at times resembles chronic graft-vs-host disease. This led us to suggest that nonself cells may play a role in the disease process. In this study we examined the relationship between HLA genotype and the presence of maternally derived chimeric cells in JDM patients and healthy controls, and assessed immunologic activity in the chimeric cells. We identified chimeric cells more often in children with JDM (60 of 72) than in their unaffected siblings (11 of 48) or in healthy controls (5 of 29). The presence of chimerism in the JDM patients, their healthy siblings, and unaffected control children was associated with a HLA-DQA1*0501 allele in the mother (p = 0.011). Further, we show that maternally transferred chimeric T cells are responsive to the host's (JDM childs') lymphocytes (33.75 +/- 8.4 IFN-gamma-producing cells from JDM cells vs 5.0 +/- 1.25 from maternal cells), and that this is a memory response. These combined data indicate that chimeric cells play a direct role in the JDM disease process and that the mother's HLA genotype facilitates the transfer and/or persistence of maternal cells in the fetal circulation.

Adolescent↗
PubMed2004

Th cell-independent immune responses to chimeric hemagglutinin/simian human immunodeficiency virus-like particles vaccine.

CD4(+) Th cells are believed to be essential for the induction of humoral and cellular immune responses. In this study we tested the effect and possible mechanisms of the major antigenic component in influenza, hemagglutinin (HA), in helping HIV Env to induce immune responses in CD4(+) T cell knockout (CD4 KO) mice. Simian HIV virus-like particles (SHIV VLPs) or phenotypically mixed chimeric influenza HA/SHIV VLPs were used as immunogens to immunize CD4 KO mice either i.p. or intranasally (i.n.). We found that chimeric HA/SHIV VLPs significantly induced a greater IgG Ab response in both i.p. and i.n. immunized mice and a greater IgA Ab response in mucosal washes in i.n. immunized mice compared with SHIV VLPs. Importantly, chimeric HA/SHIV VLPs induced approximately 3-fold higher neutralizing Ab titers against HIV 89.6 than SHIV VLPs in the absence of CD4(+) T cell help. There was also approximately 40% more specific lysis of the HIV Env-expressing target cells in chimeric HA/SHIV VLP-immunized than in SHIV VLP-immunized CD4 KO mouse splenocytes. Moreover, we have found that chimeric HA/SHIV VLPs could efficiently bind and activate dendritic cells and stimulate the activated dendritic cells to secret TNF-alpha and IFN-gamma. Therefore, chimeric HA/SHIV VLPs could efficiently prime and activate APCs, which could, in turn, induce immune responses in a CD4(+) T cell-independent manner. This study suggests a novel adjuvant role of influenza HA as well as a new strategy to develop more effective therapeutic vaccines for AIDS patients with low CD4(+) T cell counts.

Adjuvants, Immunologic↗
PubMed2000

Allogeneic hematopoietic chimerism in mice treated with sublethal myeloablation and anti-CD154 antibody: absence of graft-versus-host disease, induction of skin allograft tolerance, and prevention of recurrent autoimmunity in islet-allografted NOD/Lt mice.

We describe a tolerance-based stem cell transplantation protocol that combines sublethal radiation with transient blockade of the CD40-CD154 costimulatory pathway using an anti-CD154 antibody. With this protocol, we established hematopoietic chimerism in BALB/c mice transplanted with fully allogeneic C57BL/6 bone marrow. The percentage of donor-origin mononuclear cells in recipients was more than 99%. In addition, all chimeric mice treated with anti-CD154 antibody remained free of graft-versus-host disease (GVHD) and accepted donor-origin but not third-party skin allografts. It was similarly possible to create allogeneic hematopoietic chimerism in NOD/Lt mice with spontaneous autoimmune diabetes. Pancreatic islet allografts transplanted into chimeric NOD/Lt mice were resistant not only to allorejection but also to recurrence of autoimmunity. We conclude that it is possible to establish robust allogeneic hematopoietic chimerism in sublethally irradiated mice without subsequent GVHD by blocking the CD40-CD154 costimulatory pathway using as few as 2 injections of anti-CD154 antibody. We also conclude that chimerism created in this way generates donor-specific allograft tolerance and reverses the predisposition to recurrent autoimmune diabetes in NOD/Lt mice, enabling them to accept curative islet allografts. (Blood. 2000;95:2175-2182)

Animals↗
PubMedDate not supplied

[Construction of chimeric tumor suppressor p53 resistant to the dominant-negative interaction with p53 mutants].

A chimeric p53 cDNA was constructed so that the fragment coding for 39 residues of the chicken p53 tetramerization domain replaced the corresponding region of human p53. The chimeric cDNA substantially inhibited the colony-forming ability of transfected human and mouse cells, suggesting a suppressory potential for its product. The chimeric p53 activated promoters containing p53-responsive elements. In contrast to wild-type human p53, the chimeric p53 remained capable of transcription activation in the presence of dominant-negative mutant p53-His175. This makes the chimeric p53 a convenient model for elaborating gene therapy protocols for tumors with dominant-negative p53 forms. The chimeric p53 may be used to study the role of transdominance of p53 mutants in carcinogenesis and the interactions of p53 with related transcription factors (p73, p63).

Amino Acid Sequence↗
PubMed1977

T-and B-lymphocyte chimerism in the marmoset.

Marmosets are natural blood chimeras, this condition resulting from the high frequency of fraternal twinning and the consistent development of placental vasular anastomoses between the two embryos. Identification of chimerism by sex-chromosome analysis of cultured blood lymphocytes provided a means of determining the proportion of chimerism among T and B lymphocytes. Peripheral blood lymphocytes were enriched for T or B cells by filtration through a nylon column (yields greater than 95 per cent T-cells) or inactivation of T lymphocytes by treatment with a goat anti-marmoset thymocyte antiserum in the presence of complement (yeilds greater than 95 per cent B cells). Mitogenic stimulation of these separated, enriched cell populations yielded metaphase plates which could be scored for percentage male and female cells. Tests on five different blood chimeras showed the T- and B-lymphocyte chimerism to be the same. Stimulation of blood lymphocytes with cells from another species of marmoset in a mixed lymphocyte culture test revealed the chimeric T-cell response (i.e., host and co-twin cells) to be similar to that obtained with a mitogenic lectin. The demonstration of equivalent T- and B-cell chimerism in these animals suggests derivation of these cells from a common stem cell pool and the response of both T-cell populations to an antigenic stimulus in proportions similar to their percentage chimerism suggests complete immunologic tolerance exists in this species for co-twin histocompatibility antigens.

Animals↗
PubMed1992

Functional assembly of chimeric T-cell receptor chains.

We have generated cytotoxic T-cell hybridomas expressing chimeric T-cell receptors (cTCR) with an antibody-type specificity for the TNP hapten. Transfectants expressing the cTCR genes could mediate specific lysis of haptenated tumor cell lines of various types and secrete IL-2 upon stimulation with TNP modified cells. In a previous report, we showed that double-gene transfectants expressing either VHC alpha and VLC beta or VHC beta and VLC alpha could be activated by TNP-modified stimulator cells or TNP proteins immobilized on plastic. Single-chain transfectants (expressing VHC alpha or VHC beta alone) could be mainly activated by TNP-cells. We now report that transfection of chimeric VHC alpha gene into an alpha-chain-defective mutant restores the surface expression of the TCR/CD3 complex. In parallel, such transfectants regained the ability to respond to mitogen and anti-CD3 antibodies and responded weakly to TNP cells. Double gene transfectants, bearing 2 complementary chimeric chains, expressed high amounts of cTCR on their surface, sufficient to acquire sound anti-TNP reactivity. Cells expressing the VHC beta gene only were not functional and had no detectable surface TCR chains. Taken together, our results suggest that chimeric VHC alpha chains can pair with endogenous V beta C beta chains, but that there is preferential association between complementary chimeric chains, resulting in higher functional expression of the chimeric TCR.

Animals↗
PubMedDate not supplied

Long-term biodistribution in tumored mice of murine and chimeric B72.3-IgG antibody radiolabeled with 114mIn via both DTPA and a macrocyclic chelator.

To assess the possibilities of using 114mIn as a therapeutic agent, the long-term biodistribution of 114mIn was studied, in tumor-bearing nude mice, after injection of labeled monoclonal antibody (MoAb) B72.3 IgG, either DTPA-coupled murine, DTPA-coupled chimeric, or macrocycle-coupled chimeric antibody. Although the biodistributions in all cases were similar, there were important differences. The use of DTPA-coupled chimeric antibody led to higher concentrations of radioactivity in tumor, and to lower concentrations in liver and bone, as compared to DTPA-coupled murine antibody. The use of macrocycle-coupled chimeric antibody led to higher concentrations of radioactivity in the liver and in bone as compared to the DTPA-coupled chimeric antibody. However, in this case there were no significant differences in tumor uptake or clearance. Radiation doses were calculated based on the organ retention and by neglecting source-to-target contributions. Radiation dose distribution was marginally favorable for therapy in the group injected with DTPA-coupled chimeric antibody.

Animals↗
PubMed1992

Construction and characterization of a high-affinity chimeric anti-colorectal carcinoma antibody ccM4.

We have produced a high-affinity chimeric anti-colorectal carcinoma antibody, ccM4, chimerized in both heavy and light chains by the construction of two expression vectors, the chimeric heavy-chain expression vector mpSV2neo-EP1-Vm4Cr1 and chimeric light-chain vector mpSV2gpt-EP1-VKCK. These vectors contained the neo or gpt gene as a selection marker, the murine immunoglobulin promoter and enhancer (EP1), the genomic DNA fragments of human immunoglobulin constant region (CK and C gamma 1), and murine cDNA fragments of VH and VK region amplified and cloned directly from the B72.3 hybridoma RNA by the polymer chain reaction technique. These two vector DNAs were sequentially transfected into the SP2/0Ag14 cell line. Transfectants were selected in media containing both G418 and mycophenolic acid. The ccM4 antibody was purified from transfectant supernatants with positive binding reactivity for the TAG72 antigen on a protein A column. We demonstrated that ccM4 antibody retained the same high binding reactivity for the TAG72 antigen as its counterpart, the high-affinity chimeric heavy-chain cB72.3m4 antibody. The ccM4 antibody bound specifically to human colon cancer cells, displayed biodistribution patterns similar to cB72.3m4 antibody, and mediated effective antibody-dependent cellular cytotoxicity to human OVCAR3 tumor cells. Therefore, the high-affinity chimeric ccM4 antibody should be useful in cancer immunotherapy.

Animals↗
PubMed2004

[Allogeneic chimerism induced by B7 antisense peptide pre-treated splenocytes prolongs the survival of allograft in mice].

OBJECTIVE: To investigate the roles of B7 antisense peptide (B7AP) in blocking the CD28-B7 pathway and inducing the allogeneic chimerism. METHODS: B7 antisense peptide was synthesized by solid phase synthetic methods and purified with HPLC. The C57BL/6 splenocytes of mice were pre-treated by B7AP, and subsequently injected in travenously to BALB/c mice. Three days later the mice were injected with fresh-made bone marrow cells derived from C57BL/6 mice. The B7 expression and allogeneic chimerism were analyzed with FACS. The lymphocyte proliferation reaction and the mice pinna cardiac transplantation model were exerted to study the relation between chimerism and prolongation of allograft in vitro and in vivo. RESULTS: Lymphoproliferation of the splenocytes derived from BALB/c mice immunized with the B7AP pretreated C57BL/6 splenocytes versus splenocytes from C57BL/6 mice was inhibited dramatically with a inhibition rates up to 43%. Under this condition, the allogeneic chimerism was successfully induced after BMT. Both the chimerism and the survival of allogeneic cardiac grafts were prolonged over 100 days (n = 6). CONCLUSION: Synthetic B7 antisense peptide can induce allogeneic chimerism in mice and consequently prolong the survival of allogeneic cardiac grafts.

Animals↗