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D Llanes

Publications and source records attributed to D Llanes.

At least 19 recordsLinked to original sources
PubMed2004

Analysis of swine beta1 integrin (CD29) epitopes through monoclonal antibodies developed using two immunization strategies.

This report describes the production and characterization of monoclonal antibodies (MAbs) to swine beta1 integrin subunit (CD29) using two different immunization strategies. MAb GP4B4 was developed from a mouse immunized with porcine peripheral blood mononuclear cells (PBMC), while MAbs GP1A5, GP1A6, and GP4A1 were produced by immunizing mice with a porcine CD29 recombinant protein (rpCD29) developed in our laboratory, which includes the ligand binding site. GP4B4 and UCP1D2 (specific to porcine CD29) immunoprecipitated two bands of approximately 115 and 150 kDa under reducing conditions. The molecule recognized by these two antibodies was studied using flow cytometry and was found in practically all cells studied, displaying a similar reaction pattern. Western blot assays performed with rpCD29 indicated that MAbs GP1A5, GP1A6, and GP4A1 recognized the 30-kDa band for this recombinant protein, confirming their specificity for the beta1, integrin subunit. Immunohistochemical analyses of these MAbs disclosed a morphological pattern associated with smooth muscle, epithelium, and myeloid cells, as expected in MAbs recognizing CD29. This MAb panel could be useful as a general anti-CD29 reagent and would allow further research into this important integrin in swine.

Animals↗
PubMed2003

Molecular cloning, expression pattern and chromosomal mapping of pig CD9 antigen.

CD9 is a member of the transmembrane-4 superfamily of surface molecules that seems to have a relevant role in cell migration and adhesion, as well as malignant progression. This work describes the isolation of the cDNA coding for the porcine CD9 molecule. Pig CD9 cDNA was isolated from a smooth muscle cDNA library and contains a 678-bp open reading frame with its predicted polypeptide sequence of 226 amino acids. The deduced amino acid sequence conserves the main characteristics of TM4 proteins, including the presence of four transmembrane domains. Like their homologous molecules from other species, pig CD9 has two extracellular regions of a different size with the minor loop bearing two possible glycosylation sites. The pig CD9 gene was localized to chromosome 5q25 by using a somatic cell hybrid panel. Analysis of CD9 expression in different porcine cells and tissues demonstrated that CD9 mRNA is ubiquitously expressed.

Amino Acid Sequence↗
PubMed2002

Production and characterization of monoclonal antibodies against dog immunoglobulin isotypes.

A panel of six monoclonal antibodies (mAbs) recognizing antigenic determinants on canine immunoglobulin (Ig) heavy or light chains was produced and characterized. All monoclonals recognized the IgG(2) subclass, although only two were subclass-specific (CA3H1 and CA4F1). The CA3B8 mAb was found to be specific for an epitope on canine immunoglobulin G heavy chain, (IgG(1) and IgG(2) subclasses). Two mAbs (CA2E9 and CA5B2) reacted with an epitope on the heavy chain of canine IgG and IgM and another, CA4E7, bound to canine IgA, IgG and IgM isotypes; CA4E7 recognized an epitope on canine immunoglobulin light chain. CA4E7, CA4F1 and CA5B2 recognized an epitope in the Fab region. Three mAbs, CA3B8, CA4E7 and CA5B2, showed much lower reactivity with canine IgG by ELISA when IgG was periodate-treated, suggesting that they recognized a carbohydrate determinant. Cross-reactivity analysis of these mAbs with sera from horse, goat, cow, sheep, pig, cat, rabbit, hamster, rat, mouse and human indicated that two mAbs, CA3B8 and CA5B2, recognized a canine IgG-specific epitope; two others, CA3H1 and CA4E7, recognized an epitope also present in rabbit and sheep immunoglobulin respectively; and the remaining two (CA2E9 and CA4F1) recognized an epitope broadly present on the Igs of the species analyzed. This panel of antibodies will be a useful tool for future canine immunodiagnosis tests. With the exception of CA2E9, all mAbs were able to recognize plasma cells on paraffin-embedded tissues, and will thus be useful for immunohistochemical assays.

Animals↗
PubMed2002

Immunohistochemical analysis of beta3 integrin (CD61): expression in pig tissues and human tumors.

CD61 is a membrane glycoprotein that associates with CD41 (alphaIIb) to form the heterodimeric complex gpIIb/IIIa (CD41/CD61), predominantly expressed in platelets and megakariocytes. CD61 or beta3 integrin also associates with alpha v (CD51) to form the vitronectin receptor, which is expressed in many tissues. We have used a monoclonal antibody against the porcine gpIIIa or CD61 (JM2E5) to study the distribution of this molecule in different normal pig tissues. As in humans, CD61 was broadly expressed in all tissues examined. In the kidney, strong expression of CD61 was observed in epithelial cells from renal tubules. In the testis, CD61 expression was detected in the Leydig cells. However, in liver, CD61 was weak or not detected. Many integrins are particularly involved in tumogenicity and in tumor progression mediating cell-cell interaction. Immunofluorescence experiments using cultured human tumor HeLa cells showed nuclear and cytoplasmic staining of mAb JM2E5. Immunohistochemical analysis of human tumor sections from several organs showed a heterogeneus distribution in metastatic cases from colon and breast carcinoma. However, no staining was found in metastasis from melanoma.

Animals↗
PubMed2001

Swine platelet antigens: section report.

A total of 14 antibodies were found to label resting and/or activated swine platelets. Six recognized CD previously characterized for swine (CD29, CD41/61 and CD46). One had been characterized for human cells (CD47). Two antibodies with CD14 and SLA class I specificity suggested by the donor as well as five blind antibodies were also positive on platelets. One antibody appeared to recognize the swine homologue to human CD47, and four remained unclustered.

Animals↗
PubMed2001

Overview of the Third International Workshop on Swine Leukocyte Differentiation Antigens.

The aim of the Third International Workshop on Swine Leukocyte Differentiation Antigens (CD workshop), supported by the Veterinary Immunology Committee (VIC) of the International Union of Immunological Societies (IUIS), was to standardize the assignment of monoclonal antibodies (mAb) reactive with porcine leukocyte differentiation antigens and to define new antibody clusters, using nomenclature in accordance with human and ruminant CD nomenclature, as agreed at the summary meeting of the Second International Swine CD Workshop in Davis, 1995: only mAb with proven reactivity for the orthologous porcine gene product or cross-reactivity for the human gene products, were given the full CD nomenclature, all other allocations were prefixed with "w". As in previous workshops, the overall organization was entrusted to the chair and first author, with support by the chair of the previous workshop and second author. In addition to the existing 26 pig leukocyte CD/SWC determinants established in previous workshops, this workshop established/confirmed another 11 CDs for pig leukocytes, identified by a total of 21 mAb: CD11R1 (2 mAb), CD11R2 (1 mAb), CD11R3 (4 mAb), wCD40 (1 mAb), wCD46 (4 mAb), wCD47 (3 mAb), wCD49d (1 mAb), CD61 (1 mAb), wCD92 (1 mAb), wCD93 (1 mAb) and CD163 (2 mAb).

Animals↗
PubMed2001

Summary of the first round analyses of the Third International Workshop on Swine Leukocyte Differentiation Antigens.

The reactivity of 155 monoclonal antibodies submitted to the Third International Workshop on Swine Leukocyte Differentiation Antigens, together with 41 internal standards, was analysed by flow cytometry on 29 different pig cell targets as well as two human cell targets as a means of establishing suitable panels of monoclonal antibodies for more detailed clustering analyses by the various subsections of the workshop. Results were collected either without further gating, with gating based on FS/SS characteristics or with gating based on the co-expression of a reference antibody in two-colour flow cytometry. The CD or SWC reactivity of the internal standards had been established in previous workshops. Data sets were subsequently analysed by statistical clustering using the Leucocyte Typing Database IV software. The resulting 18 cluster groups were allocated to the appropriate second round sections of the workshop, after reviewing the overall cellular reactivity of each cluster as well as the specificity of known standards which clustered in a group.

Animals↗
PubMed2001

Expression of CD61 (beta3 integrin subunit) on canine cells.

A monoclonal antibody (JM2E5) specific for the integrin beta3 chain, or CD61 or GPIIIa subunit, has been employed to determine the expression of the canine homologue CD41/CD61 or CD51/CD61 complex on different canine cells in peripheral blood lymphocytes, monocytes, granulocytes, platelets, erythrocytes, lymph-node cells, spleen cells and breast tumour cells). The canine homologue CD41/CD61 or CD51/61 was present on peripheral blood lymphocytes, monocytes, granulocytes, breast tumour cells and spleen cells as well as on platelets and it was absent from erythrocytes and lymph-node cells. An antigen with components of molecular masses of 25/100/120 kDa (under reducing conditions) was immunoprecipitated from canine peripheral lymphocytes and platelets, but not from granulocytes or monocytes. Expression on canine lymphocytes of the canine homologue of the human beta3 integrin chain was unexpected, based on the expression pattern of this molecule in human tissue.

Animals↗
PubMed2000

Molecular cloning and characterization of the pig homologue to human CD29, the integrin beta1 subunit.

BACKGROUND: CD29 is the beta1 subunit, a member of the integrin gene superfamily that function as receptor for cell adhesion molecules of the extracellular matrix. Porcine integrin beta1 subunit is involved in rejection of pig-to-human tissue xenografts as target of the natural antibodies present in the human serum. Moreover since CD29, as part of the beta1 integrins very late antigen 4 (VLA-4) and VLA-6, is involved in homing and differentiation of haematopoietic progenitor cells, its characterization in pig is critical to study the interaction of porcine adhesion molecules with human ligands in the induction of donor-specific tolerance toward porcine antigens, a process extremely desirable to prevent rejection of xenogeneic organs. METHODS: The porcine CD29 cDNA has been isolated from a cDNA library and its structure determined. In addition, reverse transcription-polymerase chain reaction (RT-PCR) was performed to determine the expression of CD29 in different tissues. RESULTS: The nucleotide sequence of the porcine cDNA includes an open reading frame encoding a polypeptide of 798 amino acids. Expression analysis showed that porcine CD29 is expressed in all lymphoid tissues tested and, in lower amounts, in nonlymphoid tissues. Pig CD29 deduced amino acid sequence displays extensive conservation compared with CD29 sequences from other species and a common structural feature with all the other CD29 molecules analyzed in mammals, including the 12 potential N-glycosilation sites. Punctual changes between human and swine CD29 molecule into the ligand binding domain, and/or into the regulatory domain, suggest potential differences between human and porcine CD29 relative to the human CD29 ligands. CONCLUSIONS: Cloning of the swine CD29 gene offers a new tool for an alternative protocol of removing xenoreactive antibodies in the recipient. In addition, the determination of the differences between human and swine CD29 will help to understand the adhesion molecule-ligand interactions and their function across the swine-human barrier in xenotransplantation.

Amino Acid Sequence↗
PubMed2000

Induction of aggregation in porcine lymphoid cells by antibodies to CD46.

CD46 is a major transmembrane glycoprotein that belongs to the regulator of complement activation (RCA) family. Recently, mAbs to human CD46 were shown to suppress IL-12 production. Here, we describe that mAbs against different porcine CD46 epitopes induced a marked adhesion of normal lymphocytes. Addition of low amounts of antibody to freshly isolated lymphocytes or thymocytes resulted in the clustering of the cells. Cross-linking of CD46 molecules seems essential since Fab fragments failed to induce aggregation. This aggregation was dependent on active cell metabolism and on the presence of divalent cations and required a functional cytoskeleton. It was not inhibited by antibodies to CD18, CD29, CD2, CD11a and CD11b. Staurosporine, an inhibitor of protein kinases, partially blocked the aggregation. This finding is indicative of a role of protein kinases in the transduction of the signal generated by CD46 engagement.

Animals↗
PubMed1999

A new epitope on sheep CD45R molecule detected by a monoclonal antibody.

This paper describes the production and characterization of a monoclonal antibody (mAb), Co-46D5, which recognizes a new epitope on the isoform of the homologous sheep leukocyte common antigen (LCA) or CD45. This nmAb was submitted to the 3rd workshop on ruminant leukocyte antigens and was assigned to a cluster reactive with B- and T-cells subsets. Co-46D recognizes a 220 kDa molecule on peripheral blood mononuclear cells (PBMC) and spleen cells but not on thymocytes. Flow cytometry (FCM) analysis shows that Co-46D5 reacted with 30% of PBMC and 50% of spleen cells and more than 95% of cells freshly isolated from lymphoid follicles of the ileal Peyer's patches (IPP) of young lambs. By immunohistochemistry, the antigen was detected mainly on B-cell areas of lymph nodes and spleen. It was also found on a subpopulation of medullar thymocytes. Based on these results, we assume that Co-46D5 recognizes a new epitope on the largest isoform of the sheep CD45 receptor, probably on the homologous to the human CD45RA isoform.

Animals↗
PubMed1999

Epitope mapping of 10 monoclonal antibodies against the pig analogue of human membrane cofactor protein (MCP).

Pig membrane cofactor protein (MCP; CD46) is a 50 000-60 000 MW glycoprotein that is expressed on a wide variety of cells, including erythrocytes. Pig MCP has cofactor activity for factor I-mediated cleavage of C3b and is an efficient regulator of the classical and alternative pathway of human and pig complement. A panel of 10 monoclonal antibodies (mAbs) was collected from two different laboratories; all of these mAbs were raised against pig leucocytes and all recognized the same complex banding pattern on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of erythrocyte membranes. All were shown to be reactive with pig MCP and were divided into four groups of mutually competitive antibodies based on competition studies for membrane-bound MCP and for soluble MCP, the latter by surface plasmon resonance (SPR) analysis. The antigenic properties of membrane-bound and soluble MCP were similar, although some interesting differences were revealed. None of the 10 mAbs were cross-reactive with human MCP and only one showed cross-reactivity with leucocytes from a panel of large mammals - a weak cross-reactivity with a subset of dog leucocytes. All antibodies in one of the epitope groups and some in a second epitope group were able to block the functional activity of pig MCP, as measured by inhibition of MCP-catalysed C3 degradation by factor I.

Animals↗
PubMed1998

A monoclonal antibody raised against pig leukocytes and platelets recognizes fibrinogen from pig plasma.

Monoclonal antibody (mab) JM7E6 was produced through immunization of mice with porcine peripheral blood mononuclear cells and platelets. Biochemical characterization of the antigen showed three bands of 48, 55 and 60 kDa approximately, under reducing condition, and a single band greater than 200 kDa, under non-reducing condition. The antigen distribution among leukocyte subpopulations was reduced, but abundant in platelets, which suggests the recognition of a platelet antigen. However, immunohistochemical analysis of paraffin-embedded porcine tissues showed reactivity on blood vessel plasma, and indicates recognition of a plasma protein. ELISA and immunoblotting techniques, which were performed with commercially available porcine fibrinogen, not only confirmed the identification of this antigen, but also localized the epitope recognized by JM7E6 in the fibrinogen gamma light chain. JM7E6 failed to recognize human, ovine, bovine and dog fibrinogen molecules, thus showing species specificity of the epitope recognized by this antibody. Since JM7E6 is able to precipitate fibrinogen molecules from porcine leukocytes and platelets, it may be a valuable tool for some interesting clinical applications.

Journal Article↗
PubMed1997

Purification and characterization of the pig analogue of human membrane cofactor protein (CD46/MCP).

A panel of mAbs were raised against pig lymphocytes. Seven mAbs immunoprecipitated a 50- to 60-kDa membrane-bound protein. This protein, termed JM4C8-Ag, was expressed on a wide variety of cells, including all circulating cells and cells of fibroblast, epithelial, and endothelial origin. The JM4C8-Ag was transmembrane-anchored and glycosylated. One of the Abs was used in immunoaffinity chromatography to isolate JM4C8-Ag from erythrocyte membranes. N-terminal amino acid analysis through the first 28 residues showed a 43% homology with the human complement regulatory molecule membrane cofactor protein (MCP; CD46). The purified protein had cofactor activity for factor I-mediated cleavage of human and pig C3b, confirming its identity as the pig analogue of human MCP. The purified protein also strongly inhibited lysis of rabbit erythrocytes by human and pig complement after activation of the classical or alternative pathway. This is the first report of a nonprimate analogue of MCP. The presence of a resident MCP on pig cells capable of acting as a cofactor in the control of human complement activation has consequences for the use of pig organs in xenotransplantation.

Amino Acid Sequence↗
PubMed1997

Characterization of the porcine homologue to human platelet glycoprotein IIb-IIIa (CD41/CD61) by a monoclonal antibody.

Human gpIIb-IIIa or CD41/CD61 is a Ca(2+)-complex dependent heterodimer, abundant on platelets, that plays a key role in hemostasis. This report describes a murine monoclonal antibody, JM2E5, able to recognize and immunoprecipitate the gpIIb/IIIa surface glycoprotein from porcine platelets. Immunoprecipitation analysis showed an antigen molecular weight of 115 and 85 kDa under nonreducing conditions, and of 110, 100 and 25 kDa under reducing conditions. Immunohistochemistry analyses of frozen sections from several porcine lymphoid organs gave specific staining on platelets. EDTA treated platelets were studied by flow cytometry indicating that the epitope recognized was Ca(2+)-complex independent. Western-blotting experiments with porcine platelet extracts gave an antigen molecular weight of 85 kDa under nonreducing conditions, thus localizing the epitope recognized by JM2E5 on the complex light chain gpIIIa or CD61. JM2E5 was also cross-reacting with human, bovine and horse platelets, as shown by flow cytometry. This mAb would allow further studies on this important adhesion molecule on horses, ruminants and pigs, and it should be especially useful as a general anti-porcine platelet reagent.

Animals↗