Publications by authors named "Lewin H"

A BoLA-DQB cDNA clone (BoLA-DQ beta-1) was isolated by screening a bovine lymphoblastoid cDNA library with a HLA-DQB genomic clone. The DNA and predicted protein sequences were compared to class II sequences from cattle and other species. BoLA-DQ beta-1 has 92.

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Blood samples from 54 animals were exchanged between 15 laboratories in nine countries to improve and expand BoLA class I and class II typing. A total of 27 out of 33 (82%) of previously accepted BoLA-w specificities were represented within the cell panel. Seventeen new serum-defined BoLA specificities were accepted by the workshop participants, thus expanding the number of internationally recognized BoLA specificities to 50.

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Segregation of polymorphic marker genes in a paternal half-sib family of Angus cattle was used to detect associations between genetic markers and quantitative traits. The half-sib family selected (n = 146) had a sire that was heterozygous at six polymorphic marker loci; BoLA-A (class I major histocompatibility complex), B, C and F blood group systems, serum transferrin and vitamin D binding protein. Segregation of alleles fit the expected ratios for all marker loci.

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Cytochemical and immunological markers were used to phenotype the bovine lymphoblastoid cell lines BL-3*, EBL-1, and EBL-2. Southern blot experiments were also performed to test these lines for the presence of proviral bovine leukemia virus (BLV). The BL-3* cell line, originally derived from a case of sporadic bovine leukosis (non BLV-associated) but later infected with BLV in vitro, was found to contain BLV provirus and expressed the BLV-encoded envelope glycoprotein BLV-gp51.

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A total of 95 registered Guernsey cows and heifers sired by 34 bulls were typed for class I antigens encoded by the bovine major histocompatibility complex (BoLA). A panel of alloantisera was used to detect 21 of the 33 internationally recognized BoLA specificities. Fourteen BoLA specificities were detected in the herd using a standard lymphocyte microcytotoxicity test.

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The products of the major histocompatibility complex (MHC) loci regulate an individual's immune response to pathogens. Cattle provide an important model to study the relationship between disease susceptibility and MHC haplotype since large half-sibling families are common. The definitive demonstration, however, of a firm relationship between MHC phenotype and disease susceptibility in cattle will require a precise definition of the bovine MHC allelic products.

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The possibility of breeding or genetically engineering cattle for resistance to disease has tremendous potential for increasing the efficiency of milk and meat production. In cattle and other species, major genes that control humoral and cellular immune responses to a variety of antigens have been mapped to a chromosomal region known as the major histocompatibility complex. However, resistance or susceptibility to viral, bacterial, and parasitic diseases in noninbred species is often a complex phenotype, with age, stress, and physiologic status all being important factors in the outcome of infection.

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Serological approaches have been relatively unsuccessful in defining the allelic products of the bovine major histocompatibility (MHC) class II loci. We demonstrate that bovine class II allelic products can be characterized by precipitation with a polyclonal antiserum and separation using one-dimensional isoelectric focusing. Polymorphic beta chains were present in immunoprecipitates from both biosynthetically and surface-labeled lectin-stimulated bovine T cells.

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Genetic potentials (pedigree-estimated breeding value) for milk and for fat were compared in cows grouped according to subclinical stage of bovine leukemia virus infection. Genetic potential for milk production was significantly greater in seropositive cows with persistent lymphocytosis (622 +/- 72 kg) and in seropositive hematologically normal cows (554 +/- 34 34 kg) than in seronegative herdmates (418 +/- 53 kg). When 305-day twice-daily-milking mature equivalent milk production records for the current lactation were adjusted for genetic potential, bovine leukemia virus-infected cows that were hematologically normal had significantly greater milk production than did seronegative herdmates, suggesting that early bovine leukemia virus infection was positively associated with milk yield.

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Two hundred and eighty-two alloantisera were submitted by 20 participating laboratories from 13 countries and tested against lymphocytes of 1298 cattle. The cell panel consisted of samples from 38 Bos taurus breeds, 11 Bos taurus crossbreeds, 4 Bos indicus breeds, 6 Bos taurus x Bos indicus, and a variety of other crossbred populations. Using a standardized lymphocytotoxicity test, all 17 previously identified BoLA specificities were confirmed.

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The relationship between percentage of B cells in peripheral blood and subclinical bovine leukemia virus infection was examined in a herd of 240 Holstein-Friesian cows. Absolute leukocyte count and absolute lymphocyte count were significantly positively correlated with B cell percentage in cows that were seropositive to bovine leukemia virus envelope glycoprotein, but these parameters were not correlated in seronegative cows. The B cell percentage was not affected by age.

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The role of the bovine major histocompatibility system (BoLA) in subclinical bovine leukemia virus (BLV) infection was investigated in a herd of Holstein-Friesian cows (n = 240). The BoLA W8.1 allele was negatively associated with the presence of antibodies to the major BLV envelope glycoprotein, BLV-gp51 (corrected P less than 0.

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We examined the potential of developing a set of species specific and cross reactive monoclonal antibodies (MoAbs) for use in the study of the phylogenetic and functional relation of class I and class II antigens of the major histocompatibility complex (MHC) and leukocyte differentiation antigens in cattle and other species. Comparing immunization strategies demonstrated the number of hybrids producing cross reactive antibodies can be increased by hyperimmunization of mice with lymphoid cells from multiple species. Comparing various methods of assay (antibody-complement mediated cytotoxicity [CT], enzyme linked immunosorbent assay [ELISA] and flow microfluorimetry [FMF]), revealed FMF is the most useful technique for the primary assay of hybridomas producing MoAbs of potential interest.

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Monoclonal antibodies represent a natural extension of research efforts directed at understanding the structure and function of antibody molecules. In this paper, essential concepts that led to development of monoclonal antibody technology are outlined, including a short discussion on antibody structure and genetics. An overview of the theory of monoclonal antibody production is presented, as well as a comparison of the properties of monoclonal antibodies and conventional antisera.

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The role of the bovine major histocompatibility complex in bovine leukaemia virus (BLV) infection and disease progression was investigated in a herd of Shorthorn cattle (n = 117). The frequency of cows that were seropositive to BLV-glycoprotein antigen was 51%. Twenty-three per cent of the seropositive cows were lymphocytotic.

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The specificities of three monoclonal antibodies (MAbs) were investigated using microcytotoxicity, fluorescence microscopy and laser flow cytometry (LFC) techniques. By microcytotoxicity, bovine thymocytes (n = 4) were estimated to be 85% B26A+, 4% TH21A+, and 1% H4+. Nylon wool enriched peripheral blood T lymphocytes (n = 3) were 90% B26A+, 10% TH21A+ and 10% H4+.

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Ficoll-thrombin purified suspensions of bovine, equine, ovine, and porcine peripheral blood lymphocytes were fractionated on nylon-wool columns. The percentages of surface immunoglobulin (SIg+)-bearing lymphocytes in the adherent (B-cell enriched) and nonadherent (T-cell enriched) fractions were determined for individual animals using fluorescein isothiocyanate conjugated species-specific anti-Ig sera. Subsequently, the human leukocyte antigen DR-specific monoclonal antibody, H4, was tested for its ability to recognize a cross-reactive antigen on the fractionated lymphocytes, using the microcytotoxicity technique.

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A model-independent program for pharmacokinetic analyses based on statistical moment theory is presented and demonstrated. The program uses an inexpensive and portable TI-59; a PC-100A printer adds convenience but is optional. The program may be used in analysis of blood, serum, or plasma concentration vs.

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Studying treatment data for 1,385 patients with traumatic paraplegia registered with the National Spinal Cord Injury Data Research Center during 1973-1979, we investigated: (1) current treatment trends; (2) continuity or change in such trends; (3) trend implications; and (4) whether current practices reflect the controversy in the literature. The data showed little change in the proportion of patients treated surgically, but statistically significant changes in the procedures, especially as related to Harrington rod instrumentation, which increased dramatically both with bony fusion (from none to 24.4%) and in the triple procedure, which adds laminectomy (from 6.

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Chicken fetal antigen (CFA) is an oncodevelopmental antigen associated with hematolymphoid development and differentiation. The immunodominant structures of two CFA determinants were characterized by hapten inhibition of microcytotoxicity (HIM) and were found to be defined by specific monosaccharides. CFA determinants 5 and 11 were effectively (greater than 50%) inhibited by D-mannose and D-glucose, respectively.

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The immunodominant structure of a chicken fetal antigen (CFA) determinant was investigated using a new hapten inhibition of microcytotoxicity (HIM) assay. This HIM assay employing avian erythrocytes was shown to be a highly sensitive, economical technique and was verified in a separate experiment using bovine serum albumin (BSA) coupled to Japanese quail peripheral red blood cells (QPRBCs). Inhibition of microcytotoxicity was measured following preincubation of 1 microliter of specific antiserum with 1 microliter of antigen solution.

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Rabbit antisera capable of detecting chicken fetal antigen (CFA) was prepared against 1-day chick red blood cells (RBCs) and made specific by exhaustive adsorption with adult chicken peripheral RBCs (PRBCs) from the same strain. Microcytotoxicity was used to study the incidence of CFA on lymphocytes obtained from several organs at different developmental stages in the chicken. Lymphocyte-associated CFA (LA-CFA) determinants and erythrocyte-specific CFA (ES-CFA) determinants were distinguished through the use of adsorption analysis.

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