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A study on association between mastitis and serologically defined class I bovine lymphocyte antigens (BoLA-A) in Norwegian cows.

A total of 102 cows was tested for class I antigens of the bovine major histocompatibility complex. Half of the animals (51) had completed at least four lactations without any veterinary treatment for mastitis. The distribution of BoLA-A antigens among these relative mastitis-resistant cows was compared to that in the other half of the material (51), which comprised animals with at least one recorded treatment for mastitis. There were no statistically significant differences in BoLA-A antigen frequency between cows with mastitis and cows without mastitis. The two most common antigens were A2 and w16. The frequency of these two antigens deviated from earlier estimates within the Norwegian cattle (NRF) population, the difference for w16 being statistically significant.

Animals↗

A polymorphic monoclonal anti-BoLA class I antibody.

Cytotoxic monoclonal antibody IVA 44 was generated after the intraperitoneal immunization with peripheral blood mononuclear (PBM) cells and the boost by the intrasplenic inoculation of skin graft. The detected membrane antigen isolated by immunoprecipitation appears to be composed of two subunits characteristic for the MHC class I molecules. The antibody IVA 44 exhibited a different reactivity: it recognized the BoLA A14 (A8) specificity in animals typed in the Fifth BoLA workshop, while it reacted with all A8 positive animals including subtypes A14 and A15 in Czech and Slovak cattle. It is concluded that mAb IVA 44 might detect the broad subtype of A8 covering A14 and certain A15 split(s). The diverse A15 reactivity of this mAb in the workshop and our population could be explained by the different occurrence of A15 splits in both populations.

Animals↗

Structure of the BoLA-DRB3 gene and promoter.

The cattle major histocompatibility complex (MHC) class II DR gene product is a heterodimer encoded by the BoLA-DRA and -DRB3 genes. Several groups have isolated cDNA and genomic clones for these genes, but their full genomic organization has not been described. We used a combination of long-range polymerase chain reaction (PCR), cloning and sequencing to define the organization of the DRB3 gene on existing genomic clones and in genomic DNA. We estimate the size of the coding region to be 11.4 kbp. Sequencing of full-length PCR clones from two different haplotypes confirmed that they carried complete DRB3 genes and allowed the design of probes and primers to isolate and characterize the DRB3 promoter and 3' end. Fragments carrying the 5' end of the DRB3 gene and its promoter were identified on bacterial artificial chromosome (BAC) clones carrying the BoLA-DR genes. A 10-kbp promoter fragment was subcloned from one clone and a 1.7-kbp region including exon 1 and the promoter was sequenced. A 3-kbp fragment encoding exons 4-6 and the entire 3' untranslated region of the DRB3 gene was isolated from lambda clone A1 and sequenced. This provides us with improved characterization of the DRB3*0101 and DRB3*2002 alleles, and also subcloned 5' and 3' flanking regions of the polymorphic DRB3 gene for use in functional studies.

3' Flanking Region↗

Bovine lymphocyte antigens (BoLA) of bovine lymphocytes and derived lymphoblastoid lines transformed by Theileria parva and Theileria annulata.

The BoLA phenotypes of lymphocytes from seven cattle have been compared with those of 19 lymphoblastoid cell lines derived from them by infection in vitro with either Theileria parva or T. annulata. Two long-established lines were also studied. In all cases except one, the BoLA phenotypes of the lymphoblastoid lines were identical with those of the original animal from whose lymphocytes they were derived. The one exception was a chimeric twin where a minor population appeared to have been transformed by T. parva. The antigens present on this line were present in the parents of the chimera, but not detectable in its own peripheral blood. The implications of these results as they relate to the use of these cell lins in immunizing cattle against East Coast fever and tropical theileriosis are discussed.

Animals↗

Polymorphism of the BoLA system.

The bovine lymphocyte antigen system (BoLA) was studied by serological methods. Evidence for the existence of one locus was established and six codominant alleles were found to segregate at this first locus. The frequency varied considerably among these genes, and the presence of a null allele suggests that new BoLA specificities are likely to be found in the cattle population.

Alleles↗

Selective loss of BoLA class I determinants from the lymphocyte surface after acid treatment.

Acid treatment of bovine lymphocytes by a buffered solution of 0.263 m citric acid and 0.123 M Na2HPO4 at pH = 3.0, originally described for human and murine lymphocytes, selectively eliminated the antigenicity of MHC (BoLA) class I determinants also from bovine lymphocytes. The viability of acid-treated cell suspension was higher than 90%. The reactivity of acid-treated lymphocytes with BoLA class I typing alloantisera was lost in microcytotoxicity test, while their reactions with cross-reactive anti-HLA class II, anti-BoCD2 and BoCD5 monoclonal antibodies, and with antisera detecting two non-MHC lymphocyte alloantigenic specificities (BoLY w1 and R') remained unchanged in the microcytotoxicity and/or indirect immunofluorescence tests. The results thus show that this approach of modulating cell surface expression of MHC class I determinants may be used in cattle.

Animals↗

Growth phase-regulated expression of bolA and morphology of stationary-phase Escherichia coli cells are controlled by the novel sigma factor sigma S.

The novel sigma factor (sigma S) encoded by rpoS (katF) is required for induction of many growth phase-regulated genes and expression of a variety of stationary-phase phenotypes in Escherichia coli. Here we demonstrate that wild-type cells exhibit spherical morphology in stationary phase, whereas rpoS mutant cells remain rod shaped and are generally larger. Size reduction of E. coli cells along the growth curve is a continuous and at least biphasic process, the second phase of which is absent in rpoS-deficient cells and correlates with induction of the morphogene bolA in wild-type cells. Stationary-phase induction of bolA is dependent on sigma S. The "gearbox" a characteristic sequence motif present in the sigma S-dependent growth phase- and growth rate-regulated bolAp1 promoter, is not recognized by sigma S, since stationary-phase induction of the mcbA promoter, which also contains a gearbox, does not require sigma S, and other sigma S-controlled promoters do not contain gearboxes. However, good homology to the potential -35 and -10 consensus sequences for sigma S regulation is found in the bolAp1 promoter.

Bacterial Proteins↗

Selection assisted by a BoLA-DR/DQ haplotype against susceptibility to bovine dermatophilosis.

Bovine dermatophilosis is a severe skin infection of tropical ruminants inducing a severe loss in productivity and a 15% mortality rate. This disease is caused by the actinomycete bacterium Dermatophilus congolensis associated with the tick Amblyomma variegatum. Currently there are no prospects for a vaccine, and acaricide or antibiotic control is hampered by the development of chemoresistance. Animal breeders have observed that dermatophilosis susceptibility seems to be determined genetically, and we previously identified a BoLA-DRB3-DQB class II haplotype marker for high (R2= 0.96) susceptibility to the disease. With this marker, we developed a successful eugenic selection procedure for zebu Brahman cattle in Martinique (FWI). Over a period of five years, a marked reduction in disease prevalence, from 0.76 to 0.02 was achieved, and this low level has been maintained over the last two years. The selection procedure, based on a genetic marker system targeting the highly polymorphic BoLA locus, eliminates only those individuals which are at the highest risk of contracting the disease. In the present work, we discuss the properties of this system, including the "heterozygote advantage" and the "frequency dependence" theories, and examine their involvement in the biological mechanisms at the host/pathogen interface. We speculate on the exact role of the MHC molecules in the control of the disease, how the natural selection pressure imposed by the pathogens selectively maintains MHC diversity, and how our results can be practically applied for integrated control of dermatophilosis in developing countries.

Actinomycetales Infections↗

Association of major histocompatibility complex antigens (BoLA-A) with AI bull progeny test results for mastitis, ketosis and fertility in Norwegian cattle.

Altogether 424 Norwegian AI bulls, progeny tested for clinical mastitis, ketosis and fertility (recorded as nonreturn percentage), were typed by Edinburgh and Oslo allo-antisera to bovine lymphocyte antigens (BoLA-A) over a 7-year period. Significant effects of BoLA-A on disease were revealed. A2 was associated with relative resistance to mastitis, a positive influence on fertility, and a possible relative resistance to ketosis, while A13 was associated with relative resistance to ketosis. The previously reported associations of A11 and w16 with relative susceptibility to mastitis were not confirmed in the present material.

Animals↗

Association of BoLA class II haplotypes with subclinical progression of bovine leukaemia virus infection in Holstein-Friesian cattle.

The influence of bovine lymphocyte antigen (BoLA) complex polymorphism on subclinical progression of bovine leukaemia virus (BLV) infection was investigated in 41 Holstein-Friesian cows from two herds in Italy. All cows were seropositive for BLV and 22 had persistent lymphocytosis (PL). BoLA-A specificities were defined by serology, and class II haplotypes were defined based on restriction fragment length polymorphism (RFLP) and polymerase chain reaction (PCR)-RFLP analysis of DQ and DR genes. Chi-square analysis revealed a significant and absolute association of haplotype DQA*3A-DQB*3A-DRB2*2A-DRB3.2*11 with resistance to PL (P chi 2 = 0.028, relative risk (RR) = 0.061). Consistent with this observation, multiple regression analysis revealed that animals carrying this haplotype had lower lymphocyte counts (P = 0.0057). By contrast, haplotype DQA*12-DQB*12-DRB2*3A-DRB3.2*8 was associated with susceptibility to PL (P chi 2 = 0.043, RR = 9.625) and increased lymphocyte counts (P = 0.0537). These results confirm the association of haplotype DQA*3A-DQB*3A-DRB2*2A-DRB3.2*11 with resistance to PL, and substantiate earlier findings of haplotype DQA*12-DQB*12-DRB2*3A-DRB3.2*8 as a risk factor for subclinical progression to PL in BLV-infected Holstein-Friesian cattle.

Animals↗

Sequence duplication at the 3' end of BoLA-DQB genes suggests multiple allelic lineages.

Full-length cDNAs encoding the DQB genes expressed by three BoLA class II haplotypes (DH8A, DH15B, and DH24A) were amplified by reverse-transcription polymerase chain reaction, cloned, and sequenced. The sequence data revealed that the DH8A haplotype expressed two DQB genes (DQB*1005 and DQB*1201) while the DH15B and DH24A haplotypes expressed the same single gene (DQB*0101). Comparison of the three alleles showed that the 3' untranslated (3'UT) sequence of the DQB*1201 allele contained a duplication of about 200 bp. This repeat was also found in other DQB alleles from cattle and sheep, but only in haplotypes with duplicated DQB genes. This 200-bp repeat and other features of the 3'UT may provide useful markers of DQB evolution, allowing us to distinguish and selectively amplify the different DQB loci.

Alleles↗

Analysis of genetic diversity at the DQA loci in African cattle: evidence for a BoLA-DQA3 locus.

We describe the development of a polymerase chain reaction (PCR)-based approach for analysis of genetic diversity at the DQA loci in African Bos indicus and Bos taurus cattle. This approach, equally effective in European and Asian cattle breeds, detects the presence or absence of DQA1 and most duplicated DQA2 genes. Nucleotide and predicted amino acid sequence analysis of the highly polymorphic second exons, in addition to analysis of the locus-specific and relatively non-polymorphic transmembrane, cytoplasmic, and 3-prime untranslated regions, has provided evidence for considerable diversity between each of the duplicated DQA2 genes. Therefore, we propose the designation BoLA-DQA3 for the previously unpublished alleles at the second DQA2 locus. Fourteen distinct PCR restriction fragment length polymorphism (RFLP) patterns, each identifying families of alleles at three DQA loci, can be distinguished. Nucleotide sequence analysis of new PCR-RFLP patterns from 193 Kenyan Boran, Ethiopian Arsi (B. indicus), and Guinean N'Dama (B. taurus) cattle identified 13 DQA1 alleles within eight major allelic families, five DQA2 alleles within a single allelic family, and seven DQA3 alleles within three major allelic families.

Alleles↗

Production and characterization of monoclonal antibodies raised against BoLA class I antigens.

Monoclonal antibodies (MoAbs) reacting with bovine leukocyte membrane antigens have been prepared by fusion of mouse myeloma cells (SP2/0.Ag.14) and spleen cells of mice immunized with various cell types. Three of these MoAbs detected membrane components showing the typical structure of class I MHC molecules; indeed, immunoprecipitation studies revealed that these components were proteins composed of two subunits of 44,000 and 12,000 daltons apparent molecular weight. The density of these antigens in the cells of various leukocyte lineages was determined by solid phase radioimmunoassay, immunogold staining and cytofluorometry. Their expression seemed similar to that of class I molecules in other species, namely heavy on the mononuclear blood cells and weaker on the neutrophils and platelets. The eosinophils appeared more positive than the neutrophils, while the erythrocytes were negative. Cross-inhibition and sequential immunoprecipitation experiments demonstrated that these MoAbs recognised different epitopes either on a single molecule or on cross-reacting molecules. One antibody appeared to be raised against the monomorphic bovine beta-2-microglobulin, while the two other antibodies detected the heavy chain of polymorphic class I-like products. The authors propose that the BoLA class I polymorphism should be studied by determination of the fixation ratio of the monomorphic anti-beta 2M versus the polymorphic anticlass I antibodies amongst the animals.

Animals↗

Anchoring and bola cationic amphiphiles for nucleotide delivery. Effects of orientation and extension of hydrophobic regions.

Novel cationic amphiphiles, based on lithocholic acid derivatives with two structural motifs, anchoring lipids and bola lipids, were designed and synthesized. Both bear extended hydrophobic space-filling substituents. A significant effect of the orientation and extension of hydrophobic regions around the ether linkage at the 3-position was found on the efficiency of DNA delivery.

3T3 Cells↗

Pores Formed by Bis-macrocyclic Bola-amphiphiles in Vesicle and Planar Bilayer Membranes.

A new series of bis-macrocyclic bola-amphiphiles were prepared, and their transport activities in vesicle and planar bilayer membranes were evaluated. From vesicle experiments, the apparent kinetic order in transporter indicates that aggregates are the kinetically active species. Step-conductance changes observed in planar bilayer membranes indicate that the compounds act as channels. Multiple copies of the same channel form in which the conductance is controlled by the macrocyclic portions of the structures. The pores are ion-selective in the sequence Cs(+) > K(+) > Na(+) > Cl(-), controlled by the polar head-groups of the structures. The data are consistent with a model involving the formation of active dimers.

Journal Article↗

Establishment of a sequence-based typing system for BoLA-DRB3 exon 2.

A rapid, high-resolution sequence-based typing (SBT) system for BoLA-DRB3 exon 2 was developed. Amplification of the entire exon was achieved by a fully nested PCR with locus-specific primers and sequencing was performed directly on the PCR product. Heterozygous sequence data were obtained by automated sequence analysis of both alleles. Forward and reverse sequence data were assembled to improve identification of all heterozygous positions. Specific software (Haplofinder, Roslin Institute Software, Roslin, UK) was designed for allele assignment. Fifty-four females from a Holstein-Charolais resource herd cross, their 12 sires and five unrelated Holstein animals were used to establish the method. In parallel, these animals were typed by DRB3 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to confirm the results. Polymerase chain reaction-RFLP analysis defined 15 known types in the 71 animals, while SBT of the same animals showed 19 known alleles. Subsequently, 72 more animals from the same resource herd were typed by the established SBT method without PCR-RFLP typing. This SBT strategy and the Haplofinder software can be applied to the analysis of any polymorphic locus for which suitable locus-specific primers and allelic sequences are available.

Alleles↗

Characterization of 18 new BoLA-DRB3 alleles.

The second exon of the bovine MHC class II DRB3 gene was amplified by polymerase chain reaction (PCR) from DNA samples of 568 zebu Brahman cattle (Bos indicus) from Martinique (French West Indies). Cloning of these PCR products allowed the isolation of both alleles from each animal, which were characterized by the PCR-restriction fragment length polymorphism (RFLP) technique using the restriction enzymes RsaI, BstYI and HaeIII. Four new PCR-RFLP patterns were obtained by digestion with RsaI. These patterns were named 'v', 'w', 'x' and 'y' continuing the accepted nomenclature. Sequencing of each allele allowed the identification of 18 new BoLA-DRB3 exon 2 nucleotide sequences and their deduced amino acid sequences.

Alleles↗

Breed differences in frequency of BoLA specificities.

A total of 675 cattle of five purebred and one crossbred group were tested for lymphocyte antigens. The purebred animals represented progeny of 107 sires. Lymphocytotoxicity sera obtained from parous cows were used to detect six antigens which are controlled by codominant alleles at the BoLA-TxA locus. Gene frequencies for the six alleles varied within breeds and large differences were observed between breeds for a given allele.

Alleles↗