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PubMed2006

Association of BoLA-DRB3.2 alleles with tick (Boophilus microplus) resistance in cattle.

Losses caused by bovine tick burdens in tropical countries have a tremendous economic impact on production systems. Besides reducing production, this parasite can cause death in the most susceptible animals. The use of commercial acaricides has been the major method of control, but their misuse has led to tick resistance to many chemicals. More recently, vaccines have been used in some countries without solving the problem completely. An alternative could be the development of resistant animals and the use of genetic markers and candidate genes that could help with the enormous task of selecting resistant animals. The bovine lymphocyte antigen genes (BoLA) have been shown to be associated with some parasitic infestations and disease incidence. Thus, the objective of the present study was to determine the association of BoLA-DRB3.2 alleles with tick resistance in cattle. The study was conducted on 231 F2 (Gyr x Holstein) animals that were artificially infested with 10,000 tick larvae. Log of tick count +1 was used as the dependent variable in a mixed animal model with allele substitution effects in addition to fixed effects of year and season at tick count, sex of calves, age of animal at tick count, hair type (short-straight, short-curl, long-straight, and long-curl), coat color (white, >75% white, 50- 75% white, and 25-50% white), and additive genetic, permanent environmental and residual effects as random. Females showed fewer ticks than males. Animals with short-straight hair were more resistant to tick infestation than animals with long-curl hair, and animals with whiter coat color also had fewer ticks. An association between BoLA alleles and lower tick number was found for alleles DRB3.2 *18, *20 and *27 at the 5% significance level. Also, one allele (DRB3.2*16) showed an association at the 10% level. Allele *27 was the most frequent in the population (30.7%), followed by alleles *16 (10.8%), *20 (8.7%) and *18 (2.4%). These results suggest that BoLA-DRB3.2 alleles could be used to help in the selection of animals resistant to tick infestation. However, further studies involving a larger population of cattle in combination with other BoLA genes may help to understand the mechanisms of resistance to parasites.

Alleles↗
PubMed1983

Cell-mediated cytotoxicity in Theileria annulata infection of cattle with evidence for BoLA restriction.

Recovery of calves from tropical theileriosis was accompanied by the disappearance of macroschizonts from lymph nodes and the appearance of cytotoxic cells in the blood and lymph nodes. Acute, fatal disease was associated with incremental parasitosis and parasitaemia and, in general, an absence of detectable cytotoxic cells in the blood or lymph nodes. After recovery from infection, calves were resistant to challenge. Challenge with sporozoites was followed sometimes by an immediate reappearance or by a later peak, or sometimes by twin peaks of cytotoxic cells but macroschizonts were not detected. Histocompatibility (BoLA) typing indicated that calves produced two sequential populations of cytotoxic cells during recovery from primary infection with Theileria annulata. The expression of lysis by the first appeared to be BoLA restricted. In contrast, both the peaks of lysis manifest after challenge appeared to be BoLA restricted. Results suggest that BoLA restricted cells are established in the immunological memory and are probably analogous to cytotoxic T cells, while non-BoLA restricted cytotoxic cells are natural killer like cells. The results suggest a role for cytotoxic cells in recovery from primary infection, in the inhibition of proliferation of macroschizonts which evade mechanisms of acquired resistance and in the lysis of macroschizont infected cells deriving from challenge sporozoites which have evaded serum-mediated inhibition.

Animals↗
PubMed1994

Evidence for at least three transcribed BoLA class I loci.

Serological data identify a single major histocompatibility complex (MHC) class I locus in cattle. Molecular data, however, demonstrate the presence of at least two cattle MHC (BoLA) class I loci. To investigate the number of transcribed BoLA class I genes, we amplified cattle cDNA by using a single MHC class I-specific primer that hybridized to a conserved region of exon 4 and a non-specific 3' primer. Six BoLA class I cDNAs have been cloned and sequenced from a Bos taurus bull heterozygous for BoLA class I serological antigens, demonstrating the presence of a minimum of three loci. Sequence comparisons suggested that one of these cDNAs may be an unexpressed allele or the product of a nonclassical locus.

Alleles↗
PubMed1986

Possible association of antibody responses to human serum albumin and (T,G)-A--L with the bovine major histocompatibility complex (BoLA).

Antibody responses to human serum albumin (HSA) and (T,G)-A--L were determined in 130 young bulls in Norway and the BoLA types of the bulls were defined. Significant associations of some BoLA antigens with immune responsiveness were shown, indicating the likely existence of an immune response (Ir) region linked to the BoLA class I antigens. High response to HSA seems to be a dominant trait. BoLA w2 showed an association with low response to HSA. This may reflect the effect of a specific MHC-associated immune suppressor gene.

Aging↗
PubMed2004

Polymorphism in the bovine BOLA-DRB3 upstream regulatory regions detected through PCR-SSCP and DNA sequencing.

In the present work, we describe through polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing the polymorphism within the URR-BoLA-DRB3 in 15 cattle breeds. In total, seven PCR-SSCP defined alleles were detected. The alignment of studied sequences showed six polymorphic sites (four transitions, one transversion and one deletion) in the interconsensus regions of the BoLA-DRB3 upstream regulatory region (URR), while the consensus boxes were invariant. Five out of six detected polymorphic sites were of one nucleotide substitution in the interconsensus regions. It is expected that these mutations do not affect significantly the level of expression. In contrast, the deletion observed in the sequence between CCAAT and TATA boxes could have some effect on affinity interactions between the promoter region and the transcription factors. The URR-BoLA-DRB3 DNA analyzed sequences showed moderate level of nucleotide diversity, high level of identity among them and were grouped in the same clade in the phylogenetic tree. In addition, the phylogenetic tree, the similarity analysis and the sequence structure confirmed that the fragment analyzed in this study corresponds to the URR-BoLA-DRB3. The functional role of the observed polymorphic sites among the regulatory motifs in bovine needs to be analyzed and confirmed by means of gene expression assays.

Animals↗
PubMed2000

Presence of glutamine at position 74 of pocket 4 in the BoLA-DR antigen binding groove is associated with occurrence of clinical mastitis caused by Staphylococcus species.

Potential relationships between amino acid motifs in the antigen binding groove of various alleles of the bovine major histocompatibility complex DR (BoLA-DR) molecule and occurrence of clinical mastitis caused by Staphylococcus species (non-Staphylococcus aureus) were investigated in a case-control study. A significant association (P< or =0.05) was detected between the presence of glutamic acid at position beta 74 and occurrence of mastitis caused by Staphylococcus spp. with a relative risk of 11. This motif is present in BoLA-DRB3.2*22, *23 and *24 alleles. Presence of a positively charged residue (arginine or lysine) at position 13 also showed a tendency (P< o r=0.1) towards an association with a higher risk of clinical mastitis caused by the same bacteria. This motif is present in BoLA-DRB3.2*23 and *8 alleles. Similarly, presence of arginine at position beta 71 (present in alleles *23 and *22) was associated with occurrence of this disease. These positions (beta 13, beta 71 and beta 74) form pocket 4 of the antigen binding groove, which plays an instrumental role in antigen binding and recognition by T-lymphocytes. Thus, it can be concluded that pocket 4 of the BoLA-DR molecule is involved in conferring susceptibility to clinical mastitis caused by Staphylococcus spp.

Alleles↗
PubMed2002

A single amino acid deletion in the antigen binding site of BoLA-DRB3 is predicted to affect peptide binding.

Two bovine MHC class II alleles, BoLA-DRB3*0201 and BoLA-DRB3*3301, contain a three base pair deletion which results in the deletion of a lysine (K beta 65) in the antigen recognition site (ARS). Modelling of BoLA-DRB3*0201 with the conserved lysine K beta 65 and BoLA-DRB3*0201 without K beta 65 indicated that this deletion altered the peptide specificity of the ARS, and may impact on the immune response. To test this hypothesis, the presence of K beta 65 was analysed in a sample of cattle vaccinated with the commercial cattle tick vaccine (TickGARD). Homozygous deletion of K beta 65 was significantly associated with high response to TickGARD (P<0.05). Screening of the TickGARD antigen identified a potential T cell epitope that is recognised better by animals that are homozygous for the K beta 65 deletion. This study provides evidence that changes in the ARS of MHC class II molecules may be associated with the well recognised animal to animal variation in magnitude of vaccine response.

Animals↗
PubMed1997

Computer simulations to identify in polyproteins of FMDV OK1 and A12 strains putative nonapeptides with amino acid motifs for binding to BoLA class I A11 and A20 haplotype molecules.

The computer program "Findpatterns" was used to search FMDV- (OK1 and A12 strains) coded structural and nonstructural proteins for the availability of putative proteasome-generated nonapeptides with motifs reported for BoLA class I A11 and A20 haplotypes. These BoLA class I A11 and A20 nonapeptide motifs are identical to motifs of nonapeptides that interact with the peptide binding grooves of HLA class I B35 and B27 haplotypes, respectively. The computer findpattern program was used to analyze the FMDV-coded polyproteins for proteolytically cleavable nonapeptides with motifs for binding to the peptide binding grooves of BoLA class I A11 or 20 haplotypes. The computer simulations revealed that FMDV-infected cells (keratinocytes and antigen presenting cells. e.g., dendritic Langerhans cells in bovines) may be able to present viral nonapeptides to CD8+ cytolytic T cells (CTLs) in a BoLA-restricted manner. The role of the cellular arm of the immune response in the protection of bovines against FMDV is not known. Thus, the present computer analysis may encourage further experiments to develop a new generation of FMDV nonapeptide vaccines to stimulate the anti-FMDV cytolytic T cell response in bovine so this would complement the humoral immune response achieved by immunization with the inactivated virus vaccine.

Amino Acid Sequence↗
PubMed2001

Restriction fragment length polymorphism (RFLP) in exon 2 of the BoLA-DRB3 gene in South American cattle.

The Bola-DRB3 gene participates in the development of the immune response and is highly polymorphic. For these reasons, it has been a candidate gene in studies of the genetic basis of disease resistance and in population genetic analysis. South American native cattle breeds have been widely replaced by improved exotic breeds leading to a loss of genetic resources. In particular, South American native breeds have high levels of fertility and disease resistance. This work describes genetic variability in the BoLA-DRB3 gene in native (Caracu, Pantaneiro, Argentinean Creole) and exotic (Holstein, Jersey, Nelore, Gir) cattle breeds in Brazil and Argentina. PCR-RFLP alleles were identified by combining the restriction patterns for the BoLA-DRB3.2 locus obtained with RsaI, BstY and HaeIII restriction enzymes. Allelic frequencies and deviations from the Hardy-Weinberg equilibrium were also calculated. Analysis of the 24 BoLA-DRB3 PCR-RFLP alleles identified showed differences in the allele distributions among breeds.

Alleles↗
PubMed1999

The stationary-phase morphogene bolA from Escherichia coli is induced by stress during early stages of growth.

The Escherichia coli morphogene bolA causes round morphology when overexpressed. The expression of bolA is mainly regulated by a sigmas-dependent gearbox promoter bolA1p. Such regulation results in increased relative levels of expression at slow growth rates, as seen with those attained at the onset of stationary phase. We demonstrate that bolA1p is also induced during early logarithmic growth in response to several forms of stress, and that this induction can be partially sigmas independent. Sudden carbon starvation results in a 17-fold increase in mRNA levels derived from bolA1p 1 h after stress imposition. Increased osmolarity results in a more than 20-fold increase after the same period. Considerable increases in bolA1p mRNA levels were also detected as a result of heat shock, acidic stress and oxidative stress, which has been shown to inhibit sigmas translation. The orders of magnitude of bolA1p induction in log phase due to sudden starvation, osmotic shock and oxidative stress surpass the levels reached in stationary phase. Under sudden carbon starvation and osmotic shock, the cells changed their morphology, resembling those cells in which bolA is overexpressed in stationary phase. Increased expression and morphological changes due to sudden carbon starvation and osmotic shock still occur when sigmaS is not present in a rpoS- background. The results show that expression of bolA is not confined to stationary phase, but it can also play an important role in general stress response. We propose that bolA1p stress induction overrides the normal regulation imposed by growth rate, which is strictly the result of sigmaS-directed transcription.

Cell Division↗
PubMed2004

Solution structure of a BolA-like protein from Mus musculus.

The BolA-like proteins are widely conserved from prokaryotes to eukaryotes. The BolA-like proteins seem to be involved in cell proliferation or cell-cycle regulation, but the molecular function is still unknown. Here we determined the structure of a mouse BolA-like protein. The overall topology is alphabetabetaalphaalphabetaalpha, in which beta(1) and beta(2) are antiparallel, and beta(3) is parallel to beta(2). This fold is similar to the class II KH fold, except for the absence of the GXXG loop, which is well conserved in the KH fold. The conserved residues in the BolA-like proteins are assembled on the one side of the protein.

Amino Acid Sequence↗
PubMed1993

1D-IEF analysis of BoLA class I expression using allo-antisera reveals additional complexity.

The use of the bovine allo-antisera in lymphocyte microcytotoxicity assays suggests that there is a single highly polymorphic class I product expressed by the BoLA system encoded by one locus. In contrast, biochemical techniques, such as 1D-IEF, reveal a complex pattern of bands for BoLA class I molecules from each animal. In order to understand the origins of this heterogeneity bovine allo-antisera were used in the immunoprecipitation step of 1D-IEF and the results compared with those from immunoprecipitation using the monoclonal antibody W6/32. By modifying existing protocols to include Gammabind G a range of bovine allo-antisera were used successfully to immunoprecipitate bovine MHC class I molecules. The results indicate that the bovine allo-antisera do not recognize all molecules previously assigned to BoLA class I serotypes by 1D-IEF. Furthermore, some of the allo-antisera immunoprecipitated molecules are not recognized by W6/32 and vice versa. This suggests that more than one polymorphic locus is expressed from the bovine MHC and that each allo-antiserum recognizes molecules encoded by different loci. Examination of the results also suggests the existence of linkage disequilibrium in the BoLA class I region.

Animals↗
PubMedDate not supplied

Genetic analysis of the antigens defined at the third international BoLA workshop.

A comparison of lymphocyte antigens showed that 32 of the 33 BoLA antigens defined at the third international BoLA workshop (Bull et al., 1989) corresponded to previously defined local antigens (Stear et al., 1988). The third workshop antigen w18 had no locally defined equivalent. All 32 antigens were shown in family studies to be expressed by autosomal co-dominant genes, and all 32 workshop antigens were shown to be products of the BoLA system. After excluding the supertypic antigens, nearly all animals tested possessed only one or two antigens and there were no observed recombinants in family studies. These results do not exclude the possibility that the 32 workshop antigens are the products of one locus (BoLA-A).

Alleles↗
PubMed1994

Polymorphism of bovine MHC class I genes. Joint report of the Fifth International Bovine Lymphocyte Antigen (BoLA) Workshop, Interlaken, Switzerland, 1 August 1992.

The objectives of the Fifth International BoLA Workshop were to: standardize nomenclature, compare typing methods, and characterize BoLA haplotypes. The workshop was based on the distribution of blood samples (cells) from 60 selected cattle to 14 laboratories. Results for the class I (BoLA-A) region are presented in this paper while results for the class II regions are presented in a separate report. Thirty-six of the 50 previously established serological class I specificities were represented in the cell panel. However, only 30 specificities could be confirmed. Two specificities, A16 and A32, were upgraded from provisional, workshop (w) specificities to BoLA-A locus specificities and three new specificities, w51(w28), w52 and w53(w28), were defined. The 39 specificities distinguished 30 class I haplotypes in the 60 animals. Class I isoelectric focusing proved to be a useful adjunct to the serology. Isoelectric focusing confirmed several serologically defined splits and detected splits of A15(A8), A18(A6) and A22(w49) that had not been detected by serology. Subsequently, serological support for splits of A15(A8) and A22(w49) was found.

Animals↗
PubMed1998

BoLA DYA polymorphism in Czech cattle.

Polymorphism at the BoLA DYA locus was determined in two groups of Czech Black Pied cattle by PCR-RFLP detecting substitutions at nucleotide positions 112 and 219. Animals for this study were nonrandomly selected according to their health status in two BoLA-associated infections: bovine leukosis (n = 59) and Johne's disease (n = 36). A group of noninfected Czech Red Pied cows (n = 37) was used for comparison. The frequencies of DYA alleles and haplotypes were virtually identical in the two selected groups as well as in the infection-free animals. In contrast, distribution of BoLA DRB3.2 alleles differed considerably between the infected groups as expected based on the previously detected associations with BoLA. The results suggest that the polymorphism of the DYA unexpressed gene was not influenced by selecting animals for this study according to their health status.

Alleles↗
PubMed1995

Analysis of associations between major histocompatibility complex (BoLA) class I haplotypes and subclinical mastitis of dairy cows.

The associations between BoLA class I haplotypes and subclinical mastitis were investigated using information on 333 cows from three different breeds and crossbreeds from 14 dairy herds in Denmark. Somatic cell count and bacteriological status were used as markers for subclinical mastitis. Associations between BoLA class I haplotypes and IMI status were also determined. The association between BoLA class I haplotypes and subclinical mastitis was weak. The A10(W50), A11, A12(A30), A16, A19(A6), A21, A26, and A31(A30) alleles were associated with different markers of subclinical mastitis. Susceptibility or resistance to the two bacteria categories was associated with different alleles. This study indicated that BoLA antigens may be involved in resistance to mastitis and that resistance may be specific for a particular pathogen.

Alleles↗
PubMed1987

Bovine alloreactive cytotoxic cells generated in vitro detect BoLA w6 subgroups.

Alloreactive cytotoxic T cells (CTL) were generated in mixed lymphocyte culture against cells bearing subgroups of BoLA w6, as well as in BoLA w4, w10 and w16. Primary cultures were restimulated at weekly intervals with irradiated stimulator cells and tested in a 51Cr-release assay with target cells derived from Theileria annulata-infected cell lines. Generation of CTL was accelerated in animals that had been previously primed in vivo by skin grafting. CTL were generated that were specific for BoLA w6 subgroups and not w6. With w6.1 the specific killing was significant at the 5% level, and with w6.2, 6.3 and 6.4 it was significant at the 0.1% level. Where CTL were potentially generated against two BoLA-A locus allele products at the same time (i.e. with heterozygous stimulator cells), one of which was a w6 subgroup, there was similar CTL activity against both products when w6.4 and w16 or w6.1 and w4 were the combinations involved. In two generations against w10 and either w6.1 or w6.2 there was significantly more killing of w10-bearing targets than those with the w6 subgroup.

Animals↗
PubMed1993

The DA6-147 monoclonal antibody raised against the HLA-DR alpha chain identifies a cryptic epitope on the BoLA-DR alpha chain.

By combining immunoprecipitation of BoLA molecules with monoclonal antibodies raised against 2 different major histocompatibility class II antigens, TH14B and TH81A, and western blotting using the anti-HLA DR alpha monoclonal antibody DA6-147, we characterized an epitope conserved on BoLA- and HLA-DR alpha chains. This epitope, not accessible on intact cells, was revealed after cell lysis. In addition, these results allowed us to define TH14B as an anti-BoLA-DR monoclonal antibody whereas TH81A, raised against the products of a second MHC locus, is probably an anti-BoLA-DQ monoclonal antibody.

Animals↗