Joint report of the Third International Workshop on Canine Immunogenetics. I. Analysis of homozygous typing cells

Dog leukocyte antigen class II alleles and haplotypes associated with meningoencephalomyelitis of unknown origin in Chihuahuas

Idiopathic non-infectious meningoencephalomyelitis (NIME), which is thought to be an immune-mediated disease, is a common inflammatory disease in dogs. Meningoencephalomyelitis of unknown origin (MUO), a subgroup of NIME, consists of necrotizing meningoencephalitis (NME), necrotizing leukoencephalitis, and granulomatous meningoencephalomyelitis. Recent studies have shown associations between disease development and dog leukocyte antigen (DLA) class II genes in NME in Pugs and in NIME in Greyhounds. This study focused on Chihuahuas, which have a high incidence of MUO and are one of the most common dog breeds in Japan. Because the development of MUO seems to be associated with DLA class II genes, we aimed to evaluate the association between DLA class II genes and MUO development in Chihuahuas. Blood samples were obtained from 22 Chihuahuas with MUO (MUO group) and 46 without neurological diseases (control). The allele sequences of three DLA class II loci were determined, and haplotypes were estimated from these data. In total, 23 haplotypes were detected. The frequency of one haplotype (DLA-DRB1*015:01--DQA1*006:01--DQB1*023:01) was significantly higher in the MUO group than in the control group (odds ratio, 7.11; 95% confidence interval, 1.37-36.81; P=0.0141). The results suggest that the development of MUO in Chihuahuas may be associated with DLA class II genes. Because the identified risk haplotypes differed from those of other breeds, the pathogenesis of NIME-related diseases may differ among dog breeds.

A DLA-associated polymorphic cell surface determinant defined by the murine monoclonal antibody W3G10

A polymorphic determinant on the surface of canine peripheral blood mononuclear cells (PBMC) has been identified using the murine monoclonal antibody W3G10. The determinant, which has a molecular weight of approximately 39 Kd, is associated with DLA-Dw1 (w = workshop designation), -Dw3, -Dw4, -Dw10, -Dsea1 (sea = Seattle designation) and -Dsea9, but not -Dw8, -Dw9, -Dsea4, -Dsea10, -Dsea16 or -Dsea17, and segregates in Mendelian fashion. There does not appear to be any linkage disequilibrium with currently recognized DLA-A, -B or -C alleles. Cytotoxic effector function was eliminated when W3G10 positive alloantigen primed PBMC were treated with W3G10. However, cytotoxicity was not affected when W3G10 negative PBMC were used, thus further confirming polymorphism. The data suggest that the antigen identified by McAb W3G10 is not a typical class I or class II MHC antigen, but may be encoded by a closely linked gene.

Sequence of the canine major histocompatibility complex region containing non-classical class I genes

We have sequenced a segment of 150,102 nucleotides of canine major histocompatibility complex (MHC) DNA, corresponding to the junction of the class I and class III regions. The distal portion contained five class III genes including two tumor necrosis factor genes and the proximal portion contained five genes or pseudogenes belonging to the class I region. The order of the class III region genes was conserved as in the porcine and human MHC regions. The order of the class Ib loci from the proximal side outwards was DLA-53, DLA-12a, DLA-64, stress-induced phosphoprotein-1, followed by DLA-12. Only DLA-64 and DLA-12 display an overall predicted protein sequence compatible with the expression of membrane-anchored glycoproteins. The other class 1b loci do not appear to be functional by sequence analysis. In all, these 10 genes spanned 24% of the total sequence. The remaining 76% comprised of a number of non-coding and repetitive DNA elements including long interspersed nuclear element (LINE) fragments, short interspersed nuclear elements (SINE), and microsatellites.

Minor histocompatibility antigens on canine hemopoietic progenitor cells

Adoptive immunotherapy with CTL against minor histocompatibility Ags (mHA) provides a promising way to treat leukemia relapse in allogeneic chimeras. Here we describe the in vitro generation of CTL against mHA in the dog. We tested their inhibitory effect on the growth of hemopoietic progenitor cells stimulated by hemopoietic growth factors in a 4-day suspension culture. CTL were produced by coculture of donor PBMC with bone marrow-derived dendritic cells (DCs). These DCs were characterized by morphology, high expression of MHC class II and CD1a, and the absence of the monocyte-specific marker CD14. Characteristically these cells stimulated allogeneic lymphocytes (MLR) and, after pulsing with a foreign Ag (keyhole limpet hemocyanin), autologous T cells. CTL were generated either ex vivo by coculture with DCs of DLA-identical littermates or in vivo by immunization of the responder with DCs obtained from a DLA-identical littermate. In suspension culture assays the growth of hemopoietic progenitor cells was inhibited in 53% of DLA-identical littermate combinations. In canine families mHA segregated with DLA as restriction elements. One-way reactivity against mHA was found in five littermate combinations. In two cases mHA might be Y chromosome associated, in three cases autosomally inherited alleles were detected. We conclude that CTL can be produced in vitro and in vivo against mHA on canine hemopoietic progenitor cells using bone marrow-derived DCs.

Tolerance and chimerism

Stem-cell transplantation from human leukocyte antigen (HLA)-haploidentical family members carries a high risk of rejection and graft-versus-host disease (GVHD) if donor and recipient differ by more than one HLA antigen. The authors have developed treatment protocols from studies in dog leukocyte antigen-haploidentical dogs that prevent rejection and modify GVHD to the extent that patients with aggressive hematologic neoplasia can be treated with success. Principal improvements have been achieved in the use of cyclophosphamide and total-body irradiation for conditioning and T-cell depletion for prevention of GVHD. More recently, the combination of marrow and CD6-depleted mobilized donor blood cells (MDBC) has been introduced for HLA-haploidentical transplantation on the basis that CD6-depleted MDBC contain immunoregulatory cells besides stem cells and natural killer cells. Clinical results are reported on 36 patients with high-risk hematologic neoplasia. The results encourage the use of HLA-haploidentical stem-cell transplantation at an earlier stage of the disease. This method could also be of use for tolerance induction in organ transplantation.

Hematopoietic cell transplantation in the treatment of leukemia

OBJECTIVES

To review the current evidence regarding the role and benefits of hematopoietic cell transplantation (HCT) in leukemia.

DATA SOURCES

Review articles, original articles, internet web sites, and books.

CONCLUSION

HCT is a potentially curative treatment modality for patients with hematologic malignancies such as leukemia.

IMPLICATIONS FOR NURSING PRACTICE

Nurses working with patients undergoing HCT need awareness of the type of leukemia, source of the hematopoietic cell product, type of preparative regimen used, and the complications of the procedure will enable nurses to educate and intervene with patients and their family members throughout the transplant trajectory.

Cellular, serological, and molecular polymorphism of the class I and class II loci of the canine Major Histocompatibility Complex

This study was undertaken to determine the relationships between canine cellular and serological determinants and more recently described genes. Such relationships might reveal information about immunological reactivity or function of various proteins. To do this we studied the haplotypic associations of dog leukocyte antigen (DLA) class I and class II alleles determined from a panel of 14 DLA-D homozygous dogs. This panel of dogs was typed for the serological determinants DLA-A, DLA-B and DLA-C. Polymorphisms for DLA-DQA1, DLA-DQB1, DLA-DRB1 and DLA-88 were also determined. The number of alleles (one or two) for two microsatellite markers in the DLA region were also determined. Analyses of the nucleotide sequences and of the serological and cellular typing data revealed that phenotypic homozygosity, as defined by the DLA-D type in mixed leukocyte culture (MLC), tended to correlate with homozygosity at the DLA-DRB1 locus but not necessarily at the DLA-DQB1 locus. Furthermore, MLC specificity was determined by other loci besides DLA-DRB1 and DLA-DQB1. The amino acid at position 63 of the DR beta chain could contribute to the DLA-B serological specificity. DLA-88, the most polymorphic class I gene characterized to date, did not have an easily identifiable association with either the DLA-A or DLA-C class I serological specificities. Homozygosity or heterozygosity of each of two microsatellite markers, FH 2200 and FH 2202, located in the class I or class II region, respectively, did not correlate with homozygosity or heterozygosity of the most polymorphic known class I (DLA-88) or class II (DLA-DRB1) genes.

History of haematopoietic stem-cell transplantation

After fifty years of investigations into the use of pluripotent haematopoietic stem-cell transplantation for cancer therapy, this procedure has progressed from one that was thought to be plagued with insurmountable complications to a standard treatment for many haematological malignancies. How have these hurdles been overcome, and how can the therapy be expanded to include patients who are too old or medically infirm to tolerate conventional transplant approaches?

DLA-DQA1 polymorphisms in dogs defined by sequence-specific oligonucleotide probes (SSOP)

Several recent studies have identified DNA sequences for alleles of the DLA-DQA1 locus in the dog. To date, 10 DQA1 alleles have been reported. No data exists on the frequencies of these alleles within the general dog population, nor is there any indication of whether alleles are breed specific. We have addressed this issue by establishing a molecular-based sequence-specific oligonucleotide probing (SSOP) method to identify all published DQA1 alleles and have used these methods to type a large number of dogs. Oligonucleotide probes were designed to detect all the polymorphic sites in exon 2. This allowed assignment at the allele level. Three hundred and thirty dogs were typed for DQA1. All but two of the published DQA1 alleles were identified in these animals. One new allele was identified, and confirmed by DNA cloning and sequencing. This typing method provides a powerful tool for generating data that will be essential for studies investigating the genetic relationships between different breeds.

Nomenclature for factors of the dog major histocompatibility system (DLA), 1998: first report of the ISAG DLA Nomenclature Committee

A Nomenclature committee for Factors of the Dog Major Histocompatibility System or Dog Leukocyte Antigen (DLA) has been convened under the auspices of the International Society for Animal Genetics (ISAG) to define a sequence based nomenclature for the genes of the DLA system. The remit of this committee includes: assignment of gene names rules for naming alleles assignment of names to published alleles assignment of names to new alleles rules for acceptance of new alleles DLA Nomenclature Committee, rules for acceptance, DLA genes and alleles, sequence based nomenclature.

Nomenclature for factors of the dog major histocompatibility system (DLA), 1998. First report of the ISAG DLA Nomenclature Committee. International Society for Animals Genetics

A Nomenclature Committee for factors of the dog major histocompatibility system or dog leukocyte antigen (DLA) has been convened under the auspices of the International Society for Animal Genetics (ISAG) to define a sequence-based nomenclature for the genes of the DLA system. The remit of this committee includes: i) assignment of gene names; ii) rules for naming alleles; iii) assignment of names to published alleles; iv) assignment of names to new alleles; and v) rules for acceptance of new alleles.

Interbreed variation of DLA-DRB1, DQA1 alleles and haplotypes in the dog

Although 36 DLA-DRB1 and 10 DLA-DQA1 allele sequences have been published to date, no data on individual allele frequencies exists, either for specific breeds or cross breeds, and the full extent of the polymorphism at each of these loci is still not known. We have used sequence-specific oligonucleotide probing (SSOP) to characterise a series of 367 dogs for their DRB1 and DQA1 alleles. These included individual animals from over 60 different breeds, with numbers per breed ranging from 1 to 39. DLA types were generated from 218 dogs for DRB1 and from 330 dogs for DQA1, while 181 dogs were characterised for both these loci. The frequency of individual DRB1 and DQA1 alleles showed considerable interbreed variation, e.g. 83% of West Highland White Terriers were DRB1*01 as opposed to 9% of Collies. No breed had >9 of the 22 DRB1 types defined in this study; several breeds had only two DRB1 types. DLA-DQA1 showed less variation in allele numbers per breed, but also showed considerable interbreed frequency variation. Haplotype analysis revealed over 44 different DRB1/DQA1 combinations. Of these, 25 were in a number of animals, and also in an animal that was homozygous for one or both of these loci. Some DRB1 alleles could be found in combination with several different DQA1 alleles, while others were only present in one haplotypic combination. DLA allele frequency data in normal dogs will be critical for disease association studies. It may also be possible to use haplotype data to establish the genetic relationships between different dog breeds.

DLA-DRB1 histocompatibility genotyping using RT-nested PCR and cycle sequencing

Class-II histocompatibility genes are associated with predisposition to autoimmune diseases in many mammal species. We have developed a technique using reverse transcriptase and nested-PCR for amplification from blood samples of expressed sequences encoded by canine DLA-DRB1 loci. In the first polymerase chain reaction (PCR), we utilize primers DR-SP and DR-STOP as developed by Sarmiento et al. (1990). In the nested PCR, we utilize two additional primers, namely primer 57 [5'-TCTTGGAGGCTCCTGGATGACAGC-3'] and primer 367 [5'-CACAACTACGGGGTGATTGAGAGC-3'] to produce a 334 bp amplified product. After digestion with restriction endonucleases, some of the alleles can be identified by restriction fragment length polymorphism (RFLP). The increasing information on new DLA-DRB1 alleles over the last two years renders the DLA-DRB1 too diverse for convenient use of RFLP. However, the expressed sequences amplified by our protocol can be conveniently identified by cycle sequencing. This RT n-PCR protocol will suffice for the genotyping of individual dogs at the DLA-DRB1 locus.

DLA-DRB1 polymorphisms in dogs defined by sequence-specific oligonucleotide probes (SSOP)

To date, DNA sequences for 29 dog DLA-DRB1 alleles have been reported. However, no data exists on the frequencies of these alleles within the general dog population, nor is there any indication of whether there is interbreed variation of allele distribution. We have addressed this by establishing a molecular based sequence-specific oligonucleotide probing (SSOP) method to identify all of the known broad DRB1 types and we have used this to type a random panel of dogs. A series of oligonucleotide probes were designed to detect known polymorphisms in the three DRB1 hypervariable regions, together with two distinctive motifs in other regions of exon 2. This set of probes enabled us to assign broad DRB1 types. Two hundred and eighteen dogs were SSOP typed for DRB1. All but 4 of the published DLA-DRB1 alleles were identified in these animals. Interbreed variation in both allele distributions and allele frequencies were observed, which may be useful in the study of genetic variation between breeds. This variation also has implications for the selection of control groups for studies aimed at identifying MHC associations with disease susceptibility in the dog.

Epitope Specificity of CD44 for Monoclonal Antibody–Dependent Facilitation of Marrow Engraftment in a Canine Model

Primary graft rejection after marrow transplantation occurs more frequently in patients receiving HLA-haploidentical compared with HLA-identical sibling transplants. Both human and experimental animal data suggest that the cells responsible for this phenomenon are either host natural killer (NK) cells, T cells, or both. To investigate the mechanisms of graft rejection, we have developed a canine model of marrow transplantation, which uses DLA-nonidentical unrelated donors in the absence of postgrafting immunosuppression. In this model most animals rejected their marrow grafts after a preparative regimen of 9.2 Gy total body irradiation (TBI). However, engraftment of DLA-nonidentical marrow can be facilitated when the recipients are pretreated with monoclonal antibody (MoAb) S5, which recognizes CD44. In this report, we extended these observations by first cloning the canine CD44 and, next, mapping the epitope recognized by S5, which was located in a region conserved among human and canine CD44 and was distinct from the hyaluronan binding domain. However, in vitro binding of S5 caused a conformational change in CD44, which allowed increased hyaluronan binding. Then, we reexamined the in vivo model of marrow transplantation and compared results with MoAb S5 to those with two other anti-CD44 MoAbs, IM7 and S3. Only MoAb S5 significantly increased the engraftment rate of DLA-nonidentical unrelated marrow, whereas the two other anti-CD44 MoAbs were ineffective. The enhanced in vivo effect was not related to differences in the MoAbs' avidities, since both S5 and IM7 had equivalent binding to CD44, but most likely related to the specific epitope that S5 recognizes. Thus, this study shows that the effect of the anti-CD44 MoAb S5 in facilitating engraftment is epitope specific and if one is to use an anti-CD44 to facilitate engraftment of marrow in humans, one cannot assume that any anti-CD44 would work.

Epitope Specificity of CD44 for Monoclonal Antibody–Dependent Facilitation of Marrow Engraftment in a Canine Model

Primary graft rejection after marrow transplantation occurs more frequently in patients receiving HLA-haploidentical compared with HLA-identical sibling transplants. Both human and experimental animal data suggest that the cells responsible for this phenomenon are either host natural killer (NK) cells, T cells, or both. To investigate the mechanisms of graft rejection, we have developed a canine model of marrow transplantation, which uses DLA-nonidentical unrelated donors in the absence of postgrafting immunosuppression. In this model most animals rejected their marrow grafts after a preparative regimen of 9.2 Gy total body irradiation (TBI). However, engraftment of DLA-nonidentical marrow can be facilitated when the recipients are pretreated with monoclonal antibody (MoAb) S5, which recognizes CD44. In this report, we extended these observations by first cloning the canine CD44 and, next, mapping the epitope recognized by S5, which was located in a region conserved among human and canine CD44 and was distinct from the hyaluronan binding domain. However, in vitro binding of S5 caused a conformational change in CD44, which allowed increased hyaluronan binding. Then, we reexamined the in vivo model of marrow transplantation and compared results with MoAb S5 to those with two other anti-CD44 MoAbs, IM7 and S3. Only MoAb S5 significantly increased the engraftment rate of DLA-nonidentical unrelated marrow, whereas the two other anti-CD44 MoAbs were ineffective. The enhanced in vivo effect was not related to differences in the MoAbs' avidities, since both S5 and IM7 had equivalent binding to CD44, but most likely related to the specific epitope that S5 recognizes. Thus, this study shows that the effect of the anti-CD44 MoAb S5 in facilitating engraftment is epitope specific and if one is to use an anti-CD44 to facilitate engraftment of marrow in humans, one cannot assume that any anti-CD44 would work.

Polymorphism analysis of four canine MHC class I genes

We have studied the variability of four structurally complete dog leukocyte antigen (DLA) class I genes, termed DLA-12, -88, -79 and -64, in a population of mixed breed, unrelated dogs. The human HLA and canine DLA loci share a high degree of similarity in terms of gene structure. This analysis focused on the first three exons of each of four complete canine genes. Exons two and three are the major source of polymorphism in the corresponding human genes. In this analysis, DLA-88 was found to be significantly more polymorphic than the other three genes, with 44 distinct alleles observed among 63 mixed breed, unrelated dogs. The remaining genes had between one and four alleles when examined in 25 dogs. This work was carried out as part of an effort to develop an MHC typing system for the dog, which is critical to the further development of preclinical studies of hematopoietic stem cell and solid organ transplantation in the canine model.

Canine major histocompatibility complex genes DQA and DQB in Irish setter dogs

Information about genetic variation within the canine major histocompatibility complex (MHC) class II genes is limited. In common with most other vertebrate species the canine MHC, or DLA, includes genes which are homologous to human DR, DQ, and DP. Recently, at least one functional DLA DQ gene-pair has been characterized, but so far systematic screening efforts have been lacking. In the present study, we sequenced both cDNA and genomic clones derived from DLA DQ genes of Irish setter dogs. This breed was of interest, since it shows a high prevalence of gluten sensitive enteropathy (GSE), which may be a useful animal model for celiac disease (CD) of man. Interestingly, few of the alleles found in Irish setters were identical to those previously detected in other breeds. Three novel DLA DQA and four novel DLA DQB alleles were discovered in 19 unrelated dogs. Strong association between certain HLA DQ alleles and CD of man prompted us to screen the DQ alleles of members of a family of gluten-sensitive Irish setter dogs. No haplotypes or alleles were shared by all affected dogs, but one frequent haplotype in this family was also detected in an unrelated gluten-sensitive Irish setter; this haplotype was absent in the healthy dogs. This observation warrants further investigation by screening the DQ alleles of a large population of unrelated gluten-sensitive Irish setters.

Adoptive immunotherapy in canine chimeras

Chimerism and tolerance after bone marrow transplantation provide excellent conditions for adoptive immunotherapy with T cells of the marrow donor. We studied adoptive immunotherapy in dog leukocyte antigen-identical canine littermate chimeras. Mixed chimeras were produced by conditioning treatment with total body irradiation of a dose of 10 Gy, a uniformly lethal dose in dogs, and infusion of between 1 x 10(8) and 2 x 10(8)/kg mononuclear marrow cells treated with absorbed antithymocyte globulin for inactivation of T cells. Donors were of opposite sex. Persistent mixed chimerism was induced in six of nine dogs, chimerism was complete in one dog, and only transient in two dogs. Tolerance to donor skin grafts was demonstrated in eight dogs, including a dog without cytogenetic evidence of chimerism. Lymphocytes of the marrow donor (between 3.2 x 10(8)/kg and 4.1 x 10(8)/kg) were transfused at various times after transplantation. Nontransfused dogs survived without graft-versus-host disease (GVHD), whereas dogs transfused on days 1 and 2 and dogs transfused on days 21 and 22 developed GVHD and died. In contrast, dogs transfused on days 61 and 62 or later survived without GVHD. Chimerism converted from mixed to complete in six of six transfused dogs and in one of eight nontransfused dogs (P<0.005). Donor lymphocyte transfusions 2 years and 4.5 years after transplantation induced split chimerism with lymphoid cells of donor origin and myeloid cells of host origin in one dog and complete chimerism in the other dog. Before lymphocyte collection, donors were immunized against tetanus toxin. Seven days after lymphocyte transfusion, recipients were given booster injections of tetanus toxoid and primary immunization against diphtheria toxin. In transfused animals, antibody titers against tetanus were demonstrated already before the booster injection. Transfused animals developed higher titers of antibody against tetanus and diphtheria toxin than nontransfused animals. Donor lymphocytes converted mixed chimerism into complete chimerism without producing GVHD, when the transfusion was delayed for 2 months or later after transplantation. Transfusion of donor lymphocytes transferred immune reactivity against tetanus toxin and improved reactivity against diphtheria toxin as a new antigen.

Fresh venous allografts in peripheral arterial reconstruction in dogs. Effects of histocompatibility and of short-term immunosuppression with cyclosporine A and mycophenolate mofetil

To date, no arterial substitute has been shown to be as effective as the autologous saphenous vein in peripheral revascularization procedures. In the present study, the venous allograft was evaluated as a vascular substitute in terms of patency and induction of host immune reactivity, whether used in major histocompatibility complex-incompatible, major histocompatibility complex-incompatible dogs. The immunosuppressive drug therapies were given for a period of 31 days, beginning 1 day before transplantation, and consisted of the use of cyclosporine A, mycophenolate mofetil, or a combination of both. All histoincompatible allografts were thrombosed at 4 or 8 weeks after transplantation with antibody development and cell-mediated cytotoxicity in the graft, whereas histocompatible allografts showed late stenosis without immunologic reactions directed toward donor cells. Given alone, neither cyclosporine A nor mycophenolate mofetil improved the overall patency of venous allografts; thrombosis occurred shortly after cessation of immunosuppression. Still, the cyclosporine A-mycophenolate mofetil combination therapy led to a 100% patency rate at 20 weeks after implantation and immune reactions were markedly reduced. This study shows that the fresh vein allograft is still an attractive and functional alternative to the autologous saphenous vein if the host immunologic reactions are controlled by cyclosporine A-mycophenolate mofetil immunosuppression.

Biochemical definition of DLA-A and DLA-B gene products by one-dimensional isoelectric focusing and immunoblotting

The serologically defined canine MHC gene products (DLA-A and DLA-B) were investigated by one-dimensional isoelectric focusing after detergent phase separation, and immunoblotting (1D-IEF). The animals studied (n = 36) represented three different breeds. Since DLA-A and DLA-B antigens are MHC class I and class II molecules, respectively, cross-reactive polyclonal antibodies specific for human class I or class II molecules were utilized to visualize the protein pattern. The relative positions of the bands were correlated with the DLA-A and DLA-B antigens. In most cases DLA antigens of identical serological type did not differ in their 1D-IEF pattern except for DLA-A9 and the serologically undefined DLA-B gene product DLA-B 'blank'. For DLA-A9, two subtypes (A9.1 and A9.2) were identified in Beagle and associations of A9.1 with the haplotype A9,B4 and of A9.2 with A9,B6 were seen. In contrast, the haplotype A9,B6 in Labradors was associated with A9.1. Whereas all six serologically defined DLA-A antigens possessed distinct isoelectric points (IEP), not all DLA-B antigens could be differentiated by 1D-IEF:B5 as well as B13 coband with one B 'blank' specificity (BE1). Furthermore, a second B 'blank' (BE2) could be identified by 1D-IEF, underlining the advantage of this technique in the immunogenetic analysis of DLA gene products in dogs.

A research on DLA-DRB1 genotyping by PCR-RFLP. I. To select a appropriate oligonucleotide primer pair

In order to study the DLA (Dog Leucocyte Antigen) class II region we utilized the polymerase chain reaction based restriction fragment length polymorphism (PCR-RFLP) method, which has been reported previously as an efficient and simple technique for accurate definition of the HLA class II alleles. To search for a appropriate primer pair a series of amplifications with 4 different primer pairs DLA-DR-SP/Stop, DLA-DR-SP/P3, HLA-DRB-GH46/50 and HLA-DRB-AMP-A/B were provided. Only one satisfactory amplification was obtained with the primer pair HLA-DRB-AMP-A/B. The analogous sequences of the primer pair are found in the sequence of HLA-DRB-cDNA. The amplification region of the primer pair includes also the three hypervariable regions (HVR) in the sequence of DLA-DRB cDNA. Southern blot hybridization analysis confirmed the specificity of the primer pair HLA-DRB-AMP-A/B. The results of Hae III and Hinfl digestion show high polymorphism in DLA-D region and allele specific polymorphic patterns. Therefore, it is suggested that the primer pair HLA-DRB-AMP-A/B is at present the only available and usefull primer pair in PCR-RFLP study of DLA-DRB1 gene.

Researches on DLA-DRB1 genotyping by PCR-RFLP. II. A study of serology and cellularly defined DLA haplotypes and their segregation

The polymerase chain reaction based restriction fragment length polymorphism (PCR-RFLP) method was used to study DLA class II gene in dogs. Genomic DNA from 11 DLA homozygous reference dogs representing 8 different haplotypes and 2 families with a total of 16 animals were amplified by the oligonucleotide primer pair (HLA-DRB-AMP-A/B) cross-hybridizing HLA-DRB specific and fit for the amplification of DLA-DRB1 gene. The corresponding amplified DNA products were 235 base pairs. Amplified DNA was digested by 32 different restriction endonucleases, which could recognize allelic variations within DLA-DRB. After digesting only with Hae III, Hha I, Hinf I, Rsa I and Sau96 I high polymorphism was revealed respectively and 9 distinct RFLP pattern were shown, which could be correlate to the DLA haplotypes studied. The 8 cellular established DLA-D specificities present in the reference panel were defined unequivocally by PCR-RFLP and correlated with DLA-Dw5 and Dw6 two subtypes. The segregation pattern of four different DLA-DRB types could be demonstrated in two families. Based on these data we conclude that PCR-RFLP typing utilizing the above mentioned primer pair and endonucleases is a valuable tool to define DLA class II types in the dog.

Allelic variation in the DR subregion of the canine major histocompatibility complex

Allelic variation in the DR subregion of the canine major histocompatibility complex (DLA) has been analyzed by nucleic acid sequencing of cDNA clones of DRB genes amplified in vitro by the reverse transcriptase-polymerase chain reaction (RT-PCR). Sequence analysis of a panel of 19 homozygous typing cell dogs representing 12 different DLA-D types (defined by mixed leucocyte reaction) demonstrated the presence of one expressed DRB locus with at least nine distinct alleles in the dog. Unique DLA-DRB alleles were found in the DLA-D types Dw1, Dw3, Dw4, Dw8 (workshop assignments) and D4, D6, D7, D8, and D9 (Seattle assignments). In contrast, the DRB genes of the remaining three DLA-D types (D1, D10, and D16) were identical to those of Dw3/Dw4 (for D1), Dw8 (for D10), and D6 (for D16). The nucleotide sequences of all nine DLA-DRB alleles were typical of functional major histocompatibility complex (MHC) class II beta chains and contained three allelic hypervariable regions (HVRs) in the beta 1 domain at positions 8-16, 26-39, and 57-74. At each variable residue, two to five amino acid substitutions were found. The most polymorphic residues were located at positions 37 (with five amino acid substitutions), 11, 13, 28, and 71 (each with four substitutions). The DLA-DRB alleles had 96%-99% overall nucleotide sequence similarity and 93%-99% amino acid sequence similarity with each other. Cluster analysis of the nucleotide and predicted amino acid sequences subdivided the DLA-DRB alleles into three major allelic groups which may represent the canine counterparts of the supertypic groups described in man.

RFLP analysis of DLA class I genes in the dog

Human major histocompatibility complex (HLA) cDNA probes for class I genes HLA-A,B and HLA-E were used to analyze the Restriction Fragment Length Polymorphism (RFLP) of the class I region of the canine major histocompatibility complex (DLA) in 40 dogs. The Southern blot analysis demonstrated that the dog genome contains at least eight class I genes, including the canine homologues of HLA-A,B and HLA-E genes. The DNA polymorphism detected by the HLA-B7 probe corresponded to the serologically defined DLA-A allelic series. Restriction fragments that correlated with the DLA-A2, -A7 and -A9 antigenic specificities were identified in PstI digests of genomic DNA. The RFLP analysis was particularly useful in genotyping dogs which were not clearly DLA-A typable by serology. This technique can be used as a supplement to serotyping and as a genotyping tool for DLA antigenic specificities for which specific antisera are not available.

Characterization of class II alpha genes and DLA-D region allelic associations in the dog

Human major histocompatibility complex (HLA) cDNA probes were used to analyze the restriction fragment length polymorphism (RFLP) of the alpha genes of the DLA-D region in dogs. Genomic DNA from peripheral blood leucocytes of 23 unrelated DLA-D homozygous dogs representing nine DLA-D types (defined by mixed leucocyte reaction) was digested with restriction enzymes (BamHI, EcoRI, Hind III, Pvu II, Taq I, Rsa I, Msp I, Pst I and Bgl II), separated by agarose gel electrophoresis and transferred onto Biotrace membrane. The Southern blots were successively hybridized with radiolabelled HLA cDNA probes corresponding to DQ, DP, DZ and DR alpha genes. Clear evidence was obtained for the canine homologues of DQ and DR alpha genes with simple bi- or tri-allelic polymorphism respectively. Evidence for a single, nonpolymorphic DP alpha gene was also obtained. However, the presence of a DZ alpha gene could not be clearly demonstrated in canine genomic DNA. This report extends our previous RFLP analysis documenting polymorphism of DLA class II beta genes in the same panel of homozygous typing cell dogs, and provides the basis for DLA-D genotyping at a population level. This study also characterizes the RFLP-defined preferential allelic associations across the DLA-D region in nine different homozygous typing cell specificities.

Comparative reactivity of anti-Ia monoclonal antibodies in man and laboratory animals

Sixteen murine monoclonal antibodies (MAb), reactive with HLA-DR, DR + DP or DR + DQ, were tested, using indirect immunocytofluorescence, for their reactivity with peripheral blood mononuclear cells (PBMC) from the dog, cat, guinea pig, sheep, rabbit and rat. In addition, the MAb were evaluated for inhibitory activity in the canine mixed lymphocyte culture (MLC). Fourteen of 16 MAb reacted with canine PBMC. There was a greater tendency for DR + DP reactive MAb to inhibit canine MLC and subsequently react with PBMC of the guinea pig, sheep, and, cat. MAb failing to block the canine MLC were generally nonreactive with guinea pig PBMC (7 of 9 nonreactive) suggesting the guinea pig may be a useful model to study the functional relevance of specific Ia molecules. One MAb, H81.98.21 (reactive with HLA-DR) blocked canine MLC and reacted with PBMC from all species tested suggesting the determinant it recognized to be very well conserved in nature.

Restriction fragment length polymorphism of the major histocompatibility complex of the dog

Human major histocompatibility complex (HLA) cDNA probes were used to analyze the restriction fragment length polymorphism (RFLP) of the DLA-D region in dogs. Genomic DNA from peripheral blood leucocytes of 23 unrelated DLA-D-homozygous dogs representing nine DLA-D types (defined by mixed leucocyte reaction) was digested with restriction enzymes (Bam HI, Eco RI, Hind III, Pvu II, Taq I, Rsa I, Msp I, Pst I, and Bgl II), separated by agarose gel electrophoresis, and transferred onto Biotrace membrane. The Southern blots were successively hybridized with radiolabeled HLA cDNA probes corresponding to DR, DQ, DP, and DO beta genes. The autoradiograms for all nine enzyme digests displayed multiple bands with the DRb, DQb, and DPb probes while the DOb probe hybridized with one to two bands. The RFLP patterns were highly polymorphic but consistent within each DLA-D type. Standard RFLP patterns were established for nine DLA-D types which could be discriminated from each other by using two enzymes (Rsa I and Pst I) and the HLA-DPb probe. Cluster analysis of the polymorphic restriction fragments detected by the DRb probe revealed four closely related supertypic groups or DLA-DR families: Dw3 + Dw4 + D1, Dw8 + D10, D7 + D16 + D9, and Dw1. This study provides the basis for DLA-D genotyping at a population level by RFLP analysis. These results also suggest that the genetic organization of the DLA-D region may closely resemble that of the HLA complex.

Statement on the nomenclature of dog C4 allotypes

As a collaborative work of three laboratories the polymorphism of the canine fourth complement component (C4) was studied in a total of 131 unrelated dogs from different breeds and mongrels. Using high voltage electrophoresis followed by an immunoblotting technique, we detected eight distinct variants. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of canine C4 showed an additional heterogeneity of the alpha and gamma chains which resulted in a total of 11 variants in the population studied. So that more precise information concerning the respective C4 allotypes will be available, a nomenclature is proposed designating not only the migration pattern of the C4 variants in agarose gels but also the heterogeneity of the C4 chains observed in SDS-PAGE.