DQ-haplotype analysis in rhesus macaques: implications for the evolution of these genes

Abstract: The DQA1 and DQB1 alleles of 258 rhesus monkeys ( Macaca mulatto ) of different origin were typed by PCR-RFLP. Five novel Mamu-DQA1 and five novel - DQB1 alleles were detected and 15 Mamu-DQAl-DQB1 haplotypes were identified. Haplotype analysis confirmed the conservation of the DQA1 * O1-DQB1 * O6 haplotypes in evolution. The most conspicuous finding was the tight linkage between the Mamu-DQAl and DQB1 alleles. Almost in every case the Mamu-DQA1 allele was linked to only one particular Mamu-DQB1 allele. Although there also are constraints in the formation of DQ haplotypes in humans, such tight linkages are not observed. These findings support the hypothesis of some kind of co-evolution between DQA1 and DQB1 alleles and may reflect a stronger force of natural selection in macaques than in humans.     

Allelic diversity within the high frequency Mamu-A2*05/Mane-A2*05 (Mane-A*06)/Mafa-A2*05 family of macaque MHC-A loci

Macaque species serve as important animal models of human infection and immunity. To more fully scrutinize their potential in both the analysis of disease pathogenesis and vaccine development, it is necessary to characterize the major histocompatibility complex (MHC) class I loci of Macaca mulatta (Mamu), Macaca nemestrina (Mane), and Macaca fascicularis (Mafa) at the genomic level. The oligomorphic Mamu-A2*05/Mane-A2*05 (previously known as Mane-A*06) family of macaque MHC-A alleles has recently been shown to be present at high frequency in both Indian rhesus and pig-tailed macaque populations. Using a locus-specific amplification and direct DNA typing methodology, we have additionally found that the locus encoding this family is very prevalent (75%) among a sampling of 182 Chinese rhesus macaques and has a high prevalence (80%) within a larger, independent cohort of 309 pig-tailed macaques. Interestingly, among the Chinese rhesus macaques, only six alleles previously identified in Indian-origin animals were observed, while three recently identified in Chinese-origin animals and 25 new alleles were characterized. Among the pig-tailed macaques, we observed 1 previously known (Mane-A*06) and 19 new alleles. Examination of the orthologous locus in a preliminary sampling of 30 cynomolgus macaques showed an even higher presence (87%) of Mafa-A2*05 family alleles, with 5 previously identified and 15 new alleles characterized. The continued discovery of novel alleles and thus further diversity within the Mamu-A2*05/Mane-A2*05/Mafa-A2*05 family indicates that this MHC-A locus, although highly conserved across the three species of macaques, has remained a dynamic entity during evolution.     

Mhc-DQ-DRB haplotype analysis in the rhesus macaque: evidence for a number of different haplotypes displaying a low allelic polymorphism

In the HLA-DRB subregion of man, five major groups of haplotypes, often displaying a remarkable polymorphism, are distinguishable. The polymorphism is thought to be generated by point mutation, microgene conversion and gene rearrangement by recombination. In order to gain insight into the organization of the rhesus macaque major histocompatibility complex (MHC) class II region, DRB genes from monkeys of different origins previously typed for their DQ genes were analyzed. At first DRB haplotypes were deduced from DQ-homozygous monkeys. The stability of these haplotypes was then examined in DQ-heterozygous monkeys by sequence-based typing for the presence of members of the DRB1*03 and DRB1*04 lineage, and for seven single alleles detected on the haplotypes. Six DRB haplotypes linked to the five most frequent and three haplotypes linked to less frequent DQ haplotypes were identified. Six novel DRB alleles were detected. The number of DRB genes per haplotype varied between two and four. The results altogether suggest that in rhesus macaques, in comparison to man, the DQ haplotypes are linked to only a small number of DRB haplotypes, the number and diversity of DRB haplotypes is larger, and the allelic polymorphism of a given haplotype is smaller. The diversity of the DRB haplotypes was partly due to the varying number and identity of genes linked to DRB1*03 and DRB1*04. Furthermore, the number of DRB1 genes themselves varied from zero to two.     

Comparative genomics of the human,macaque and mouse major histocompatibility complex

The MHC is a highly polymorphic genomic region that encodes the transplantation and immune regulatory molecules. It receives special attention for genetic investigation because of its important role in the regulation of innate and adaptive immune responses and its strong association with numerous infectious and/or autoimmune diseases. The MHC locus was first discovered in the mouse and for the past 50 years it has been studied most intensively in both mice and humans. However, in recent years the macaque species have emerged as some of the more important and advanced experimental animal models for biomedical research into MHC with important human immunodeficiency virus/simian immunodeficiency virus and transplantation studies undertaken in association with precise MHC genotyping and haplotyping methods using Sanger sequencing and next‐generation sequencing. Here, in this special issue on ‘Macaque Immunology’ we provide a short review of the genomic similarities and differences among the human, macaque and mouse MHC class I and class II regions, with an emphasis on the association of the macaque class I region with MHC polymorphism, haplotype structure and function.     

MHC-DRB allelic sequences incorporate distinct intragenic trans-specific segments

The second exon of primate MHC-DRB genes encodes discrete areas of allelic hypervariability (HVR), which are used as the basis for lineage assignments to determine genetic and evolutionary relationships. Comparisons of these regions have led to the "trans-species hypothesis", which proposes that certain MHC alleles from one species are more closely related to those from other species than they are to each other; i.e., that allelic lineages are ancestral in origin. We evaluated this paradigm in an analysis of macaque and baboon MHC-DRB genes using oligotyping and sequencing of 87 new nonhuman primate DRB alleles. A remarkable conservation of sequence motifs in the HVR_III region (codon 60–79) was observed, detected both by hybridization and by sequencing; some of these motifs were found in species such as prosimians that have diverged from the human lineage 50 MYA. However, these fixed HVR_III motif sequences nevertheless occur on a background of diverse lineages suggesting that it is the segmental motif, rather than the allele per se which is trans-specific in origin. Sequences within the first hypervariable region (codons 7–14) identified lineage assignments to several DRB loci (DRB1, DRB3, DRB4, DRB5, DRB6 and DRB7), although a large number of DRB nucleotide sequences did not correspond to a defined allelic motif, suggesting that many of the nonhuman sequences lack human HVR_I homologs and have accumulated additional intraspecies variation subsequent to speciation. While there are certain allelic lineages in HVR_I that show trans-species conservation, other sequence motifs seem purely species-specific. These differences suggest that HVR_I and HVR_III regions have distinct mechanisms for maintenance of trans-specific sequence elements, with different evolutionary histories for segmental nucleotide conservation.     

PCR-RFLP-based Mamu-DQB1 typing of rhesus monkeys: characterization of two novel alleles

Up to now 19 allelic sequences of the rhesus monkey DQB1 locus have been published. Referring to these sequences, we have developed a typing protocol for Mamu-DQB1 alleles which was verified by additional cloning, sequence analysis and segregation studies. The protocol is based on the amplification of the second exon with only one specific primer pair followed by the digestion of the PCR products with up to 10 different restriction endonucleases. The alleles can be identified in homozyous and heterozygous combinations since most amplified second exon sequences give unique band patterns after digestion with at least one of the selected restriction endonucleases. By the use of this protocol we analyzed DNA-samples from 182 rhesus monkeys. Among these samples two novel Mamu-DQB1 alleles were detected, subsequently cloned and their nucleic sequence determined. Since we typed four complete breeding groups consisting of two generations we were able to identify several DQ haplotypes by segregation analysis using the previously developed typing protocol for DQA1.     

Enhancement of class I HLA antigen expression by cytomegalovirus: role in amplification of virus infection

We have investigated the effect of cytomegalovirus (CMV) infection on the expression of class I HLA antigens on fibroblasts in vitro. Scanning and integrating microdensitometry was used to quantitate the level of cytoplasmic class I antigen expression, and an antibody binding assay was used to quantitate cell surface expression of class I HLA molecules. CMV infection resulted in a significant increase in the level of cytoplasmic and cell surface class I HLA antigen expression of fibroblast monolayers. The maximal effect was seen at 72 hours postinfection and was observed with both the laboratory strain of CMV, strain AD169, and with CMV purified directly from clinical specimens. Part of the increased HLA expression was mediated by interferon released from infected cells; however, an additional direct effect of the virus itself has not been ruled out. Interferon-induced increased expression of class I HLA antigens was accompanied by increased binding of CMV to the cells, consistent with our recent demonstration that class I HLA molecules can function as a cellular receptor for CMV.     

In vitro production of a hybrid monoclonal antibody that preferentially binds to cells that express both HLA-A2 and HLA-B7

A hybrid mouse monoclonal IgGl having one low affinity combining site for HLA-A2 and one low affinity combining site for HLA-B7 was made by the chemical method of Nisonoff and Palmer (Science 143:376,1964). This involved selective reduction of interchain disulphides, a splitting of the IgGl into half molecules at low pH and ionic strength, and reassociation of the half molecules by neutralization. Serologically active hybrids were separated from parental IgGl by an absorbtion procedure and recovered in about 10% yield. The hybrid discriminated between cells that express either HLA-A2 of HLA-B7 from cells that express both A2 and B7. This is because it could bind bivalently to the cell with both A2 and B7 but could only bind with a single combining site to cells expressing A2 or B7. The consequence of these different modes of attachment was to give up to sevenfold greater binding to the cell expressing A2 and B7 in comparison to the cell expressing only A2 or B7.     

The association between HLA and rheumatoid artlmtis in Zimbabwean Blacks

HLA-A, B, C, DR and DQ typing was done on 26 black Zimbabweans with rheumatoid arthritis and the respective antigen frequencies were compared with those in a group of 119 normal individuals from the same ethnic background. Only the DR4 antigen was significantly increased in frequency in the patients, confirming the association with this disease seen in other Black African populations.     

Adult onset spinocerebellar ataxia linked to HLA in a South African kindred of mixed ancestry

Hereditary spinocerebellar ataxia (SCA) is a relatively common disorder in the Western Cape region of South Africa. At present there are no genetic markers available for prenatal or presymptomatic diagnosis. A large kindred of mixed ancestry with late onset SCA was studied in which the disorder segregated in an autosomal dominant fashion. HLA typing was undertaken on 44 family members, and the HLA haplotypes were assigned on the basis of segregation. The LIPED computer program, with a correction factor allowing for the age of onset, was used to analyze the pedigree for linkage to HLA. Of 22 individuals in whom disease status could be definitely assessed, only one recombinant between HLA and the SCA locus occurred. The lod score reached a maximum of 4.13 at a recombination fraction of 0.05, indicating the odds to be approximately 13,500 to 1 in favor of linkage between HLA and the putative disease allele for SCA. A possible recombination within the HLA region suggested that the disease allele lies telomeric of the HLA region. In view of the recent demonstration of tight linkage between SCA1 and D6S89, however, HLA should not be used for presymptomatic diagnosis or genetic counselling.     

Major histocompatibility complex status in breast carcinogenesis and relationship to apoptosis

Major histocompatibility complex (MHC) molecules are of central importance in regulating the immune response against tumors. In this study we used immunohistochemistry to study human leukocyte antigen (HLA) class I and II antigen expression in normal breast tissues and benign, preneoplastic, primary, and metastatic breast lesions using antibodies against beta-2-microglobulin (beta2-m), heavy-chain, and HLA-DR antigens. Whereas all normal tissues and benign lesions were positive for beta2-m and HLA-A, -B, and -C antigens, total loss of HLA class I antigens was found in 37% (11 of 30) of in situ carcinomas, in 43% (56 of 131) of the primary tumors, and in 70% (31 of 45) of the lymph node metastases. HLA-DR was also underexpressed in breast cancer cells; thus 20% (6 of 30) of in situ carcinomas, 15% of invasive carcinomas (20 of 131), and only 1 metastatic case were positive for this antigen. Both HLA class I and II antigen expression were more frequently down-regulated in metastatic lesions than in primary breast lesions (P <0.05), and a tendency toward a simultaneous defective expression of HLA class I and II antigens was observed in primary carcinomas (P = 0.07). However, no correlation was found between the expression of any of the aforementioned molecules and pathological parameters or survival. Interestingly, HLA class I expression was expressed more frequently in tissues with high apoptotic activity and was significantly associated with the expression of the proapoptotic bax gene (P = 0.02), and was inversely associated with expression of the antiapoptotic bcl-2 gene (P = 0.03). We conclude that alterations in HLA class I and II antigen expression are early events in breast carcinogenesis and play significant roles in metastatic progression. In addition, their expression is correlated with apoptosis-regulating proteins, which may influence the cytotoxicity of T cells against HLA class I-specific tumor antigens.     

The Impact of Jack Stimpfling's Recombinants on Immunogenetics

An angler dreams of a rising rainbow, chooses just the precise fly currently hatching in order to complete the dream of a mountain stream battle that would ensue. The fly must land and drift perfectly so that the trout will be fooled. A camper dreams of just the right location for a warm fire to rest his tent where he will be protected from the wind, yet be able to view the natural beauty surrounding him. A scientist hopes that by pursuing his love of truth and awe of the unknown, he will be contributing to the benefit of his fellow man. Once upon a time, just such a scientist began such a career on the island of Mount Desert. He not only fulfilled his scientific dreams, but also in later years would enjoy the tranquility of nature, open space and the big skies. This is a chronicle of one aspect of his scientific contribution to his fellow man.     

HLA class II specificities and haplotypes in South Africa detected using polymerase chain reaction and sequence-specific oligonucleotide typing

Abstract: DNA sequencing of HLA class II alleles has revealed a degree of polymorphism much greater than was expected on the basis of the standard serological typing methods. Amplification of the polymorphic second exon of the class II genes using the polymerase chain reaction, followed by hybridization with sequence-specific oligonucleotide probes, allows the unambiguous identification of alleles which could not be detected previously. Using the protocols of the Eleventh International Histocompatibility Workshop, we have applied this procedure for the typing of several individuals and their families with suspected alleles that had been observed using serology, cellular typing and restriction fragment length polymorphism (RFLPs). These included an allele related to DRw8 and DRwl4, which has only been observed in the mixed ancestral South African population. In addition, unusual combinations of class II genes forming unique haplotypic associations were seen.     

Genetic differences in immune reactions to radiation exposure in humans and experimental animals

Examination of populations living in regions of fallout radiation revealed changes in the distribution of HLA genes not only in irradiated individuals, but also in their children and grandchildren. Combined irradiation of inbred mice in comparable doses showed that H-2 genes determine immune reactions in animals and their offspring to radiation. Our results indicate that the immune system in mammals is immunogenetically regulated by low-dose radiation.     

A novel spontaneous mutation in the TAP2 gene unravels its role in macrophage survival

We report a new mouse strain with a single point mutation in the type 2 transporter associated with antigen processing (TAP2). This strain randomly arose in one of our C57BL/6J mouse colonies and was initially discovered because of the lack of CD8⁺ T cells in the periphery. Following our observation, we subsequently revealed a lack of cell surface MHC‐I expression, derived from TAP2 protein deficiency. Our strain, named eightless, has a C to T substitution in exon 5 resulting in a glutamine to stop codon substitution at position 285 in the TAP2 protein. Interestingly, in addition to the expected lack of CD8⁺ T cell phenotype, eightless mice have a diminished number of macrophages in their peritoneum. Moreover, following peritoneal inflammation, elicited eightless macrophages showed impaired survival both in vivo and ex vivo. Our study describes the first ever TAP2 complete knockout mouse strain and provides a possible explanation for why patients with TAP2 deficiency syndrome present clinical manifestations that would suggest a phagocyte defect rather than a lack of CD8⁺ T cells.     

介导可溶性MHCⅠ产生的去整合素金属蛋白酶初步筛选研究

目的:以HEK293细胞为研究模型,筛选介导可溶性MHCⅠ产生的去整合素金属蛋白酶。方法:将ADAM8、ADAM10、ADAM15和ADAM17cDNA分别克隆入pcDNA3.1/V5载体,并用TransIT-LT1转染试剂将构建好的载体转染入HEK293细胞,用潮霉素B筛选ADAMs蛋白稳定表达克隆;用SDS-PAGE、免疫印迹结合化学发光法检测ADAMs在HEK293细胞中的表达;用细胞表面生物素标记、免疫沉淀、SDS-PAGE、免疫印迹结合化学发光检测ADAMs过表达对可溶性MHCⅠ产生的影响。结果:成功获得稳定表达ADAMs的HEK293细胞;过表达ADAM10和ADAM17可增强HEK293细胞产生可溶性MHCⅠ。结论:ADAM10和AD-AM17具介导可溶性MHCⅠ产生的潜能。     

A short history of HLA

In 1958, just a little more than 50 years ago, an alloantigen present on human leucocytes was detected, which was to become the 'first' human leucocyte antigen (HLA); HLA-A2. Since then, we have seen a tremendous development of the HLA field, which has moved from histocompatibility to become one of the most central fields in basic and clinical immunology. This development is briefly reviewed in this article, focusing on some highlights of the history of HLA class I and II molecules and their role in immune responses. It is emphasized that the quick and extensive development of the HLA field is the result not only of excellent individual contributions by outstanding pioneers in the field, but also of an extensive international collaboration, in particular through the many international histocompatibility workshops. Admitting that it is too late to change the name now, it is concluded that instead of calling the HLA complex and similar complexes in other species the major histocompatibility complex , these gene complexes should better have been named the major immune response complex , the MIRC .