Antigen B27 Research Articles

B5, a new B cell-restricted activation antigen.

The characterization of a new human B cell-restricted activation antigen (B5) is described in this report. With the use of a monoclonal antibody to B5, we show that B5 can be detected on peripheral blood or splenic B cells after 1 day of stimulation with either anti-immunoglobulin, protein A, Epstein Barr virus, or pokeweed mitogen. In contrast, B5 was not expressed on resting B, T, or myeloid cells. More important, B5 could not be detected on activated T cells or monocytes. The B5 antigen was expressed on some lymphoblastoid B cell lines and B cell neoplasms but was not expressed on leukemias or lymphomas of T or myeloid origin. The B5 antigen is distinct from previously reported B cell activation antigens by its m.w. and pattern of cellular expression. These studies suggest that B5 is a novel B cell-restricted activation antigen, which may be useful to study the events of early human B cell activation.

Sporadic and familial-occurring multiple sclerosis. HLA typing and study of chromosomal sister chromatid exchange rate

HLA and sister chromatid exchange (SCE) has been investigated in 17 multiple sclerosis cases and 10 controls. While the HLA showed no differences between familial cases of MS and the control group, in sporadic cases of MS the occurrence of the antigen A3 and B7 have been confirmed. The study showed a significant increase of the SCE-rate in sporadic cases of multiple sclerosis, in the contrary, in those cases with familial occurrence no changes in the SCE-rate could be found. A different etiology for sporadic and familial cases of multiple sclerosis is assumed.

1 - Genetic Aspects of the Spondyloarthropathies

Family studies and investigation of the HLA associations have in recent years added to our understanding of the spondyloarthropathies. In regard to ankylosing spondylitis it is likely that B27 itself is the major susceptibility gene but that additional genes may play a secondary role. Heterogeneity of the B27 antigen has been demonstrated but has not yet been shown to be relevant to disease susceptibility. Haplotypes including Cw6 are related to susceptibility to psoriasis and psoriatic arthritis and although the risk for the arthropathy is increased in B27-positive individuals, there is some uncertainty regarding the association with other B locus antigens and further work is needed. There is also uncertainty as to whether B27-associated disorders occur randomly within families, or whether particular disorders cluster in certain families and further evidence in this field would be of considerable interest. Genetic studies, as here outlined, have not as yet had a major impact in clinical medicine but it is anticipated that a deeper understanding of the mechanisms of HLA-linked susceptibility genes and in particular of how they interact with environmental agents, will improve our ability to treat and possibly prevent the relevant diseases.

HLA-A, B, C, DR, MT, and MB antigens in recurrent aphthous stomatitis

In this report we have investigated the frequencies of HLA-A, B, C, DR, MT, and MB markers in 26 Silician subjects affected by recurrent aphthous stomatitis (RAS) and in 84 healthy controls. Our data show that the frequency of HLA-DR7 antigen is significantly increased in RAS-affected persons (61.5% versus 21.4%; pc < 0.0025), whereas the B5 antigen frequency is decreased significantly (absent in patients versus 27.3% in controls; pc = 0.04). Thus, present results suggest that HLA-linked genetic factors may play a role in the development of RAS.

HLA-antigens and tuberculosis in the Egyptian population

Peripheral blood lymphocytes from 42 unrelated Egyptian patients with tuberculosis and 156 healthy persons were HLA phenotyped for the A,B and DR loci using the NIH lymphocytotoxicity tests. Statistical analysis of the results showed that A2 and B5 had significantly increased frequencies among patients with tuberculosis compared with the controls. Patients with A2 had more severe disease than did patients without A2 and the number with B5 antigen was less than those without the antigen. This observation suggests that A2 and B5 may influence susceptibility to tuberculosis, but not the course of the disease. Furthermore, a linkage disequilibrium was found between A2 and B5 antigen among tuberculous patients, but their association bore no relation to the severity of the disease.

Clinical symptoms and HLA antigens in a family with Reiter's disease.

A clinical and immunogenetic study was performed on a three-generation family with Reiter's disease (RD). Twelve of 56 members of the family (33 clinically examined) including one in-law, had symptoms of arthritis, urethritis, conjunctivitis, uveitis, and/or mucocutaneous manifestations, but only one had the complete triad of Reiter's syndrome (RS). Radiographic sacro-iliitis was found in 7 individuals, and monoarticular onset was reported in 5 out of 7 with peripheral arthritis. HLA B27 was found in 26 of the 37 family members who were tissue typed (including one in-law). All individuals with RD were B27-positive. Seven different B27 phenotypes were identified. This finding suggests that RD is associated with the B27 antigen itself, and not to a gene closely linked to B27. From a pedigree analysis of this family an autosomal dominant inheritance with incomplete penetrance or multifactorial inheritance seemed the most probable alternatives. The family history is a useful adjunct in the diagnosis of RD.

HLA-antigens in Guillain-Barré syndrome.

A microlymphocytotoxicity test determined serologically the frequency of HLA antigens in 32 patients with Guillain-Barré syndrome and in 234 healthy control subjects. The results demonstrated significantly increased frequencies of A3 and B8. The relative risk was estimated to be 9.6 and 4.6 for the A3 and B8 antigens, respectively. Study of the gametic association revealed weak positive linkage disequilibrium and biological association. The results are discussed, and it is concluded that the aberrant genetic make-up of the patients makes them more susceptible to develop the syndrome after exposure to the environmental factor(s).

Structure and polymorphism of class I MHC antigen mRNA.

We have used cDNA cloning and primer extension techniques to determine the complete nucleotide sequence of HLA-B7 mRNA. The 5'-untranslated sequence of the mRNA is rather short and the putative promoter has weak homology to the conventional "TATA" sequences. The 5' end and the polyadenylation site define the transcription unit of the B7 gene to be about 3.5 kb long. Comparison of the translated nucleotide sequence of this cDNA with the amino acid sequence of the heavy chain of the B7 antigen showed two amino acid differences. In addition, comparison with the sequences of the coding and untranslated regions of several HLA and H-2 genes showed that the class I histocompatibility molecules consist of four variable segments separated by three regions of homology. Analysis of the DNA polymorphisms revealed that in the variable segments the majority of the nucleotide substitutions are nonsilent, while in the homology regions the majority of substitutions are silent. Further analysis of the nature of the amino acid substitutions revealed the predominance of nonconservative replacements/changes in both the variable segments and the homology regions except the transmembrane part of the molecule. Selection at both the protein and the codon levels contributes to the pattern of mutations found in class I histocompatibility molecules.

Recognition of HLA-A2 and -B7 antigens by cloned cytotoxic T lymphocytes after gene transfer into human and monkey, but not mouse, cells.

The genes that code for the human major histocompatibility class I antigens, HLA-A2 and HLA-B7, were introduced into human, monkey, and mouse cell lines by cotransfection with suitable biochemical markers and the fluorescence-activated cell sorter was used to identify and/or select stable cell populations expressing high surface levels of these antigens. Levels of expression obtained were similar to those observed for endogenous HLA antigens on various human cell lines and were 25-80% of those observed on the human B-lymphoblastoid cell line JY. Serologically defined HLA-A2 and HLA-B7 polymorphic determinants remained intact on all transfected recipient cells analyzed. Cloned human allospecific cytotoxic T lymphocytes (CTL) specific for HLA-A2 or HLA-B7 were capable of lysing appropriate HLA-transfected human cells with comparable efficiency to JY cell lysis. Two of 10 CTL clones lysed appropriate monkey cell transfectants with approximately equal to 20% the efficiency of human cell transfectants. No specific lysis of any HLA-transfected mouse cell lines, including a B cell lymphoma, was observed despite comparable levels of surface antigen expression or after induction of higher levels by mouse gamma-interferon. Furthermore, L cells expressing human beta 2-microglobulin in addition to HLA-A2 or -B7 were not lysed by these CTL. Thus, an additional species-specific component may be involved in lysis by allogeneic CTL--possibly related to the function(s) of other surface proteins on target cells.

IgM, IgG, and IgA synthesis in vitro in persons suffering from yersinia arthritis and in patients with ankylosing spondylitis.

In ankylosing spondylitis (AS) and in yersinia arthritis the main findings in serum immunoglobulin (Ig) studies have been raised IgA in AS and a high anti-yersinia IgA and IgG response and the persistence of IgA class antibodies in yersinia arthritis. In order to study predisposition to high IgA response in AS and yersinia arthritis we measured the in-vitro Ig production in patients with AS and in persons who have once had yersinia arthritis, and we compared it with the Ig production in persons who have had yersiniosis but recovered without getting arthritis and with that in healthy controls. IgA secretion by peripheral blood lymphocytes stimulated by pokeweed mitogen was the same in all 4 groups, and no signs of higher IgA production in AS patients could be found. In AS patients lymphocyte activation by whole yersinia bacteria resulted in higher total IgG production than in healthy controls. The total number of plaque-forming cells in yersinia-stimulated cultures was significantly higher in persons who have had yersiniosis without arthritis than in persons who have suffered from yersinia arthritis or in persons in other groups. AS patients had low IgM production, which reverted to normal when hydrocortisone was added to the culture. The in-vitro Ig production in general did not correlate with the presence of the HLA B27 antigen but rather with the clinical history of the subjects studied.

Two-dimensional gel analysis demonstrates no structural alteration of HLA-B27 polypeptides between patients with ankylosing spondylitis and healthy individuals.

After precipitation of the HLA-B27 antigen from the surface of peripheral blood lymphocytes (PBL) by means of an anti-HLA-B27 allospecific monoclonal antibody 2-dimensional gel electrophoresis was used to compare the structure of the B27 antigens derived from 5 patients with ankylosing spondylitis with that of healthy HLA-B27 positive counterparts. No significant difference in polypeptide structure was noted, which suggests that the pathogenesis of ankylosing spondylitis does not involve a structural alteration in cell surface HLA-B27 molecules.

Clinical sacroiliac tests in ankylosing spondylitis and other causes of low back pain--2 studies.

Independent assessment by 2 observers of 4 tests for sacroiliac (SI) pain in patients with either mechanical/degenerative low back pain (M/D LBP) or ankylosing spondylitis (AS) showed all 4 to be reproducible, but only 2 of them, namely, pressure over the anterior superior iliac spines and pressure over the lower half of the sacrum, gave worthwhile discrimination. Positive results in these 2 tests were significantly associated with definite AS but also with the combination of low back pain, the HLA B27 antigen, and normal or near normal radiographs, a condition we have called presumptive ankylosing spondylitis.

A new indicator of human malignant tumour.

In haemagglutination tests we have found that the monoclonal antibody B5 discriminates between erythrocytes from patients with malignant cancer (total 386; greater than 80% B5 positive) and individuals with no known tumour (total 247; less than 20% B5 positive). The B5 antigen detected on intact erythrocytes is a tightly bound surface component which does not appear to be derived from the plasma. The B5 antigen is not T, Tn, Ca1, CEA or the Forsmann antigen; nor is it related to any of the major blood group antigens. Abnormal levels of surface B5 are found on erythrocytes from patients with a great diversity of tumours and this fact presents B5 as an indirect marker of malignancy. Successful eradication of tumour is associated with a switch from positive to negative B5 haemagglutination. We believe that B5 is a valuable addition to the few useful tumour markers already employed for monitoring tumour status.

Cytotoxic T lymphocyte recognition of HLA-A/B antigens introduced into EL4 cells by cell-liposome fusion.

HLA-A2 and -B7 antigens were introduced into EL4 (H-2b) cells by cell-liposome fusion and were used as targets or stimulators for cytotoxic T lymphocytes (CTL) generated in C57B1/6 (H-2b) mice. It was found that such EL4-HLA cells were not recognized by CTL that had been raised against either a human cell line bearing these HLA antigens or the purified HLA-A2 and -B7 antigens reconstituted into liposomes. In addition, EL4-HLA cells were not capable of inducing CTL that could recognize a human cell line bearing HLA-A2 and -B7 antigens. Instead, EL4-HLA cells induced CTL that specifically lysed EL4-HLA cells and not human cells expressing HLA-A2 and -B7. CTL recognition required the presence of HLA antigens on the EL4 cell surface and was inhibited by antibodies against either H-2b or HLA-A/B. Monoclonal antibody binding studies showed that the expected polymorphic determinants of the HLA-A2 and -B7 antigens were still present on EL4-HLA cells. However, the specificity of CTL or their precursors that are capable of recognizing HLA-A2 or -B7 was altered after these antigens became associated with the EL4 surface. Possible explanations for these results are discussed.

Serum ferritin in haemodialysis patients: role of blood transfusions and 'haemochromatosis alleles' HLA A3, B7 and B14.

In 48 patients on maintenance haemodialysis (HD), serum ferritin (SF) levels were measured and compared with 'haemochromatosis alleles', (HA), HLA A3, B7 and B14. A positive correlation was found between high SF levels and the presence of HA. When patients who had received 10 or fewer blood transfusions were studied, it was observed that this correlation did not exist, but it was evident, however, in patients who had received more than 10 blood transfusions. After 14 months in which blood transfusions were restricted, no significant difference in SF was observed between HA carriers and the rest. Our findings suggest that repeated blood transfusions can cause high SF in HD patients, especially in those with HLA A3, B7 or B14 antigens. Among our patients, restriction of blood transfusions seems sufficient to decrease high SF levels.

A family study of ankylosing spondylitis.

Clinical, radiological and scintigraphic studies and HLA type assessment were performed in 38 subjects, constituting all the first-degree members of three generations of the families of six patients affected with ankylosing spondylitis (AS). The families included both parents, all siblings and all children of the probands. Definite AS was found in three men and possible AS in another. In another man and in a woman, a diagnosis of asymptomatic bilateral sacroiliitis was made. These six subjects indicate a family prevalence of AS reaching 15.8%. HLA B27 was present in 20 individuals (52.6%), including those with definite and possible AS and the case with asymptomatic sacroiliitis. The woman with asymptomatic sacroiliitis lacked HLA B27 antigen. Our study confirms the familial occurrence of AS, but it shows the occurrence to be lower than that previously reported.

Cross-reactivity of self-HLA-restricted Epstein-Barr virus-specific cytotoxic T lymphocytes for allo-HLA determinants.

Epstein-Barr (EB) virus-specific cytotoxic T cells, prepared from virus-immune donors by reactivation in vitro and maintained thereafter as IL-2-dependent T cell lines, have been tested against large panels of EB virus-transformed lymphoblastoid cell lines of known HLA type. Whilst the pattern of lysis of the majority of targets was always consistent with HLA-A and HLA-B antigen restriction of effector function, in several cases it was noticed that certain HLA-mismatched targets were also reproducibly lysed. When this "anomalous" lysis was investigated in detail, it was found to be directed against allodeterminants on class I HLA antigens; thus, mitogen-stimulated as well as EB virus-transformed lymphoblasts from the relevant target cell donors were sensitive to the killing, and in each case the lysis could be specifically blocked by monoclonal antibodies to class I HLA antigens. In one example the target for this alloreactive lysis could be identified as a single serologically defined antigen, HLA-Bw57, while in another example lysis was directed against a "public" epitope common to HLA-Bw35, -Bw62, and a subset of -B12 antigens. Both cold target inhibition experiments and limiting dilution analysis strongly suggested that this alloreactive lysis was being mediated by the same effector T cells that recognize EB viral antigens in the context of self-HLA. This is the first demonstration in man that alloreactive responses can be derived from within the antigen-specific, self MHC-restricted T cell repertoire.

HLA B27 related 'unclassifiable' seronegative spondyloarthropathies.

Twenty-five patients (22 males and 3 females) are described who had 'unclassifiable' seronegative peripheral arthritis affecting mainly the large joints of the lower limbs with other typical features of spondyloarthropathies such as heel pain, low back pain, and mucosal ulcers. But their disorders could not be diagnosed as any specific spondyloarthropathy such as ankylosing spondylitis, Reiter's disease, etc. The mean age of onset of disease was 21.4 years and 60% of them had mono- or oligoarthritis; 60% had arthritis of only lower limb joints. Knee, ankle, and hip joints were most commonly involved, often asymmetrically (mean degree of asymmetry = 0.28). Minimal radiographic sacroiliitis was present in 4 patients, though 13 had low back pain. HLA B27 antigen was detected in 21 (84%) of these patients and only 5.9% of 118 controls (relative risk 83). In addition to these 25 patients there were 4 others whose only symptom was severe bilateral heel pain: 3 of them were positive for HLA B27.

A reanalysis of the HLA-B7 cross-reactive group.

Cross-reactivity between antigens of the HLA-B7 cross-reactive group (B7 CREG) was investigated by the serological analysis of 60 "broad" cytotoxic HLA antisera produces by pregnancy alone, the HLA typing of the antiserum donors and the identification of their immunizing antigens. Thirty-five sera, made in response to B7, covered (as a group) HLA-B7, B27, Bw42, Bw48, Bw54, Bw55, Bw56, Bw60 and Bw61--the B7 CREG antigens. Bidirectional cross-reactivity occurred between the B7 antigen and B27, Bw55, Bw56 and Bw60 antigens but not between the major B7 CREG antigens B27, Bw22 and B40. HLA-B27 stimulated antisera included B7, B13 and Bw47 within their reaction range and Bw55/Bw56 cross-reacted with Bw42, Bw54, Bw57, Bw58, Bw62 and Bw63. Bidirectional cross-reactivity was observed between Bw55 and Bw57. Fourteen responders possessed an antigen cross-reactive with their immunizing antigen. These findings are discussed in relation to the sharing of determinants by pairs and "families" of HLA antigens.

Specificity of anti-HLA-B27 cytotoxic T lymphocytes.

Sub-types of HLA-B27 were detected by cytotoxic T lymphocytes (CTL) generated between HLA-A, -B- and -C-identical B27-positive individuals. We now report the specificity of six independent CTL's generated by mixed lymphocyte culture (MLC) of HLA-A, -B and -C serologically identical B27-positive responder and stimulator cells. Three CTL's recognize one sub-type, and three the other. The combined reactivity of all CTL's allows unequivocal "typing" of B27-positive cells for the two different sub-types B27K and B27W. The specificity of two CTL's was analysed by cold-target inhibition. The results indicate that (1) no further sub-types of HLA-B27 can be detected by the CTL's raised in these combinations; (2) the majority of the CTL's is directed against the B27 antigens; and (3) "extra reactions" on B27-negative cells are caused by a subset(s) of CTL's recognizing unknown antigens shared between stimulator and target cells. CTL's raised by stimulation of HLA-B27-negative responder cells with B27-positive cells of either sub-type lysed all B27-positive target cells indiscriminately. In cold-target inhibition, however, B27-positive cells, carrying the sub-type of B27 different from that of the stimulator, could not inhibit the lysis of cells bearing the stimulator sub-type of B27. This indicates the activation, in B27-negative responders, of at least two different groups of CTL clones, one directed against shared determinants of HLA-B27, and one against the HLA-B27 sub-type. Heterogeneity of the HLA-B27 antigen may have implications for studies on the well-known association between this antigen and various diseases.