Murine monoclonal antibodies against HLA structures

Recognition of HLA-A1 by murine monoclonal antibodies

Balb/c mice were immunized with cells from the mouse mastocytoma line P815 transfected with an HLA-A1 gene. The splenocytes of the immunized mice were fused with cells from the murine myeloma NS-1. In an initial screening, supernatants of growing cultures were tested for their binding capacity to the immunizing P815/A1+ cells as well as to P815/A2+ cells. Three out of 756 hybrids produced antibodies which bound to P815/A1+ cells only. They were cloned and further analyzed for their binding reactivity to reference B-lymphoblastoid cells from the Tenth International Histocompatibility Workshop. One monoclonal antibody, designated 6B11, reacted only with HLA-A1+ cells, while the two other antibodies, 3G3 and 7F10, appeared to detect antigenic determinants shared by HLA-A1, A3, A11, A26, and A30 (3G3) and by HLA-A1, A3, A11, A26, A28 and A30 (7F10). Flow cytometric studies on B-lymphoblastoid cell lines as well as on a series of tumor cell lines, including melanoma and colon carcinoma lines, confirmed the specificity of these antibodies. Monoclonal antibodies 7F10 and 6B11 were found to be of the IgM class and 3G3 of the IgG1 class. By complement-dependent 51Cr release experiments it was further shown that the two IgM antibodies 7F10 and 6B11 were able to lyse all cell lines of the HLA-A1 haplotype tested.

Gold-specific T cells in rheumatoid arthritis patients treated with gold

Gold-specific T lymphocyte clones were isolated from a patient with rheumatoid arthritis who developed delayed type hypersensitivity reactions to gold. All of the isolated T cell clones required histocompatible antigen presenting cells as well as gold for induction of proliferation. Using a panel of HLA-homozygous Epstein Barr virus-transformed B (EBV-B) cells and anti-HLA antibodies, the clones were shown to recognize gold in the context of DR1 molecules. Gold recognition did not require active antigen processing since specific proliferation was not affected by glutaraldehyde fixation of the DR1 homozygous antigen presenting cells. Furthermore, we could show that gold salts inhibited peptide-induced responses of a peptide-specific T cell clone. In addition to providing evidence for gold-specific T cells in gold-treated RA patients exhibiting delayed type hypersensitivity responses, these data suggest that gold can alter MHC-peptide complexes. The latter observation may in part explain the mechanism/s responsible for both the therapeutic and the toxic effects of gold.

Identification of immunodominant T cell epitopes of the hepatitis B virus nucleocapsid antigen

Several lines of experimental evidence suggest that inclusion of core sequences in the hepatitis B vaccine may represent a feasible strategy to increase the efficacy of the vaccination. In order to identify immunodominant core epitopes, peripheral blood T cells purified from 23 patients with acute hepatitis B and different HLA haplotypes were tested with a panel of 18 short synthetic peptides (15 to 20 amino acids [AA]) covering the entire core region. All patients except one showed a strong T cell proliferative response to a single immunodominant 20 amino acid sequence located within the aminoterminal half of the core molecule. Two additional important sequences were also identified at the aminoterminal end and within the carboxyterminal half of the core molecule. These sequences were able to induce significant levels of T cell proliferation in 69 and 73% of the patients studied, respectively. T cell response to these epitopes was HLA class II restricted. The observations that (a) polyclonal T cell lines produced by PBMC stimulation with native HBcAg were specifically reactive with the relevant peptides and that (b) polyclonal T cell lines produced with synthetic peptides could be restimulated with native HBcAg, provide evidence that AA sequences contained within the synthetic peptides represent real products of the intracellular processing of the native core molecule. In conclusion, the identification of immunodominant T cell epitopes within the core molecule provides the molecular basis for the design of alternative and hopefully more immunogenic vaccines.

HLA-DR and -DQ epitopes and monoclonal antibody specificity

The polymorphism of the HLA system-originally studied serologically using antisera from multiparous women and cellularly using the mixed lymphocyte reaction-has now been further revealed by the use of monoclonal antibodies and, at the most basic level, by the nucleotide and amino acid sequences of the different alleles. In this article, Steven Marsh and Julia Bodmer examine the specificity of mainly well-known HLA-DR and HLA-DQ monoclonal antibodies and postulate the positions of their binding sites, or at least of the polymorphic sites determining their patterns of reactivity. The publication together of all available amino acid sequences of the first domain of the DR beta and DQ alpha and the DQ beta chains (updated and corrected where necessary in collaboration with their authors) provides a useful tool with which to identify binding sites of other antibodies and perhaps to attempt to correlate their position in the structure with their function. Outlines of strategies to produce a wider range of polymorphic antibodies are discussed.

Monoclonal antibody to a supertypic determinant associated with HLA-DRw52

A cytotoxic mouse monoclonal antibody UL-52 (IgG2b) was obtained after immunization of a BALB/c mouse with the lymphoblastoid cell line STA homozygous for HLA-A3, B8, Cw7, DR3, DRw52, DQw2, DPw2. Fluorescence analysis on a panel of B lymphoblastoid cell lines from the 10th International Histocompatibility Workshop 1987 showed almost exact concordance of UL-52 reactivity with the presence of the HLA-DRw52 antigen. Cytotoxicity testing of UL-52 on mononuclear cells of HLA-typed individuals revealed a pattern of reactivity closely associated with the HLA-DRw52 specificity as defined by conventional alloantisera (R = 0.77). UL-52 precipitated appropriate 29,000- and 33,000-dalton bands on SDS- polyacrylamide gels under reducing conditions from an HLA-DRw52 positive B lymphoblastoid cell line. Thus, by serological and biochemical criteria UL-52 defines a supertypic determinant associated with HLA-DRw52. In contrast to most DRw52- like monoclonal antibodies, UL-52 binds to DRw8 positive cells.

Binding of labelled influenza matrix peptide to HLA DR in living B lymphoid cells

T cells recognize protein antigens as fragments (peptides) held in a defined binding site of class I or class II major histocompatibility (MHC) molecules. The formation of complexes between various immunologically active peptides and different MHC molecules has been demonstrated directly in binding studies between the peptides and solubilized, purified molecules of class II MHC. Studies with intact cells, living or fixed, have not directly demonstrated the binding of the peptides to MHC molecules on antigen-presenting cells, but the formation of such complexes has been shown indirectly through the capacity of antigen-presenting cells to stimulate specific T cells. Here we report evidence that supports directly the binding of radiolabelled influenza matrix peptide 17-29 to products of the human class II MHC locus HLA-DR, on living homozygous B-cell lines, and we show that the kinetics of such binding is much faster with living cells than with fixed cells. Furthermore, whereas the peptide reacts with HLA-DR molecules of all alleles, it binds preferentially to DR1, the restricting element in antigen presentation.

Serological analysis of cell surface antigens in choriocarcinoma cell lines

Major histocompatibility complex (MHC) antigens as well as blood group related antigens were investigated in four newly established gestational choriocarcinoma cell lines (NaUCC-1, -2, -3, and -4) using protein A and immune adherence assays. Antibodies to both monomorphic determinants of HLA class I antigens and beta 2 microglobulin reacted with all of the choriocarcinoma cell lines at levels equal to or much greater than SCH, which was teratoid choriocarcinoma cell line. Antibodies to polymorphic determinants not only of the patient's HLA type, but also of the husband's type, reacted to NaUCC-1 and -2. These results indicated that all four newly established choriocarcinoma cell lines express class I HLA antigens. However, we could not demonstrate expression of class II antigens. No expression of blood group A and B antigens could be established, and binding of antibody to Rho(D) antigens was only positive in the NaUCC-1 cell line. These results suggest that some choriocarcinoma cell lines actually express alloantigens and that choriocarcinomas have the character of transplanted tumors that have activities to induce transplantation immunity of the patients.

Vaccine T-cell epitope selection by a peptide competition assay

The binding of several peptides derived from the Plasmodium falciparum circumsporozoite protein (CS protein) to the human major histocompatibility complex class II proteins HLA-DR5 and -DRw6 was examined in a competition assay. Fixed antigen-presenting cells (APCs) were incubated with various concentrations of each peptide and suboptimal concentrations of stimulator peptides. The binding of the CS peptides to DR5 or DRw6 proteins was then determined in a proliferation assay using two established DR5 or DRw6-restricted T-cell clones with specificity for the stimulator peptides as responder cells. One of five CS peptides, comprising together about 50% of the CS protein sequence, was found to compete with the binding of the stimulator peptides to DR5 and DRw6. The CS peptide CS-(378-398), binding to DR5 and DRw6, was then shown to be able to induce primary in vitro responses of T cells from donors with DR5 and DRw6 haplotypes. CS-(378-398)-induced T-cell clones responded not only to the homologous peptide but also to the native CS protein in the presence of appropriate APCs. The strategy we have applied is of considerable general interest for the engineering of vaccines against any pathogen, since it greatly facilitates the selection of appropriate T-cell epitopes to be incorporated in the vaccine.

A malaria T-cell epitope recognized in association with most mouse and human MHC class II molecules

An ideal vaccine should elicit a long lasting immune response against the natural parasite, both at the T- and B-cell level. The immune response should occur in all individuals and be directed against determinants that do not vary in the natural parasite population. A major problem in designing synthetic peptide vaccines is that T cells generally recognize peptide antigens only in association with one or a few of the many variants of major histocompatibility complex (MHC) antigens. During the characterization of epitopes of the malaria parasite Plasmodium falciparum that are recognized by human T cells, we analysed a sequence of the circumsporozoite protein, and found that synthetic peptides corresponding to this sequence are recognized by T cells in association with many different MHC class II molecules, both in mouse and in man. This region of the circumsporozoite protein is invariant in different parasite isolates. Peptides derived from this region should be capable of inducing T-cell responses in individuals of most HLA-DR types, and may represent good candidates for inclusion in an effective anti-malaria peptide vaccine.

Epitopes recognized by human T cells map within the conserved part of the GP190 of P. falciparum

In a study aimed at developing a vaccine against the asexual blood stages of Plasmodium falciparum, two T cell epitopes were identified within a nonpolymorphic region of gp190 of Plasmodium falciparum merozoites. The two epitopes, which were revealed by deletion analysis, stimulated human T cell clones. Peptides containing sequences of the epitopes stimulated the cloned T cells and peripheral blood mononuclear cells (PBMC) from malaria-infected individuals. Moreover, the T cell clones responded to 11 different Plasmodium falciparum isolates in culture, showing that the epitopes are recognized in native parasites.

HLA (class I) antigens on platelets are involved in platelet function

HLA (Class I) antigens are ubiquitous in their cellular distribution and, while their function in major histocompatibility complex (MHC)-restricted phenomena are clear, their function on other cells, such as platelets, is not so obvious. We now report that several anti-HLA monoclonal antibodies (including an anti-beta 2 microglobulin antibody) selectively affect platelet function in that three different anti-HLA monoclonal antibodies caused not only the aggregation of human platelets, but also caused the release of 14C-serotonin. In addition, the anti-HLA antibodies could selectively block the binding of several platelet agonists such as collagen, adrenalin, ADP, but not the binding of others such as thrombin and arachidonic acid. In blocking studies there also appeared to be an association between platelet glycoprotein IIb-IIIa and HLA Class I antigens. We propose that both heavy and light chains of Class I HLA antigens on platelets may be involved in platelet aggregation and release and suggest an additional role for HLA antigens on platelets.

Anti-BoLA-w8 monoclonal antibody: production of a tissue typing reagent after blocking monomorphic sites on bovine mononuclear cells

A murine monoclonal antibody, WIM-8 with specificity for BoLA-w8, was generated after using an immunization protocol designed to reduce the response to bovine monomorphic determinants. BoLA-w8/w9 peripheral blood mononuclear (PBM) cells were incubated with an antiserum from mice immunized with BoLA-w10/w20 PBM cells. Splenocytes from a mouse that received three intravenous injections of the treated cells were fused with murine myelomas. A hybridoma supernatant with alloreactivity in ELISA against BoLA-w8 positive but not BoLA-w8 negative PBM cells was tested for lymphocytotoxicity in parallel with parous alloantisera. WIM-8, an IgG2b monoclonal antibody, identified the 44,000 dalton protein of the bovine MHC class I molecule present on Bos taurus and Bos indicus animals.

Molecular and physical arrangements of human DNA in HRAS1-selected, chromosome-mediated transfectants

We used mitotic chromosomes isolated from a human EJ bladder carcinoma cell line for morphological transformation of mouse C127 cells. These chromosome-mediated transformants were analyzed for cotransfer of markers syntenic with c-Ha-ras-1 on human chromosome 11. We also used cloned, dispersed human DNA repeats, in a general mapping strategy, to quantitate the amounts and molecular state of human DNA transferred along with the activated c-Ha-ras-1 gene. In situ hybridization was used to visualize the physical state of the transfected human chromatin. The combined use of these various techniques revealed the occurrence of both chromosomal and DNA rearrangements. However, our analysis also demonstrated that, in general, very substantial lengths of DNA are transferred intact. Closely linked markers are likely to cosegregate. Therefore, these transformants should be invaluable sources for the complete molecular cloning of isolated fragments of the short arm of human chromosome 11.

A novel family of human major histocompatibility complex-related genes not mapping to chromosome 6

Thymocyte antigens CD1 [Thy,gp45,12] are thought to be the human counterparts of mouse thymus leukaemia (TL) antigens. Serological and biochemical analyses indicate that at least three subsets exist, the first of which (HTA 1/T6) was initially identified by the monoclonal antibody NA1/34. Like TL, CD1 are expressed on cortical thymocytes as well as on some lymphoid neoplasias, and resemble in structure major histocompatibility complex (MHC) class I antigens. However HTA 1/T6 is loosely associated with beta 2-microglobulin and is also found linked by a disulphide bridge to CD8(T8). A molecular genetic approach is needed to investigate the CD1 system, to clarify its relationship to TL antigens and to understand its regulation. We report the isolation of complementary DNA (cDNA) clones encoding a CD1 antigen. These clones reveal a novel family of genes which are MHC-related but are neither equivalent to mouse TL antigens nor linked to the MHC.

Molecular and physical arrangements of human DNA in HRAS1-selected, chromosome-mediated transfectants

We used mitotic chromosomes isolated from a human EJ bladder carcinoma cell line for morphological transformation of mouse C127 cells. These chromosome-mediated transformants were analyzed for cotransfer of markers syntenic with c-Ha-ras-1 on human chromosome 11. We also used cloned, dispersed human DNA repeats, in a general mapping strategy, to quantitate the amounts and molecular state of human DNA transferred along with the activated c-Ha-ras-1 gene. In situ hybridization was used to visualize the physical state of the transfected human chromatin. The combined use of these various techniques revealed the occurrence of both chromosomal and DNA rearrangements. However, our analysis also demonstrated that, in general, very substantial lengths of DNA are transferred intact. Closely linked markers are likely to cosegregate. Therefore, these transformants should be invaluable sources for the complete molecular cloning of isolated fragments of the short arm of human chromosome 11.

Gamma ray-induced mutants as a tool for the production and characterisation of monoclonal antibodies against HLA-alloantigens

To simplify the screening procedure for murine monoclonal antibodies specific for polymorphic HLA determinants, spleen cells from a mouse immunized with the human cell line BJAB-B95.8.6 were fused with NS1 mouse myeloma cells, and hybridoma supernatants were screened for their reactivity on BJAB-B95.8.6 and two gamma ray-induced HLA-loss mutants of this line. The use of these HLA-loss mutants allowed the rapid identification of two new allospecific MOABs designated TU160 and TU161. Serological as well as biochemical studies revealed TU160 to be specific for HLA-A2, and TU161 for HLA-B13 molecules, respectively. Both MOABs were determined to be antibodies of the IgG class and were able to precipitate their antigens from lysates of radioactively labeled cells.

Rapid and quantitative detection of unique sequence donor DNA in extracts of cultured mammalian cells: an aid to chromosome mapping

A rapid and highly sensitive method for screening the human DNA content of hybrid or transfected mammalian cells is described. Transfectants containing as little as 200 kb of otherwise undefined human DNA can be readily detected in a background of mouse chromatin. At the highest stringency, single-copy sequences can be detected. Large numbers of independent gene-transfer products are easily screened, making the method ideally suited to the identification of rare, but otherwise unselectable, events. The method does not rely upon the expression of the gene sequence of interest; the sole proviso is the availability of an appropriate DNA probe for the chromosomal region or locus of interest.

Inhibitory effect of a human T cell hybrid factor on both cell growth and mixed lymphocyte reactivity. Correlation with class II molecule expression

We recently reported the biological activity and some of the biochemical characteristics of a factor produced by a human T cell hybrid clone able to block hematopoietic progenitor cell proliferation. This 85-kD protein factor, which we have termed colony-inhibiting lymphokine (CIL), has growth regulatory activity on bone marrow precursors bearing Ia (class II) antigens of either granulocytic-monocytic (CFU-GM) or erythroid lineage (BFU-E and CFU-E). Experiments aimed to investigate the specificity of the inhibitory effect on hematopoietic progenitor cell growth suggested that the expression of HLA-DR surface antigens was required on the target cells. We describe in this communication how DR+ cell lines ceased dividing after a few days of culture in the presence of CIL, whereas DR- cell lines were completely unaffected. The increased DR expression on the ML3 cell surface, mediated by the activity of the gamma interferon (IFN gamma), increases the sensitivity to the growth inhibition factor of the ML3 cell line. To verify the hypothesis that the DR antigens might serve as receptors for the factor, enabling it also to interfere in the immune response, we tested CIL in a mixed lymphocyte reaction (MLR), one of the best known in vitro Ia antigen-dependent T cell-mediated immune responses. CIL is able to block major histocompatibility complex-allogeneic MLR both in human and mouse systems. The data indicate that CIL recognizes a nonpolymorphic structure (presumably on all Ia molecules) presented by stimulator cells of either species, and thereby interferes with specific interactions between stimulator and responder cells. Blocking of the alloantigen stimulation stage is also indicated, since CIL is effective only if added to the culture medium during the first 48 h of the MLR. Finally, mouse monoclonal anti-DR antibodies are able to sharply reduce CIL activity on sensitive DR+ cell lines. CIL may act physiologically as a multifunctional mediator in a complex network that links regulation of bone marrow differentiation and the generation of immune responses.

A monoclonal antibody recognizing a determinant shared by HLA-A2 and HLA-Aw69 (A28* variant)

A cytotoxic murine monoclonal antibody, designated P5.1, was tested against 613 unrelated donors and found to react with 401 who were positive for HLA-A2 (sensitivity = 100%) and with 8 of 82 positive for HLA-A28. The latter split of A28 corresponds to the "A28* variant" that in the Ninth International Histocompatibility Workshop (9WS) was designated Aw69(28*). The epitope recognized by antibody P5.1 is distinct from the alloantisera-defined determinants that characterize HLA-A2 and A28. Immunoprecipitation of specific antigens with selected monoclonal antibodies and isoelectric focusing gel electrophoresis demonstrated that A2, Aw68(28) and Aw69(28*) are distinct polypeptides. Thus, the A2-A28 antigen family consists of at least three different alleles definable using alloantiserums specific for A2 and A28, and monoclonal antibodies such as P5.1 recognizing the A2,Aw-69(28*)-epitope.

Distinctions between endemic and sporadic forms of Epstein-Barr virus-positive Burkitt's lymphoma

Tumour cell lines were established in vitro from 16 cases of Epstein-Barr (EB) virus genome-positive Burkitt's lymphoma (BL), 7 of "endemic" origin (i.e. from holoendemic malarial areas of Africa and of New Guinea) and 9 of "sporadic" origin (i.e. from outside such high-incidence areas). All the BL cell lines thus established were monoclonal by immunoglobulin isotype expression and displayed a characteristic chromosomal translocation, t(8:14) or t(8:22), confirming their malignant origin. Clear differences observed between the individual BL cell lines appeared to be related to their endemic or sporadic status. All 7 endemic cell lines began growth as a carpet of single cells, often with small, loose clumps appearing in later passage. Whilst 3 lines of sporadic origin displayed a similar pattern to the above, the majority of sporadic lines grew as large, tight clumps of cells from the first passage onwards. These differences in growth pattern were reflected by differences in cell surface phenotype, as defined in indirect immunofluorescence tests using a panel of monoclonal antibodies (MAbs) specific for B-lineage-associated antigens. BL cell lines could be classified into 3 separate groups on the basis of their reactivity with 6 particular antibodies (MHM6, AC2, Ki-1, Ki-24, J5 and 38.13). All 7 endemic BL cell lines and 2 of the 3 sporadic BL cell lines which began growth as single cells showed a group-I cell-surface phenotype (MHM6, AC2, Ki-1, Ki-24 negative; J5, 38.13 positive) in early passage. In contrast, all 6 sporadic BL cell lines which began growth in large clumps displayed a distinct group-II phenotype (MHM6, AC2, Ki-1 positive/negative; Ki-24, J5, 38.13 positive); in later passage most of these sporadic lines progressed to a group-III phenotype (MHM6, AC2, Ki-1, Ki-24 positive; J5, 38.13 negative) without loss of those immunoglobulin and chromosomal markers identifying the cells' malignant origin. These clear differences between endemic BL cell lines on the one hand and the majority of sporadic BL cell lines on the other suggest that endemic BL arises from a more restricted range of progenitor B cells than does the sporadic form of the disease.

Recognition by a murine monoclonal antibody of a unique epitope specific for the human alloantigen HLA-B8

A cytotoxic murine monoclonal antibody recognizing a specific HLA alloantigen was produced from the spleen cells of a BALB/c immunized with partially purified class I glycoproteins from an HLA-A1,B8 homozygous B-lymphoblastoid cell line. The antibody, designated P8.1, was tested against cells from 521 unrelated donors. It reacted with each of the 83 donors known to be HLA-B8 positive and with no HLA-B8 negative donors (sensitivity, 100%; specificity, 100%). Immunoprecipitation with antibody P8.1 and polyacrylamide gel electrophoresis confirmed that the antigen recognized was a class I structure. Although most murine monoclonal anti-HLA antibodies previously described have recognized "public" or supertypic specificities, the identification of a monoclonal antibody specific for a "private" HLA alloantigen indicates first that the BALB/c mouse has the appropriate immune response repertoire for recognizing certain HLA allospecificities and second that HLA-B8 can be defined by a single unique epitope.

Monoclonal antibodies to polymorphic epitopes on Ia antigens: three independent groups of determinants expressed on DRw6 homozygous cells

Murine monoclonal antibodies directed against polymorphic epitopes on HLA-linked antigens were readily obtained following a single immunization with DRw6-homozygous cells. Five antibodies directed against class II antigens were isolated. Two precipitated DC-like molecules and 3 DR-like molecules from the immunizing lymphoblastoid cell line. Analysis of association with HLA-DR antigens in a panel of 60 individuals revealed 2 antibodies directed against the DC1 specificity (S1, R1) and one against the MT2 specificity (R3). Antibodies S2 and S3 showed significant association with DRw6 (chi 2 = 30.27) and DRw6 and w8 (chi 2 = 18.86), respectively. An analysis of 29 haplotypes indicated that epitopes defined by these monoclonal antibodies appear to identify polymorphic determinants on three independent gene products which can be encoded by a single HLA haplotype.

Reed-Sternberg/lymphocyte rosette: lymphocyte subpopulations as defined by monoclonal antibodies

The Reed-Sternberg cell/lymphocyte rosette characteristic of Hodgkin's disease tissue and cell suspensions was investigated with monoclonal antibodies on fresh viable cell suspensions prepared from nine cases of Hodgkin's disease. The biopsy material comprised six spleens and three lymph nodes. The majority of the rosetting lymphocytes were T cells, primarily of the helper subset. Some of the attached lymphocytes were suppressor T cells. In addition, a few of the rosetting lymphocytes around Reed-Sternberg cells were B cells.

A novel human lymphokine that inhibits haematopoietic progenitor cell proliferation

T lymphocytes in culture synthesize and secrete a variety of factors that activate and guide the differentiation, replication and maturation of haematopoietic cells in vitro. Malignant T-cell lines as well as T-cell hybridomas producing several of these factors have been established. We report here a factor produced by a human cell line that exerts a potent inhibitory effect on the growth of bone marrow progenitor cells. The properties of this factor, which we have termed colony-inhibiting lymphokine ( CIL ), differ from other inhibitors of haematopoietic progenitor cell proliferation, but resemble those of a T-cell-derived factor causally linked with some cases of severe aplastic anaemia in humans. Sensitivity of cells to this factor appears to correlate positively with expression of HLA-DR surface antigens.

A monoclonal antibody that blocks class II histocompatibility-related immune interactions

Previous studies using conventional hetero- or isoantisera have indicated the involvement of class II (Ia) molecules in presentation of soluble antigen by monocytes to inducer T lymphocytes, stimulation of inducer T cells in MLR, and recognition of Ia-bearing target cells by cytotoxic T lymphocytes (CTL). The experience in using monoclonal anti-Ia reagents capable of blocking these phenomena in the human system is limited. Recently, however, we have characterized a lytic IgG2a monoclonal antibody, 9-49, that binds to functionally significant class II molecules. This antibody blocks (in the absence of complement): (1) specific binding of peripheral blood lymphocytes (PBL) to antigen-pulsed monocyte monolayers, (2) proliferation of PBL in response to soluble antigen (tetanus toxoid or mumps) or cell surface class II antigen stimulation in allogeneic or autologous MLR, (3) proliferation of cloned T4+ (inducer) lymphocyte cell lines to class II antigens, (4) generation of cytotoxic lymphocytes during allogeneic MLR, and (5) recognition (and killing) of class II-bearing target cells by T4+ CTL clones. Proliferation and CTL activity of a T8+ clone is unaffected by the 9-49 antibody. These results indicate the usefulness of this monoclonal reagent in studies evaluating the functional role of Ia molecules in immune recognition phenomena.

Anti-HLA-A2 and -A28 monoclonal antibody: production and study of the cross-reaction

An anti-HLA-A2 and -A28 monoclonal antibody, XV.17, has been prepared by immunizing a Balb/c mouse with PBL. This XV.17 monoclonal antibody is a cytotoxic IgM. Its reactivity was tested by lymphocytotoxicity test and indirect immunofluorescence technique, in parallel with an alloantiserum ORA having the same anti-HLA-A2, -A28 reactivity pattern, against different panels. Family studies were undertaken. Absorptions-elutions and cytofluorometry experiments were performed to study the cross-reaction. The XV.17 monoclonal antibody is cytotoxic against all the HLA-A2 and -A28 tested cells, and is absorbed by HLA-Aw23 and -Aw24 cell suspensions.

A mouse monoclonal antibody detecting a DR-related MT2-like specificity: serology and biochemistry

A mouse monoclonal antibody (7.3.19.1) was produced which reacts with class II molecules on B cells and monocytes of DR3, DR5, and/or DRw6 positive donors only. Using this moab and two others, three different groups of class II molecules could be identified. Furthermore, a differential precipitation pattern was found which correlates with a DR-related variable expression of the MT2-like polymorphic determinants on the cell surface. Addition of 7.3.19.1 to MLCs did not result in significant inhibition in controls to the two other moabs tested. Normal CTL activity was found in such a stimulated responder population.

Expression of major histocompatibility antigens and leucocyte infiltration in benign and malignant human breast disease

The reactivity of murine monoclonal antibodies (McAbs) directed against the monomorphic determinants of Class I and Class II antigens of the major histocompatibility complex (MHC), and against antigens expressed by discrete populations of leucocytes was studied using the indirect immunoperoxidase technique on serial tissue sections of 16 benign and 17 malignant primary human breast tumours. Class I antigens (detected by the McAb 2A1) were consistently associated with stromal leucocytes, fibroblasts and vascular endothelium, but expression on epithelial cells particularly of malignant provenance, was more variable. Class II antigens (detected by TDR 31.1) were present upon a variety of cell types which also included sporadic expression on malignant and benign epithelia. The distribution of leucocytes grossly monitored with 2D1 (reactive with a common leucocyte antigen) was largely interepithelial and periductal in benign lesions. Leucocytes were generally more numerous in malignant tumours, where they were largely confined to the stroma. The majority (approximately 75%) of leucocytes were T lymphocytes (reactive with UCHT1), some of which appeared to react with TDR 31.1 and were therefore activated. Ratios of helper/inducer (OKT4+) and suppressor/cytotoxic (OKT8+) subsets generally exceeded unity in malignant neoplasms. There was no correlation between the extent and distribution of T cells and the HLA status of the epithelial cells. Leucocytes detected by the monoclonal antibody OKM1 which reacts with monocytes/macrophages, granulocytes and large granular lymphocytes were numerically few and again mainly confined to the stroma. In a limited number of tests, leucocytes detected with HNKl, reactive with a differentiation antigen expressed on some cells which mediate natural and antibody-dependent cellular cytotoxicity in vitro although detectable interepithelially in benign tumours, were virtually absent from malignant tissue. HNK1 also cross-reacted with myoepithelial cells in the ducts of benign lesions.

Characterization of a murine monoclonal antibody specific for human early lymphohemopoietic cells

This paper summarizes the results of the characterization of A10, a murine monoclonal antibody which recognizes an epitope not restricted to cells of a definite lineage, but which seems to be specific for an early differentiation antigen present on precursors of circulating T and B cells. The structure recognized by the A10 monoclonal antibody, although strikingly structurally similar to the HLA-A,B,C complex, is immunologically different both from histocompatibility antigens and from beta 2 microglobulin. Furthermore, the distribution of the A10 antigen is analyzed in different cell and tissue samples, both in health and disease conditions.

Electrophoretic analysis of human HLA-DR antigens from HLA-DR4 homozygous cell lines: correlation between beta-chain diversity and HLA-D

Two-dimensional gel electrophoresis of immunoprecipitated human HLA-DR antigens from cells expressing the HLA-DR4 haplotype shows distinct clustering of beta-chain patterns. Six unique electrophoretic variants were observed among 17 HLA-DR4 homozygous cell lines (HCL) analyzed. These patterns correlate precisely with the HLA-D phenotype of the HCL donor as determined by reactivity in mixed lymphocyte culture. All DR4 HCL that belong to one of the well-defined HLA-D antigen groups (Dw4, Dw10, LD "40", LD "DYT", LD "KT2", or LD "TAS") have identical DR beta-chain patterns; DR4 HCL belonging to different HLA-D antigen groups do not. The concordance of the functional expression in mixed lymphocyte culture of a specific D phenotype with a distinct DR beta-chain pattern on gel analysis provides a direct structural basis for understanding the genetic control of HLA-D polymorphisms; HLA-D specificities as revealed by T-cell recognition in mixed lymphocyte culture thus might be accounted for by DR beta-chain polymorphisms. The extent of this beta-chain diversity within a single DR haplotype may aid in understanding variations in Ia-regulated functions, such as Ir gene control and certain disease susceptibilities.

Histocompatibility antigens, transferrin receptors and extra-embryonic markers of human amniotic epithelial cells in vitro

This study has shown that fresh amniotic epithelial cells which are negative by indirect immunofluorescence for HLA and Trf receptors become positive for both of these markers following prolonged culture. In addition, the amniotic antigens which are characteristic of fresh amniotic epithelial cells are lost and replaced by trophoblast antigens subsequent to maintenance of the cells in vitro. These observations suggest that, although the expression of HLA and Trf receptors are apparently negative in vivo, such gene products become activated and manifest in plasma membranes following exposure of the cells to culture conditions. In addition, the normal manifestation of the amnion antigens is lost following prolonged periods of culture. These findings indicate that the coding and expression of normally accepted transplantation antigens undergo a significant perturbation in vitro, and that markers of normal extra-embryonic epithelium in vivo are lost after the cells have been cultured in vitro.

Monoclonal antibodies in urology

The recent development of hybridoma technology has made it possible to obtain large quantities of antibody against a single determinant (monoclonal antibodies). This review describes the history of hybridoma technology and the method of producing monoclonal antibodies. It examines the role of such antibodies in diagnosis, tissue typing, histochemistry, developmental biology and study and treatment of diseases, including cancer, emphasizing the work being done on urological diseases.

Internalized membrane immunoglobulin meets intracytoplasmic DR antigen in human B lymphoblastoid cells

The important role of type II antigens of the major histocompatibility complex (Ia and DR) in the antigen presentation and in the antigen-specific cooperation between T and B cells is by now firmly established. Human B lymphoblastoid lines MWE and BL were stained with different fluoresceinated anti-DR antibodies. Not only surface but intracytoplasmic DR structures were brightly stained. The intracellular stain accumulated in a cluster close to the nucleus. Different specificity controls were performed. MWE and BL cells quickly internalize membrane IgM if cross-linked by corresponding antibodies. The intracellular location of the vesicles containing these complexes showed substantial coincidence with DR-positive structures in the paranuclear location. It is speculated that IgM-ligand complexes meet internal DR molecules and are both reexpressed on the plasma membrane to be recognized by primed T cells.

Hu Ly-m5: a unique antigen physically associated with HLA molecules

A new human cell surface antigen (Hu Ly-m5) detected by a murine monoclonal antibody (E4.3) is described. The tissue distribution of the Hu Ly-m5 antigen is similar to the HLA antigens (with which it was initially confused) but it is not present on all bone marrow cells nor the U266 myeloma, and is expressed on the HLA-negative K562 cell line. Nevertheless, the Hu Ly-m5 antigen has some affinity for HLA molecules as the two entities cocap and the Hu Ly-m5 antigen copurifies with the HLA antigens on an anti-beta 2-microglobulin immunoabsorbent column; however, the antigen complexes did not withstand the procedures used for coprecipitation. Despite their similarities, the Hu Ly-m5 and HLA antigens are distinct molecular entities--Hu Ly-m5 consists of two bands of apparent molecular weight 69 and 60 K while HLA is comprised of the 43 and 12 K bands of the HLA heavy chain and beta 2-microglobulin, respectively. The function of the Hu Ly-m5 antigen is unknown, but no involvement in the cytotoxic T-lymphocyte response to influenza virus-infected cells could be demonstrated. The two properties described (apparent molecular weight and physical association with the HLA antigens) suggests that the Hu Ly-m5 antigen may be a viral-encoded protein.

The definition of an MB related specificity by a monoclonal antibody

A number of monoclonal antibodies have been described that react with monomorphic and polymorphic Ia-like specificities on human B cells, but it is not clear whether these react with HLA-DR encoded molecules or with the products of other closely linked genes within the MHC, such as MB, MT, or DC 1 antigens. A monoclonal antibody is described herein (MC-26.1) which detects a new Ia-like specificity as shown by B-cell reactivity, chemistry, family studies, including recombinant family and coprecipitation studies. The latter studies showed that specificity detected by the MC-26.1 antibody coprecipitated with determinants detected by conventional anti-MB3 and MT3, but not with HLA-DR4 antisera. The determinant was polymorphic but not related to any of the known MB or MT specificities. However, cross-reactions were demonstrated by the variability of reaction on different individuals. Coprecipitation studies indicate that the antigen defined by MC-26.1 coprecipitates with MB and MT specificities suggesting that the antibody defines a new specificity on the MB3 and MT3 molecules.

Associated peptides isolated from human seminal fluid containing beta 2-microglobulin determinants

Proteins in human semen that react with a monoclonal mouse antibody to human beta 2-microglobulin (h beta 2M) have been isolated using immunoaffinity chromatography. As well as material of the same size as h beta 2M, a peptide of approximately 18000 kdaltons was isolated. It is suggested that this substance either contains h beta 2-M sequences itself or, as is more likely, is non-covalently associated with an h beta 2M-like peptide chain.

A monoclonal antibody that detects a polymorphic determinant common to HLA-DR1 and 2

In an attempt to study the gene products of the HLA complex, a monoclonal antibody, named HU-30, was produced by immunizing BALB/c mice with a cultured human B lymphoblastoid cell line, Shi-C3 (Aw24, Aw31, Bw51, Bw52, DR2, DR blank, MT1, MT2, MB3). HU-30 belonged to the IgG2 subclass and was active in complement dependent cytotoxicity. When the serological specificity was evaluated with a panel of 15 cultured human lymphoblastoid cell lines, it was found that HU-30 detected a polymorphic determinant, common to HLA-DR1 and 2, with much stronger cytotoxic activity against HLA-DR2 positive B cell lines. When HU-30 was tested against a panel of B cells from 84 healthy donors at a dilution of 2(-13), it gave positive reactions only with cells typed as HLA-DR2. Furthermore, sequential coprecipitation studies indicated that the HU-30 determinant was borne on the molecules carrying the HLA-DR determinants. Thus, HU-30 appears to be of great value as a tissue typing reagent monospecific for HLA-DR2.

A monoclonal anti-HLA antibody recognizes a mouse tumor-associated antigen

The monoclonal antibody W6/32.1 recognizes a public determinant on the HLA-A, B and C antigens of all tested human haplotypes. Though the antibody does not bind to normal mouse cells of any H-2 haplotype, it does show an unexpected specificity for the T cell leukemia line MBL-2 from a C57BL/6 mouse. It is shown that the murine antigen recognized by W6/32.1 is on an H-2-like molecule which also carries the determinant recognized by the monoclonal antibody B22-249 R1, specific for the H-2Db antigen. Unlike B22-249 R1, however, W6/32.1 does not bind to normal H-2b lymphocytes, nor to a variety of tumor cell lines of the H-2b haplotype. This cross-reaction is specific to W6/32.1, and is not shared by other monoclonal antibodies of similar anti-HLA specificities. Moreover, the affinity of W6/32.1 for its human antigen is substantially higher than for its mouse antigen. We conclude that W6/32.1 fortuitously recognizes a novel determinant on the H-2Db antigen of MBL-2, rather than an extensive region of structural homology shared between HLA and H-2. Thus for cells of the H-2b allotype this determinant is detected only on MBL-2, and by definition is thus an example of a tumor-associated antigen.

Anticorps Monoclonaux: Principes Fondamentaux Et Applications

The technique of hybridization of myeloma and B-lymphoid cells synthetizing antibodies, allows to obtain cellular clones producing a pre-defined antibody, during an undefined time and in unlimited quantity. The monoclonal antibodies have analytical properties which have never been obtained until now. They also constitute a major progress in the production of antisera, allowing their standardization, not only of place (unlimited production) but of time, thanks to the immortality (at least in principle) of the hybridoma clones. Finally, they represent a possible revival of serotherapy.

Transformation of LMTK- cells with purified HLA class I genes. II. Serologic characterization of HLA-A3 and CW3 molecules

The expression of two different HLA class I genes was observed after transformation of LMTK- cells. The corresponding class I molecules reacted differentially with monomorphic monoclonal antibodies (m.Ab). Absorption and elution studies of the human alloantibodies reacting with the transformed cells and cellular radioimmunoassay of these cells with polymorphic m.Ab resulted in the identification of HLA-A3 and CW3 molecules. These transformed cells were used to immunize C3H mice and induce the production of xenogeneic antisera, which, following absorption, showed polymorphic reactivity with human cells, suggesting that some of these sera could be used as typing reagents.