Relationship between DQ alpha and DQ beta RFLP and cell surface polymorphisms of class II HLA antigens

DQ alpha and beta DNA probes of the human major histocompatibility complex (MHC) were hybridized to restriction enzyme-digested genomic DNA with the aim of establishing a correspondence between the polymorphisms recognized by classical serology and DNA restriction fragment length polymorphisms (RFLP). In DR homozygous human cell lines, three distinct PstI fragments were recognized by the DQ alpha probe and four PstI fragments were recognized by the DQ beta probe. Each fragment was associated with a different group of DR antigens. Three allelic forms of either DX alpha or beta genes were identified, but none showed any strong association with DR or DQ. Family segregation analysis at the DNA level further confirmed the DR linkage of the DQ alleles in estimations of gene frequencies of different alleles of DQ alpha, DQ beta, DX alpha and DX beta. Evidence was presented that the DQ alpha and DQ beta allelic forms described at the DNA level correspond to polymorphic determinants at the cell surface which can be defined serologically or in cellular assays. Our data suggest that the HLA-DQ subregion-encoded alloantigens should be defined at the individual alpha and beta chain levels.

DQ alpha and beta RFLP reveals the composition of the DQ molecule recognized by T-cell clones

Pst I RFLP, revealed with DQ alpha and DQ beta probes, was compared with Taq I RFLP using a panel of DR-homozygous cell lines and HLA-typed family members. Taq I patterns, characteristic for each DR-associated DQ alpha and beta allelic forms, were recognized in the homozygous state and then proven to segregate in the heterozygous members of informative families. The presence of both specific alpha and beta chains was found to be necessary to form the type of DQ molecule specifically recognized by two alloreactive T-cell clones. Particular alpha and beta associations also seem to be responsible for some Dw splits of the DRw6-positive cells. Taq I RFLP analysis may be more complex than the Pst I analysis, but is certainly more informative and complete, considering the type of information we were seeking by performing these types of experiments.

[Evaluation of the effects of citicoline in chronic cerebrovascular diseases]

A double-blind random block trial was carried out on 58 patients suffering from chronic cerebrovascular diseases as defined by the "Ad Hoc Committee, Paris 1980". The trial was carried out to assess the effects of citicoline on chronic cerebrovascular disease. Particular attention was paid to the selection of the assessment tools (neuropsychological and psychological tests). Citicoline treatment brought about an improvement in awareness and perceptive-motor faculties. This effect can be attributed to an overall drug action on neural energy metabolism.

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.

Antimigraine drugs in the management of daily chronic headaches: clinical profiles of responsive patients

Flunarizine, a Ca-antagonist with demonstrated antimigraine properties, and indoprofen, an anti-inflammatory non-steroidal agent, were used in the treatment of daily chronic headache. Forty-two migraineurs with interval headache (MIH) were treated with flunarizine in a 6-month open trial, while indoprofen was administered to 23 patients with MIH and 7 with chronic tension headache (CTH) in a 2-month, double-blind, cross-over placebo-controlled study. Flunarizine was found effective in over 65% of the patients, while indoprofen was able to improve headache severity in only 30% of the subjects. In the responder patients, the effectiveness of both drugs is more pronounced in MIH, and seems to be ascribable to the ability of the treatments to reduce number and severity of attacks. A higher incidence of previous affective disturbances is found in non-responsive cases. The analysis of factors converting episodic into chronic headache shows slight but not significant differences between responders and non-responders. An impairment of plasma beta-endorphin levels, in the presence of normal ACTH, cortisol and nociceptive RIII threshold values, characterizes daily chronic headache (DCH) patients. Moreover, indoprofen does not significantly affect these biological and neurophysiological parameters independently of the therapeutic response.

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.

Differentiation antigens of human hemopoietic cells: patterns of reactivity of two monoclonal antibodies

Two mouse anti-human monoclonal antibodies (S3.13 and S5.7) raised against cells of acute myelogenous leukemia were found to react with antigens expressed on the surface of subsets of monocytes and lymphocytes. S3.13 precipitates a peptide of Mr 29,000, and S5.7 precipitates a peptide of Mr 20,000 present on the surface of all the cell types tested. These two surface antigens were distributed on discrete subpopulations of normal hemopoietic cells. The antibodies reacted with all (S5.7) or a subpopulation (S3.13) of peripheral blood T-lymphocytes, and with a subset of monocytes. Both antibodies reacted with bone marrow blast cell progenitors of the myelomonocytes and erythroid lineage. S5.7 also reacted with non-T-lymphocytes and with cells of the eosinophilic lineage. Both antigens disappeared from the cell surface during normal myeloid and erythroid differentiation. Thus, these monoclonal antibodies define the molecular characteristics and the cellular distribution of two differentiation antigens present on cells of the hemopoietic lineage.

A monoclonal antibody that detects expression of transferrin receptor in human erythroid precursor cells

A monoclonal antibody, L5.1, obtained by immunizing a Balb/c mouse with HL60 human promyelocytic leukemia cells, was found to react with both HL60 cells and with the K562(S) cell line. This monoclonal antibody binds and immunoprecipitates a glycoprotein (Mr 87,000) present on the cell surface membrane of K562(S) as a disulfide bonded dimer. In competition experiments L5.1 competes with both transferrin and OKT9 (a known antitransferrin receptor antibody) for binding to target K562(S) erythroleukemia cells. Binding of both L5.1 and transferrin to the surface of K562(S) cells is inhibited by treatment with 12--O-tetradecanoyl-phorbol-13-acetate, and the extent and time course of inhibition is similar in both cases. Cell sorting analysis of normal human marrow cells incubated with L5.1 indicates that L5.1 reacts strongly with all the morphologically recognizable erythroid lineage precursors, from the pronormoblast to the orthochromatic normoblast, and with reticulocytes. Erythrocytes, myeloid elements, monocytes, megakaryocytes and platelets, peripheral blood B and T lymphocytes do not bind significantly with this antibody and only a small fraction of promyelocytes was reactive. Antibody L5.1 did not react with leukemic cells of patients with acute lymphoblastic, myeloblastic and promyelocytic leukemias, but it did react with some established B (1 of 5) and T (2 of 3) cell lines, and a myeloid (1 of 3) cell line, and with PHA-stimulated peripheral blood lymphocytes. The nonhemopoietic cell lines tested did not bind with L5.1 with the exception of a colorectal adenocarcinoma and a melanoma cell line, which were both strongly positive. The relationship of antibody L5.1 to other monoclonal antibodies that bind the transferrin receptor is discussed.

A xenogeneic monoclonal antibody recognizing specificities controlled by HLA-A and B alleles

In the present paper one reagent among the many prepared has been carefully studied. It is a xenogeneic monoclonal antibody, F10.13/13, obtained by immunizing mice with human peripheral blood lymphocytes. The splenocytes of the immunized mice were fused with a murine were fused with a murine myeloma and the supernatants of the resulting Ig-secreting hybridomas were tested against appropriate targets. --F10.13/13 behaves in a very peculiar manner from the serological point of view and we think that it reacts with maximal affinity with an epitope expressed most strongly on HLA glycoproteins controlled by genes B8, B7, and Aw19.

Modulation of expression of HLA components at the cell surface induced by anti-beta 2m reagents

Antibodies against lymphocytes surface components are able to rearrange profoundly the topography of the cell membrane with a differential modulation of surface antigens. Of particular interest is the effect of anti-beta 2m reagents, which are able to suppress completely the reactivity of epitopes carried by the two chains of the ABC dimers, while th expressivity of other antigens, such as DR, is significantly increased. These results have been obtained with immunoradiobinding under a variety of conditions, thus confirming the validity of the "bb" (beta 2m blanketing) test.

Quantitative analysis of cell surface HLA structures by means of monoclonal antibodies

Quantitative data on the binding of murine monoclonal antibodies ot whole human lymphoblastoid lines and peripheral blood lymphocytes (PBL) are reported. Antibodies reacting with beta 2m or a common part of the HLA heavy chains and nonpolymorphic determinants of the DR dimer were used. The equilibrium constant (K) of the reaction and the total number of antigenic determinants was graphically estimated. For the above-mentioned antibodies, K ranged between 5 X 10(8) and 4 C 10(9) l/mole at 0 degrees C and progressively decreased with the increasing temperature. T cells expressed less HLA and beta 2M determinants than the B cells. The number of determinants per surface unit is higher on the B cell from PBL than on E.B. virus-transformed cell lines and is generally very low, suggesting that the complement-dependent cytotoxic activity is a phenomenon depending on membrane fluidity. A portion of beta 2m seems not to be bound to the HLA heavy chains on B cells as well as on T line surface, as already shown for Molt 4 line.

Separation of human cells bearing HLA-DR antigens using a monoclonal antibody rosetting method

A technique is described for enriching, from human blood, cells bearing HLA-DR antigens. The method depends on the use of monoclonal mouse antibody which reacts with HLA-DR structures. Cells to which this antibody has bound can be separated after rosetting with bovine erythrocytes coated with anti-mouse immunoglobulin. The cells thus enriched may be used for HLA-DR typing by standard cytotoxicity methods with allogeneic sera.