Search PubMed⌕ Search

Biomedical subjects

J Colombani

Publications and source records attributed to J Colombani.

At least 73 records · Page 4Linked to original sources
PubMed1981

Inhibition of secondary mouse mixed lymphocyte reaction by anti-Ia sera.

Secondary mixed lymphocyte reaction (MLR-II) was studied in A.TH anti A.TL and A.TL anti-A.TH combinations in which stimulation was mainly due to H-21-region differences. In both cases of MLR-II was specifically inhibited by the responder anti-stimulator Ia serum. The level of inhibition was dependent on the ratio of the amount of immune serum to the number of stimulating cells. The inhibitory activity and Ia antibodies were specifically absorbed and eluted together. The results confirm that the lymphocyte-activating determinants of the MLR-II (1) are carried by the Ia molecules and (2) are identical to the serologically defined Ia determinants. - Anti-Ia sera directed against private and public specificities of the stimulating cell induced a higher level of inhibition than anti-Ia sera directed only against public specificities, indicating that both private and public Ia specificities are involved in re-stimulation during MLR-II. - These results, in connection with others, suggest that the receptor of the proliferating T cell recognizes the same Ia determinant as the combining site of the Ia-recognizing antibody.

Animals↗
PubMed1981

Screening and use of high titered anti-HLA-DR sera in PHA-blast complement fixation and B-lymphocytotoxicity techniques.

Screening for anti-HLA-DR sera was performed by complement fixation on PHA stimulated peripheral blood lymphocytes (PHA-CF), or cultured B lymphoid cell lines. Out of 1,350 sera from multiparous women, multitransfused patients, and patients transfused during extra-corporal circulation (ECC), 219 contained anti-HLA-DR activity (16.2%). Anti-HLA-DR antibodies developed after ECC were often high titered (1:10 to 1:100). In half of these sera anti-HLA-A, B antibodies were weak or absent, making it possible to use then as anti-HLA-DR reagents without platelet absorption. Of the 219 positive sera 51 contained defined anti-DR antibodies (20 monospecific and 31 bi- or multispecific). The 13 best sera recognized DR1 and DR7 specificities with r values from 0.83 to 1. Twenty-four sera selected by CF were also studied by lymphocytotoxicity technique against peripheral blood B lymphocytes (B-LCT). Both PHA-CF and B-LCT techniques gave similar results, detecting the same specificities and showing comparable sensitivity. The advantages of CF are: easy storage of target cells at -80 degrees C or + 4 degrees C, and fast reading. For these reasons PHA-CF or CF on cultured B lymphoid cell lines can be proposed for large scale screening of anti-HLA-DR sera. The sera thus screened can be used for HLA-DR typing either by PHA-CF or B-LCT.

Antibodies↗
PubMed1980

[Serological study of Ia antigens determined at the I-A and I-E sub-regions of the H-E complex in the H-2 complex of mice].

Immune serum B10.S (7R) anti-B10.S (9R)(anti I-JEkCd) contained as expected an anti-Ia7 antibody. A series of weaker but reproducible extra-reactions might recognize Ia3 specificity coded at the I-A subregion of the H-2 complex. Results with recombinant haplotypes confirmed this mapping. Such a reactivity could be interpreted as an interlocus cross-reaction (I-E/I-A) since the immunization was induced against an I-E subregion product. Another interpretation was possible: the immune serum would thus contain an antibody recognizing Ia7 (on the E alpha k Ia chain) and another antibody recognizing an antigenic determinant carried by the E beta k Ia chain. The latter antibody might recognize by cross-reaction as specificity carried by the A beta chain of various haplotypes (H-2b,k,q).

Animals↗
PubMed1979

Immunological and serological data concerning human histocompatibility antigens (HLA) and alpha 1-microglobulin co-purified from urine.

Serologically active glycoproteins (HLA) purified from urine contained only about 4% HLA antigens co-purified with alpha 1-microglobulin. The immunization of rabbits with the serologically active product gave rise to an antiserum containing two kinds of antibodies: anti-HLA-A9 and anti-alpha 1-microglobulin. The anti-HLA-A9 antibodies were detected by the lymphocytotoxicity and indirect immunofluorescence techniques against peripheral blood lymphocytes and cultured lymphoid cell lines. Anti-alpha 1-microblobulin antibodies were detected by immunoprecipitation in gel. Pure alpha 1-microglobulin gave rise to an antiserum directed only against alpha 1-microglobulin. This antiserum did not react with peripheral blood lymphocytes and cultured lymphoid cell lines.

Alpha-Globulins↗
PubMed1978

Molecular data on urinary glycoproteins with human leucocyte antigen (HLA) activity.

Two glycoproteins characterized by their serological activities (HLA-A9 and HLA-B12), their isoelectric points and their molecular weights were purified from urine from a patient suffering from tubular proteinuria (cystinosis). Their physicochemical properties as well as an important increase of their specific activities during the different purification steps suggested that they behave as human leucocyte antigens (HLA) which had been excreted into urine. Their amino acid compositions and N-terminal sequences were different to those described for HLA solubilized from cultured human lymphoblast cell lines. The N-terminal sequences of the two serologically active glycoproteins were identical to the N-terminal sequence of another recently purified human urinary glycoprotein called human complex-forming glycoprotein. The relationship between HLA, human complex-forming glycoprotein and the serologically active urinary glycoproteins is discussed.

Amino Acid Sequence↗
PubMed1977

[Molecular aspects of 2 human urinary glycoproteins with histocompatibility antigen (HLA) serological activity].

Two serologically active urinary glycoproteins (HLA-A 9 and HLA-B 12) were isolated from urine provided by a patient suffering from tubular proteinuria. Their N-terminal sequences were automatically determined. The latter were identical with the sequence of another urinary glycoprotein (protein HC). The relationship between protein HC and the serological activity is discussed.

Amino Acid Sequence↗
PubMed1977

Reactivity of anti-HLA sera against mouse lymphocytes.

The reactivity of anti-HLA hyper-immune sera was tested by the microlymphocytotoxicity technique (LCT) against a panel of mouse lymphocytes. Three levels of reactivity were observed: negative (immune sera titre 1:20 or less), weak (titre 1:40 to 1:80 with a percentage of dead cells less than 50%) or strong (titre 1:60 or more with 100% killing). Thirteen normal human sera were non-reactive. Eleven out of 60 hyper-immune sera were strongly reactive. Tests using congenic lines showed that the reactivity was controlled at the H-2 complex. One serum (CODRON) was studied in detail. When tested against a panel of strains carrying 10 different H-2 haplotypes, it reacted strongly against lymphocytes H-2d, ja, k, p and r; and did not react, or at least only weakly, against lymphocytes H-2b, f, q, s and v. Tests using mouse strains carrying the recombinant H-2 haplotypes h4, i5, i, y2, g, g2 and t1, suggested that the observed reactivity was directed against structures controlled at the K end of the H-2 complex (H-2.47?). Absorption-elution experiments with human and murine lymphocytes and platelets confirmed that the structures recognised by serum CODRON were determined at the major histocompatibility complex.

Animals↗
PubMed1977

Molecular defect in platelets from patients with bernard-soulier syndrome.

An IgG antibody isolated from the serum of a patient with the Bernard-Soulier syndrome induced platelet agglutination in the platelet-rich plasma of 50 normal subjects regardless of their ABO, KOa, KOb, HLA, or PlA1 types. This antibody was nonreactive with platelets from three other Bernard-Saulier syndrome patients. Indirect immunoprecipitation tests using this serum (or purified IgG) and soluble membrane antigens labeled with 125I that had been extracted from normal platelets by the nonionic detergent Nonidet P-40 gave a single radioactive peak at 150,000 MW in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These findings strongly suggest that the antigenic determinant reacting with this antibody is absent from platelets of Bernard-Soulier syndrome patients and that the deficient molecule is of 150,000 MW. The role of this molecule in subendothelial adhesion and macromolecular-mediated aggregations is discussed.

Antibodies↗
PubMed1976

Separation of anti-Ia (I-region associated antigens) from anti-H-2 antibodies in complex sera, by absorption on blood platelets. description of three new Ia specificities.

H-2 antigens are expressed in substantial amounts of murine blood platelets (for H-2 antigenic content 1 lymphocyte approximately 50 platelets) whereas Ia antigens are probably not expressed at all (minimal Ia antigenic content more than 35 times lower than for H-2). This property of blood platelets makes them very useful for the selective absorption of anti-H-2 antibodies from complex sera and for the preparation of specific anti-Ia antibodies from such sera. In 20 sera produced against the complete H-2 complex, 12 sera contained anti-Ia antibodies beside the expected anti-H-2 antibodies. In two sera, separation of the anti-Ia antibodies was easily obtained by absorption of the anti-H--2 antibodies on platelets. The analysis of one serum (C3H.Q X B10.D2) anti-C3H [(q X d) anti-k] showed that, in addition to be expected anti-H--2.23 and anti-Ia.2 antibodies, it contained at least three other Ia antibodies, separable by absorption on lymphocytes, which recognized three antigens--Ia.17, determined by the haplotypes k, f, s, r, j; Ia.18, determined by the haplotypes k, f, s; and Ia.19 determined by the haplotypes k and r. The genes are located in the I--A and/or I--B subregions of the H--2 complex.

Absorption↗