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P Démant

Publications and source records attributed to P Démant.

At least 19 recordsLinked to original sources
PubMed1992

Slp is an essential component of an EDTA-resistant activation pathway of mouse complement.

Slp (sex-limited protein) is a mouse serum protein encoded by a major histocompatibility complex class III gene. It is considered to be a product of a duplicated complement component C4 gene, but without functional activity. Originally it has been found expressed only in adult males with the S region of the H-2d or H-2s haplotype. In this report we present evidence that Slp is involved in a form of mouse complement activation that occurs after fractionation of serum by polyethylene glycol precipitation. This activation pathway is EDTA-resistant (i.e., independent of classical and alternative pathway activation), is regulated by C1 inhibitor, and leads to the generation of hemolytically active membrane attack complexes. A positive correlation between this EDTA-resistant mouse complement activity and reported Slp levels was found. Direct evidence for a functional role of Slp came from substitution experiments in which purified Slp induced hemolytic activity in polyethylene glycol-fractionated, Slp-deficient mouse serum. Selective depletion of other complement components suggested a role for C1s-, C2, and C5, but not C3, in the Slp-dependent complement activation. A model for this type of mouse complement activation is presented.

Aging↗
PubMed1985

H-2 class I antigen expression on mouse teratocarcinoma cell lines.

Immunity against PCC3 teratocarcinoma cells (129, H-2b) was induced in allogeneic (C3H, H-2k) mice by preimmunization with L cells (C3H, H-2k) expressing cosmid-introduced Kb or Db genes, but not with nontransfected L cells. In addition, the growth of PCC3 cells in sublethally irradiated (C3H X B6-H-2bm1)F1 and (C3H X B6-H-2bm13)F1 mice bearing the Kbm1 and Dbm13 mutations, respectively, was either prevented, stopped, or delayed in comparison with the (C3H X B6)F1 (k X b) mice, which failed to reject the PCC3 cells. The teratocarcinoma line OC15S was exceptional because it reacted specifically with Kb- and Db-specific (but not Ib-specific) alloantisera, and because Kb- and Db-specific antibodies could be absorbed by OC15S cells. The subpopulation of OC15S cells bearing the ECMA-7 antigen characteristic for embryonic carcinoma (EC) cells was isolated by the fluorescence-activated cell sorter and was shown to react specifically with Kb- and Db-specific antisera. These experiments show that teratocarcinoma cells express antigens similar or identical to the K- and D-region products of differentiated cells. The lack of expression of class I antigens is thus neither a condition nor a consequence of the pluripotentiality of the EC cells. The exact nature of the major histocompatibility complex antigens on EC cells has yet to be established using the methods of molecular biology and biochemistry.

Animals↗
PubMed1984

Genetics of human C4 polymorphism: detection and segregation of rare and duplicated haplotypes.

Applying a combined technology for the detection of allotypic variation of the fourth component of human complement (C4), including immunofixation with anti-C4 and C4-dependent lysis after agarose electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of C4 to separate the C4A and B alpha-chains, and the determination of Rodgers (Rg) and Chido (Ch) determinants of C4 in serum and at the blotted C4 alpha-chains, we detected rare human C4 allotypes and studied the genetic linkage. Partial inhibitors (p.i.) of anti-Rg and anti-Ch sera were found; the C4A51 allotype characterized as Rg p.i. and the C4A1 and C4B51 allotypes as Ch p.i. were genetically inherited. The C4A1 allotype has a unique Rg- Ch+ C4A alpha-chain. Duplicated C4A loci, A*3, A*2, and A*5, A*2 were both associated with a C4BQO and the HLA haplotype A3-Cw4-Bw35-DR1. These additions to the already known extensive C4 polymorphism may help to sort out their significance for the biological functions of human C4.

Complement C4↗
PubMed1984

Subdivision of the S region of the mouse major histocompatibility complex by identification of genomic polymorphisms of the class III genes.

The S region of the mouse major histocompatibility complex (MHC) encodes the class III proteins, the second (C2) and fourth (C4) components of complement, and factor B. Previously, the assignment of S-region haplotypes was based on analysis of protein polymorphisms. The recent availability of C2, C4, and factor B cDNA probes prompted a search for restriction fragment length polymorphisms which would serve as additional genetic markers for these loci. DNA was isolated from livers of mice of all standard inbred H-2 haplotypes and of haplotypes pz and bs. These DNA samples were digested with restriction endonucleases and analyzed by Southern blot. By the pattern of restriction fragment length polymorphism observed, specific markers have been identified in factor B of haplotypes f, u, z, bs, r, and v, and in C4 of haplotypes b,q,f,j,p,s,pz,r, and v. These genetic markers were used in the analysis of S-region composition in strains B10.TFR5(H-2ap5) and C3H.LG(H-2dx), and a possible intra-S-region recombinant was revealed in the H-2dx haplotype. The genetic markers identified here subdivide the S region and will be of value in defining further the composition of the complement gene complex of the mouse MHC.

Alleles↗
PubMed1984

A new determinant, Qa-m208, detected on T lymphocytes and transfected L cells by a Kb-specific monoclonal antibody.

A Kb-specific monoclonal antibody, 6.3.4, defining a new class I specificity, m208, reacts with some K and D region products and with a Qa determinant present on T lymphocytes but not detectable on thymocytes and B lymphocytes. The strain distribution of reactions indicates that this determinant is controlled by the Qa-Tla region, and shows no concordance with the strain distribution pattern of any of the known Qa antigens. The antibody reacts also with L cells expressing a cloned H-2b class I gene mapping in the Qa-Tla region.

Alleles↗
PubMed1983

Specific selection of host cell glycoproteins during assembly of murine leukaemia virus and vesicular stomatitis virus: presence of Thy-1 glycoprotein and absence of H-2, Pgp-1 and T-200 glycoproteins on the envelopes of these virus particles.

Using the indirect immunoelectron microscopy technique, it was investigated whether during assembly of murine leukaemia virus (MuLV) and vesicular stomatitis virus (VSV), the glycoproteins (gp) Thy-1, H-2, Pgp-1 and T-200 present on the surface of BW5147 and BuEL4 leukaemia cell lines were incorporated into the virus envelopes. This work was done mainly with monoclonal antibodies against these gps to exclude the presence of antibodies against endogenous MuLV present in conventional mouse antisera. Thy-1 gps were incorporated into MuLV and VSV envelopes. In contrast, H-2, Pgp-1 and T-200 gps were excluded from the budding of both virus particles. To study whether the presence of Thy-1 gps on the viral envelopes is due to some lateral affinity of this molecule with viral gps, the physical association of Thy-1.1 antigens and MuLV antigens was studied with antibody-induced redistribution of both antigens on the BW5147 cell surface. Antibody-induced patching of the viral antigens did not result in co-patching of the Thy-1.1 antigens. In the reciprocal tests no co-redistribution of viral antigens with Thy-1.1 antigens was seen. These studies show that the presence of Thy-1.1 gp on the MuLV envelope cannot be due to a lateral affinity of this molecule with viral gps and that a selection of surface gps takes place during assembly of MuLV and VSV.

Animals↗
PubMed1983

One (H-2D2b) of the three Db region-controlled molecules (H-2D1b, H-2D2b, H-2Lb) is not detected in bm13 mutant.

Analysis of the antigenic heterogeneity of Db region products by the technique of antibody-induced redistribution of cell surface antigens (capping) revealed the existence of two types of H-2 molecules reactive with the monoclonal anti-Db antibody, B22-249R 1 (H-2.m2). The relationship of the two H-2.2-positive molecules described here is similar to that of H-2D and H-2M detected in the products of the Dd region; they differ in the repertoire of the H-2 public specificities, although they share the private specificity. We designate them, in accordance to recently proposed nomenclature, H-2D1b and H-2D2b. Both types of molecule have been detected on T lymphocytes of C57BL/6 (H-2b), C3H.B10(H-2b), and B10.A(2R) (H-2h2, KkDb) strains. In mutant strain B6.C-H-2bm13, however, only one type of H-2.2-positive molecule, H-2D1b, could be detected. This finding resembles the situation in the d haplotype, in which mutant strain B10.D2 (M504) (H-2dm1) had only one molecule (H-2Dd), of the two H-2.4-positive molecules H-2Dd and H-2Md that could be detected. A third Db region molecule, H-2Lb, does not carry the Db private specificity H-2.2, and it is detectable by some of the antibodies against the H-2.28 family of specificities; it is distinct from the Qa-2 molecule. The H-2Lb molecule was detected in all strains tested in this experiment, including the bm13 mutant.

Animals↗
PubMed1982

A molecular basis for the two locus model of human complement component C4.

The major histocompatibility complex(MHC)-linked fourth component of complement (C4) shows a high degree of polymorphism in several animal species. In man C4 polymorphism was detected by distinct charge differences of the variants. O'Neill et al. showed that this C4 polymorphism was controlled by two closely linked genetic loci, F (C4A) and S (C4B) and these results were extended by Awdeh et al. with an improved typing method. Biochemical analysis of human C4 has revealed that it consists of three polypeptide chains, alpha, beta and gamma. In all reports so far on the molecular analysis of human C4, no molecular weight differences between the A and B locus-encoded molecules have been noticed. Here we demonstrate that the C4A and C4B locus-encoded alpha-chains have a molecular weight (MW) of 96,000 and 94,000, respectively, presenting for the first time a molecular basis for the difference between all C4A and C4B variants tested. Even rare variants that are difficult to allocate to the A or B locus on the basis of charge differences could be identified as C4A or C4B variants in this way, thereby providing new insights into the relationships between the C4A and C4B loci.

Complement C4↗
PubMed1982

Molecular heterogeneity of D-end products detected by anti-H-2.28 sera. I. A. molecule similar to Qa-2, detected in the BALB/cBy but not in the BALB/c-H-2dm2 mutant.

Immunoprecipitation of NP-40 lysates of 125I-labeled lymph-node cells with different anti-H-2 sera and with anti-Qa-2 serum has shown that the BALB/cByA strain (H-2d, Qa-2-negative) expresses, besides H-2Ld, another molecule that is not detectable in the BALB/c-H-2dm2 strain. Electrophoresis in SDS polyacrylamide gels indicated that this molecule, provisionally designated Lq, has an apparent molecular weight of 41000 daltons, in contrast to approximately 49000 daltons for H-2Kd and H-2Ld, and 47000 daltons for H-2Dd molecules. The anti-Qa-2 serum precipitated from the Qa-2-positive strains BALB/cHeA but not from the Qa-2-negative strains BALB/cByA and BALB/c-H-2dm2 a protein that gave a very strong band corresponding to the molecular weight 41000 daltons in the gel electrophoresis. The biochemical characteristics of the Lq molecule are thus more similar to those of Qa-2 than of H-2 antigens.

Animals↗
PubMed1982

Molecular heterogeneity of D-end products detected by anti-H-2.28 sera. II. B10.D2(M504) (H-2dm1) mutant fails to express one of the two H-2.4-, 28 + Dd region molecules.

By the technique of antibody-induced redistribution of cell surface antigens (capping), two serologically distinct molecules that do not react with anti-D-private sera were detected in the products of Dd and Dq regions. One of them is H2L, H-2Ld and H-2Lq. The other molecule is different from H-2L as well as from any known Qa molecule and it is either an H-2-like or Qa-like molecule. We designate it provisionally L2d and L2q, respectively. All these molecules carry the specificity H-2.28. Nevertheless, one antiserum against a H-2.28-like specificity, D29 (s X k anti-m) shows differences between these molecules. This antiserum reacted with H-2Ld and H-2Lq but not with L2d and Leq molecules. The same antiserum reacted, however, only with the H-2.4 positive (H-2D) molecule in mutant B10.D2 (M504) (H-2dml) cells. No antipublic serum was found that was able to distinguish different H-2.4 negative molecules in dml haplotype. The serological characterization of H-2.4 negative molecule in dml mutant indicated that this molecule is similar to the L2d molecule detected in the parental H-2d haplotype. Thus, dml mutant fails to express the H-2Ld molecule but does express H-2.4 negative, H-2.28 positive molecule, analogical to L2d. Together with our recent data demonstrating previously unknown molecules in the products of Dd and Kd regions, six serologically distinct molecules other than Qa-2 controlled by H-2d haplotype could be detected -- H-2K1d, H-2K2d, H-2Dd, H-2Md, H-2Ld, and L2d. BALB/c-H-2dm2 mutant fails to express H-2Ld and L2d molecules, while B10.D2(M504) (H-2dm1) mutant fails to express H-2Md and H-2Ld molecules.

Animals↗
PubMed1982

Molecular heterogeneity of D-end products detected by anti-H-2.28 sera. III. Reactivity of certain anti-H-2.28 alloantisera with Qa-2 antigen.

In capping experiments with peripheral T lymphocytes, two anti-H-2.28 sera (AKR anti-AKR.L, anti-Kb, and C3H anti-C3H.B10, k anti-b) that do not contain any Qa-2-specific antibodies are able to redistribute not only the H-2.28-positive H-2 molecules, but also Qa-2 molecules. This is due to the capacity of these sera to react with Qa-2 molecules because on cells where all known molecules of the H-2d haplotype were capped (K1d, K2d, Dd, Md, Ld, L2d), both antisera still reacted when the cells came from a Qa-2 positive Dd strain (B10.A) but not when the cells were of Qa-2 negative strain (BALB/cByA). The reaction with Ia and non-H-2 antigens was excluded in these experiments. These data show that Qa-2 and H-2 antigens share some specificities of the H-2.28 family. Other anti-private and anti-public anti-H-2 sera failed to react with the Qa-2 molecules.

Animals↗
PubMed1982

Murine complement factor B (BF): sexual dimorphism and H-2-linked polymorphism.

Polymorphism of murine BF is described using agarose gel electrophoresis of EDTA-plasma. The proteins were blotted onto cellulose nitrate sheets and BF was detected by incubation of these sheets with anti-BF serum, anti-IgG serum, and 125I-labeled protein A successively. After autoradiography, four or five main BF bands were found in plasma of male mice. The strain WLL/BrA (H-2bs) carried a more anodal variant than the strains 020/A(H-2pz), B10 (H-2b), B10.A (H-2a), B10.M (H-2f), and OIR (H-2q). In backcross and F2 generations the BF variants always cosegregated with the H-2 haplotypes. In this way linkage to H-2 could be established. When the electrophoretic BF patterns of males and females were compared, a sexual dimorphism was discovered; the females of each strain had only three main BF bands compared with the four or five found in males. However, no difference in level between males and females could be detected, probably because the three BF bands in the females were stronger. These data extend the information on the interspecies homology of the MHC and may open new possibilities for studies of the genetic organization and hormonal regulation of the H-2 complex.

Animals↗