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M H Roos

Publications and source records attributed to M H Roos.

45 records · Page 3Linked to original sources
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↗
PubMed1981

Molecular heterogeneity of H-2 antigens.

Since the discovery of the H-2Ld molecule (Lemonnier et al. 1975) we have demonstrated that several K and D region alleles produce more than one type of H-2 molecules. Two of four different molecules were distinguished in the products of different alleles. Some of these molecules are products of different genes (H-2D, H-2L), in other instances the evidence for distinct genes is not available. Some of the different molecules produced by the same region might be modified products of the same gene. In the instances where no information implicating different genes is available, we use a neutral terminology which does not presume a genetic difference: H-2K1d and H-2K2d, H-2D1k, H-2D2k, H-2D1dx, H-2D2dx, H-2L1d, H-2L2d, etc. Immunoprecipitation experiments with some anti-H-2L and anti-Qa-2 sera revealed proteins with the apparent molecular weight of 41,000. We designate these antigens provisionally Lq and Qx, respectively. The Lq protein is polymorphic and it is at least partly under the control of H-2L-linked genes since it is absent from BALB/c-H-2dm2 cells. Since we have never seen the 41,000 proteins in precipitates of H-2K or H-2D antigens, it appears that whatever the origin of these molecules, they reveal some features common to products of L and Qa region. The basic relationship of H-2 K, D, L antigens is revealed also by the shared antigenic specificities between these H-2 molecules which we demonstrate using anti-H-2.28 sera. In summary, our results show that the class I antigens in each haplotype represent a family of several distinct but antigenically related molecules. The specificities of the H-2.28 family are the strongest allotype common to different H-2 K, D, and L molecules. Recent direct demonstration of several different genes in the Dd region (Steinmetz et al. 1981) provides evidence for the genetic complexity of H-2 genes which may be underlying basis of the molecular heterogeneity of H-2 antigens discussed here.

Animals↗
PubMed1980

Genetic and structural characterization of H-2-controlled allelic forms of murine C4.

The patterns of expression of several types of genetic variation in murine C4 were investigated. Dominance was assessed for S-region-determined differences in molecular weight of the C4 alpha-chain from Sw7 strains relative to all other strains examined and in C4 hemolytic titers. Codominant expression in F1 hybrids was shown for both of the above variations. Comparison of tryptic peptide profiles of radiolabeled C4 beta-chains encoded by different S regions revealed differences in their primary structures. The demonstration of codominant expression for the variant C4 traits examined and the evidence from tryptic peptide maps for haplotype differences in C4 primary structure strongly support the hypothesis that polymorphism of murine C4 is controlled by structural genes which are located in the S region.

Alleles↗
PubMed1980

Characterization of the oligosaccharide units of the fourth component of complement (Ss protein) synthesized by murine macrophages.

The glycosylation of murine C4 (Ss protein) synthesized by peritoneal macrophages has been investigated. Both the intracellular precursor, P-C4 (185), and the C4 alpha- and beta-chains that were secreted into medium were found to be glycosylated; however, no carbohydrate units were detected on the gamma-chain. Analyses of the oligosaccharide units showed that P-C4 (185) appears to contain both a "complex" and a "high mannose" carbohydrate group, the alpha-chain a "complex" group and the beta-chain a "high mannose" carbohydrate unit.

Acetylglucosaminidase↗
PubMed1979

Structural characterization of the murine fourth component of complement and sex-limited protein and their precursors: evidence for two loci in the S region of the H-2 complex.

The S region of the murine major histocompatibility complex controls the expression of two related, serum substance-positive proteins; one (C4) has functional complement activity, whereas the other, the sex-limited protein (Slp), is hemolytically nonfunctional. The structural relationships of these molecules to each other and to their putative intracellular precursors have been examined. Radiolabeled intracellular C4 and Slp precursors were isolated from lysates of cultured peritoneal cells. The C4 and Slp precursors and their processed subunits were purified by immunoprecipitation and sodium dodecyl sulfate/polyacrylamide gel electrophoresis. Antigenically distinct precursors for C4 and Slp were demonstrated by sequential immunoprecipitation experiments in which anti-Slp-reactive molecules were precleared by exhaustive immunoprecipitation and residual C4 molecules were precipitated by antibody to serum substance. Both molecules had apparent molecular weights of 185,000. Their molecular identities as precursors of the mature C4 and Slp proteins were established in pulse-chase studies and by comparisons of their tryptic peptide profiles with those of isolated subunits from the processed proteins. When isolated alpha- or beta-subunits from C4 and Slp proteins were compared by peptide mapping, it was possible to detect multiple distinct and multiple shared peptides. This evidence indicates that the C4 and Slp proteins derive from distinct precursor polypeptides and suggests that the primary structures of the C4 and Slp alpha- and beta-subunits are different. These results support the postulate that the S region contains two discrete structural loci that specify discrete C4 and Slp proteins.

Animals↗