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Biomedical subjects

E C Franklin

Publications and source records attributed to E C Franklin.

At least 37 records · Page 2Linked to original sources
PubMed1981

Demonstration of membrane-bound proteolytic activity on the surface of mononuclear leukocytes.

The existence of proteolytic enzymes bound to the surface of migrating cells has often been surmised. That such enzymes are present on mononuclear leukocytes was suggested by studies showing that serum amyloid A (SAA), the presumed precursor of amyloid protein A, is degraded in the presence of monocytes without endocytosis and with only negligible activity in the cells' supernates. Experiments using immunofluorescence were designed to support this view. It was shown that SAA binds to the cells' surface at low temperatures, whereas binding at 37 degrees C could only be demonstrated when the cells were pretreated with the serine protease inhibitor, diisopropyl-fluorophosphate (DFP) or the elastase inhibitor Ac-Ala-Ala-Pro-Val-CH2Cl. Exposure of the cells to these inhibitors before incubation with SAA at 0 degrees C permitted detection of the protein for an indefinite period of time. At 37 degrees C the DFP-treated cells polarized and eventually lost the surface-bound protein. No interiorized SAA could be demonstrated. Radioautography of cells that had been treated with 3H-DFP revealed grains on the plasma membrane and in the cytoplasm of sectioned monocytes, whereas only 8-15% of lymphocytes were labeled. In lymphocytes radioactivity was restricted to the surface membrane. Additional experiments showed that alpha-naphthyl acetate esterase activity is also located on the surface of monocytes and a subpopulation of lymphocytes. These observations have led to the conclusion that some functions of mononuclear leukocytes may be mediated by enzymes associated with the external surface of these cells.

Autoradiography↗
PubMed1981

Factors affecting the release of proteases from peripheral blood monocytes.

Serum amyloid A (SAA) protein is degraded by serine proteases associated with the external plasma membrane of peripheral blood monocytes. The plasma membrane-associated enzymes are serine proteases of high molecular weight. In addition, cells grown in suspension release enzymatic activity into the surrounding medium. The origin and nature of the released SAA degrading enzymes remains obscure, but they appear to belong to the general class of serine proteases. Conditions of culture were determined which minimized release of the secreted enzymes and will ultimately permit the characterization of the properties of the membrane associated enzymes uncontaminated with the cytoplasmic proteases. It seems likely that there are two compartments of proteases-one surface-associated and one cytoplasmic.

B-Lymphocytes↗
PubMed1980

Human monoclonal macroglobulins with specificity for Klebsiella K polysaccharides that contain 3,4-pyruvylated-D-galactose and 4,6-pyruvylated-D-galactose.

Two human IgM myeloma proteins, IgMWEA and IgMMAY, were found to react with agar and Klebsiella polysaccharides that contain pyruvylated D-galactose (DGal). Quantitative precipitin data and precipitin inhibition studies with methyl alpha- and beta-glycosides of 4,6-pyruvylated-D-galactose showed their combining sites to be different, although each was directed against the pyruvylated-D-Gal, one reacting most specifically with Klebsiella polysaccharides with terminal nonreducing beta-linked 2,4 pyruvylated-D-Gal, whereas the other reacted equally well with Klebsiella polysaccharides that contain 3,4 beta-linked and 4,6 alpha-linked terminal nonreducing pyruvylated-DGal. Inhibition studies showed that both sites are directed toward one of the two space isomers of 3,4- or 4,6-pyruvylated DGal, the form in which the methyl group of the pyruvate is equatorial, or endo, and its carboxyl group axial, or exo, to the plane of the acetal ring. Coprecipitation studies showed the combining site of IgMWEA to be located on an (Fab')2 fragment and not on the (Fc)5mu fragment. The monoclonal peak in the serum of IgMMAY was specifically precipitated by Klebsiella polysaccharide. Myeloma proteins with specificities of this type may occur with reasonable frequency in humans and may be a consequence of clonal expansion from inapparent infection, carrier states, or disease produced by various Klebsiella organisms.

Adult↗
PubMed1980

Primary structure of human gamma 3 immunoglobulin deletion mutant: gamma 3 heavy-chain disease protein Wis.

The complete sequence of a gamma 3 heavy-chain disease (HCD) protein Wis is presented. The molecule is a dimer of a 289-residue chain linked by 12 disulfide bonds. Protein Wis has an unusual amino terminus, followed by a deletion of most of the VH domain. After a small stretch homologous to the VC joining region, there is a second deletion which ends at the beginning of the quadruplicated hinge. Two carbohydrate groups are linked to Asn-6 and -140. the molecule has an extra interchain disulfide bridge at position 7 in addition to the 11 normally present in the quadruplicated hinge. The previously noted homology to the gamma 1 heavy chain is striking; from positions 224 to 234, protein Wis resembles gamma 1 Nei [Ponstingl, H., & Hilschmann, N. (1976) Hoppe-Seyler's Z. Physiol. Chem. 357, 1571--1604] except for a serine which replaces Asn at position 227. The results, taken together with studies of other immunoglobulin heavy-chain deletion mutants, support the suggestion that the different domains and interdomain regions of human H chains are coded for by different gene segments and that the deleted proteins reflect alterations in the recombination of different genes and/or the splicing of heterogeneous nuclear messenger ribonucleic acid (hn mRNA).

Amino Acid Sequence↗
PubMed1980

AA protein in a case of "primary" or "idiopathic" amyloidosis.

Amyloidosis constitutes a group of diseases in which extracellular fibrils with a characteristic appearance are deposited in a variety of tissues. Several different proteins have been identified as the major subunits of the fibrils. In the primary and myeloma-associated type, the amyloid fibrils consist of immunoglobulin light chain fragments, whereas in the secondary type and the amyloid associated with familial Mediterranean fever the major component is the AA protein. In this report a 21 year old man of Yemenite extraction with no underlying disease and no family history of amyloidosis was found to have amyloid deposits composed of AA protein. Although clinically this might be classified as primary amyloidosis, the absence of light chain fragments makes that diagnosis unlikely. Therefore, it is suggested that whenever possible the clinical classification be supplemented by a description of the biochemical nature of the fibrils.

Adult↗
PubMed1980

Mixed cryoglobulinemia: clinical aspects and long-term follow-up of 40 patients.

The clinical course of 40 patients with significant quantities of mixed cryoglobulins, but without lymphoproliferative, collagen-vascular or chronic infectious diseases, is presented. These cases comprise 51.3 percent of all mixed and 31.7 percent of all types of cryoglobulins evaluated by us over the period 1960--1978. A characteristic clinical syndrome, consisting of recurrent palpable purpura (100 percent), polyarthralgias (72.5 percent) and renal disease (55 percent), was seen. Biopsy specimens of skin lesions showed cutaneous vasculitis, and half had immune reactants in vessel walls. Seventy percent of patients had evidence of hepatic dysfunction, often subclinical, and more than 60 percent of those tested had serologic evidence of prior infection with hepatitis B virus. Hepatic lesions ranged from minimal triaditis to chronic active hepatitis and/or cirrhosis. All 22 patients in whom clinical renal disease developed had significant proteinuria; 63.6 percent had diastolic hypertension, 77.3 percent edema, 45.5 percent renal failure and 22.7 percent were nephrotic. Glomerular disease associated with deposition of immunoglobulin G, immunoglobulin M and complement, often with coexistent renal arteritis, was confirmed pathologically in 15 cases. All cryoglobulins had rheumatoid factor activity and consisted of IgM and polyclonal IgG; five also contained IgA. Thirteen had a monoclonal IgM kappa component. Serum protein electrophoresis was unremarkable or showed diffuse hyperglobulinemia. Striking depression of early complement components was noted but did not correlate well with the cryoprotein concentration, renal involvement or clinical course. Follow-up for periods up to 21 years from onset of symptoms revealed that renal involvement has a deleterious effect on prognosis. Postmorten examinations of nine patients demonstrated widespread vasculitis in addition to renal involvement. Preterminal infection was found in eight.

Cryoglobulins↗
PubMed1980

The role of cryoglobulins and immune complexes in vasculitis.

Immune complexes play a major role in a variety of diseases such as lupus and rheumatoid arthritis. Cryoglobulins, especially those of the mixed type, represent a type of immune complex that is particularly easy to isolate, and hence lend themselves readily to the identification of the responsible precipitating agents. This report presents the clinical, laboratory, and pathologic features of 40 patients with mixed cryoglobulinemia and offers some speculation based on currently available evidence on the role of cryoglobulins in pathogenesis.

Antigen-Antibody Complex↗
PubMed1980

Immunopathology of the amyloid diseases.

The relentless accumulation of nonimmunogenic fibrils that resist phagocytosis, proteolysis, and other normal host defense mechanisms leads to death when amyloidosis involves vital organs. Effective treatment for most of the amyloidoses lies in the future, but recent findings have enabled a classification of these diseases and are beginning to shed some light on possible pathogenetic mechanisms.

Amyloid↗
PubMed1980

A gamma l heavy-chain disease protein *EST) lacking the entire VH and CHl domains.

A gamma l heavy-chain disease protein (EST) is described which lacks the entire VH and CHl domains and starts with the normal sequence of gamma l H-chains corresponding to the beginning of the hinger region (position 216). Although degradation cannot be excluded with certainty, it is probable that this protein is synthesized as an internally deleted gamma heavy-chain disease protein. Presumably a DNA recombination has occurred resulting in the deletion of the genes of coding for the VH and CHl domains with splicing of the precursor RNA to the sequence coding for the hinge region.

Amino Acid Sequence↗
PubMed1980

Antiidiotypic activity in the IgM fractions of mixed cryoglobulins.

To search for human antiidiotypic antibodies, cryoglobulins from 11 patients with mixed cryoglobulinemia, 7 of whom had evidence of prior hepatitis B virus infection were separated on Sephadex G-200. Each of the IgM, 8 of which were IgM kappa, was tested with the F(ab')2 fragments prepared from each of the IgG fractions in a solid phase assay by using binding of 125I Staph A protein after the addition of rabbit anti-IgM. Unlike rabbit anti-Fab, which reacted approximately to the same extent with all F(ab')2 fragments, the IgM varied in their binding to F(ab')2 fragments, reacting with 2 to 10 antigens. Nine reacted with their autologous antigen and in 5 instances autologous reactivity exceeded that with heterologous F(ab')2 fragments. Reactivity was not related to prior exposure to HBV. Though absorption with Cohn fraction II F(ab')2 fragments generally abolished reactivity, 1 IgM protein continued to react with nine F(ab')2 fragments and 4 others with the F(ab')2 fragment from a single patient. Even when they contained only a single type of kappa-chain, the IgM appeared to contain multiple antibodies since absorption with solid phase Fc fragments or IgG removed anti-Fc rheumatoid factor activity but failed to affect binding to F(ab')2 fragments. Five of 7 IgM were able to bind the Fv region of a monoclonal IgM kappa-protein. Some of the anti-Fab antibodies were directed against idiotypes since addition of HbsAg to F(ab')2 fragments from HBsAb-positive IgG resulted in a marked decrease in binding of the IgM fraction in 6 out of 7 studies, whereas no decrease was noted in 6 experiments with F(ab')2 fragments that were HBsAb negative. The possible existence of antibodies against other idiotypes or other determinants in the Fab region cannot be excluded.

Absorption↗
PubMed1980

Elastase-type proteases on the surface of human blood monocytes: possible role in amyloid formation.

A group of DFP-inhibitable serine proteases that are associated with the cell surface of human peripheral blood monocytes and degrade the amyloid precursor protein SAA has been partially characterized. Enzymes that resemble elastases in being inhibitable by Ac-Ala-Ala-Pro-Val-CH2Cl but differ from the secreted macrophage elastase in m.w. can be recovered from SDS gels in the region ranging from 58 to 72 x 10(3) daltons. These enzymes degrade SAA to a product similar in m.w. and antigenic properties to the amyloid A protein. When intact cells are labeled with 3H Ac-Ala-Ala-Pro-Val-CH2Cl at 4 degrees C for 3 min, a major 58 x 10(3) and two minor 48 and 65 x 10(3) dalton bands are seen. Another group of enzymes that digests SAA completely through a transient AA-like intermediate can be recovered from the 40 to 58 x 10(3) dalton region of the gels. These enzymes are only minimally inhibited by Ac-Ala-Ala-Pro-Val-CH2Cl. We suggest that both types of enzymes may be involved in the proteolytic processes that lead to amyloid formation in secondary amyloidosis.

Amyloid↗
PubMed1979

Correlation between fragmented immunoglobulin genes and heavy chain deletion mutants.

It is generally accepted that the variable (V) and constant (C) regions of immunoglobulin (Ig) chains are under separate genetic control. The notion that the different domains and interdomain regions are also under the control of independent genetic units was initially based on the clearcut results obtained by studying the primary structure of deletion mutants and received definitive support from direct analysis of cloned heavy (H) and light (L) chain genes. Here we present additional studies carried out on two selected gamma 3 deletion mutants which indicate the genetic control of human H chains may be even more complex than previously believed.

Base Sequence↗