Biomedical subjects

J Holmgren

Publications and source records attributed to J Holmgren.

At least 145 records · Page 8Linked to original sources

PubMed1992

Coexpression of ganglioside antigen Fuc-GM1, neural-cell adhesion molecule, carcinoembryonic antigen, and carbohydrate tumor-associated antigen CA 50 in lung cancer.

With the aid of specific monoclonal antibodies, tumor tissues from 68 patients with lung cancer were examined for their expression of two small cell lung carcinoma (SCLC) antigens, Fuc-GM1 (fucosyl GM1; IV2FucII3NeuAc GgOse4) and neural-cell adhesion molecule (NCAM), and two broader tumor antigens, carcinoembryonic antigen (CEA) and carbohydrate cancer-associated antigen CA 50. Expression of Fuc-GM1 was seen in 75% and NCAM in 78% of the SCLC specimens, but also in 12 and 20% of non-SCLC. Either or both of these antigens were expressed in more than 90% of SCLC and in 25% of non-SCLC. CEA was found in more than 80% of SCLC and non-SCLC. Expression of CA 50 was seen in 65-68% of non-SCLC and SCLC, showing preference for SCLC and lung adenocarcinoma. In SCLC, cellular expression of Fuc-GM1 was generally seen together with NCAM and CA 50, but rarely with CEA. There was considerable inter- and intratumor heterogeneity in the expression of all four antigens. The results suggest that CEA is the antigen of choice for the detection of lung cancer regardless of histotype. In combined analysis of CEA, CA 50, Fuc-GM1 and NCAM, two patterns of antigen expression were recognized that appear to discriminate between SCLC and non-SCLC tumors, respectively. A considerable fraction of SCLC and non-SCLC tumors, however, exhibited similar patterns of antigen expression. The biological and clinical significance of these observations remains to be investigated.

Antibodies, Monoclonal↗

PubMed1992

[Duchenne and Becker muscular dystrophy in Chile].

Duchenne muscular dystrophy is one of the best known forms of muscular dystrophy. The incidence in different countries varies from 130 to 390 per million male live births. Becker variety may be considered a mild form of Duchenne dystrophy, with an incidence 10 times lower. A sex linked recessive inheritance is involved in both forms, the affected gene is placed at locus X21. The incidence of both forms in Chile is similar to that reported worldwide, and has been increasing since 1950. Increased CK and LDH levels are confirmed in patients, and overall, they are also higher in female carriers. However only 26% of carriers have increased CK levels and 21% increased LDH levels, compared to normal subjects. Electromyograms show myopathic characteristics in all carrier women. The scope of a prospective clinical, genetic and epidemiologic study currently underway is discussed.

Biomarkers↗

PubMed1992

Bacterial enteric infections and vaccine development.

There is a great need for effective vaccines against the major bacterial enteropathogens. Bacterial enteric infections resulting in diarrhea, dysentery, or enteric fever constitute a huge public health problem, with more than a billion episodes of disease and several million deaths annually in developing countries. Diarrhea caused by a bacterial enteric infection is also the commonest illness experienced by international travellers. Studies of pathogenesis have established the importance of specific ligand-receptor interactions between the enteropathogens and the intestinal epithelium, resulting in attachment and colonization of the bacteria and production of disease through either invasive mechanisms or production of toxins. Studies of protective immune mechanisms have emphasized the importance of secretory IgA antibodies and mucosal memory for protection against noninvasive, enterotoxigenic infections such as cholera and ETEC diarrhea and also drawn attention to the possible protective role of IFN-gamma production by intestinal T cells in these secretory diarrheas. In invasive dysenteric and enteric-fever infections caused by such organisms as Shigella and Salmonella, optimal protection may depend on a combination of mucosal and systemic immunity. On the basis of this knowledge, several new vaccines have been developed and proved to be efficacious in large field tests. These include an oral killed B-WC vaccine and a killed WC-alone vaccine against cholera, and both a live attenuated oral vaccine (Ty21a) and an injectable Vi antigen vaccine against typhoid fever. In addition, a killed oral ETEC vaccine and live attenuated oral Shigella vaccines have begun to be tested in phase 1 and phase 2 studies in humans. The properties of the new vaccines against bacterial enteric infections give promise that these vaccines should be useful both in control programs in developing countries and for immunoprophylaxis against travellers' diarrhea.

Bacteria↗

PubMed1991

Tumor-cell killing by MAbs against fucosyl GM1, a ganglioside antigen associated with small-cell lung carcinoma.

Monoclonal antibodies (MAbs) reactive with the ganglioside fucosyl GM1 (Fuc-GM1), an antigen associated with small-cell carcinoma of the lung (SCLC), were tested for their ability to mediate tumor-cell killing in vitro in conjunction with humoral and cellular effectors and to inhibit tumor engraftment in nude mice in vivo. MAbs F12 and F15, both IgG3k, induced human complement-mediated cytolysis of 3 Fuc-GM1-expressing tumor cell lines: one rat hepatoma cell line, H4-II-E, and 2 human SCLC cell lines, NC1 H69 and NC1 H128. F12 and F15 also induced ADCC of these cell lines in the presence of either murine or human effector cells. Addition of sub-cytolytic amounts of fresh human serum as complement source resulted in enhanced ADCC induced by MAb F12 (IgG3). Also a Fuc-GM1-reactive MAb of IgM isotype, F9, was able to induce such complement-aided ADCC (CADCC). F12 and F15 both proved to effectively inhibit engraftment of H4-II-E tumors in nude mice. A single dose of a modest amount (40 micrograms) of MAb conferred 65 to 100% protection against development of tumors. Our results demonstrate that Fuc-GM1 can act as a target antigen on tumor cells for specific immunotherapy in vitro and in a mouse model in vivo. Complement and murine and human mononuclear effector cells were effective mediators of tumor cytolysis in vitro in the presence of murine Fuc-GM1-reactive MAbs. Our results also suggest that humoral and cellular effectors may co-operate in specific tumoricidal reactions and that these may be induced by antibodies of both IgG and IgM isotypes.

Animals↗

PubMed1991

Immunizations of monkeys with synthetic peptides disclose conserved areas on gp120 of human immunodeficiency virus type 1 associated with cross-neutralizing antibodies and T-cell recognition.

Site-directed immunization was employed to identify sites on the envelope glycoprotein gp120 for antibody-mediated neutralization of human immunodeficiency virus type 1 (HIV-1). Antisera were raised in monkeys (Macaca fascicularis) against a series of 40 overlapping synthetic peptides covering the entire amino acid sequence of gp120 from the HTLV-IIIB strain of HIV-1. Immune sera against 12 of these peptides were reactive with gp120 by immunoblotting analysis, and antisera raised against 5 peptides, corresponding to amino acids (aa) 152-176, 193-218, 206-230, 248-269, and 307-330, were highly efficient in neutralizing HIV-1 (HTLV-IIIB) infectivity in vitro. Admixture of individual neutralizing anti-peptide monkey sera resulted in increment in neutralizing antibody titer. Antisera with reactivity to the relatively conserved regions defined by aa 152-176, 193-230, and 248-269 also neutralized to different extents the infectivity of the five Swedish clinical isolates of HIV-1 tested. Only a few HIV-1-infected people were found to make antibodies to these three conserved domains of gp120 as judged by ELISA using synthetic peptides as antigens. Three of the peptides (aa 152-176, 248-269, and 307-330) that induced neutralization antibodies also induced interleukin 2 production and lymphocyte proliferation when added to cultures of peripheral blood mononuclear cells from monkeys immunized with the corresponding peptides, indicating that these domains accommodate T-cell recognition sites. The results have obvious implications for the rational design of subunit vaccines against HIV-1 infection.

Acquired Immunodeficiency Syndrome↗

PubMed1991

A recombinant Escherichia coli heat-stable enterotoxin (STa) fusion protein eliciting anti-STa neutralizing antibodies.

A recombinant fusion protein consisting of native Escherichia coli heat-stable enterotoxin (STa) and a dimer of a synthetic IgG-binding fragment (ZZ), derived from Staphylococcus aureus protein A was produced in E. coli. The fusion protein (ZZSTa) was secreted in large quantities into the growth medium and recovered by affinity chromatography on IgG-Sepharose. Rabbits immunized with the fusion protein responded by producing high serum levels of anti-STa antibodies that also effectively neutralized STa toxicity in infant mice. The fusion peptide ZZSTa had a substantially decreased toxicity as compared with native STa. A polymeric form of ZZSTa separated by size fractionation was about 100 times less toxic than the monomeric fusion protein, yet both forms had the same capacity to induce neutralizing antibodies. This suggests that modified non-toxic forms of ZZSTa with retained immunogenicity may be produced and tested for their usefulness as functional components in a vaccine against diarrhoea caused by enterotoxigenic E. coli.

Antibodies, Bacterial↗

PubMed1991

Cholera toxin stimulates IL-1 production and enhances antigen presentation by macrophages in vitro.

Cholera toxin (CT) is a strong systemic and mucosal adjuvant that greatly enhances IgG and IgA immune responses. We investigated whether CT potentiates Ag presentation by macrophages as a possible mechanism underlying its adjuvant function. This was tested by preculturing APC in CT and analyzing the effect of CT treatment on the capacity to trigger 1) an allogeneic proliferative response of normal mesenteric lymph node T cells (H-2b) to the macrophage cell line P388D1 (H-2d) or 2) an Ag-specific proliferative response of D10.G4.1 clonal T cells in co-culture with normal macrophages and Ag. Pretreatment of APC, normal peritoneal macrophages or the P388D1 cells, with CT strongly enhanced Ag- and allogen-specific T cell proliferation. Also P388D1 APC treated with CT and then formalin-fixed demonstrated enhanced ability to stimulate T cell proliferation as compared to cells not exposed to CT, suggesting that the effect of CT on APC might be to enhance expression of a cell-associated factor. Flow microfluorimetry analysis of P388D1 cells cultured in CT-containing medium failed to detect an increase in class II MHC-Ag expression as compared to that found on cells not cultured in CT. In contrast, both soluble and cell-associated IL-1 formation was increased several-fold by CT, but with different CT dose requirements. A total of 10 to 100 times more CT were required for elevating the soluble IL-1 as compared to the cell associated IL-1, which was increased by as little as 1 ng/ml of CT. The soluble and cell-associated IL-1 activity induced by CT was abrogated by a polyclonal antiserum to IL-1-alpha. Similarly, the potentiating effect of CT on the ability of P388D1 APC to trigger alloreactive T cell proliferation was also blocked completely by the addition of the anti-IL-1-alpha antibody to the test system. This is the first study to demonstrate that CT potentiates Ag presentation. The mechanism for this effect probably involves induction of IL-1 production and in particular of a cell-associated form of IL-1 (IL-1-alpha). Potentiation of APC function might be important for the adjuvant action of CT on the immune response in vivo.

Animals↗

PubMed1991

Synthesis in Vibrio cholerae and secretion of hepatitis B virus antigens fused to Escherichia coli heat-labile enterotoxin subunit B.

A simple and effective electroporation method for the transformation of Vibrio cholerae with nonmobilizable plasmids is described. Expression plasmids directing the synthesis of fusion proteins with the subunit B of Escherichia coli heat-labile enterotoxin B (LT-B) were transformed into nontoxinogenic V. cholerae vaccine strains. A protein consisting of two overlapping immunodominant antibody-binding sites of the hepatitis B virus (HBV) middle surface antigen fused to the C terminus of full-length LT-B was secreted into the supernatant of V. cholerae cultures, whereas two other LT-B/HBV fusion proteins were mostly retained within the cells or rapidly degraded in the culture supernatant. While the secretion of fusion proteins with cholera toxin subunit B (CT-B) from V. cholerae has been described, this is to our knowledge the first report describing extracellular secretion of defined foreign epitopes fused to LT-B in V. cholerae. The fusion of guest epitopes to LT-B or CT-B and secretion in V. cholerae could be an interesting system to rapidly produce pure fusion proteins for immunisation, functional studies or diagnostic procedures. An LT-B/pre-S2 fusion protein purified from the supernatant of recombinant V. cholerae induced serum IgG antibodies against LT-B and against the HBV middle surface antigen in mice after parenteral and oral immunisation.

Animals↗

PubMed1991

CA 50 determination in body fluids: can we screen patients at risk for gastric cancer?

CA 50 (a tumor-associated gangliosidic antigen) levels have been determined by an RIA test in serum, gastric juice and urine of patients undergoing upper gastrointestinal tract endoscopy: 22 control subjects (no macroscopic or microscopic lesions), 29 patients with chronic atrophic gastritis, 20 with epithelial dysplasia and 16 with gastric cancer entered the study. Gastric juices were also tested for pH, protein concentration and specific gravity, urines for protein concentration and osmolarity. Serum and gastric juices were also tested for CEA levels and the results obtained with the two markers compared. In patients with gastric cancer, CA 50 gastric juice levels were statistically higher than in controls; a wide overlap was however present among groups, and sensitivity and specificity were respectively 38% and 85% for serum and 69% and 82% for gastric juice. Sensitivity and specificity were respectively 23% and 89% for CA 50 determination in urines. In this case, no statistically significant difference was observed between gastric cancer and control patients. A trend toward higher median values was observed in advanced with respect to early gastric cancer. A correlation was found between gastric juice and serum CA 50 levels, as well as between serum and urine levels of the marker. A correlation was also observed between CA 50 values and protein concentration in gastric juice and with osmolarity in urines. Overall, CA 50 levels were statistically higher in patients with intestinal metaplasia than in those who did not present the lesion. Increased CA 50 gastric juice levels are also observed in patients with chronic atrophic gastritis and epithelial dysplasia. CA 50 gastric juice and urine levels appear to be dependent, at least in part, on the concentration of the fluid.

Adult↗

PubMed1991

Identification of a mannose-binding pilus on Vibrio cholerae El Tor.

The mannose-sensitive hemagglutinin (MSHA) that is associated with Vibrio cholerae strains of El Tor biotype is identified as a pilus composed of subunits with a molecular mass of approximately 17 kDa. In immunoelectron microscopy, a monoclonal antibody against MSHA that inhibited El Tor vibrio-mediated mannose-sensitive agglutination of chicken erythrocytes or El Tor bacterial binding to mannose-coated agarose beads, bound specifically to repetitive subunits along typical fimbriae extending from the surface of El Tor vibrios. No such pili were seen on the surface of MSHA negative classical vibrios, although non-surface exposed fimbrial subunits could be demonstrated in these bacteria by immunoblotting techniques.

Antibodies, Monoclonal↗

PubMed1991

Epitope differences in toxin-coregulated pili produced by classical and El Tor Vibrio cholerae O1.

A toxin-coregulated pilus (TCP), that is important for intestinal colonization of Vibrio cholerae O1, may be produced by vibrios of both classical and EI Tor biotypes. By comparing TCP produced by various strains of the two biotypes in immunoblotting and enzyme-linked immunosorbent assays (ELISA) using monoclonal antibodies (mAbs) and polyclonal antisera against TCP from classical vibrios, we have found biotype-related epitope differences in TCP. Our results indicate that TCP of classical strains has an epitope in the TcpA-subunit (20.5 kDa) that is missing in EI Tor TcpA, and an additional epitope that is more strongly expressed in classical TcpA. A polyclonal antiserum reacted strongly with TcpA from strains of both biotypes in immunoblotting suggesting both the presence of major shared TcpA epitopes and that the low or absent reactivity of EI Tor TcpA with the mAbs was not due to lower production of TcpA by EI Tor strains. Whereas all the TcpA-positive classical strains inhibited the binding of polyclonal antiserum and mAbs to solid phase-bound TCP-positive bacteria in an inhibition ELISA, practically no inhibition was observed with TcpA-positive EI Tor strains. This together with findings in immunoelectron microscopy studies that TCP 'bundles' were only detected on classical strains, suggest that TCP is poorly expressed on EI Tor vibrios.

Blotting, Western↗

PubMed1991

Swedish Agency for Research Cooperation with Developing Countries. Prospects for public health benefits in developing countries from new vaccines against enteric infections.

The symposium participants concluded that vaccines with even moderate efficacy can be highly useful to prevent large numbers of severe illness episodes and deaths and that the decision of whether to initiate a vaccine program should be based on measures or estimates of public health effectiveness rather than only on protective efficacy. Studies of protective efficacy are of course critical to establish the vaccine's biologic activity, but additional aspects of public health effectiveness are also crucial in making these decisions. First-generation vaccines are available against typhoid, cholera, and soon rotavirus diarrhea, and vaccines against enterotoxigenic E. coli diarrhea and shigellosis are under development. The problems related to enteric diseases are enormous; the vaccines may soon be produced at low cost and promise to be relatively more easy to distribute than most previous vaccines. The number of illnesses and deaths averted from vaccine programs are potentially great. Pilot programs using the new vaccines should urgently be considered in areas where the disease burden is high, and steps should be taken to monitor effectiveness of the intervention in these programs. Such studies of vaccine effectiveness and costs in a "real world" situation are an essential step of the research process and should be used to guide the organization of larger-scale programs. Finally, many of the necessary research and development activities relevant to public health vaccinology must address country-specific problems. Developing countries should consider the role of vaccine-related research among the priorities for their essential national health research and build the necessary capabilities in applied and basic medical sciences and in the social sciences.(ABSTRACT TRUNCATED AT 250 WORDS)

Cost-Benefit Analysis↗

PubMed1991

Mucosal immunity and vaccination.

The gut mucosal immune system is a critical component of the body's defense against pathogenic organisms, especially those responsible for enteric infections associated with diarrhoeal disease. Attempts to vaccinate against infections of mucosal tissues have been less successful than vaccination against systemic infections, to a large extent reflecting a still incomplete knowledge about the most efficient means for inducing protective local immune responses at these sites. Secretory IgA (SIgA) is the predominating immunoglobulin along mucosal surfaces, and SIgA antibodies generated in gastrointestinal, respiratory or genito-urinary mucosal tissues can confer protection against infections affecting or originating in these sites. An efficacious intestinal SIgA immunity-inducing oral vaccine against cholera has been developed recently, and development of oral vaccines against other enteric infections such as those caused by enterotoxigenic Escherichia coli, Shigella and rotaviruses is in progress as well. Based on the concept of a common mucosal immune system through which activated lymphocytes from the gut can disseminate immunity to other mucosal and glandular tissues, there is currently also much interest in the possibility of developing oral vaccines against infections in the respiratory and urogenital tracts. However, the large and repeated antigen doses often required to achieve a protective immune response still makes this vaccination approach impractical for many purified antigens. There is, therefore, a great need to develop strategies for enhancing delivery of antigen to the mucosal immune system as well as to identify mucosa-active immunostimulating agents (adjuvants). These and other aspects of mucosal immunity in relation to immunization and vaccine development are discussed in this short review article.

Adjuvants, Immunologic↗

PubMed1991

Immunohistochemical detection of two small cell lung carcinoma-associated antigens defined by MAbs F12 and 123C3 in bronchoscopy biopsy tissues.

We have studied MAbs* for their ability to detect SCLC and differentiate this tumor type from the other lung tumor histotypes in cryostat sections of biopsy specimens taken at bronchoscopy from patients with suspected primary lung tumor disease. MAb F12, specific for the ganglioside fucosyl-GM1, reacted with 58% of the cases with SCLC (n = 19) and with less than 3% of those with non-SCLC (n = 38). MAb 123C3, specifically reactive with NCAM, reacted with 78% of the SCLC cases (n = 23). With this MAb no positive staining was seen in the non-SCLC cases (n = 41). None of the two MAbs reacted with tissue sections without tumor. In combined analysis with MAbs F12 and 123C3, all SCLC cases (n = 15) were positive with either and 47% with both of the MAbs. Our results show that both MAbs F12 and 123C3 are highly specific for SCLC in bronchoscopic biopsy tissue specimens, whereas the sensitivity for this histotype tends to be higher with MAb 123C3 than with F12 (P = 0.14). When used in combination, all SCLC cases could be identified. These MAbs may therefore be valuable as complements to current histopathologic characterization and differentiation of lung cancer.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed1991

Antibody-producing cells in peripheral blood and salivary glands after oral cholera vaccination of humans.

We examined whether immunization with a newly developed oral cholera vaccine would elicit gut-derived antibody-producing cells in the blood and in distant mucosal tissues, such as the minor salivary glands, in 30 adult Swedish volunteers. The results of this study demonstrated that this vaccine indeed induced production of specific antibody-producing cells against the cholera toxin B subunit in both peripheral blood and salivary glands. The response in blood, which after primary and booster immunizations comprised both immunoglobulin A (IgA) and IgG antibody-forming cells, was highly transient and preceded the response in salivary glands; the latter response was restricted to the IgA isotype. The results provide further evidence of the existence of a common mucosal immune system in humans. Furthermore, these findings support previous observations that in animals, the cholera toxin B subunit may be a useful carrier protein for preparing enteric vaccines against pathogens encountered at intestinal and extraintestinal mucosal sites.

Administration, Oral↗

PubMed1991

Intestinal immune responses in humans. Oral cholera vaccination induces strong intestinal antibody responses and interferon-gamma production and evokes local immunological memory.

We have examined secretory antibody and cell-mediated immune responses to oral cholera vaccine in the human gastrointestinal mucosa. Freshly isolated peripheral blood lymphocytes and intestinal lymphocytes obtained by enzymatic dispersion of duodenal biopsies were assayed for numbers of total and vaccine specific immunoglobulin-secreting cells by enzyme-linked immunospot assay (ELISPOT) techniques; the frequency of cells secreting interferon-gamma (IFN-gamma) was also examined by a new modification of the ELISPOT technique. After booster immunizations with oral cholera vaccine, large numbers of cholera toxin-specific antibody-secreting cells (ASC) appeared in the small intestine. The responses were dominated by IgA ASC. A single immunization, performed 5 mo after the initial vaccinations, gave rise to an ASC response similar to that seen after the first booster immunization, with respect to both magnitude and isotype distribution. Each of the immunizations also evoked an ASC response in blood which was of lower magnitude than that seen in the small intestine, and comprised similar proportions of IgA and IgG ASC. A booster immunization also resulted in increased frequencies of IFN-gamma-secreting cells, but this increase was confined to the duodenal mucosa. This study establishes the feasibility of studying, at the single-cell level, intestinal immune reactivity in humans. Furthermore, it indicates that the small intestinal mucosa is an enriched source of IFN-gamma. It also demonstrates marked differences between intestinal and peripheral blood immune responses after enteric immunization, and confirms the notion that the mucosal immune system in humans displays immunological memory.

Administration, Oral↗

PubMed1991

[Ceruloplasmin in patients with Duchenne muscular dystrophy].

Duchenne muscular dystrophy is a well defined form of sex linked inherited muscular disease. Approximately 1/3 of cases are the product of a new mutation. We studied 20 patients with this disease and 19 heterozygous females. Ceruloplasmin levels were significantly higher in patients compared to controls. A possible protective role of this enzyme against oxydating agents may help prevent peroxydation of lipids from the smooth muscle cell membrane.

Adult↗

PubMed1990

The binding of colonization factor antigens of enterotoxigenic Escherichia coli to intestinal cell membrane proteins.

We examined the binding of colonization factor antigens (CFAs) of enterotoxigenic Escherichia coli to electrophoretically separated membrane components of rabbit intestinal brush borders or human intestinal (and non-intestinal) cell lines using an immunoblotting technique. Both CFA/I and CFA/II bound to distinct membrane components which seemed to be identical in rabbit brush borders and in a human intestinal cell line; these binding structures were mainly missing in membranes from epithelial cell lines of non-intestinal origin. Both shared and specific binding components were identified for CFA/I and the different subcomponents of CFA/II (CS1, CS2 and CS3), respectively. Chloroform-methanol extraction of lipids from the cell membranes did not change the binding pattern for either CFA/I or CFA/II suggesting that the binding occurred to (glyco)proteins rather than to (glyco)lipids.

Animals↗