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Biomedical subjects

P Perlmann

Publications and source records attributed to P Perlmann.

At least 163 records · Page 9Linked to original sources
PubMed1985

Production of IL 2 and IFN-gamma by T cells from malaria patients in response to Plasmodium falciparum or erythrocyte antigens in vitro.

T cells from patients acutely infected with malaria exhibit a disease-related stimulation of DNA synthesis in response to Plasmodium falciparum antigen in vitro. This response is weak and short-lived, suggestive of induction of suppressor mechanisms. Exogenous T cell growth factor (IL 2) that was added to antigen-stimulated T cell cultures enhanced proliferation in antigen-responsive cultures, indicating that the lymphocytes expressed IL 2 receptors. In contrast, the addition of IL 2 to cultures that did not respond to antigen had no effect. Antigen-responsive cultures contained endogenous IL 2 as well, and the antigen-induced lymphocyte proliferation was correlated with IL 2 production. However, the results suggested that IL 2 production by the patients' T cells was insufficient or actively shut off, and that this was responsible for the premature cessation of their DNA synthesis. Supernatants from 60% of the T cell cultures treated with malaria antigen and from 30% treated with RBC ghost antigen contained interferon-gamma (IFN-gamma), as determined by a cytopathic effect inhibition assay combined with acid treatment and antibody neutralization or by an IFN-gamma-specific ELISA. There was no obvious correlation between antigen-induced lymphocyte proliferation and the presence of IFN-gamma in the culture supernatants. A high IFN-gamma activity was also seen in antigen-treated cultures from P. falciparum-immune donors living in highly endemic malaria areas. In contrast, no IFN-gamma was found in supernatants of antigen-treated T cells from healthy donors or patients with Plasmodium vivax malaria. Thus, the IFN-gamma activity of these cultures appears to reflect the presence of antigen-reactive T cells and may be useful as a sensitive indicator of cellular immunity in P. falciparum malaria.

ABO Blood-Group System↗
PubMed1984

Virus-mediated induction in human lymphocytes of antibody-independent cytotoxicity (VDCC) and enhancement of antibody-dependent cytotoxicity (ADCC) against natural killer-resistant tumor target cells.

The effect of Parotis virus on the in vitro cytotoxicity of human lymphocytes against NK-resistant mouse mastocytoma cells was studied. In the 51Cr-release assay, treatment of lymphocytes with virus induced a rapid cytotoxicity in the absence of anti-P815 antibody (virus-dependent cellular cytotoxicity, VDCC) and strongly enhanced antibody-dependent cytotoxicity (ADCC). At the effector cell level, virus treatment was found to increase the frequency of target-binding cells (TBC) as well as the proportion thereof mediating VDCC and/or ADCC, indicating recruitment of active effector cells. The recruited cells were heterogeneous but contained a major fraction bearing the T-cell-associated antigen T3. Virus was found to decrease rather than to increase the recycling capacity of the cytotoxic lymphocytes, suggesting that VDCC induction and ADCC enhancement were due to a virus-mediated improvement of effector cell-target cell interactions. VDCC and ADCC enhancement may be of protective importance in early phases of virus infection as well as for the production of nonspecific tissue injuries associated with viral disease.

Animals↗
PubMed1984

Antibodies in malarial sera to parasite antigens in the membrane of erythrocytes infected with early asexual stages of Plasmodium falciparum.

Monolayers of human erythrocytes (E) infected with Plasmodium falciparum were briefly fixed with 1% glutaraldehyde and air dried. They were then exposed to sera from patients with P. falciparum malaria or from donors immune to this parasite and tested in an indirect immunofluorescence assay (IFA). Parasites in infected E were made visible by counterstaining with ethidium bromide. Immunofluorescence (IF) was restricted to the surface of infected E. No antibody binding was detected unless the E were dried, suggesting that the relevant antigens were not available on the outer layers of the E surface. Staining over large parts of the E surface was seen already when the merozoite penetrated noninfected cells and was strong in E containing early stages of the parasite (rings, trophozoites). It was weak or absent from E containing schizonts. Antibodies in sera from different parts of Africa, Colombia, or Sweden reacted similarly with E infected with a Tanzanian P. falciparum strain kept in culture for many years and with parasitized E freshly drawn from African, Swedish, or Colombian patients. All sera from residents of a holoendemic area (Liberia) were IFA positive. In contrast, some sera from Colombian or Swedish patients with primary infection gave negative results. The results of the IFA and of an enzyme-linked immunosorbent assay in which fixed and dried E were the targets were well-correlated, suggesting that the same antibodies were detected by these assays. The antigens involved in the IFA were susceptible to pronase but not to trypsin or neuraminidase. E surface IF was inhibited by lysates of infected E, merozoite extracts, or soluble antigens present in P. falciparum culture supernatants but not by lysates of normal E or ghost extracts. The inhibitory antigens were heat stable (100 degrees C, 5 min). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by immunoblotting of either antigen-enriched preparations from culture supernatants or merozoite extracts showed that antibodies eluted from monolayers of infected E reacted consistently with a predominant polypeptide of Mr 155,000 and two to four minor polypeptides of lower molecular weights. Metabolic labeling of the parasites with 75Se-methionine indicated that these antigens were parasite derived. We conclude that the antigens involved in these reactions are released from bursting schizonts or merozoites and are deposited in the E membrane in the course of invasion.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies↗
PubMed1984

Immunochemical characterization of charge isomers of bacteria-derived human growth hormone with monoclonal antibodies.

Monoclonal antibodies were used to study the immunochemical nature of charge isomers of bacterially produced methionyl human growth hormone. After isoelectric focusing of the hormone the 12 monoclonal antibodies reacted similarly in immunoblotting experiments and none of them could discriminate between the two isolated charge isomers in ELISA. This indicates that the generation of charge isomers of met-hGH does not result in loss of the determinants recognized by the monoclonal antibodies and that the conformation of the two main charge isomers is identical within these determinants.

Antibodies, Monoclonal↗
PubMed1984

Helper function of human T cells with different affinity for Helix pomatia A hemagglutinin in a tetanus toxoid-induced B cell differentiation system.

T cells from human peripheral blood were enriched in T4+ cells by lysis of T8+ cells with the monoclonal antibody OKT8 plus complement. The T4+ subset was separated into 4 fractions differing in avidity for the lectin Helix pomatia A hemagglutinin (HP). The fractions were studied for their capacity to help autologous B cells to differentiate and mature into immunoglobulin (Ig) synthesis and secretion after activation with tetanus toxoid (TT) in vitro. To ensure the antigen specificity of induction, very low doses of TT (1-100 ng/ml) were used for activation of the lymphocytes, all obtained from previously sensitized donors. The T4+ cells with low avidity for HP (fractions HP-I and HP-II) exerted little help for B cell differentiation. Removal of these cells enhanced the helper function of the remaining T4+ cells, indicating that fractions HP-I and HP-II contained suppressor cells. In contrast, efficient B cell help was provided by T4+ cells with high avidity for HP (fractions HP-III and HP-IV). However, these fractions differed in the quality of help provided. Thus, while HP-III cells induced IgG secretion, HP-IV cells mainly induced IgM secretion. Moreover, while the Ig secreted after help from HP-III cells was TT-specific antibody, the Ig secreted by B cells in the presence of autologous HP-IV cells was polyclonal, probably reflecting induction of B cells differing in their responsiveness to signals provided by different types of T cells. The results indicate that T4+ cells vary in their stage of differentiation as seen by differences in expression of the HP marker and that differences in HP-marker expression appear to be associated with differences in cellular functions.

Antibodies, Monoclonal↗
PubMed1984

Inhibition of proliferative and cytotoxic activities of human T lymphocytes with rabbit antibodies directed against leucoagglutinin-reactive T cell surface components.

Three rabbit antisera (870, 872 and 873) were raised against leucoagglutinin-reactive components from the surface of human T cells. The antibodies reacted with two major glycoproteins of 175 kDa and 105 kDa. None of the antibodies triggered peripheral blood lymphocytes or T cells to proliferation when tested under different culture conditions. All antibodies inhibited the proliferative response to concanavalin A or to allogeneic lymphocytes in mixed lymphocyte culture when whole IgG fractions were used. Complete inhibition of cytotoxic activity was obtained in cell-mediated lympholysis and in natural killer cell cytotoxicity (NK) when fresh peripheral blood lymphocytes were used as effector cells. Weak inhibition was also obtained in NK when mixed lymphocyte culture-activated effector cells were used. The inhibition was stronger, when NK activity was determined against MOLT4 target cells as compared to K562. Whereas F(ab')2 fragments of 873 IgG inhibited cytotoxic T lymphocyte activity completely, Fab fragments of 873 IgG neither inhibited proliferation nor cytotoxic T lymphocyte activity, but gave some inhibition of NK against MOLT4 targets. The results indicate that antibodies against these leucoagglutinin-reactive structures reacted with polypeptides similar to or identical with the human "leukocyte function-associated antigen-1" (LFA-1) considered to be an important mediator of cell-cell interactions and nonspecific adherence.

Agglutinins↗
PubMed1984

Monoclonal antibodies to antigens associated with transitional cell carcinoma of the human urinary bladder. I. Determination of the selectivity of six antibodies by cell ELISA and immunofluorescence.

Spleen cells from BALB/c mice immunized with cells derived from transitional cell carcinomas (TCC) of the human urinary bladder were fused with mouse myeloma Sp 2/0 Ag14 cells. Monoclonal antibodies from six established hybridomas were investigated for specificity in a cell ELISA and in indirect immunofluorescence against a large panel of fixed intact cells. Three of the antibodies reacted with half or more of the eight bladder tumors and with a few unrelated tumors. They did not react at all with malignant or normal cells of hematopoietic origin. A fourth antibody reacted with seven of eight bladder tumors. It also reacted weakly with a prostatic carcinoma, with five of six malignant or transformed B cell lines, and with a subpopulation of normal lymphocytes, but not with any of the other cells on the test panel. These four antibodies did not react with cells derived from normal urothelium. The results suggest that these antibodies might recognize cell-type-restricted antigens associated with malignancy. Another antibody reacted with almost all urothelium-derived cells. It also reacted with three of three melanomas but not with any other cells on the panel. The sixth antibody reacted with 32 of the 37 cells tested. The spectrum of reactivities displayed by the antibody suggested that it recognizes HLA antigens.

Antibodies, Monoclonal↗
PubMed1984

Monoclonal antibodies to antigens associated with transitional cell carcinoma of the human urinary bladder. II. Identification of the cellular target structures by immunoprecipitation and SDS-PAGE analysis.

The cellular target structures for six monoclonal antibodies raised against cultured human bladder carcinoma cells (TCC) were investigated. The specificities of these antibodies when tested against a large panel of cells have been described in the companion paper. Radiolabeled cell lysates were precipitated with the different monoclonal antibodies bound to protein A (Staphylococcus aureus) on a matrix of Sepharose beads. The precipitates were separated by sodium dodecyl sulfate- gel electrophoresis (SDS-PAGE) and analyzed by autoradiography. The antibodies 4B5, 7E9, and 14B11 have previously been found to react in a similar way with TCC-targets and some non-TCC tumor cells, but not with normal urothelial cells or cells of hematopoietic origin. When tested with lysates of a TCC-cell line (TCCSuP) a strong 92K band and a weak 23K band were precipitated with any one of these antibodies. These polypeptides were expressed on the cell surface and were not linked by disulfide bonds. Depletion experiments confirmed that the three antibodies recognized the same antigens. Another antibody (4E8) probably directed to a differentiation antigen present on both urothelial and melanoma cells detected two high molecular polypeptides, 190K and 170K. Antibodies from the S2C6 hybridoma, which displayed a distinct dual specificity for TCC- targets and for malignant or transformed cells of B cell origin, precipitated a 50K component from extracts of either TCC- or B cell-derived cell lines. Antibodies produced by the S2A9 hybridoma were shown to bind to a framework epitope of the HLA-A, B, C heavy chain.

Antibodies, Monoclonal↗
PubMed1984

Immunoelectrophoretic analysis of erythrocytic stages of Plasmodium yoelii and P. chabaudi.

Triton X-100 extracts of erythrocytes infected with Plasmodium chabaudi and P. yoelii were analysed in crossed immunoelectrophoresis with rabbit antisera. The parasite origin of the antigens detected was assessed by metabolic radiolabelling of the parasites with 35S-methionine. About 12 immunoprecipitates were obtained with both extracts and their homologous antiserum. Cross-tests showed that the two parasite strains were very similar antigenically. Species-specific antigens could, however, also be demonstrated. Two antigens, present on both P. yoelii- and P. chabaudi-infected erythrocytes, were located on the surface of the host cell membrane as judged from 125I-labellings with lactoperoxidase. Experiments with phenyl-Sepharose showed that most of the antigens detected were hydrophilic and none of them reacted with concanavalin A.

Animals↗
PubMed1984

Monoclonal antibodies recognize conformational alterations leading to decreased bioactivity of human growth hormone.

By means of monoclonal antibodies to five different antigenic determinants on human growth hormone (hGH) and polyclonal antisera from mice and rabbits, the immunoactivity of native hGH was compared with that of reduced and S-carboxymethylated hGH, which has an unstable conformation. Native and reduced and S-carboxymethylated hGH were also tested in a radioreceptor assay which reflects the bioactivity of the hormone. The IM-9 cell line was used as a receptor source in this assay. All five monoclonal antibodies were superior in discriminating between the native active form of hGH and its reduced and S-carboxymethylated form, which has a markedly reduced receptor binding activity.

Animals↗
PubMed1984

Human antibodies to a Mr 155,000 Plasmodium falciparum antigen efficiently inhibit merozoite invasion.

IgG from a donor clinically immune to Plasmodium falciparum malaria strongly inhibited reinvasion in vitro of human erythrocytes by the parasite. When added to monolayers of glutaraldehyde-fixed and air-dried erythrocytes infected with the parasite, this IgG also displayed a characteristic immunofluorescence restricted to the surface of infected erythrocytes. Elution of the IgG adsorbed to such monolayers gave an antibody fraction that was 40 times more efficient in the reinvasion inhibition assay (50% inhibition titer, less than 1 microgram/ml) than the original IgG preparation. The major antibody in this eluate was directed against a parasite-derived antigen of Mr 155,000 (Pf 155) deposited by the parasite in the erythrocyte membrane in the course of invasion. A detailed study of IgG fractions from 11 donors with acute P. falciparum malaria or clinical immunity revealed the existence of an excellent correlation between their capacities to stain the surface of infected erythrocytes, their titers in reinvasion inhibition, and the presence of antibodies to Pf 155 as detected by immunoblotting. No such correlations were seen when the IgG fractions were analyzed for immunofluorescence of intracellular parasites or for the presence of antibodies to other parasite antigens as detected by immunoprecipitation of [35S]methionine-labeled and NaDodSO4/PAGE-separated parasite extracts. The results suggest that Pf 155 has an important role in the process of erythrocyte infection and that host antibodies to this antigen may efficiently interfere with this process.

Adolescent↗
PubMed1984

Enumeration and characterization of human killer and natural killer cells by a modified single-cell assay.

Human natural killer (NK) and killer (K) cells were assayed in a modified single-cell cytotoxicity assay using poly-L-lysine-coated cover slips. When human Chang liver cells were used as targets, 20% of the lymphocytes formed conjugates and 2% were active NK cells. When anti-Chang antibodies were present, the proportion of target-binding cells (TBC) increased to 30% and that of the cytotoxic effector cells (comprising NK + K) to 6%. With the mouse mastocytoma cells (P815), which are not susceptible to NK, similar proportions of lymphocytes formed conjugates, and 6-9% were active as K cells. By an in situ rosetting assay a significant fraction of the TBC and cytotoxic effector cells bound either C3b or C3bi in both systems, with a certain predominance of C3bi-binding cells among the K cells. However, by indirect immunofluorescence, significantly more OKT3+ cells than OKM1+ cells were TBC or cytotoxic in the Chang cell system, whereas the OKT3+/OKM1+ ratios for both TBC and cytotoxic cells were 1:1 in the mouse mastocytoma system. The results indicate that TBC, NK and K cells are heterogeneous with respect to surface marker expression and that effector cells of different phenotypes predominate in different target systems.

Animals↗
PubMed1984

The role of viral glycoproteins in mumps virus-mediated antibody-dependent cellular cytotoxity in vitro.

Treatment of human peripheral blood lymphocytes with live or UV-inactivated mumps virions enhances antibody-mediated cellular cytotoxicity (ADCC), reflected by increased target cell lysis in a 51Cr-release assay or an increased number of plaque-forming cells on monolayers of bovine erythrocytes (Eb) in the presence of anti-Eb antibodies. Virus treatment of the Eb targets causes a similar enhancement. The role of viral glycoproteins in ADCC enhancement was investigated by using a panel of monoclonal antibodies raised in mice against mumps virions. Most of the lymphocytes bound mumps virions, as ascertained by indirect immunofluorescence. A high proportion of virus-treated lymphocytes also formed rosettes with Eb. Anti-HN antibodies inhibited rosetting to various degrees. Although antibodies with high haemagglutination inhibition titres were most efficient inhibitors, antibodies without this serological activity were also inhibitory. Anti-F antibodies were only weakly inhibitory, and anti-NP antibodies had no effect. Anti-HN antibodies also abrogated target cell lysis in the 51Cr-release assay and effector cell recruitment in the ADCC plaque assay by inhibiting virus-mediated Eb-lymphocyte interactions both at the target cell and at the effector cell level. Anti-F or anti-NP antibodies were only weakly or not at all inhibitory. The results suggest that virus-mediated enhancement of ADCC is caused by the HN glycoprotein, primarily (although perhaps not exclusively) by its improvement of the effector cell-target cell contacts necessary for the efficient execution of target cell lysis.

Antibodies, Monoclonal↗
PubMed1984

Production of antibodies to cellular antigens by EBV-transformed lymphocytes from patients with urinary bladder carcinoma.

Lymphocytes from patients with transitional-cell carcinoma (TCC) of the urinary bladder were transformed by infection with Epstein-Barr virus. To obtain B cells secreting antibodies reactive with TCC cells, the transformed cells were either adhered to irradiated monolayers of cultured allogeneic TCC cells or subcultured at limiting dilution. Supernatants from these cultures were tested in a modified enzyme-linked immunosorbent assay against fixed cells, isolated plasma membranes, or lipid antigens or were tested by antibody-dependent cellular cytotoxicity (ADCC). Reactions with antigens derived from the serum source were excluded by proper controls. By this approach a majority of the patients tested (7/12) gave rise to cultures producing antibodies recognizing various cellular antigens. The antibody-containing supernatants from these cultures were usually of high titres and the reactive antibodies of IgM isotype. One culture, which had been selected by repeated adherence to TCC cells, produced antibodies reactive with such cells in ADCC. None of the antibodies investigated detected antigens exclusively present on TCC cells.

Antibodies, Neoplasm↗
PubMed1984

Regulation of the immune response in Plasmodium falciparum malaria. III. Proliferative response to antigen in vitro and subset composition of T cells from patients with acute infection or from immune donors.

T cells from patients with acute Plasmodium falciparum malaria were investigated for their proliferative responses in vitro to malarial antigen. Of 26 patients, 14 had acute and short lived (less than or equal to 8 days) disease episodes, most of them for the first time, while 12 had been ill for more than 8 days at the time of the blood samples were taken. The lymphocytes from the first group gave a weak, and apparently P. falciparum specific proliferation, peaking after 3-4 days, but waning within 5-6 days, suggesting the induction of suppression. No such responses were obtained with control antigen consisting of normal RBC membranes. The P. falciparum antigen-induced proliferative response was completely lacking in the second group of patients. Since both groups responded equally to T cell mitogen, the results are indicative of a malaria specific non-responsiveness. In contrast T cells from a group of apparently immune donors living in highly endemic P. falciparum malaria areas developed strong and long lasting proliferative responses to P. falciparum antigen with a peak on days 5-6. T cells from acutely infected P. vivax patients did not respond to either the P. falciparum antigen or to the control antigen. The cellular basis of the proliferative responses were investigated by surface marker studies with monoclonal antibodies. Within the T cell preparations, the T4+/T8+ cell ratio was close to normal for both the immune donors and for those with acute P. vivax infection. In contrast, this ratio was depressed for both groups of patients with acute P. falciparum infection. However, this was due to reduced number of circulating T4+ cells in the patients with short disease episodes whereas it was due to increased numbers of T8+ cells, probably including suppressor cells, in those who were ill for more than 8 days.

Antibodies, Monoclonal↗
PubMed1984

Virus-induced enhancement of lymphocyte-mediated antibody-dependent cytotoxicity (ADCC) in vitro.

The effect of Parotis virus on antibody-dependent cellular cytotoxicity in vitro (ADCC) of human lymphocytes was investigated in a 51Cr-release assay and, at the effector cell level, in an ADCC plaque assay. Target cells were bovine or chicken erythrocytes, which are not susceptible to natural cytotoxicity (NK) of human lymphocytes. They were not killed when incubated with virus-treated lymphocytes in the absence of antibodies. Treatment of the lymphocytes or the target cells with small amounts of virus, however, resulted in a very significant enhancement of ADCC. The same results were obtained with live or UV-inactivated virus, suggesting that enhancement was a passive phenomenon not requiring infection. Enhancement was already significant after 3 hr of incubation, indicating that it was independent of endogenously released interferon. Enhancement of ADCC by virus was due to effector cell recruitment rather than due to the increase of the cytotoxic potential of the individual K cell. The highest frequency of effector cells was present in Percoll fractions enriched in large granular lymphocytes (LGL). Virus treatment resulted in recruitment of effector cells carrying T cell markers such as the T3 antigen (OKT3+), receptors for sheep erythrocytes, or Fc receptors for IgM. In contrast, the absolute number of K cells carrying the HNK-1 marker (Leu-7) or receptors for C3 fragments was not changed by the virus. It is concluded that Parotis virus enhances ADCC by improving effector cell-target cell contacts, resulting in recruitment of effector cells with T cell characteristics. Recruitment is accompanied by a significant reduction of the antibody concentration needed for ADCC induction. This virus-mediated enhancement of ADCC may be of importance for protection of the host in the early phases of a virus infection in which the amounts of anti-viral IgG antibodies capable of inducing cellular cytotoxicity may yet be very small.

Adult↗
PubMed1983

The use of supernatants from neuraminidase and galactose oxidase (NAGO)-treated lymphocytes as a source of T cell growth factor.

Human peripheral blood or tonsil lymphocytes produce T cell growth factor (TCGF), when activated with neuraminidase (NA) and galactose oxidase (GO). Partial purification of NAGO-TCGF on Sepharose G-100 columns gave a TCGF-active fraction within the same molecular weight range as the conventional lectin-induced TCGF (approximately 15,000 Da). Human T cells, activated in mixed lymphocyte culture (MLC) with irradiated allogeneic EB-virus transformed B-cells (LCL) could be maintained in continuous culture for several months with retained functional activities. The cells showed similar growth patterns when cultured in the presence of either NAGO-TCGF or PHA-TCGF. The growing cells were characterized by means of monoclonal antibodies. After 4 weeks of culture 98% of these were OKT3+ and 87% were also OKT8+. The cytolytic activities of the cultures were tested in cell-mediated lympholysis (CML) against allogeneic LCL as target cells, in natural cytotoxicity (NK) against K562 cells and in antibody dependent cytotoxicity (ADCC) against bovine erythrocytes. Cultures displaying one or several of these functions were obtained. The results indicate, that TCGF obtained from supernatants of NAGO-activated lymphocytes is as potent as the T cell growth promoting factor obtained by lectin stimulation. One major advantage of using NAGO-generated TCGF is that contamination with lectin is avoided.

Antigens, Surface↗