Protection against cucumber mosaic virus (CMV) strains O and Y and chrysanthemum mild mottle virus in transgenic tobacco plants expressing CMV-O coat protein

Transgenic tobacco expressing the coat protein (CP) of cucumber mosaic virus strain O (CMV-O) showed a significant level of protection against CMV strains O and Y. When inoculum concentrations were increased, the transformants showed a stronger level of protection against CMV-O than against CMV-Y. The substitution of an amino acid residue between CMV-O and CMV-Y, which is presumed to change the conformation of CP, may reflect the difference in susceptibility to these viruses. Furthermore the transgenic tobacco plants showed a significant level of protection against chrysanthemum mild mottle virus, a member of the cucumovirus group but with no serological relationship to CMV.

Efficient pathogen-derived resistance induced by integrated potato virus Y coat protein gene in tobacco

The coat protein (CP) gene from potato virus Y (Hungarian isolate, PVY-H) was engineered into Agrobacterium tumefaciens binary vector for expression in different tobacco lines. Three different Nicotiana tabacum breeding lines were transformed and the integration of the CP gene was confirmed by PCR technique using genomic DNA preparations. The transcription and expression of the integrated CP gene was detected by Northern and Western blots. Pathogen-derived resistance was demonstrated by inoculation of the R1 progeny of the transformed lines with purified PVY-H. The efficiency of protection varied between different transgenic plants ranging from almost complete to no protection. Five CP expressing tobacco lines were resistant to challenge infection with PVY-H as indicated by attenuation or absence of symptom development associated with reduction or lack of detectable virus accumulation. Data from Western blots showed that there is no correlation between the level of the expressed CP and the extent of protection. This suggests that the mechanism of the observed resistance is independent of the level of CP accumulation in the transgenic tobacco plants.

High resistance to cucumber mosaic virus conferred by satellite RNA and coat protein in transgenic commercial tobacco cultivar G-140

A chimeric vector was constructed to express cucumber mosaic virus (CMV) satellite (Sat) RNA and coat protein (CP). Transgenic lines of tobacco cultivar G-140 expressing CP and Sat-RNA were obtained; these lines had high resistance to CMV. Fifty to 70% of the transgenic plants were symptomless 90 days after inoculation with 25-50 micrograms/ml of CMV. Resistance was about twice that conferred by the Sat-RNA or the CP gene alone in transformed plants.

Evidence for sense RNA-mediated protection to PVYN in tobacco plants transformed with the viral coat protein cistron

The coat protein (CP) cistron of the tobacco veinal necrosis strain of potato virus Y (PVYN), supplemented with translational start signals, was cloned into an Agrobacterium tumefaciens Ti transformation vector. Transformation of tobacco leaf discs resulted in 99 transgenic lines which were subsequently analysed for the presence and expression, at both the transcriptional and translational level, of the CP-gene. Although CP-specific RNA transcripts were produced in all plants no CP could be detected by several sensitive immunological techniques. Upon mechanical inoculation of progeny lines of self-pollinated original transformants (S1) with PVYN, protection levels of 20 and 95%, respectively, could be observed in two out of ten lines tested. This level of protection increased to 100% in the S2 progeny obtained from self-pollination of virus-protected S1 plants. Transformation of tobacco leaf discs with a PVYN CP construct from which the ATG start codon had been removed by site-directed mutagenesis resulted in 57 transgenic lines that all produced CP-specific transcripts. Mechanical inoculation with PVYN of S1 progeny plants of several of these lines resulted in resistance to a similar level and extent as in the S1 progeny of plants transformed with the intact CP cistron. The results obtained strongly suggest that the resistance observed in the transgenic plants is principally based on the presence of PVYN CP RNA sequences rather than on the accumulation of viral coat protein.

IL-1, IL-6, and PDGF mRNA expression in alveolar cells following stimulation with a tobacco-derived antigen

To test the hypothesis that inflammatory cytokine production might be an early event in the development of the disease associated with smoking, we used alveolar cells from healthy nonsmokers stimulated with TGP as a model system. TGP, a phenol-rich glycoprotein which is present in tobacco leaves and cigarette smoke condensate, activates the immune system. It stimulates polyclonal B cell differentiation, induces primarily an IgE response, and activates human leukocytes to produce IL-1. Using in situ nucleic acid hybridization we show that the steady-state levels of IL-1 alpha, IL-1 beta, IL-6, platelet-derived growth factor (PDGF)-A, and PDGF-B mRNAs are consistently elevated in the alveolar cells of all donors following TGP stimulation. The kinetics of mRNA expression suggest that IL-1 alpha and IL-1 beta mRNAs are independently regulated in alveolar cells, while the regulation of PDGF-A and PDGF-B mRNA seems to be similar. The activated cells also synthesize elevated levels of IL-1 and IL-6. These findings lend support to the suggestion that some clinical consequences of smoking might be initiated and enhanced by the production of inflammatory cytokines. Moreover, IL-6 could also activate a polyclonal B cell response, which could lead to the synthesis of autoantibodies and thus cause immune-mediated tissue injury.

Characterization of RNA-mediated resistance to tomato spotted wilt virus in transgenic tobacco plants

Recently high levels of protection against tomato spotted wilt virus (TSWV), a negative-strand RNA virus infecting plants, have been obtained by transforming tobacco with viral nucleoprotein (N) gene sequences. Here we demonstrate that this protection is primarily due to the presence of N gene transcripts in the cells of transgenic plants, and hence appears to be RNA-mediated. Further, transgenic tobacco plants are only protected to isolates and strains of TSWV and not to other tospoviruses that share considerable nucleotide sequence homology in their N genes to TSWV. In addition to being protected after mechanical inoculation, the transgenic tobacco plants are also resistant to inoculation using viruliferous thrips, i.e. Frankliniella occidentalis (Perg.), one of the most important natural vector species.

[Immunoglobulin A and tobacco antigens in patients with pneumopathy]

Smoking is an addiction related with several cardiopulmonary diseases. Some compounds derived from tobacco combustion can be induce a response of secretory immune system, because antigen penetration is by respiratory tract epithelium, with IgA antibodies synthesis and immune complex (IC) generation. Seric anti-tobacco antibodies were showed in 44% of healthy smokers and 71% of non-smoker. In 56% of smokers and 38% at non smokers were found IC with 0.19 and 0.15 mg/ml of IgA respectively. Molecular weight of IC constituents were between 12 and 80 Kd. Sera were without free tobacco antigen. Pneumopathic patients had anti-tobacco antibodies in 100% of them and positive IC in 72% of smokers and 65% of non-smokers. IgA concentration in CI was 1.41 and 1.26 mg/ml respectively. Molecular weight of IC compounds were from 14 to 90 Kd. Free tobacco antigen in serum was observed in 44% of smokers and 41% of non-smokers pneumopathic patients. We concluded that patients with lung disease had higher frequency of anti-tobacco antibodies and IC, further IgA concentration in IC was higher and free tobacco antigen present in pneumopathic sera comparing with healthy people. The presence of circulating IC with IgA antibodies and the potential inductive influence of tobacco products in these entities, should provide an energetic stimulus to search the role of tobacco antigens in pulmonary inflammatory diseases.

Autoimmune mechanisms in thromboangiitis obliterans (Buerger's disease): the role of tobacco antigen and the major histocompatibility complex

This study is a continuation of our previous work that showed that patients with thromboangiitis obliterans (TAO; Buerger's disease) demonstrate a cell-mediated immune response to human artery type-specific collagens. To investigate the role of cigarette smoking in patients with TAO, cellular and humoral sensitivity was tested to a tobacco glycoprotein (TGP) antigen in 13 patients with Buerger's disease, 16 healthy smokers, and 12 nonsmoking healthy young male subjects. In this study, patients with Buerger's disease and healthy smokers had the same rate of cellular response to TGP, whereas nonsmokers did not respond. All three groups had a 30% to 40% measurable antibody response to TGP. If TGP has an immunologic role in the pathogenesis of TAO, an additional factor (or factors) may be operative. A specific genetic makeup may be one such factor, although at this stage other pathogenic mechanisms cannot be ruled out. Eleven patients with Buerger's disease and two control groups of 10 young healthy smoking male subjects and 12 young nonsmokers underwent histocompatibility leukocyte antigen (HLA) typing. Patients with Buerger's disease had a statistically significantly higher frequency of HLA-DR4 and a significantly lower frequency of the HLA-DRW6 antigen than had both control groups. Because similar findings have been reported in other autoimmune diseases, this observation may serve as further evidence that an autoimmune mechanism is involved in Buerger's disease.

Pathogen-derived resistance to a potyvirus: immune and resistant phenotypes in transgenic tobacco expressing altered forms of a potyvirus coat protein nucleotide sequence

Transgenic Nicotiana tabacum 'Burley 49' plants containing one of six different forms of the tobacco etch virus (TEV) coat protein (CP) nucleotide sequence have been generated. In whole plant studies, R1 and R2 progeny were inoculated mechanically with TEV, and the appearance and severity of symptoms were recorded. Symptom phenotype was altered, ranging from near wild type susceptibility to apparent immunity. Protoplasts derived from wild type and transgenic Burley 49 plant lines were transfected with TEV RNA. Protoplasts from transgenic plants expressing full-length or truncated forms of TEV CP supported virus replication. Protoplasts from certain transgenic plants, producing plus- or minus-sense CP transcripts but no CP, did not support virus replication at wild type levels. A model is proposed to account for these observations.

Antibody from hen's eggs against a conserved sequence of the gametophytic self-incompatibility proteins of plants

A convenient way of producing effective antibodies to plant proteins is presented. It takes into account the following facts: (1) many plant proteins are highly glycosylated, thus giving rise to nonspecific antibodies which cross-react with other glycoproteins, (2) it is more common nowadays to know the DNA sequence of a protein coding gene than to have significant amounts of that protein well purified as antigen, and (3) eggs from immunized hens are very convenient sources of large amounts of antibodies. An antibody which specifically detects self-incompatibility proteins (S-proteins) in Solanaceae was isolated. The published cDNA sequences and deduced amino acid sequences of Nicotiana alata (an ornamental tobacco) S-proteins were computer analyzed in order to recognize a peptide with a conserved sequence which would effectively give rise to antibodies. An adequate amount of this peptide was synthesized and part of it was coupled to a macromolecular carrier (bovine serum albumin). Antibodies to this peptide-carrier complex were recovered from egg yolks of immunized hen in amounts corresponding to 300 ml of antiserum per month. From the total immunoglobulin fraction isolated, the antibody specific for S-proteins was affinity purified over 100-fold on a peptide-coupled column. The antibody showed high levels of specificity for putative S-specific sequences in N. alata and in petunia. Also the size, polymorphy, and quantity of the detected antigens were in very good accordance with previously published data. In addition to the present application, this procedure should be useful for a wide variety of proteins.

Evaluation of immunoglobulins from plant cells

Expression of cDNA constructs encoding full-length mouse immunoglobulin chains with their native leader sequences or fusion constructs substituting the native leader with a pre-pro sequence derived from Saccharomyces cerevisiae yielded blocked N-termini on the gamma chain or the correct amino terminal sequence on the mature kappa chain. Lectin binding assays revealed that assembled immunoglobulin complexes contained a glycosylated heavy chain. The attached glycan was resistant to digestion by endoglycosidase H and its lectin binding pattern was distinguishable from that of the mammalian glycan. The results indicated processing of the immunoglobulin carbohydrate in the tobacco Golgi to yield a complex oligosaccharide. Secretion of antibody by protoplasts isolated from regenerated transgenic plants or from suspension callus cells was demonstrated by pulse-chase labeling experiments. When purified, the tobacco-produced antibody was found to possess the antigen binding and catalytic properties of the murine monoclonal antibody. Kinetic parameters (Km, Ki, Vmax, and kcat) of the tobacco-derived antibody were comparable to those of the mouse-derived antibody. The results in general show that the endomembrane system of tobacco cells possesses cognate mechanisms for the recognition of diverse leader sequences. These signals can be used to initiate the assembly, processing, and secretion by plant cells of complex foreign proteins.

Protection against detrimental effects of potyvirus infection in transgenic tobacco plants expressing the papaya ringspot virus coat protein gene

We obtained transgenic tobacco plants expressing the papaya ringspot virus (PRV) coat protein (CP) gene by transformation via Agrobacterium tumefaciens. Expression was effectively monitored by enzyme-linked immunosorbent assays (ELISA) of crude tissue extracts. Subcloned plants derived from eight original Ro transformants were inoculated with potyviruses: tobacco etch (TEV), potato virus Y (PVY), and pepper mottle (PeMV). Plants that accumulated detectable levels of the PRV CP showed significant delay in symptom development and the symptoms were attenuated. Similar results were obtained with inoculated R1 plants. We conclude that the expression of the PRV CP-gene imparts protection against infection by a broad spectrum of potyviruses.

Microwave energy fixation of plant tissue: an alternative approach that provides excellent preservation of ultrastructure and antigenicity

Immunocytochemical techniques are confronted with the problem of obtaining adequate tissue preservation together with retention of protein antigenicity. Various methods, including freeze-drying and freeze-substitution, have been devised to circumvent this problem. In the present study, we report that microwave energy used in combination with low concentrations of glutaraldehyde (0.1%) and paraformaldehyde (2%) preserved the structural integrity of plant tissue and antigenicity of proteins. Tobacco leaf samples fixed in a time as brief as 15-20 s exhibited excellent preservation of fine structures. By contrast, specimens irradiated for shorter (5-10 s) or longer (30-40 s) periods showed poor morphological preservation. Microwave irradiation for 15-20 s was found useful for immobilizing large amounts of soluble antigens. The fast microwave fixation method was successfully used to preserve pathogenesis-related (PR) proteins, which were subsequently localized by a postembedding immunogold procedure. In addition to soluble antigens, cellulose subunits and pectic substances, two major plant cell wall components, were found to be highly preserved in microwave-irradiated tobacco plant tissue. The present study demonstrates that microwave fixation of plant tissue is a simple and inexpensive method that is easy to perform with commercially available microwave ovens. The incubation time for fixation is reduced from 2 h to 15-20 s without loss of fine structural details. This method will undoubtedly acquire increasing applicability and relevance in plant biology.

Isolation and characterization of a proteinaceous inhibitor of microbial proteinases induced during the hypersensitive reaction of tobacco to tobacco mosaic virus

A proteinase inhibitor is strongly induced in tobacco leaves reacting hypersensitively to tobacco mosaic virus. The tobacco inhibitor is highly active against four different serine endoproteinases of fungal and bacterial origin (EC 3.4.21.14) but inhibits poorly two serine endoproteinases of animal origin, trypsin (EC 3.4.21.4) and chymotrypsin (EC 3.4.21.1). The inhibitor has been purified to homogeneity by successive steps of conventional and high-performance liquid chromatography. When electrophoresed under denaturing conditions, it behaves as a small polypeptide with a molecular weight of about 6,000. From its amino acid composition and NH2-terminal amino acid sequence analysis, it appears that the inhibitor belongs to the potato inhibitor I family. A polyclonal antiserum was raised against the purified tobacco inhibitor and was used in immunoblotting experiments to follow inhibitor accumulation during the hypersensitive reaction of tobacco to tobacco mosaic virus. The inhibitor is highly efficient and might represent a potent fungicide and/or bactericide to be used in plant biotechnology.

Immunological characterization of plant ornithine transcarbamylases

Pea (Pisum sativum L.) ornithine transcarbamylase (OTC) antisera were used to investigate the immunological relatedness of several plant and animal OTC enzymes. The antisera immunoprecipitated OTC activity in all monocot and dicot species tested, and sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of immunoprecipitated protein revealed monomeric proteins ranging from 35,200 to 36,800 daltons in size. Pea OTC antisera did not recognize mammalian OTC protein. OTC activity and protein levels detected on sodium dodecyl sulfate polyacrylamide gel electrophoresis immunoblots from homogenates of green leaf, etiolated epicotyl and cotyledon, and root tissues of pea were poorly correlated. This might result from differences in amounts of enzymatically active OTC protein in the homogenates. Alternatively, the antisera may fail to recognize different isozyme forms of OTC, which have been reported for some plant species. A putative cytosolic precursor OTC (pOTC) polypeptide exhibiting and Mr = 39,500 to 40,000 daltons was immunoprecipitated from in vitro translation mixtures of total pea leaf poly(A)+ RNA. The size of the pOTC polypeptide, as compared with mature OTC monomer (36,000 daltons), suggests that a 4 kilodalton N-terminal leader sequence, like that responsible for mitochondrial targeting of the mammalian enzyme, may be involved in organellar import of the plant enzyme.

[Clinical variants of the course and the characteristics of the x-ray changes in extrinsic allergic alveolitis--tobacco growers' disease]

Analysis is made of the clinical varieties and x-ray changes in the lungs in 143 persons engaged in tobacco growing. The immunological studies revealed sensitization to tobacco antigen in all the patients. Pointing to the polymorphism of the x-ray appearance the authors group at the same time the main signs into the x-ray symptom complexes: emphysematous interstitial, parenchymatous interstitial and pneumonic. Preliminary analysis indicates that the x-ray symptom complexes thus distinguished correlate with the main clinical varieties of the disease which may run its course by the type of obstructive bronchitis, bronchial asthma and recurrent pneumonias.

[Clinical manifestations of extrinsic allergic alveolitis--a disease of tobacco growers]

Clinicoroentgenological and functional manifestations of exogenic allergic alveolitis (EAA) have been studied in 143 patients. The disease is often masked and runs in the form of chronic nonspecific bronchopulmonary inflammation. The presence of antigen-dependent symptom complexes associated with involvement of other organs characterizes EAA more specifically. Finally, the disease progresses to parenchymatous interstitial fibrosis. Pulmonary ventilation and blood oxygen saturation are reduced.

[Effect of cigarette smoke on the airway of asthmatic children]

A study was carried out on 62 asthmatic children for observed the acute effects of one hour of passive cigarette smoking on pulmonary function test before and after 1-hour exposure. Three parameters were measured: Forced vital capacity (FVC), Forced expiratory volume in one second (FEV 1), and Mid-Maximum expiratory flow rate (MMEF). Of those measurement MMEF showed the most important changed in 23% of patients. Passive smoking produced changed on 32.2% on asthmatic patients in any of pulmonary function test. Finally, correlation were made between parental cigarette smoking habits and skin test sensitivity at tobacco antigen, we didn't found correlation between this parameters.

Preparation by two-dimensional electrophoresis of proteins for antibody production: antibodies against proteins whose synthesis is reduced by auxin in tobacco mesophyll protoplasts

Using phenol extraction from tobacco callus, we have prepared extracts with a high protein content. These proteins were separated in cylindrical non-equilibrium pH gradient gels and visualized by dipping in sodium dodecyl sulfate (SDS)-containing solution. Three gel sections, each containing proteins previously detected as abundantly synthesized in tobacco mesophyll protoplasts and whose synthesis is reduced by auxin application, were excised from each gel and collected. These proteins were further separated on slab SDS gels and protein bands were excised after Coomassie Brilliant Blue R-250 staining and used to inject three rabbits. After one booster, highly specific antibodies were detected in their sera by ELISA and immunoblotting. Using these sera we have confirmed that the corresponding proteins are identical in callus and mesophyll protoplast and demonstrated that they are abundantly accumulated in tobacco roots but are undetectable in aerial organs and seeds.

Molecular cloning of a Pseudomonas syringae pv. syringae gene cluster that enables Pseudomonas fluorescens to elicit the hypersensitive response in tobacco plants

A cosmid clone isolated from a genomic library of Pseudomonas syringae pv. syringae 61 restored to all Tn5 mutants of this strain studied the ability to elicit the hypersensitive response (HR) in tobacco. Cosmid pHIR11 also enabled Escherichia coli TB1 to elicit an HR-like reaction when high levels of inoculum (10(9) cells per ml) were infiltrated into tobacco leaves. The cosmid, which contains a 31-kilobase DNA insert, was mobilized by triparental matings into Pseudomonas fluorescens 55 (a nonpathogen that normally causes no plant reactions), P. syringae pv. syringae 226 (a tomato pathogen that causes the HR in tobacco), and P. syringae pv. tabaci (a tobacco pathogen that causes the HR in tomato). The plant reaction phenotypes of all of the transconjugants were altered. P. fluorescens(pHIR11) caused the HR in tobacco and tomato leaves and stimulated an apparent proton influx in suspension-cultured tobacco cells that was indistinguishable from the proton influx caused by incompatible pathogenic pseudomonads. P. syringae pv. tabaci(pHIR11) and P. syringae pv. syringae 226(pHIR11) elicited the HR rather than disease symptoms on their respective hosts and were no longer pathogenic. pHIR11 was mutagenized with TnphoA (Tn5 IS50L::phoA). One randomly chosen mutant, pHIR11-18, no longer conferred the HR phenotype to P. fluorescens. The mutation was marker-exchanged into the genomes of P. syringae pv. syringae strains 61 and 226. The TnphoA insertions in the two pseudomonads abolished their ability to elicit any plant reactions in all plants tested. The results indicate that a relatively small portion of the P. syringae genome is sufficient for the elicitation of plant reactions.

Cigarette smoke-sensitive asthma: challenge studies

The effects of exposure to environmental tobacco smoke on pulmonary function were assessed in 21 subjects with asthma who claimed respiratory complaints (cough, shortness of breath, and chest tightness) on previous exposure to cigarette smoke. Exposure to mechanically produced tobacco smoke was performed in a static inhalation chamber for two-hour intervals at two distinct smoke levels (as measured by carbon monoxide, nicotine, and particulate levels). Seven of the 21 smoke-challenged subjects experienced a significant (greater than 20%) decline in FEV1 during passive exposure to tobacco smoke. One of these seven subjects was nonatopic, whereas a second subject had a negative response to methacholine challenge. The smoke-challenge responses were reproducible in all seven reactive subjects. Increasing concentrations of tobacco smoke failed to elicit pulmonary changes in previously challenged, unreactive or "smoke-tolerant" subjects. There was no association between a positive smoke challenge and the presence of serum IgE antibodies and/or a positive immediate wheal-and-flare skin test to a tobacco leaf extract. Collectively, these studies document a significant decline in pulmonary function in a substantial percentage (33%) of a population of "smoke-sensitive" subjects with asthma exposed to environmental tobacco smoke. The data also dissociate this effect from tobacco-leaf hypersensitivity.

Analysis of tobacco leaf allergens by crossed radioimmunoelectrophoresis

The reactivity of eleven 'tobacco smoke sensitive' and eight 'non-sensitive' individuals to tobacco leaf allergens was tested by Crossed Radioimmunoelectrophoresis (CRIE). All nineteen study subjects had IgE antibodies to tobacco leaf antigens as measured by Radioallergosorbent Test (RAST) and seventeen of the nineteen individuals were atopic. Of the thirty-seven tobacco leaf precipitins detected by Cross Immunoelectrophoresis (CIE), three were identified as allergens by CRIE. All nineteen subjects reacted to at least one of the three allergens detected. However, neither the intensity nor the incidence of reactivity with any of the three allergens correlated with smoking or 'smoke sensitivity'.

Increased IgE antibody responses in rats exposed to tobacco smoke

Raised serum IgE levels were found in a high proportion of rats that had been exposed to tobacco smoke twice daily 5 days a week for 8 wk in a Dontenville-type smoking machine. Levels above 1 ng/ml of IgE were found in nine of 20 animals exposed to cigarette smoke and in five of 20 rats exposed to smoke from cigarettes with 1.45% phenylmethyloxidiazole added for possible protection against the effects of the smoke. None of the 20 control rats exhibited similarly increased serum IgE. Exposure to tobacco smoke did not significantly affect the serum concentrations of IgM and IgG. The development of specific IgE and IgG antibodies was also influenced by tobacco smoke exposure. Rats exposed to ovalbumin aerosol developed increased levels of IgG and IgE antibodies, whereas no effect on the development of antibody titers was found in rats immunized by the subcutaneous route. This study demonstrates that exposure to tobacco smoke increases serum IgE levels and enhances sensitization via the airways by a local effect, thus supporting the "mucosal theory of atopy."

The immunologic response to tobacco antigens in smokers. VI. Phagocytosis of tobacco antigens by peripheral blood polymorphonuclear leucocytes studied by immunofluorescence

Polymorphonuclear leucocytes (PMNL) isolated from the defibrinated blood of 44 healthy volunteers (20 no smoking subjects and 22 smokers) were examined for the presence of tobacco antigens using specific rabbit antiserum conjugated with FITC. In 11 persons from the smokers group PMNL were examined by the direct immunofluorescence technique, using appropriate antisera, as well as for the presence of IgG, IgM and C3. It was stated that the number of PMNL with fluorescent tobacco antigens rose significantly after exposure to tobacco smoke. The above cells were detected both in non-smokers and smokers venous blood, while their percentage was more important in the latter. IgG, IgM and C3 were found in PMNL of all 11 examined smoking subjects. In the authors opinion, tobacco antigens are phagocytized after penetration into the organism, either alone or in the shape of immune complexes formed with specific serum antibodies. The possibility of vascular injuries caused by the above complexes as well as the question of a presumed affinity of tobacco and solanaceae antigens are discussed.

Tobacco smoke "sensitivity"--is there an immunologic basis?

This study was undertaken to determine if there is an immunologic basis for reported tobacco-smoke hypersensitivity in man. Ninety-three individuals who were recruited on the basis of their smoking history and/or claimed sensitivity to tobacco smoke were skin prick tested with tobacco smoke and leaf extracts and their sera analyzed for reaginic and precipitating antibodies to these antigens. Results demonstrated that a significant number of the individuals who were tested had positive skin test and RAST responses to tobacco leaf antigens, whereas only a small number responded to smoke antigens. RAST or skin test responses of study subjects to leaf or smoke antigens did not correlate with symptoms of tobacco-smoke "sensitivity" or smoking history but did correlate with atopic status. Precipitins were detected only to tobacco leaf C in 46 of the 93 individuals who were tested but did not correlate with smoking history or smoke "sensitivity." These results suggest that subjective tobacco-smoke sensitivity is not caused by hypersensitivity to tobacco leaf or smoke antigens.

Role of antigen structure in the regulation of IgE isotype expression

Tobacco glycoprotein (TGP) is a glycoprotein containing rutin-like polyphenol groups that is purified from cured tobacco leaves and can be detected in condensates of tobacco smoke. One-third of normal humans have been shown to manifest immediate, IgE-mediated, wheal and flare reactions to an intradermal injection of TGP. Rutin-like moieties are also found in a wide variety of vegetable foods. The possible importance of sensitivity to TGP in the pathogenesis of the vascular and pulmonary complications of tobacco smoking has stimulated us to study the immune response of mice to TGP and the role of rutin groups in influencing isotype expression. A series of three intradermal injections of TGP elicits a long-lasting IgE antibody response in mice. However, no hemagglutinating antibodies are produced. Similarly, immunization with a rutin derivative of bovine serum albumin stimulates IgE antibodies to bovine serum albumin but little hemagglutinating antibodies. In contrast, mice injected in the same manner with bovine serum albumin produce both IgE and hemagglutinating antibodies. Thus, the rutin moiety is implicated as exerting a regulatory effect on isotype expression by suppressing the production of serum antibodies of isotypes other than IgE. The immunization procedure employed (which involves an initial injection of 100 micrograms of antigen in phosphate-buffered saline, followed, at monthly intervals, by two intradermal injections of 100 micrograms of antigen precipitated on alum) apparently fails to stimulate the normal "down-regulation" of the IgE response so that a persisting high-titered response is obtained.

Hypersensitivity to tobacco antigens in smokers and nonsmokers

The examinations were carried out in 336 tobacco smokers, 91 persons who gave up smoking, 175 persons exposed to tobacco smoke indirectly and 112 persons who had nothing to do with tobacco smoke. Together 714 persons were examined. The examinations, which were carried out on the grounds of the clinic observations and the data obtained from interviews, aimed at the discovering of the causal nexus between the attacks of atopic bronchial asthma as well as the occurrence of acute urticaria and the exposure to tobacco smoke. All the patients underwent the dermic allergometric test with the extract from cigarette tobacco. The results of these examinations have not delivered any evidence concerning the allergenic reaction of the immediate type to tobacco smoke.

Tobacco, cocoa, coffee, and ragweed: cross-reacting allergens that activate factor-XII-dependent pathways

A glycoprotein antigen has been isolated from cured tobacco leaves (TGP-L) Nicotiana tabacum) and from cigarette smoke condensate (TGP-CSC) to which approximately one-third of human volunteers, smokers and non-smokers, exhibit immediate cutaneous hypersensitivity. TGP-L and TGP-CSC contain polyphenol haptens that activate the factor XII (Hageman factor) dependent pathways of coagulation, fibrinolysis, and kinin generation in normal human plasma. The purpose of this communication is to describe the isolation antigens from cocoa powder (Theobroma cacao), ground coffee (Coffea arabica), and ragweed (Ambrosia eliator) pollen that are immunologically cross-reactive with TGP-L and TGP-CSC, contain similar polyphenol haptens, and are capable of activating factor-XII-dependent pathways in normal human plasma.

The immunologic response to tobacco antigens in smokers. IV. Effect of heparin, aspirin, promethazine and prednisone

The effects of heparin, aspirin, promethazine and prednisone on late skin reactions, provoked by tobacco extracts were studied in four groups of 17 patients with coronary artery disease. In all patients, intracutaneous tests were made with four different tobacco preparations, both on the first day of their hospitalisation and after 14 days of therapy. It was found that strongly positive late skin reactions with tobacco extracts were decreased or suppressed in patients taking heparin and in patients taking prednisone, but not in those who were treated with promethazine or with aspirin. This seems to confirm the hypothesis that these reactions are really provoked by a local type III allergy to tobacco antigens.

[Immunological reactions to tobacco (author's transl)]

Tobacco may act as an allergenic or immunogenic agent, the antigen being present in either leaves or smoke. It is capable of producing immediate hypersensitivity reactions with respiratory disorders or cardiovascular lesions through a mechanism involving interaction between basophils and IgE. It may also induce the production of IgG-type antibodies, the significance of which remains to be elucidated. Finally, tobacco interferes with cell-mediated (alveolar macrophages, lymphocytes) lung defense mechanisms in normal subjects or patients. Any interpretation of some pathological conditions associated with tobacco should take these immunological reactions into account.

Tobacco sensitivity in the allergic population: a review with results of desensitization with 10 percent whole leaf tobacco extract

Tobacco sensitivity is seen in atopic patients who are non-smokers but who have clinical symptoms on exposure to tobacco smoke. It is estimated that 8,000,000 persons with common allergies are also clinically sensitive to tobacco. Females outnumber males by about 4:1 and children are affected as well as adults. The specificity of tobacco sensitivity in 16 atopic patients is confirmed in this study by positive skin reactions, passive transfer and gel diffusion studies. Further purification studies, using saline extracts of cured tobacco leaves, has shown the active antigenic material in tobacco to be a glycoprotein, with molecular weight of 18,000 and other known physical and chemical characteristics including amino acid analysis. The results of desensitization with 10% whole leaf tobacco extract in a larger series of 100 tobacco sensitive patients is discussed. The criteria for making the diagnosis of specific clinical tobacco sensitivity is outlined.

The influence of cigarette tobacco smoke products on the immune response. The cellular basis of immunosuppression by a water-soluble condensate of tobacco smoke

The immunosuppression exhibited by a water-soluble condensate of tobacco smoke (WSC) has been studied in vivo and in vitro. When multiple sublethal doses of WSC were injected into C57Bl/6 mice, their ability to respond to immunization with sheep erythrocytes by the formation of plaque-forming cells was severely inhibited. In addition, spleen cells from WSC-treated mice were unable to mount a primary response to SRBC in vitro. Studies on the cellular basis of the immunosuppression induced by WSC showed a decrease in T lymphocytes in the spleens of WSC-treated mice. Additional experiments were conducted in which isolated populations of T cells, B cells and macrophages from WSC-treated or normal mice were combined and then tested for responsiveness to SRBC in vitro. Results of these experiments also indicated that T cells were particularly susceptible to WSC exposure. T cells from WSC-treated mice were unable to co-operate with normal B cells and macrophages in the response to SRBC. A less marked suppression of B-cell function was noted in condensate-treated mice. While B cells from such animals were able to co-operate with normal T cells and macrophages to give a detectable primary response to SRBC, the response was depressed. In contrast, macrophages from WSC-treated animals enhanced the response of normal T and B cells to SRBC.

Immunogenicity of tobacco smoke components in rabbits and mice

Several extracts of tobacco leaf and tobacco smoke components were tested for their ability to stimulate and react with antibodies. Two experimental animal models, mice producing reaginic antibody and rabbits producing precipitating antibody, were used in this study. Results indicate that tobacco smoke extracts can stimulate immune responses to tobacco leaf antigens in rabbits and mice. The immunogen is apparently not a product of incineration because air passed through unlit cigarettes clearly extracted the antigenic component.

IgE antibody response of smokers, nonsmokers, and "smoke-sensitive" persons to tobacco leaf and smoke antigens

Serum samples from cigarette smokers, nonsmokers, and persons reporting "smoke sensitivity" were tested for IgE antibodies to tobacco leaf and smoke extracts by the radioallergosorbent test. Results indicated that none of the serum samples tested contained detectable IgE antibodies to smoke extracts. Occasionally, serum specimens from smokers or nonsmokers demonstrated reactivity to leaf antigen. The most significant reaction to leaf antigens was detected in serum from one of the 7 smoke-sensitive subjects tested. These results demonstrate that smoking, nonsmoking, and clinical "smoke sensitivity" are not correlated with the presence of IgE antibodies to tobacco leaf or smoke antigen.

Induction of IgE antibodies to antigen isolated from tobacco leaves and from cigarette smoke condensate

Neonatal California White rabbits were sensitized with a glycoprotein purified from cured Virginia Bright tobacco leaves. Their serums, but not serums from normal rabbits, were demonstrated by passive cutaneous anaphylaxis technique to contain heat-labile, homocytophilic antibodies to this antigen and to similar material purified from cigarette smoke condensate. Serums containing IgE antibodies to tobacco antigen would not be demonstrated to contain hemagglutinating antibodies to this antigen. These experiments demonstrate that antigen capable of triggering specific IgE-mediated release of inflammatory mediators is present in cigarette smoke. It can be hypothesized that IgE-mediated responses to antigen in cigarette smoke are causally related to the development of vascular injury and of myocardial arrhythmia in hypersensitive smokers.

The immunologic response to tobacco antigens in smokers. III. Type III hypersensitivity skin reactions and specific serum precipitins to four different tobacco extracts in patients suffering from coronary artery disease

In a population of 70 patients suffering from coronary heart disease (49 smokers and 21 non-smokers) intradermal tests and specific precipitation tests with four different extracts of tobacco were performed. Skin tests with tobacco extracts were positive in 41 smokers and 7 nonsmokers. In both groups the immediate and delayed type reactions were weak and of rather doubtful specificity, while the late type reaction was usually more frequent and stronger in smokers (in 14 patients it was positive with all preparations). Specific precipitins against tobacco antigens were found in the sera of 13 smokers but never in nonsmokers. The positive precipitation test correlated well with the positive late skin reactions to tobacco extracts. Such correlation with Ag 1 was observed in 9 out of 13 patients, with Ag II in four cases, with Ag IV and Ag V in 2 and 2 patients respectively. The coincidence of strongly positive late skin reactions and positive precipitation tests with tobacco extracts seems to indicate that tobacco allergy really exists and resembles, in a number of patients with coronary artery disease, type III hypersensitivity reactions to tobacco antigens. It is postulated that immune complexes of precipitins and tobacco antigens may be formed in some patients and initiate pathological processes in coronary arteries leading to their occlusion.

Immunogenic properties of tobacco smoke

The immunogenic capacity of tobacco smoke or tobacco smoke in combination with host proteins to stimulate antibody production in rabbits was investigated. Several antisera from rabbits immunized with tobacco smoke components reacted by immunoprecipitation with tobacco smoke or leaf antigens. The serum precipitins were present only in immune sera and had electrophoretic mobility and molecular size identical to immunoglobulin. These results suggest that tobacco smoke contains components capable of stimulating an immune response in rabbits. It is possible that these components are immunogenic in man, although their role as allergens remains to be determined.

The immunological response to tobacco antigens in the smoker. I. Specific precipitins against tobacco antigens in the serum of healthy cigarette smokers

A study on the presence of specific precipitins against tobacco antigens was done in a population of 361 healthy cigrette smokers and in a group of 60 healthy non-smokers. The tests were made by the gel diffusion technique of Ouchterlony using tobacco extract prepared by the Coca method. A positive precipitation reaction was observed in 11.8 per cent of the smokers' sera examined but never in the non-smokers group. The reaction occurred in subjects of both sexes and was neither dependent upon how long they had smoked nor on the number of cigarettes smoked daily. In the authors' opinion, the formation of precipitins against tobacco antigens may be the result of a sensitivity reaction. It is therefore possible that in predisposed individuals immune complexes of precipitins and tobacco antigens may be formed. They could be responsible for some cardiovascular disorders occuring in smokers. In order to confirm such a hypothesis, a study was carried out recently by the authors on a large group of patients suffering from coronary disease.

Bacterial lipopolysaccharides as inducers of disease resistance in tobacco

The cell wall component of Pseudomonas solanacearum that induces disease resistance in tobacco was highly heat stable at neutral or alkaline pH but highly labile at acid pH. Activity was unaffected by nucleases and proteases but destroyed by a mixture of beta-glycosidases. Washing of bacterial cell walls released a lipopolysaccharide (LPS) fraction with high inducer activity. Purified LPS, extracted by a variety of procedures from whole cells, isolated cell walls, and culture filtrates of both smooth and rough forms of P. solanacearum, induced disease resistance in tobacco at concentrations as low as 50 microgram/ml. The LPS from the non-plant pathogens Escherichia coli B, E. coli K, and Serratia marcescens was also active. Cell wall protein, free phospholipid, and nucleic acids were not necessary for activity. Moreover, since LPS from rough forms was active, the O-specific polysaccharide of the LPS was not required for activity. Hydrolysis of the remaining core-lipid A linkage or deacylation of lipid A destroyed inducer activity. When injected into tobacco leaves, purified LPS attached to tobacco mesophyll cell walls and induced ultrastructural changes in the host cell similar to those induced by attachment of whole heat-killed bacteria.