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At least 19 recordsLinked to original sources
PubMed1994

Mapping of T cell epitopes of the major fraction of rye grass using peripheral blood mononuclear cells from atopics and non-atopics. II. Isoallergen clone 5A of Lolium perenne group I (Lol p I).

Rye grass is the major cause of hay fever which currently affects 20% of the population. Lolium perenne group I (Lol p I) is a glycoprotein of 240 amino acid residues, representing the main allergen of rye grass. We have used peripheral blood mononuclear cells (PBMC) from controls and subjects allergic to rye grass and cultured them with L. perenne extract (LPE) and Lol p I and measured lymphocyte activation using thymidine incorporation. Patients were further studied against the 115 overlapping peptides of the iso-allergen clone 5A of Lol p I to see whether the 4 amino acid residue differences between clone 1A and clone 5A affect the T cell epitope and thus, lymphocyte activation. There are 24 peptide differences between isoallergen clone 1A and clone 5A occurring in pools 4, 13, 16 and 19 each one of which could be an immunodominant epitope. The PBMC from all allergic patients studied showed a strong proliferative response to LPE and Lol p I. Five immunogenic peptide pools, pool 6, 15, 16, 17 and 19 of the isoallergen clone 5A were also identified. Most of these pools are in the C-terminal region of Lol p I. Out of 20 pools tested in vitro 1 pool (pool-17) induced PBMC proliferation in five out of six patients who were not restricted to an HLA class II DR gene product. However, three out of the six subjects responded to various other peptide pools in addition to the immunodominant pool. In spite of the amino acid differences between the two clones, pool 17 still remains the immunodominant T cell epitope. Control subjects showed only weak responses to LPE and no detectable response to either Lol p I or peptide pools. From within the most active pool we have defined two peptides of the isoallergen clone 5A (identical in sequence with clone 1A) which stimulate lymphocytes from rye grass-sensitive patients in vitro. Previous studies with the two continuous sequences (193WGAVWRIDTPDK204 and 195AVWRIDTPDKLT206) tested in vivo by intradermal skin testing have shown typical delayed-type hypersensitivity reactions after 24-48 h in one patient. Comparison of amino acid sequences of Lol p I, Lol p II and Lol p III proteins revealed a significant level of structural similarity among them. Interestingly, 50% of the residues of the second peptide sequence are also present in Lol p II and Lol p III.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1991

The use of freeze-substitution and LR gold in the study of rye grass (Lolium perenne) pollen.

Pollen grains of Lolium perenne (rye grass) were prepared for transmission electron microscopy by rapid freezing in liquid propane, substitution in acetone, methanol or diethyl ether, and embedment in the acrylic resin London Resin gold. These were compared to pollen chemically fixed (CF) in aldehyde/osmium tetroxide and embedded in the epoxy resin Quetol 651. Ultrastructural preservation was superior in freeze-substituted (FS) pollen, particularly with the use of acetone or methanol. Optimally preserved FS pollen displayed a homogeneous aspect of the cytoplasm and nucleoplasm, and smooth, uninterrupted contour or organelles. A striking difference was also seen in the preservation of inclusions in the intine. Varied forms and sizes of intine inclusions were evident in FS pollen but these were not discernible in the CF image. The FS scheme studied here presents enormous potential for both ultrastructural and immunolabelling studies in rye grass pollen. Problems discussed include artifacts associated with each of the substitution solvents used, and a gradient of freezing damage observed within the pollen grain.

Acrylic Resins↗
PubMed1994

Stable transformation and long-term expression of the gusA reporter gene in callus lines of perennial ryegrass (Lolium perenne L.).

Stable transformation of perennial ryegrass (Lolium perenne L.) was achieved by biolistic bombardment of a non embryogenic cell suspension culture, using the hpt and gusA gene. The transformation yielded on the average 5 callus lines per bombardment (1.4 x 10(6) cells). Stable integration of the genes into the plant genome was demonstrated by Southern analysis of DNA, isolated from hygromycin-resistant callus lines. The gusA reporter gene, which was regulated by the constitutive promoter of the rice gene GOS2, was expressed in both transient and stable transformation assays, indicating that this promoter is suitable for expression of a transferred gene in perennial ryegrass. Long-term GUS expression was observed in ca. 40% of the callus lines, whereas the other callus lines showed instability after 6 months and 1 year of culture.

Blotting, Southern↗
PubMed1991

Intergeneric somatic hybridization in Gramineae: somatic hybrid plants between tall fescue (Festuca arundinacea Schreb.) and Italian ryegrass (Lolium multiflorum Lam.).

Tall fescue (Festuca arundinacea Schreb.) protoplasts, inactivated by iodoacetamide, and non-morphogenic Italian ryegrass (Lolium multiflorum Lam.) protoplasts, both derived from suspension cultures, were electrofused and putative somatic hybrid plants were recovered. Two different genotypic fusion combinations were carried out and several green plants were regenerated in one of them. With respect to plant habitus, leaf and inflorescence morphology, the regenerants had phenotypes intermediate between those of the parents. Southern hybridization analysis using a rice ribosomal DNA probe revealed that the regenerants contained both tall fescue- and Italian ryegrass-specific-DNA fragments. A cloned Italian ryegrass-specific interspersed DNA probe hybridized to total genomic DNA from Italian ryegrass and from the green regenerated somatic hybrid plants but not to tall fescue. Chromosome counts and zymograms of leaf esterases suggested nuclear genome instability of the somatic hybrid plants analyzed. Four mitochondrial probes and one chloroplast DNA probe were used in Southern hybridization experiments to analyze the organellar composition of the somatic hybrids obtained. The somatic hybrid plants analyzed showed tall fescue, additive or novel mtDNA patterns when hybridized with different mitochondrial gene-specific probes, while corresponding analysis using a chloroplast gene-specific probe revealed in all cases the tall fescue hybridization profile. Independently regenerated F. arundinacea (+) L. multiflorum somatic hybrid plants were successfully transferred to soil and grown to maturity, representing the first flowering intergeneric somatic hybrids recovered in Gramineae.

Cells, Cultured↗
PubMed1987

An investigation of human immune response to perennial ryegrass (Lolium perenne) pollen cytochrome c (Lol p X).

Cytochrome c (Lol p X) was purified from the pollen of perennial ryegrass (Lolium perenne). It was used in a sensitive double-antibody radioimmunoassay to determine specific IgG and IgE antibody (Ab) levels in the sera of grass-allergic human subjects and the relationship between immune responsiveness and HLA type. A total of 139 subjects were studied, including 63 subjects treated by grass immunotherapy and 76 untreated subjects. The sera of only four subjects were found to contain anticytochrome c IgG Ab; there was no evidence of cytochrome c-specific IgE Ab in any of these patients. Based on these data, we conclude that the prevalence of IgE and IgG Ab responses to this protein is low. Because of the small number of responders, it was not possible to demonstrate a significant association between any HLA-D specificity and immune responsiveness to ryegrass cytochrome c.

Adult↗
PubMed1987

A study of the human immune response to Lolium perenne (rye) pollen and its components, Lol p I and Lol p II (Rye I and Rye II). II. Longitudinal variation of antibody levels in relation to symptomatology and pollen exposure and correction of seasonally elevated antibody levels to basal values.

This study used a standardized, dialyzed, Lolium perenne (ryegrass) pollen extract and two of its well-characterized components, Lol p I (Rye I) and Lol p II (Rye II), to characterize the longitudinal variation of both IgE and IgG antibody (Ab) levels, as well as total serum IgE levels, in 20 grass-allergic subjects followed for 13 months. Ab levels declined toward a basal level just before, and increased just after, the grass-pollination season, returning to the same basal level just before the next grass-pollination season. The least complex allergen, Lol II, demonstrated the most uniform pattern of variation in both IgE and IgG Ab levels. Total serum IgE levels demonstrated the least regular pattern of variation. Grass-pollen counts were strongly correlated with symptom-medication scores for these subjects (rs = 0.87). Initial values were correlated with the rise in total IgE and IgE Ab to Lol II across the grass-pollen season. Skin test results were correlated with initial IgE Ab levels for L. perenne pollen extract and Lol II. Finally, a procedure for correcting IgE Ab levels to basal values was proposed and tested. The correction procedure, for each IgE Ab, was based on the average rise during the grass-pollination season (or average decline after the grass-pollination season) observed for all subjects with that IgE Ab.

Adult↗
PubMed1989

Human immune responsiveness to Lolium perenne pollen allergen Lol p III (rye III) is associated with HLA-DR3 and DR5.

A well-characterized allergen of Lolium perenne (perennial rye grass) pollen, Lol p III, has been used as a model antigen to study the genetic control of the human immune response. Associations between HLA type and IgE or IgG antibody (Ab) responsiveness to Lol p III were studied in two groups of skin-test-positive Caucasoid adults (N = 135 and 67). We found by nonparametric and parametric analyses that immune responsiveness to Lol p III was significantly associated with HLA-DR3 and DR5. No association was found between any DQ type and immune responsiveness to Lol p III. Geometric mean IgE or IgG Ab levels to Lol p III were not different between B8+, DR3+ subjects and B8-, DR3+ subjects, showing that HLA-B8 had no influence on the association. Lol p III IgG Ab data obtained on subjects after grass antigen immunotherapy showed that 100% of DR3 subjects and 100% of DR5 subjects were Ab+. A comparison of all the available protein sequences of DRB gene products showed that the first hypervariable region of DR3 and DR5 (and DRw6), and no other region, contains the sequence Glu9-Tyr-Ser-Thr-Ser13. Our observations are consistent with the possibility that immune responsiveness to the allergen Lol p III is associated with this amino acid sequence in the first hypervariable region of the DR beta 1 polypeptide chain.

Adult↗
PubMed1989

Complete primary structure of a Lolium perenne (perennial rye grass) pollen allergen, Lol p III: comparison with known Lol p I and II sequences.

The complete amino acid sequence of a Lolium perenne (rye grass) pollen allergen, Lol p III, determined by the automated Edman degradation of the protein and its selected fragments, is reported in this paper. Cleavage by enzymatic and chemical techniques established unambiguously the sequence for this 97-residue protein (Mr = 10,909), which lacks cysteine and shows no evidence of glycosylation. The sequence of Lol p III is very similar to that of another L. perenne allergen, Lol p II, which was sequenced recently; of the 97 positions in the two proteins, 57 are occupied by identical amino acids (59% identity). In addition, both allergens share a similar structure with an antibody-binding fragment of a third L. perenne allergen, Lol p I. Since human antibody responsiveness to all these three allergens is associated with HLA-DR3, and since the structure common to the three molecules shows high degrees of amphipathicity in Lol p II and III, we speculate that this common segment in the three molecules might contain or contribute to the respectively Ia/T-cell sites.

Allergens↗
PubMed1986

Physicochemical and immunochemical characterization of allergenic proteins from rye-grass (Lolium perenne) pollen prepared by a rapid and efficient purification method.

Three fractions of rye-grass (Lolium perenne) pollen extract have been isolated by preparative isoelectric focusing (i.e.f.) and characterized in terms of physicochemical and immunochemical properties. The purified components were designated 'R7' and 'R14' on the basis of their positions in relation to other rye-grass pollen extract components on SDS/polyacrylamide-gel electrophoresis and their apparent molecular masses were assessed as 31 and 11 kDa respectively. On i.e.f., R14 split into two components, one acidic (pI 5.0) and one basic (pI 9.0), termed 'R14a' and 'R14b' respectively, and R7 focused at pI 5.8. R7 and R14a were shown to be allergenic by skin-prick test and all three components were recognized by rye-grass-pollen-specific human IgE. On SDS/polyacrylamide-gel electrophoresis and i.e.f., R7 behaved in a manner identical with that shown by an authentic sample of Rye I and gave an amino acid analysis similar to published data [Johnson & Marsh (1966) Immunochemistry 3, 91-100] for Rye group-I isoallergens; the amino acid sequence of the first 27 N-terminal amino acids was also determined. Physicochemical analysis revealed that R14a was equivalent to Rye II and 14b to Rye III. Preparative i.e.f. followed by gel-permeation chromatography proved to be a rapid and efficient method for purifying the allergenic components of Rye I (R7), Rye II (R14a) and Rye III (R14b) from rye-grass pollen extract.

Amino Acid Sequence↗
PubMed1989

Characterization of the hydroxyproline-rich protein core of an arabinogalactan-protein secreted from suspension-cultured Lolium multiflorum (Italian ryegrass) endosperm cells.

An arabinogalactan-protein (AGP) purified from the filtrate of liquid-suspension-cultured Italian-ryegrass (Lolium multiflorum) endosperm cells by affinity chromatography on myeloma protein J539-Sepharose was deglycosylated with trifluoromethanesulphonic acid to remove polysaccharide chains that are covalently associated with hydroxyproline residues in the peptide component of the proteoglycan. The protein core, which accounts for less than 10% (w/w) of the intact proteoglycan, was purified by h.p.l.c. It has an apparent Mr of 35,000, but reacts very poorly with both Coomassie Brilliant Blue R and silver stains. Amino-acid-sequence analysis of the N-terminus of the h.p.l.c.-purified protein core and of tryptic peptides generated from the unpurified protein reveals a high content of hydroxyproline and alanine. These are sometimes arranged in short (Ala-Hyp) repeat sequences of up to six residues. Polyclonal antibodies raised against the protein core do not cross-react with native AGP, the synthetic peptide (Ala-Hyp)4, poly-L-hydroxyproline or poly-L-proline. The results suggest that the polysaccharide chains in the native AGP render the protein core of the proteoglycan inaccessible to the antibodies and that the immunodominant epitopes include domains of the protein other than those rich in Ala-Hyp repeating units.

Amino Acid Sequence↗
PubMed1985

The digestion of fresh perennial ryegrass (Lolium perenne L. cv. Melle) and white clover (Trifolium repens L. cv. Blanca) by growing cattle fed indoors.

1. Pure swards of perennial ryegrass (Lolium perenne L. cv. Melle) or white clover (Trifolium repens L. cv. Blanca) were harvested daily at three and two stages of growth respectively, and offered to housed cattle. The grass diets comprised primary growth (May) and two later regrowths of contrasting morphology (i.e. leaf: stem values of 1.54 and 2.84 respectively), and were characterized by high contents of water-soluble carbohydrate and neutral-detergent fibre and comparable in vitro dry matter (DM) digestibilities (mean 0.80). Total nitrogen content was higher on primary growth grass (34 g/kg DM) than on regrowths (23 g/kg DM) but lower than values obtained for the two clover diets (38 and 43 g/kg DM, respectively). The clover diets had lower water-soluble carbohydrate contents than the grasses, comparable cellulose, but lower neutral-detergent fibre contents and in vitro DM digestibilities of 0.70 and 0.77 respectively. 2. The experiment lasted from May until August, during which time a total of twenty-one young Friesian steers (initial average live weight 130 kg) were used to determine both nutrient supply to the small intestine (twelve animals) and apparent digestibility (nine animals). Each diet was offered at three levels of DM intake (i.e. 18, 22 and 26 g/kg live weight). A further six steers, all fed at the rate of 22 g DM/kg live weight, were used to determine the metabolizable energy contents of the five diets by means of open-circuit calorimetry. 3. The three grass diets and the later-cut clover had, as intended, quite similar in vivo organic matter digestibilities, but that of the earlier-cut clover was lower, and this was associated with a large number of flower heads in this crop at the time of feeding. 4. On the clover diets, proportionately less of the ingested organic matter appeared to be digested in the rumen (0.40) compared with the grass diets (0.58) (P less than 0.001). On the high-N primary grass and the clover diets, substantial rumen losses of N were detected (P less than 0.01) compared with regrowth grasses. 5. The metabolizable energy content of the primary growth of grass was 12.2 MJ/kg DM, whilst the values for the other two grass diets were lower (11.6 MJ/kg DM), despite no marked decline in overall energy digestibility. Values for the two clover diets (mean 10.5 MJ/kg DM) were considerably lower than all values noted for the grasses.(ABSTRACT TRUNCATED AT 400 WORDS)

Animal Feed↗
PubMed1987

The use of monensin or formaldehyde to control the digestion of the nitrogenous constituents of perennial ryegrass (Lolium perenne cv. Melle) and white clover (Trifolium repens cv. Blanca) in the rumen of cattle.

Pure swards of perennial ryegrass (Lolium perenne cv. Melle) and white clover (Trifolium repens cv. Blanca) were harvested daily as primary growth (grass in May, clover in June) or regrowths (clover only in July) and offered, in the long form, to growing cattle at a feeding rate of 22 g dry matter/kg live weight. With each forage, two treatments were compared with the untreated forage (C): monensin (100 g active ingredient/kg, 250 mg/d) addition to the rumen (treatment M) or formaldehyde (30 g/kg crude protein (nitrogen X 6.25] application to the diet (treatment F). The objective of the experiment was to examine means of manipulating N metabolism in the rumen and the duodenal non-ammonia-N (NAN) supply derived from fresh forages. The apparent digestion of ingested organic matter (g/kg) in the rumen was unaffected by treatment M (C 509, M 497) but was significantly (P less than 0.01) reduced by treatment F (443). The extent of cellulose digestion in the rumen was not affected by any of the treatments imposed and the changes in organic matter digestion were due mainly to effects on N digestion and rumen microbial synthesis. On the untreated diets, duodenal NAN supply averaged 0.74 g/g N intake and treatment M caused a small but non-significant increase (M 0.79 g/g N intake). In contrast, the effect of treatment F was much larger (F 0.91 g/g N intake; P less than 0.01). These differences were accompanied by corresponding reductions in rumen NH3 concentrations (mg/l; C 350, M 310, F 220; P less than 0.001). Of the increased flow of NAN to the small intestine observed on the white clover only diets with treatment F, 0.70 was accounted for by an increased net synthesis of microbial N, while treatment M had no effect on microbial N synthesis and a marginal reduction in feed N degradability only with the regrowth white clover diet. Treatment F reduced feed N degradability to a limited extent on both clover diets (C 0.82, M 0.81, F 0.77). No corresponding measurements were made for the ryegrass diets. It is concluded that the extensive loss of N from the reticulo-rumen of cattle fed on fresh forages can be reduced by the use of agents to reduce protein solubility. However, the study demonstrated that treatment F may in some circumstances increase N supply to the small intestine more through enhancing microbial N synthesis within the rumen than through increasing the passage of undegraded feed N to the small intestine.(ABSTRACT TRUNCATED AT 400 WORDS)

Animal Feed↗
PubMed1988

The digestion of perennial ryegrass (Lolium perenne cv. Melle) and white clover (Trifolium repens cv. Blanca) by grazing cattle.

1. Pure swards of perennial ryegrass (Lolium perenne cv. Melle) as a primary growth (May), trimmed primary growth (early June) and regrowth (late June), and white clover (Trifolium repens cv. Blanca) as a mature primary growth (July) and vegetative regrowth (August), were grazed by twelve Friesian steers (mean body-weights throughout experiment 152-231 kg) at daily allocation rates of forage which provided dry matter (DM) intakes ranging from 28 to 36 g/kg body-weight). 2. Total nitrogen contents of the three ryegrasses declined with season (37-20 g/kg DM), but in vitro organic matter (OM) digestibilities were relatively constant (0.76-0.79). The clovers had higher N (average 36.6 g/kg DM) and lower fibre and water-soluble carbohydrate contents than the grasses, and in vitro OM digestibilities of 0.70 and 0.76 respectively. 3. Duodenal digesta samples were obtained, using a portable sampling apparatus from the animals grazing the pasture, and estimates of the flow of nutrients into the small intestine were derived using two indigestible markers which were continuously infused into the rumen using a portable infusion apparatus. Forage intakes were calculated from estimates of faecal output of indigestible OM and the predicted in vivo OM digestibilities of the forages consumed. Coefficients of variation for OM flow to the small intestine and OM intake were 11.8 and 10.9% respectively. 4. The apparent digestion of OM in the rumen ranged from 722 to 741 g/kg digestible OM intake and from 681 to 711 g/kg digestible OM intake for the grass and clover diets respectively. Substantial losses of ingested N before the small intestine were measured on all diets except the regrowth ryegrass. Losses were 0.30 and 0.40 g/g N intake on the primary growth ryegrass and the regrowth clover respectively; N contents were 37 and 39 g/kg DM respectively. 5. Comparison of the values obtained at pasture with that obtained when similar diets were offered to housed cattle (Beever et al. 1985) indicated that combined relations relating duodenal OM and non-ammonia-N (NAN) flows to OM and N intakes respectively could be established for each diet. For two diets (primary-growth grass and regrowth clover) the relations were curvilinear; for the remaining diets, the derived relations were linear.(ABSTRACT TRUNCATED AT 400 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1989

A comparison of the digestion and reduction in particle size of lucerne hay (Medicago sativa) and Italian ryegrass hay (Lolium italicum) in the ovine digestive tract.

Four types of hay were used: an early-cut and a late-cut lucerne (Medicago sativa) and an early-cut and a late-cut ryegrass (Lolium italicum). Digestibility and voluntary intake were measured on six adult sheep maintained in metabolism crates and fed 10% above the previous day's consumption, in equal portions at 08.00 and 16.30 hours. Lucerne intake was higher than that of ryegrass at similar digestibilities. The rate of digestion of the four hays was measured using nylon bags and the rates of digestion of dry matter for late-cut lucerne were faster than those for the late-cut ryegrass. Eleven adult sheep fitted with oesophageal (four), rumen (four) or duodenal (three) fistulas were used for collecting digesta samples at the different sites. They were fed successively with the four hay types. Each was offered to appetite, once daily, in a meal taken over 4 h. The rumen of rumen-fistulated sheep was completely emptied by hand once before feeding (08.00 hours) and once after removal of refusals (12.00 hours). The number of times the ingested hay was chewed during the meal and the time spent masticating was greater for the late-cut hays and greater for the ryegrass compared with the lucerne hays. The particle size of the boluses was greater than that of the rumen contents, which in turn was greater than that of the duodenal contents and faeces. The percentage of particles greater than 8 mm in the boluses from the ryegrass was higher than that of lucerne, and that of the early-cut ryegrass was greater than that of the late-cut ryegrass. This was also the case for the percentage of particles greater than 1.6 mm in the rumen contents after the meal. The rate at which dry matter disappeared from the rumen was greatest during the meal except with late-cut ryegrass; it was particularly high with late-cut lucerne, a little less with early-cut ryegrass and much lower with the other two hays. When nylon bags containing food boluses were placed in the rumen, it was apparent that without rumination, with the exception of the very digestible early-cut ryegrass, microbial degradation alone did not reduce the particle size.

Animals↗
PubMed1989

Particle breakdown and rumen digestion of fresh ryegrass (Lolium perenne L.) and lucerne (Medicago sativa L.) fed to cows during a restricted feeding period.

1. Five rumen-fistulated cows were given freshly cut ryegrass (Lolium perenne L.) and lucerne (Medicago sativa L.), on separate occasions, to compare rates of particle breakdown and aspects of rumen fermentation. 2. Cattle were required to consume their daily allowance (offered ad lib.) in two 2 h feeding periods daily. 3. During the first 2 h feeding period, dry matter (DM) intakes of ryegrass (4.75 kg) and lucerne (4.85 kg) were similar. Eating reduced 46% of ryegrass and 61% of lucerne to a size able to pass a 2 mm sieve (P less than 0.001). Rumen DM particles retained on the 2 and 4 mm sieves had a low probability of passage out of the rumen, and accounted for only 6% of faecal DM with both feeds. 4. Ryegrass was cleared from the rumen more slowly than lucerne. During eating, rumen DM particles which could not pass the 2 mm sieve increased from 323 to 511 g/kg for ryegrass and from 201 to 389 g/kg for lucerne. The rate of particle size reduction for lucerne stem was similar to that for ryegrass. 5. When lucerne was eaten the increases in rumen volatile fatty acid (VFA) and ammonia concentrations were much greater than for ryegrass (P less than 0.001). The proportions of plant chlorophyll released during eating were similar for both feeds (0.570 and 0.607), but 2 h after eating 22.3 g had been released from lucerne (79.1%) compared with 15.0 g from ryegrass (63.8%). The flux of water from the rumen to the omasum was similar for ryegrass (10.2 litres/h) and lucerne (12.7 litres/h) during eating, but declined to 6.0 litres/h after eating with the lucerne diet.

Ammonia↗
PubMed1993

T cell epitopes of the major fraction of rye grass Lolium perenne (Lol p I) defined using overlapping peptides in vitro and in vivo. I. Isoallergen clone1A.

One hundred and fifteen overlapping synthetic peptides spanning the entire sequence of the iso-allergen clone1A of Lol p I from rye grass Lolium perenne were synthesized by the multi-pin technique. The peptides were overlapping 12mers, offset by two residues and overlapping by 10 residues. Sets of six adjacent overlapping peptides (except pool-1, 15, 20) were pooled and were used in vitro and in vivo to map the T cell epitopes on Lol p I. Six atopics who were skin test and RAST positive to rye grass showed T cell responses to L. perenne extract (LPE) and its major fraction (Lol p I). Five out of six showed T cell responses in vitro to peptide pool-17, while five non-atopics did not respond to any of the peptide pools. By testing the individual peptides of pool-17, we have located the T cell epitope on Lol p I. Interestingly, when we tested pool-17 and its single peptides in vivo by intradermal skin testing we found in one patient a typical DTH after 24-48 h to pool-17 and its peptides (peptides 3 and 4) which exactly matched the in vitro responses. By defining the T cell epitopes in this way a greater understanding of the allergic response to pollen will be obtained, and a more effective and less dangerous vaccine may be possible for treating patients with hay fever.

Adult↗
PubMed1987

Distribution of a major allergen of rye grass (Lolium perenne) pollen between other grass species.

Polyacrylamide gel electrophoresis in sodium dodecyl sulphate (SDS) followed by protein staining has shown that extracts from 11 different grass pollens contained proteins with similar molecular weights to that of the allergen R7 from rye grass (Lolium perenne) pollen extract (i.e. 29,000-31,000 daltons). Western blotting and detection with polyclonal (rabbit) antibodies raised against the purified R7 (Rye I) allergen indicated that these proteins were antigenically related and their allergenic properties were demonstrated by the binding of human IgE to immunoblots. The distribution of cross-reacting antigenic determinants was further investigated by immunoblotting with 2 mouse monoclonal antibodies, R7M1 and R7M2, produced with purified R7 as the initial immunogen. The 2 monoclonal antibodies were shown to react with 'R7-like' components of grass pollen extracts other than the component from rye grass. Differences in the distribution of R7M1 and R7M2 binding were found indicating that they are directed at separate R7 epitopes.

Allergens↗