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D D Despommier

Publications and source records attributed to D D Despommier.

At least 37 records · Page 2Linked to original sources
PubMed1984

Immunization of swine against Trichinella spiralis.

Swine were immunized with partially purified stichosome antigens derived from Trichinella spiralis muscle larvae. In 3 trials, 500 to 600 micrograms of the solubilized particle component (S3) induced moderate levels of resistance to challenge inoculation; the percent reduction in larvae per gram of muscle ranged from 43 to 55. The effect of immunization with S3 on pig intestinal expulsion of adult worms was determined in one experiment and the results indicated that S3 immunization was only weakly effective in enhancing gut expulsion. These results suggest that immunization with S3 induces a protective immune response in the pig that may be directed either against the migrating newborn larvae or against adult worm fecundity.

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PubMed1984

Antigens from trichinella spiralis that induce a protective response in the mouse.

A series of monoclonal antibodies was generated for the purpose of studying antigens of the infective L1 larva of Trichinella spiralis. Primary immunization of donor BALB/c mice was by oral infection with L1 larvae. Secondary immunization and screening procedures for hybridoma clones employed a pool of affinity-purified antigens recognized by pooled serum from infected rabbits. Three monoclonal antibodies, chosen for their high reactivity in screening assays and their unique specificities, were raised in quantity, purified, and attached to Sepharose 4B for affinity chromatography. The antigens selected by each affinity column were of different m.w. (37K, 48K, and 50/55K) and possessed different abilities to induce protection. The 48K antigen induced a high level of protection at biologically relevant doses (1.0 and 0.1 micrograms protein/mouse). The 50/55K antigen induced a lower level of protection than the 48K antigen, but was still effective at similar doses. The 37K antigen elicited protection only at a dose of 50 micrograms protein/mouse, and was not as effective as the unpurified antigen at any dose. Earlier studies indicated that many antigens involved in the immune response are secreted. Therefore, worm secretions and two subcellular fractions of homogenized worms (S2 = cytosol, S3 = soluble portion of the large particle fraction) were analyzed for content of the three purified antigens by a double antibody sandwich enzyme-linked assay. The 48K and 50/55K antigens represent significant components of the secretions (12% and 5%, respectively) but relatively minor components of the S2 and S3 fractions. The 37K antigen represents a major component of the S2 fraction, but is essentially absent from S3 and secretions. Immunocytolocalization studies employing immunoperoxidase methods on infected muscle tissue show that the 48K antigen is located in the beta-stichocytes, the lining of the gut, and the surface of the cuticle. The 50/55K antigen was detected in the alpha-stichocytes and was occasionally observed in the gut or on the cuticle. The 37K antigen was detected only in the pseudocoelom. The results from the quantitative ELISA and immunocytolocalization show that the two antigens that induce a protective response are secreted proteins. These data constitute the first account of antigens purified from a nematode that induce a strong protective response. One of these (48K) confers a level of protection comparable to that elicited by exposure of an entire infection.

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PubMed1981

Partial purification and characterization of protection-inducing antigens from the muscle larva of Trichinella spiralis by molecular sizing chromatography and preparative flatbed isoelectric focusing.

The soluble portion of a large particle fraction which was derived from the muscle larva of T. spiralis was subjected to molecular sizing column chromatography using Sephacryl S-200. Five major peaks of 280 nm absorbing material were obtained. Analysis by immunoelectrophoresis revealed that each peak contained antigens, with the majority of them occurring in peaks 3, 4 and 5. Preliminary studies indicated that peak 4(mol. wt range 20 000--10 000) contained protection-inducing antigens. Crossed-immunoelectrophoretic and single-dimension electrophoretic analysis of peak 4 revealed a minimum of 10 antigens, while analytical isoelectric focusing demonstrated the presence of proteins with widely different pl, ranging from 4.0 to 9.0. Peak 4 was fractionated by preparative flatbed isoelectric focusing (PIEF) using two gradients: one from 3.5 to 9.5 and the other from 3.5 to 5.5. Fused rocket immunoelectrophoretic (FRIEP) analysis of both runs indicated that several antigens were separated from the others: one at pl 4.0 and the other at pl 9.0. The remaining antigens focused between pl 4.3 and 4.9. One hundred micrograms of whole peak 4, pl 9.0 antigen and the group of antigens at pl 4.3--4.9 were each separately injected, along with Freund's complete adjuvant, into mice. In addition, a portion of the pl 4.0 antigen was also assayed for protection. All antigenic preparations induced significant levels of protection. The pl 4.0 was further analysed on high-performance liquid chromatography (HPLC). Two sharp peaks of antigen, as detected by FRIEP, were eluted isocratically with 65% acetonitrile from a C-18 (aliphatic) column. Both peaks of antigen showed complete cross-reactivity on FRIEP and absorbed at 220 nm. Amino acid analysis of each HPLC peak revealed no detectable differences in composition. Each peak contained predominance of aspartic (13 mol%) and glutamic (18 mol%) acid. This antigen did not contain significant quantities of aromatic amino acids, and absorbed strongly at 206 nm. Neither the pl 4.0 or pl 9.0 antigen stained positively with the PAS reaction.

Amino Acids↗
PubMed1981

Trichinella spiralis: partial characterization of antigens isolated by immuno-affinity chromatography from the large-particle fraction of the muscle larvae.

A large-particle fraction, derived from muscle larvae of Trichinella spiralis by a combination of homogenization and differential centrifugation, was treated with 0.1% Triton X-100 and then centrifuged at high speed in order to obtain the soluble portion of this fraction (i.e., S3 fraction). The S3 fraction was then subjected to immuno-affinity chromatography. The antigens were eluted from the column using glycine-HCl buffer (pH 2.5). All 20 antigens were recovered from the S3 fraction in quantities that permitted physical, chemical, and biological determinations to be made on them. Antigens analyzed on SDS-PAGE ranged in molecular weight from 105,000 to 11,000 daltons Their isoelectric points were estimated with slab gel isoelectric focusing and ranged in pI from 4.0 to 9.0. The column-purified antigens were injected into mice together with an equal volume of Freund's complete adjuvant, and 2 wk later all mice were each challenged with 200 muscle larvae given orally. Immunized mice harbored 84% fewer muscle larvae at day 30 postinfection than controls, and were as immune as those mice receiving whole S3 (86% reduction). These results showed that protection-inducing antigens can be separated from the nonprotective portion of the muscle larva by immuno-affinity chromatography without loss of protection-inducing activity.

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PubMed1977

The in vivo and in vitro analysis of immunity to Trichinella spiralis in mice and rats.

Wistar-Furth strain male rats and CFW strain male mice were immunized against Trichinella spiralis using an antigenic fraction derived from a cell-free homogenate of mature muscle larvae. In rats, animals immunized with 250 mug of antigen harboured significantly fewer (135000) muscle larvae 30 days after oral challenge than controls (231000). Further 7-day-old adult worms derived from immunized rats shed 48% fewer (P less than 0.001) newborn larvae over a 24h period in vitro than adult worms from non-immunized animals. Mice were injected with either 10 or 100 mug of antigen. In comparison with non-immunized controls, mice immunized with 100 mug of antigen harboured significatnly fewer adult worms at days 7 and 9 after oral challenge infection, while female worms recovered from immune mice on days 6-10 after challenge shed fewer newborn larvae in vitro. Finally, mice immunized with 100 mjg of antigen harboured significantly fewer (10391) muscle larvae at 30 days after challenge than did controls (47750). Immunization of mice with 10 mug of antigen did not induce a statistically significant reduction in adult worms at either day 7 or 9 after challenge (P less than 0.5). However, adult female worms from mice receiving 10 mug of antigen still shed fewer larvae than did adults from control mice (P less than 0.05). Mice immunized with 10 mug of antigen harboured significantly fewer (13700) recoverable muscle larvae than did controls at 30 days after challenge (39000).

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PubMed1977

Immunity to Trichinella spiralis. I. Transfer of resistance by two classes of lymphocytes.

Rats can be solidly immunized against Trichinella spiralis by a series of methyridine-terminated oral infections with T. spiralis larvae. Injections of thoracic duct lymphocytes (TDL) obtained from such animals can protect normal rats against a Trichinella challenge. The protective cells belong to two populations which differ with respect to their adherence to affinity columns prepared with rabbit antibody to rat F(ab')2. Immune lymphocytes in the column-adherent B cell fraction are inhibited by vinblastine, whereas those in the non-adherent, T cell fraction are resistant to this drug. The above observations suggest that acquired resistance to T. spiralis is mediated by two classes of lymphocytes: B cells which are delivered to the thoracic duct and hence to the blood while still in active cycle, and T cells which have a potentially long life-span and presumably belong to a pool of recirculating small lymphocytes.

Animals↗
PubMed1977

Immunity to Trichinella spiralis. II. Expression of immunity against adult worms.

Thoracic duct lymphocytes or purified T or B cells obtained from specifically immunized (Lewis x DA)F1 hybrid rats can protect normal recipients against an oral challenge infection with T. spiralis. The immune cells increase the rate of expulsion of adult worms from the small intestine. Immune TDL do not affect adult worm fecundity, as they do in other strains of rats, or the penetration and development of newborn larvae in muscle cells. Irradiated F1 rats reconstituted with either immune TDL or class-enriched populations of immune T or immune B cells also expel adult Trichinella more rapidly than do unprotected controls. However, unfractionated TDL and inocula enriched in B cells are more efficient than T cells in promoting worm expulsion. The above finding, taken in conjunction with the tissue disposition of labelled lymphocytes in the tissues of recipient rats, implies that immune T cells have a 'helper' function in promoting the formation of protective B cells.

Animals↗
PubMed1976

The stichosome and its secretion granules in the mature muscle larva of Trichinella spiralis.

The stichosome of the mature muscle larva of Trichinella spiralis consists of a single row of 45 to 55 stichocytes. Each stichocyte is about 25 mum in diameter and possesses a single nucleus. A duct leads from each stichocyte to the lumen of the esophagus. The stichocyte cytoplasm contains mitochondria, structures resembling Golgi-complexes, rough endoplasmic reticulum, and usually 1 of 2 types of secretory granules. The alpha-granule measures about 800 mn in diameter, contains a prominent inclusion, and has a granular matrix. The beta-granule is about 600 mn in diameter and is homogeneous in appearance. Both granule types are surrounded by a single membrane. Ten to thirteen stichocytes containing alpha-granules are confined to the posterior portion of the stichosome. After isopycnic centrifugation in sucrose gradient of large granule fractions obtained from cell-free homogenates, the alpha- and beta-granules show characteristic distribution patterns as revealed by the morphology of the fractions. The median equilibrium density of the alpha-granules is 1.245, while that of the beta-granules is 1.230. There is a correlation between the distribution of the granules and of antigens reacting with hyperimmune antitrichinella seruma. At least 4 unique antigens can be attributed to each of the granule types. Fractions enriched in mitochondria do not contain specific antigens. Antigens from both types of secretory granules cross react totally with those present in the excretion-secretion products of living muscle larvae. Cytoimmunochemical data show that antigens are distributed in a patchy fashion throughout the stichocyte cytoplasm. This finding is consistent with the distribution of the secretory granules in the intact stichocyte.

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