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L6, IL-TMP, and TM4SF5 are cell surface proteins predicted to have four transmembrane domains. Previous sequence analysis led to their assignment as members of the tetraspanin superfamily. In this paper, we identify a new sequence (L6D) that is strikingly similar to L6, IL-TMP, and TM4SF5. Analyses of these four sequences indicate that they are not significantly related to genuine tetraspanins, but instead constitute their own L6 superfamily.

CD37 is a membrane protein of the tetraspanin superfamily, which includes CD9, CD53, CD63, CD81, and CD82. Many of these molecules are expressed on leukocytes and have been implicated in signal transduction, cell-cell interactions, and cellular activation and development. We generated and analyzed mice deficient for CD37. Despite the high expression of CD37 on cells of the immune system, no changes in development and cellular composition of lymphoid organs were observed in mice lacking CD37. Analyses of humoral immune responses revealed a reduced level of immunoglobulin G1 (IgG1) in the sera of nonimmunized mice and an alteration of responses to T-cell-dependent antigens. Antibody responses to model antigen administered in the absence of adjuvant and to viral infections were generally poor in CD37-deficient mice. These poor antibody responses could be overcome by the immunization of antigen together with adjuvant. These results suggest a role for CD37 in T-cell-B-cell interactions which manifests itself under suboptimal costimulatory conditions.

The Tetraspanin/Transmembrane-4 Superfamily of cell surface molecules is defined by their four highly conserved transmembrane domains and is found in a wide variety of species and cell types. A common function for these molecules has yet to be discovered, however their broad expression patterns and conservation over evolution suggests that they will have an important general function relevant to many cell lineages. Here we describe the cloning and characterisation of the murine homologue of a recently described member of this superfamily, tspan-3. Murine tspan-3 was remarkably similar to the human molecule showing 88% identity at the nucleic acid level and 98% homology on the amino acid level. Northern blot analyses of mouse tspan-3 show a very broad pattern of expression, with expression readily detected in most organs including neural and bone marrow derived tissues.

TM4-B is a novel member of the Tetraspanin superfamily and displays characteristics typical of the superfamily. It bears significant homology to other superfamily members and is most similar to Tspan-1. This molecule is broadly expressed in most human tissues and cell lines including neural and bone marrow derived tissues. TM4-B was mapped to the q34 region on human chromosome 9.

The Schizosaccharomyces pombe dim1(+) gene is required for entry into mitosis and for chromosome segregation during mitosis. To further understand dim1p function, we undertook a synthetic lethal screen with the temperature-sensitive dim1-35 mutant and isolated lid (for lethal in dim1-35) mutants. Here, we describe the temperature-sensitive lid1-6 mutant. At the restrictive temperature of 36 degrees C, lid1-6 mutant cells arrest with a "cut" phenotype similar to that of cut4 and cut9 mutants. An epitope-tagged version of lid1p is a component of a multiprotein approximately 20S complex; the presence of lid1p in this complex depends upon functional cut9(+). lid1p-myc coimmunoprecipitates with several other proteins, including cut9p and nuc2p, and the presence of cut9p in a 20S complex depends upon the activity of lid1(+). Further, lid1(+) function is required for the multiubiquitination of cut2p, an anaphase-promoting complex or cyclosome (APC/C) target. Thus, lid1p is a component of the S. pombe APC/C. In dim1 mutants, the abundances of lid1p and the APC/C complex decline significantly, and the ubiquitination of an APC/C target is abolished. These data suggest that at least one role of dim1p is to maintain or establish the steady-state level of the APC/C.

One possible method to inhibit specifically the function of a protein inside a cell is to express an intracellular antibody combining site that can block function or prevent expression of the targeted molecule. In this report the parameters involved in the production and expression of functional, endoplasmic reticulum-retained, single chain Fv antibody fragments (scFv) were investigated. These intracellular scFv constructs were tested for their ability to inhibit specifically the expression of a CHO cell line pretransfected with the relevant cell surface antigen CD2. No scFv was detected in the cell supernatant although functional scFv, as assayed by ELISA, was detected in an NP-40 soluble fraction if an N-linked glycosylation site had been introduced into the antibody construct. This demonstrates that functional antibody combining sites can be produced even though they are not secreted. Inhibition of CD2 was obtained but was not complete and differed between clones. Levels of scFv could be increased by gene amplification but the level of functional binding activity remained constant and no further inhibition of CD2 expression was obtained. Immunofluorescence analysis at the single-cell level of the permeabilised transfected cell lines showed that less than 8% of cells expressed detectable levels of intracellular scFv, indicating selection against cells producing high levels of single-chain antibody. This selection was not seen when comparable single-chain TCR constructs, known to be retained intracellularly, were used. Thus, production of scFv with binding activity is not sufficient for good inhibition of gene expression although introduction of an N-linked glycosylation site is beneficial. The best strategy is probably to screen a panel of scFv constructs and use those that are secreted rather than those that are retained intracellularly.

The leukocyte surface antigen CD37 is a member of the transmembrane 4 superfamily (TM4SF) of glycoproteins which are predicted to span the lipid bilayer four times. The protein sequence and gene structure of mouse CD37 (Cd37) have been deduced through the isolation of cDNA and genomic clones. The Cd37 gene produces a major mRNA transcript of 1.2 kb that is restricted to cells of lymphoid and myeloid origin. Mouse CD37 is a glycoprotein of 281 amino acids in length, encoded by eight exons that span approximately 5.2 kb. CD37 is highly conserved between species, the mouse sequence sharing amino acid identities of 98% and 79% with rat and human, respectively. Cd37 shows a striking similarity in genomic organisation to other members of the TM4SF, which is consistent with the theory that this superfamily has evolved by gene duplication and divergence from a common ancestral gene.

The pan-leukocyte antigen CD53 is a member of the poorly understood transmembrane 4 superfamily (TM4SF) of cell membrane glycoproteins. CD53 is proposed to play a role in thymopoiesis, since rat CD53 is expressed on immature CD4-8-thymocytes and the functionally mature single-positive subset, but is largely absent from the intermediate CD4+8+ cells. We have characterized CD53 in the mouse through the production of two new monoclonal antibodies, MRC OX-79 and OX-80, which were raised against the RAW 264 cell line and screened on recombinant CD53 fusion proteins. The epitopes recognized by both antibodies are dependent on disulfide bonding and map to the major extracellular region of CD53, requiring the presence of a single threonine residue at position 154. Mouse CD53 has a molecular mass of 35-45 kDa and is expressed on virtually all peripheral leukocytes, but not on cells outside the lymphoid or myeloid lineages. CD53 expression distinguishes subpopulations of thymocytes in the mouse and resembles the expression pattern of rat CD53. Amongst the immature CD4-8-thymocytes, mouse CD53 is clearly detectable on the earliest CD44high25- subset, but down-regulated on the later CD44high25+, CD44low25+ and CD44low25- stages. Also, the subsequent transient TcR-/low CD4-8+ cells and most CD4+8+ thymocytes express little or no CD53. This is consistent with the idea that cells which are committed to enter the selectable CD4+8+ compartment switch off CD53. The effect of T cell receptor (TcR) engagement on the re-expression of CD53 on CD4+8+ thymocytes was studied both ex vivo and in vitro using F5 mice, transgenic for the H-2b/influenza nucleoprotein-peptide-specific TcR, back-crossed onto an H-2q or H-2b background of RAG-2-deficient mice. CD4+8+ thymocytes from non-selecting H-2q F5 mice are CD53 negative, but in vitro stimulation through the TcR dramatically induces CD53 expression. In contrast, a fraction of CD4+8+ thymocytes from positively selecting H-2b F5 transgenic mice express CD53. Therefore TcR engagement by selecting major histocompatibility complex peptide complexes, or surrogate ligands, induces CD53 expression on otherwise CD53-negative, non-selected CD4+8+ thymocytes. Whether CD53 itself participates as a signaling molecule in further stages of thymic selection is still a matter of speculation.

Cell surface proteins of the transmembrane 4 superfamily (TM4SF) are a newly characterized family of proteins which are presumed to span the plasma membrane four times. The function of this family of molecules is poorly understood, but based on monoclonal antibody studies there is some evidence that they may be involved in transmembrane signal transduction and regulation of cell proliferation, differentiation, or both, in a number of different cell types. CD53 is a member of this family that is expressed on leukocytes, and transduces activation signals through unknown mechanisms that may involve phosphorylation events. However, CD53 has never been shown to associate directly with kinases. Here, we show by immunoprecipitation from cell lysates of lymph nodes and a thymoma cell line, that immune complexes of rat CD53 contain tyrosine phosphatase activity. The CD53-associated phosphatase was able to dephosphorylate in vitro the phosphorylated tyrosine kinase Lck, as well as a synthetic substrate, and its activity was abrogated by a tyrosine phosphatase inhibitor. Although its identity has not been established, it is clear from depletion experiments that it is not CD45. CD63, a second member of the TM4SF, also co-precipitates a phosphatase activity from rat basophilic leukemia cells. These results demonstrate that the TM4SF members associate with tyrosine phosphatases. It seems possible that such associated phosphatases may contribute to the signal transduction capacity of TM4SF molecules.

The recently discovered transmembrane 4 superfamily comprises a group of cell-surface proteins that are characterized by the presence of four hydrophobic domains, which are presumed to be membrane spanning. At least seven of these molecules are expressed on leukocytes, and it seems likely that they mediate signal transduction events that play a role in the regulation of cell development, activation, growth and motility.

The influence of intrauterine administration of catecholestradiol (4-hydroxylated estradiol) on lifespan of the initial postpartum corpus luteum was evaluated in suckled beef cows. In experiment 1, postpartum cows (n = 23) were untreated (CONTROL) or received intrauterine infusions (0700 and 1700 hr) of either vehicle (SAL) or catecholestradiol (CATE; 4 micrograms) from day 15 to 22 (day 0 = parturition). Blood samples were collected three times weekly (day 15 to 100) and analyzed for progesterone. In experiment 2, cows received twice daily intrauterine infusions of either vehicle (n = 18), or catecholestradiol (n = 19), from day 25 +/- .5 to day 30 +/- .5. Following the final infusion, calves were temporarily weaned from all cows for 48 hr. At the end of the 48 hr weaning period, cows in each infusion group received either an i.m. injection of 1,000 IU hCG (SAL+hCG, n = 9; CATE+hCG, n = 9) or no further treatment (SAL, n = 9; CATE, n = 10). Blood samples were collected daily for 21 d following calf removal and 3 times weekly through 100 d postpartum. In both experiments, the initial postpartum elevation in peripheral progesterone concentrations was characterized as either a short (< 5 d) or extended (> 8 d) luteal phase. In experiment 1, postpartum anestrous interval (60 +/- 3.4 d) and incidence of short luteal phases (77%) were similar among CONTROL, SAL and CATE treatments. In experiment 2, luteal phases were induced within 10 d of onset of weaning in 90, 100, 56 and 60% of cows in SAL+hCG, CATE+hCG, SAL and CATE treatments, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

CD53 is a pan-leukocyte surface glycoprotein which spans the plasma membrane four times and is a member of the transmembrane 4 superfamily (TM4SF). The protein sequence and gene structure of mouse CD53 (Cd53) were determined by isolation of both genomic and cDNA clones. CD53 is highly conserved in evolution, as mouse Cd53 was 91% identical to rat CD53 and 82% identical to human CD53. The mouse Cd53 gene spanned approximately 9.0 kb of DNA and encoded the 219 amino acid residues of CD53 over seven exons. The Cd53 gene produced a 1.8 kb transcript which was dramatically upregulated after cell activation. The mouse Cd53 gene was mapped to chromosome 3, whereas the locus of another TM4SF member, CD37 (Cd37), was mapped to mouse chromosome 7. Three lines of evidence suggest that the TM4SF arose divergently from an ancestral gene. First, the gene structure of CD53 was strikingly similar to two other members of the TM4SF, CD63 and TAPA-1; second, Cd37 mapped to the same chromosome as Tapa-1; and, third, Cd37 mapped to a segment of chromosome 7 that contains a number of genes that are structurally or functionally related to genes closely linked to Cd53 on chromosome 3.

CD53 is a pan-leukocyte glycoprotein which is a member of the recently described Transmembrane 4 Superfamily (TM4SF) of membrane proteins that are predicted to span the lipid bilayer four times. The major hydrophilic region of murine CD53 was expressed as a glutathione-S-transferase fusion protein, and the epitopes of four mouse anti-rat CD53 monoclonal antibodies (mAb) (OX-44, 2D1, 6E2 and 7D2) were mapped to this region using mouse/rat chimeric fusion proteins. The epitopes of OX-44, 6E2 and 7D2 are restored by the substitution of a single isoleucine residue for threonine at position 154 in the mouse protein. The 2D1 epitope is non-linear and appears to require the juxtaposition of isoleucine at position 154 with one or more of the amino acids arginine (132), methionine (133) and serine (140). All of these epitopes are shown to be sensitive to reduction, thus indicating the importance of disulfide bonding in the correct folding of the CD53 hydrophilic domain. Moreover, as these four mAb recognize CD53 at the cell surface, the data provide direct molecular evidence for the proposed membrane orientation of the TM4SF.

The 23-kDa integral membrane proteins of Schistosoma mansoni and Schistosoma japonicum (Sm23 and Sj23) are Ag of some interest in terms of both antiparasite vaccination and immunodiagnosis. We have raised an antiserum against a recombinant fusion protein expressing the extracellular hydrophyllic domain of Sm23 (Sm23HD-pGEX) and used this serum, as well as other antibody reagents reacting with Sm/Sj23, in immunochemical analyses. The immunogenicity and antigenicity of Sm23HD-pGEX, and the surprising lack of cross-reactivity between Sm23 and Sj23 support the hypothesis that Sm/Sj23 are host-like molecules with a very limited number of B cell epitopes that are likely to reside in the extracellular hydrophilic domain. We also present evidence that, unlike the highly immunogenic Sj23, Sm23 is not immunogenic in chronically infected mice. Moreover, we confirm a surface location for Sj23 in adult worms, in S. japonicum.

Sj23, the 23-kDa target antigen in Schistosoma japonicum adult worms of the hybridoma monoclonal antibody (mAb) I-134, has been identified and cloned from cDNA libraries, mAb I-134 has been successfully used in immunodiagnostic assays to detect S. japonicum infection in Philippine patients. Sequence analysis has shown that Sj23 is the homologue, with 84% amino acid identity, of Sm23, a 23-kDa molecule from S. mansoni worms previously described from our laboratory. The domain structures of Sj23 and Sm23 are strikingly similar to the human membrane proteins ME491, CD37, CD53 and TAPA-1, which may suggest a functional role for the schistosome molecules in cellular proliferation.

The molecules discussed in this review include some of the leading vaccine candidates in schistosomiasis: the glutathione S-transferases, triose-phosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase and the 23 and 25 kDa surface integral membrane proteins. Mark Wright, Kathy Davem and Graham Mitchell highlight the possible biological roles and immunological relevance of these molecules.

Several attempts have been made to induce resistance in mice to Schistosoma japonicum (Philippines) or Schistosoma mansoni by exposure to living male and/or female adult worms, their antigens or irradiated cercariae. No resistance was demonstrated in the following cases: re-exposure of mice to cercariae following praziquantel (PZQ) treatment of existing infection; re-exposure of mice following cyclosporin A (CsA) treatment at the time of first cercarial exposure; subcutaneous or intraperitoneal deposition of living male or female worms; repeated intranasal administration of crude worm homogenates plus Bordetella pertussis vaccine (BPV) as adjuvant. Homologous 60Co-irradiated cercariae were very effective at inducing resistance to infection with S. mansoni but not to infection with S. japonicum (Philippines) in a limited series of experiments. A regime of infection, immunization with homologous Escherichia coli-derived glutathione-S-transferases (GST), then PZQ treatment followed by homologous re-exposure did not result in significant resistance in either the S. mansoni or the S. japonicum (Philippines) systems. Mice given irradiated cercariae plus GST were not more resistant to subsequent S. mansoni infection than mice given irradiated cercariae alone. The results generally confirm and extend those reported by others with the conclusion that resistance to schistosomes in mice is difficult to achieve by exposure to adult worm antigens alone. Moreover, additional immunization with the GST available to date as cloned gene products, and injected in Freund's complete adjuvant, does not influence the outcome of exposure to crude worm antigens including any additive effects of protective irradiated cercariae.

Two mouse strains maintained in this laboratory (WEHI) are variably resistant to infection with Schistosoma japonicum and S. mansoni in that worms cannot be found in the liver and portal system in a high proportion (WEHI 129/J mice) or low proportion (C57BL/6 mice) some weeks after exposure to cercariae. Resistance can be as high as 100% in WEHI 129/J mice and is usually around 20% in C57BL/6 mice. The proportion of resistant mice closely parallels the proportion of mice that demonstrate a shunting of microbeads, injected into a mesenteric vein, from liver to lungs. This applies to F1 x WEHI 129/J backcross mice in which the data suggest oligogenic genetic effects although no evidence for a participation of MHC-linked genes in the phenomenon has emerged. 129/J mice derived from the Jackson Laboratory do not show a shunting of beads from the portal system to the lungs but their progeny bred at WEHI do. Germ-free WEHI 129/J mice resemble conventionally-maintained, SPF-derived WEHI 129/J mice in their variable resistance to schistosome infection. No satisfactory explantation for hepato-portal system peculiarities in WEHI 129/J and C57BL/6 mice can be advanced as yet and a possibility raised in this paper is a contribution from nutritional factors such as hypervitaminosis A superimposed on a genetic predisposition in these two related mouse strains.

The effects of feeding a diet restricted in energy on the endocrine mechanisms regulating LH secretion in prepubertal heifers were examined. On Day 0, thirty heifers were assigned to be either ovariectomized (OVX; n = 10), ovariectomized and administered an estradiol implant (OVXE; n = 10), or to remain ovary-intact (INT, n = 10). Five heifers each were then assigned to be fed either a control (C) or a two-phase, low-to-high energy (L), dietary treatment. The C diet was formulated to support weight gains of 1.1 kg/day throughout the experiment (Day 0-197). Heifers receiving the L treatment were provided a diet restricted in energy (33% of C diet) from Day 0-127 followed by a diet similar to that fed to heifers receiving the C treatment from Day 128-197. Secretion of LH increased rapidly following ovariectomy in C-OVX and L-OVX heifers. During the period of energy restriction, LH pulse frequency was reduced, and mean LH concentration, pulse amplitude, and pituitary response to LHRH were greater in L-OVX than in C-OVX heifers. In L-OVXE and L-INT heifers, secretion of LH was low and unchanged during the period of dietary energy restriction. In contemporaneous treatment groups fed the C diet (C-OVXE and C-INT), frequency of LH pulses increased gradually during this period and C-INT heifers attained puberty on Day 121 +/- 18. Upon switching heifers in the L-OVX, L-OVXE, and L-INT treatments to the C diet, all characteristics of LH secretion changed markedly within 14 days to levels similar to those detected in the C treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Two experiments were conducted to study effects of cloprostenol sodium (cloprostenol) and clenbuterol HCl (clenbuterol) during postpartum anestrus on subsequent reproductive performance in cows. In Experiment I, 96 cows received either 0.5 mg cloprostenol (PGF, n = 25), 364 mg clenbuterol (CLEN, n = 24), 0.5 mg cloprostenol and 364 mg clenbuterol (CLEN+PGF, n = 21) or no treatment (Control, n = 26) on Day 20 post partum. Treatments failed to influence postpartum interval, pregnancy rate or the incidence of short estrous cycles preceding the first normal estrous cycle. In Experiment II, anestrous cows were administered cloprostenol (0.5 mg) on either Day 20 (PGF20, n = 27) or Day 35 post partum (PGF35, n = 25), or served as untreated controls (Control, n = 26). Neither postpartum interval nor pregnancy rate were affected by cloprostenol treatment. In conclusion, treatment of postpartum cows with PGF did not alter the resumption of normal estrous cycles following parturition.

A Mr 23,000 Ag of the human trematode parasite, Schistosoma mansoni, has been identified by immunoscreening an adult worm cDNA library with antibody affinity purified on the Mr 23,000 to 25,000 integral membrane protein fraction of the parasite. This Ag is immunogenic in infected humans as well as in rabbits exposed to S. mansoni. The protein sequence of the Ag as deduced from cloned DNA sequences is 218 amino acids long and contains four putative transmembrane regions. Of particular significance, the Ag is strikingly similar, with respect to both amino acid sequence (36% identity) and putative domain structure to ME491, a human stage-specific melanoma-associated Ag.

Both Schistosoma japonicum and S. mansoni contain 28- and 26-kDa glutathione S-transferases (GSTs). Despite their immunological cross-reactivity using rabbit antisera, the S. japonicum 28-kDa GST (Sj28) is weakly immunogenic relative to the S. mansoni protein (Sm28) in mouse immunization experiments using GSTs purified from adult worms. The difference in immunogenicity is also observed during schistosome infection in mice. Using surface-labeled living S. japonicum worms, evidence was obtained for a surface location of Sj28 comparable to that reported for the S. mansoni molecule. The nucleotide and deduced amino acid sequences of cDNA clones corresponding to Sj28 and Sm28 were compared. Despite obvious homology (77% identity), differences were found in regions known to contain T epitopes in the S. mansoni protein which may be an explanation for the striking differences in immunogenicity in regard to antibody production in mice. The 26-kDa GSTs of these two parasites (Sj26 and Sm26) are also closely related on the basis of nucleotide and deduced amino acid sequences, there being 82% identity in the putative coding regions. When the amino acid sequences of Sj28 and Sm28 were compared with those of Sj26 and Sm26, the overall sequence identity was approximately 20%. However, a relatively conserved region was identified in otherwise structurally different molecules which may participate in common properties of these enzymes.

In a study on the genetics of resistance to schistosomiasis in WEHI 129/J mice, susceptibility to either Schistosoma mansoni or Schistosoma japonicum was shown to be unequivocally dominant in F1 hybrid crosses between genetically resistant WEHI 129/J and susceptible BALB/c mice. The operation of only 1 or 2 genes in the expression of resistance to S. mansoni was suggested by backcross analysis. Thus, approximately 25% of (BALB/c x WEHI 129/J) F1 x WEHI 129/J mice were resistant to S. mansoni infection, whereas resistance was manifest in approximately 50% of WEHI 129/J mice. The data are consistent with resistance being controlled by 1 recessive gene having 50% penetrance. We also report that 129/J mice obtained directly from the Jackson Laboratories (Bar Harbor, Maine) (designated JAX 129/J), differ from locally bred WEHI 129/J in being entirely susceptible to S. mansoni infection. However, both WEHI 129/J and JAX 129/J are relatively resistant to S. japonicum infection.

The effect of agar sterilized by either boiling or autoclaving on human melanoma colony formation in soft agar was compared using cells from 17 biopsies of metastatic malignant melanoma. The frequency of colony formation was significantly increased for cells grown in boiled agar in 8 samples (47%), unchanged in 8 samples (47%), and decreased in only one sample (6%). There were increases in both cluster and colony formation for the melanomas which had augmented colony formation when grown in boiled agar. There was also qualitative morphological improvement, including rounder, smoother cells and less extracellular debris surrounding the colonies. These data suggest that melanoma colony formation is enhanced when cells are grown in agar which has been sterilized by boiling rather than autoclaving.

Mice of the strain WEHI 129/J are genetically resistant to chronic Schistosoma mansoni infection. Resistance is expressed in at least 50% of mice, with the remaining mice showing normal susceptibility to infection. The serum antibody specificities in the resistant proportion of WEHI 129/J were analyzed at various times after exposure to cercariae by using both Western blotting and immunoprecipitation. Comparisons with the susceptible proportion of WEHI 129/J and other permissive mouse strains revealed four antigens that were differentially recognized by resistant mice at various times of infection: Sm25, an Mr 25,000 integral membrane protein of adult worms that was better recognized by resistant mice 40 to 50 days after exposure; Sm67, an Mr 67,000 water-soluble antigen of adult worms that was better recognized by resistant mice at days 30 to 40; Sm120, an Mr 120,000 antigen expressed by cercariae and adult worms that was differentially recognized, although inconsistently, at days 20 to 40 postexposure; and Sm26, an Mr 26,000 glutathione S-transferase that was uniquely recognized by resistant mice at day 20 in two of three experiments. Analysis of antibody specificities in (BALB/c x WEHI 129/J)F1 x WEHI 129/J backcross mice indicated that high responsiveness to Sm25 at days 40 to 50 correlated with resistance. The candidacy of these four molecules as vaccines for schistosomiasis mansoni is discussed.

When aqueous extracts of Schistosoma japonicum and S. mansoni adult worms are passed over columns of glutathione-conjugated agarose, two molecular species of Mr 26,000 and Mr 28,000 are detected in eluates as analysed by SDS-PAGE, these eluates having glutathione S-transferase (GST) activity. The molecules, termed Sj26 and Sj28 from S. japonicum and Sm26 and Sm28 from S. mansoni, can be immunogenic in rabbits or mice and appear not to be linked together as subunits of GST heterodimers. The elution profile of SjGST (Sj26+Sj28) from glutathione columns resembles that of SmGST (Sm26+Sm28) and, by peptide mapping, radioiodinated Sj26 and Sm26 are related as are the two Mr 28,000 molecules. Similarities between radioiodinated Sj28 and Sm28 are also obvious on two-dimensional gel electrophoresis with some differences being observed between Sj26 and Sm26. The Mr 28,000 molecules are more prominent than the Mr 26,000 molecules and, although Sj28 and Sm28 is a poor immunogen in mice, immunological cross-reactivity between Sj28 and Sm28 is generally more readily detected than that between Sj26 and Sm26. Whether experimental vaccination against schistosomiasis japonica and schistosomiasis mansoni reported with cloned GSTs can be improved by incorporation of both Mr 28,000 and Mr 26,000 species into the vaccine remains to be determined. On this point, the present data suggest that vaccination of mice with Sj26 plus Sm28 should be a useful means of increasing antibody responses to the GSTs of S. japonicum.

A series of trials was conducted to determine the effects of supplemental rumen-protected methionine (RPMet) and lysine (RPLys) on nutrient metabolism and performance. In situ RPMet N disappearance was less than 4% following 48 h of incubation and was not affected (P greater than .05) by diet or resultant ruminal pH differences, indicating that RPMet was well protected from ruminal microbial degradation. Thirty-five Dorset-sired crossbred wether lambs (avg wt 28 kg) fed ground corn-soybean hull diets supplemented with urea were randomly assigned to one of the following treatments: 1) 0% RPMet, 2) .03% RPMet, 3) .06% RPMet, 4) .09% RPMet or 5) .12% RPMet. Dry matter, fiber and N digestibilities and N retention were not affected (P greater than .05) by treatment. Plasma methionine concentration tended to increase linearly (P less than .07) with dietary RPMet level. Six Simmental X Angus steers (avg wt 427 kg) were fed a corn grain-corn silage diet supplemented with urea and five levels of RPMet: 1) 0%, 2) .04%, 3) .08%, 4) .12% and 5) .16%. The plasma methionine concentration increased linearly (P less than .01) with dietary RPMet level. In a steer performance trial, no improvements in feedlot performance resulted due to these RPMet levels (P greater than .05), suggesting that the control diet (0% RPMet) was meeting the methionine requirement of these steers. The effects of RPMet and RPLys on growing and finishing steer feedlot performance also were evaluated. Treatments were 1) urea control, 2) soybean meal positive control, 3) .09% RPMet + .06% RPLys, 4) .12% RPMet + .08% RPLys and 5) .15% RPMet + .10% RPLys. In the growing trial, added RPMet and RPLys did not improve steer feedlot performance. In the finishing trial, only steers fed .09% RPMet + .06% RPLys had higher (P less than .05) gains than those fed the urea control diet. These trials indicate that postruminal methionine and lysine supplies were not limiting feedlot steer performance.

Experimental observation of a laser-induced dipole-quadrupole collision between Sr and Ca is reported. The laser-induced collision cross section peaks at an applied photon energy equal to the energy defect of the initial and final states of the infinitely separated atoms. A cross section of 3 x 10(-14) cm(2) was induced at a laser-power density of 7 x 10(9) W/cm(2); the linewidth was 20 cm(-1).

Macrophages were pulsed with Listeria monocytogenes antigens by intraperitoneal injection prior to harvesting and thoroughly washing the cells. The pulsed macrophages were injected into the feet of Listeria-immune or naive mice to elicit a delayed hypersensitivity reaction. Where soluble Listeria antigen was used, presentation by donor macrophages to host T cells required identity within the I region of the H-2 complex. However, presentation of alcohol-killed Listeria organisms or of a living, temperature-sensitive mutant of Listeria was apparently not H-2 restricted. When T cells enriched in vitro for Listeria reactivity were injected into the feet of naive mice, they reacted in an H-2 restricted manner to antigen presented to them either by the pulsed macrophages or host cells apparently acquiring antigen from the original pulsed macrophages.

Constituents of beri-beri-producing diets, borderline diets, and protective diets given by Braddon and others were analysed for vitamin B(1) content by Cowgill. He used a long series of assays published by numerous investigators and calculated the various units and percentage values as milligram equivalents of a yeast powder. He thus obtained approximate vitamin B(1) values for these diets. He showed that these values, together with the incidence of beri-beri, justified the application to man of a formula obtained experimentally and gave an indication of man's minimum requirement of the vitamin.In this paper the vitamin B(1) value of the same diets has been obtained from direct assays against the International Standard of the constituent foods, raw or cooked, as usually eaten. These are in good agreement with the values drawn from the less direct calculation, and indicate that man's minimum requirement may vary according to weight and food intake between 200 and 500 units daily.The desirable level of B(1) intake for adults and children has been studied by analysing in the same way a series of diets recommended by public bodies or by dietitians in England and America. Adults on good diets consume 450 to 750 units daily. High vitamin diets may contain about 1,500 units.Diets recommended for children show relatively higher levels than those for adults, that of a child aged 4 years having nearly 400 units and that of a child aged 11 years having about 650.