Opposite orientation of the alpha- and upsilon-chain constant region genes in the immunoglobulin heavy chain locus of the duck.
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Animals↗
Biomedical subjects
D A Higgins
Publications and source records attributed to D A Higgins.
Secretory immune system of the duck (Anas platyrhynchos). Identification and expression of the genes encoding IgA and IgM heavy chains.
IgA has not previously been identified in waterfowl. Studies instead revealed physical and antigenic similarities between duck bile immunoglobulin (Ig) and serum IgM. Here, a differential screening approach was used to clone, from a duck spleen library, the cDNA encoding the heavy (H) chains of IgM and the Ig, identified here as IgA, occurring in duck secretions. Phylogenetic comparisons of inferred amino acid sequences of entire H chain constant (C) regions and of individual domains revealed that the duck mu chain was closest to chicken mu (54% overall identity), and duck alpha was closest to chicken alpha (50% identity). Comparison of the mu and alpha C regions revealed areas of up to 65% amino acid similarity within the C4 domains, accounting for the previously noted antigenic overlap of duck IgM and IgA. Messages for alpha and mu were detected in duck lymphoid organs but the alpha message was most abundant in the respiratory, alimentary and reproductive tracts. The alpha message first appeared around 14 days of age and reached adult levels of expression only at 35-50 days. The results indicate that the duck has a mucosal immune system which utilizes IgA; however, the delayed expression and secretion of duck IgA explains the susceptibility of ducklings to mucosal pathogens. Since the waterfowl are among the most primitive extant birds, the recognition of IgA in the duck supports the conclusion that IgA occurs throughout the class Aves and also existed in the common ancestors of birds and mammals.
Amino Acid Sequence↗
MF59 adjuvant enhances the immunogenicity of influenza vaccine in both young and old mice.
The responses of young (8 week) and old (18 month) mice to influenza vaccine with and without the potent emulsion adjuvant MF59 were compared. In influenza naive mice, vaccine-specific antibody and T-cell proliferation were significantly lower in the old group compared to the young group. Post-immunization cytokine levels and antibody isotype profiles were different in the old compared to the young mice. The addition of the adjuvant MF59, a submicron oil-in-water emulsion composed of 5% v/v squalene, 0.5% v/v Tween 80 and 0.5% v/v Span 85, significantly increased the immune responses of both the young and old naive mice to the vaccine. The responses of the old mice given adjuvant increased to levels equivalent to those of young mice with vaccine alone. In mice previously infected with influenza virus, similarly depressed immune responses to vaccination were detected in the old mice. While the addition of MF59 to the vaccine had little effect on antibody titres of the previously infected young mice, the adjuvant significantly increased the antibody responses of the previously infected old mice. These results suggest that influenza vaccine combined with MF59 may significantly improve immune responses of elderly humans to influenza vaccination.
Adjuvants, Immunologic↗
Concerns about drawing causal inferences from meta-analyses: an example in the study of gender differences in aggression.
Meta-analysis has increasingly been used as an explanatory research tool. The present investigation was designed to illustrate the potential limitations of meta-analysis for making causal inferences. Several meta-analytic investigations have led others to conclude that gender differences are getting smaller over time, however, there has been little concern regarding changes in research methodology over time. The present findings indicate that the gender differences in aggression appear to be remarkably stable when changes in study characteristics over time are controlled. The authors discuss the implications for the use of meta-analytic procedures to make causal inferences and the implications for understanding the causes of gender differences.
Aggression↗
Purification of duck immunoglobulins: an evaluation of protein A and protein G affinity chromatography.
Duck serum proteins binding to protein A Sepharose CL-4B and protein G Sepharose 4 Fast Flow and eluted at pH 2.8 or 11.5 were characterized by sodium dodecyl sulphate polyacrylamide gel electrophoresis, radial/immunodiffusion against defined anti-immunoglobulin (Ig) reagents, and by the reactivity in immunoelectrophoresis of antisera raised in rabbits inoculated with the eluates. The results indicated that IgY (previous nomenclature 7.8S IgG) and IgY (delta Fc) (previously 5.7S IgG) bound to protein A efficiently and to protein G weakly, while IgM bound to protein A and protein G weakly. Some binding of non-Ig proteins also occurred. Attempts to separate the non-Ig proteins from the Igs by elution at different pHs (5.0, 4.0, 3.0 and 2.5) were unsuccessful, but it was found that precipitation of Igs in day-old duck serum with Na2SO4, followed by chromatography on protein A Sepharose, yielded relatively pure IgY. The efficient binding of the duck IgYs to protein A resembles high affinity binding of mammalian Igs but cannot be attributed to the Fc, as it is in mammals, since the IgY (delta Fc) does not have an Fc region. Instead, binding probably occurs through unique histidine residues occurring predominantly in the CH1 domain.
Amino Acid Sequence↗
Duck lymphocytes. VII. Selection of subpopulations using lectin-coated magnetic beads.
The optimum conditions (time, concentration of duck serum, ratio of cells:beads) for binding of duck lymphocytes to magnetic beads (Dynabeads) coated with the lectins phytohaemagglutinin (PHA), wheat germ agglutinin (WGA), lentil lectin (LL) and concanavalin A (Con A) were determined. In blood and lymphoid organs, the largest population was cells binding PHA (55-80%) and the smallest was cells binding Con A (0-15%) with cells binding WGA and LL occurring at 15-58%. Most blood lymphocytes had receptors for more than one lectin, though cells with receptors for WGA were mostly a subpopulation within those possessing receptors for PHA. It is possible that, as in some other animals, lectins identify functionally important duck lymphocyte populations. Notably, PHA deserves further investigation as a marker for duck T lymphocytes, while receptors for Con A appear to be associated with duck macrophages.
Animals↗
IgY: clues to the origins of modern antibodies.
IgY is the functional equivalent of IgG in birds, reptiles and amphibia, but many aspects of its biology are poorly understood. Recent studies have increased awareness of the genetics and functions of this molecule, and have revealed its position as the ancestor of the uniquely mammalian antibodies IgG and IgE. Here, Greg Warr, Kathy Magor and David Higgins review current knowledge of IgY structure, function and expression in the context of the evolutionary role of this primitive immunoglobulin.
Amphibians↗
One gene encodes the heavy chains for three different forms of IgY in the duck.
IgY, the major Ab of the duck (Anas platyrhynchos), exists in two secreted forms and a transmembrane (TM) form. To investigate the genetic relationships of the multiple IgY we cloned the gene encoding the IgY (upsilon) heavy chains. The heavy chain of the smaller (5.7S) IgY, which lacks the third and fourth constant domains, results from the use of a unique terminal exon found in the intron between the second and third C region exons. Alternate pre-mRNA processing pathways also produce a full-length upsilon-chain and a TM form, each having four C region domains. Although the number of secretory exons and the inferred positions of intramolecular disulfide bonds indicate structural similarity between IgY and IgE, the TM exons of duck IgY share high sequence identity and a similar pattern of RNA processing with those of IgG. These results suggest that IgG and IgE may have diverged from an ancestral molecule resembling IgY.
Alternative Splicing↗
HLA-DPB1 alleles correlate with risk for multiple sclerosis in Caucasoid and Cantonese patients lacking the high-risk DQB1*0602 allele.
Multiple sclerosis (MS) is a demyelinating disease associated with the HLA-DR2-related haplotype DRB1*1501, DQB1*0602 in Caucasoids and with DQB1*0602 in DR2-positive Cantonese. However, many MS patients do not have the high-risk HLA-D determinants and alternative genes may contribute to the pathogenesis of MS. One candidate gene is HLA-DPB1. Our reanalysis of five earlier reports of HLA-DPB1 antigen distributions in Caucasoid MS patients shows a consistent and highly significant increase (p = 1.5 x 10(-5)) in frequency of HLA-DPw3 in the combined data set. This study tests whether HLA-DPw3 (DPB1*0301) is also increased in frequency in Australian and Cantonese MS patients and whether any distortion in DPB1 allelic distributions can be attributed to linkage disequilibrium with DQB1*0602. PCR-RFLPs were used to determine distributions of 20 HLA-DPB1 alleles in 41 Australian MS patients and 67 controls of known DQB1*0602 status and in 11 Cantonese MS patients and 33 controls positive for HLA-DR2. HLA-DP distributions in Australian MS patients and controls positive for DQB1*0602 did not differ, but in those MS patients lacking DQB1*0602, the DPB1*0301 antigen (phenotype) frequency was significantly (p = 0.006) increased (50.0%) when compared with DQB1*0602-negative controls (9.1%). DPB1*0301 was associated (p = 0.003) with DQB1*0402 (DR8) in Caucasoid MS patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Alleles↗
Structural relationship between the two IgY of the duck, Anas platyrhynchos: molecular genetic evidence.
cDNA clones encoding the H chains of the 7.8S and 5.7S IgY of the White Pekin duck have been isolated and sequenced. The H chain of the 7.8S IgY possesses four C region domains and thus resembles the H chain of chicken IgY with which it shows, in the C region, 54% inferred amino acid sequence identity, and complete conservation of the C region cysteine and tryptophan residues. The H chain of the 5.7S IgY possesses only two C region domains, that are virtually identical to CH1 and CH2 of the 7.8S IgY H chain. Although Southern blot genomic analysis did not resolve whether the two transcripts encoding the H chains of the 7.8S and 5.7S IgY are derived from one or two H chain-encoding genes, the CH 1, 2, 3, and 4 exons are apparently colinear, and no evidence was found for a separate locus in which CH1 and 2 exons were present and CH3 and 4 exons were lacking. The VH domain-encoding sequences of the cDNA for the two IgY H chains showed high similarity in the inferred VH gene (93% nucleotide and 91% inferred amino acid identity) and in the inferred JH segment (89% nucleotide and 93% inferred amino acid identity) but low similarity in the D region (26% nucleotide and 7% inferred amino acid identity). Genomic Southern blot hybridization analysis showed multiple VH-hybridizing sequences represented on up to 20 restriction fragments.
Amino Acid Sequence↗
Duck lymphocytes. VI. Requirement for phagocytic and adherent cells in lymphocyte transformation.
Preparations of duck (Anas platyrhynchos) spleen and blood lymphocytes depleted of cells capable of phagocytosing carbonyl iron gave lower transformation responses to the mitogens phytohaemagglutinin (PHA), concanavalin A (Con A), Bandeiraea simplicifolia seed lectin (BSS), wheat germ agglutinin (WGA), lentil lectin (LL) and phorbol ester (PMA) than intact cell preparations. When cell populations were fractionated on the basis of their adherence to plastic, it was found that the adherent cells were responsive to PHA, Con A, BSS, WGA and PMA, while the non-adherent cells responded to LL. These observations confirm the expected requirement for phagocytic accessory cells in the induction of in vitro mitogen-driven duck lymphocyte responses. The responses of plastic-adherent populations of cells to most mitogens are believed to reflect the generally close physical relationship between the adherent accessory cells and the lymphocytes, although it remains possible that duck monocytes respond to some of the mitogens employed. The data also suggest that LL stimulates a population of cells different to those responding to other mitogens.
Animals↗
Duck lymphocytes--V. Transformation responses to phorbol ester and calcium ionophore.
1. Lymphocytes purified from duck blood and spleen were cultured in the presence of phorbol 12-myristate 13-acetate (PMA) and the calcium ionophore A23187. Stimulation was assessed by the incorporation of [3H]thymidine after 3 days' culture. 2. PMA stimulated over a wide range of concentrations, with maximum stimulation at final concentrations of 5 x 10(-7)-5 x 10(-8) M/litre. A23187 was effective in the range 5 x 10(-6)-5 x 10(-7) M/litre and also, in some experiments using spleen lymphocytes, at 5 x 10(-11)-5 x 10(-12) M/litre. 3. Synergism was observed between PMA and A23187, the pattern depending on the concentrations of these reagents employed. Synergism was also observed between PMA and suboptimum concentrations of phytohaemagglutinin (PHA), wheat germ agglutinin (WGA), pokeweed mitogen (PWM) and Bandeiraea simplicifolia seed extract (BSS), but not with concanavalin A (Con A), lentil lectin (LL) or Helix pomatia lectin (HP). Similarly, synergism occurred between A23187 and WGA or PWM, but not with PHA, BSS, Con A, LL or HP. 4. Mitomycin C and cycloheximide inhibited the response of duck lymphocytes to PMA, A23187 and lectins. Cyclosporin A inhibited responses to lectins but not to PMA or A23187. Neither hydrocortisone nor indomethacin inhibited responses to lectins, PMA or A23187. 5. These results indicate that activation of duck lymphocytes occurs by virtue of similar intracellular messenger pathways to those operating in mammalian lymphocytes.
Animals↗
Duck lymphocytes. IV. Collective effects of mitogens.
Duck (Anas platyrhynchos) blood lymphocytes were cultured in the presence of phytohaemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM), lentil lectin (LL), Roman snail lectin (HP), wheat germ agglutinin (WGA), Bandeiraea simplicifolia seed lectin (BSS), peanut agglutinin (PNA), horseshoe crab lectin (HSC) and bacterial lipopolysaccharide (LPS). Mitogens were used individually, in pairs, and in multiple combinations. Some pairs resulted in synergism; transformation, assessed by uptake of [3H]thymidine, was much greater than a direct addition of the effects of the two mitogens used separately. Best results were obtained when PHA or LL were paired with a second mitogen. In general, combinations of lectins at slightly suboptimal concentrations gave highest transformation, and all strongly synergistic combinations elicited a similar pattern of dose response through different concentrations of PHA. If a third mitogen was included, some combinations gave some further synergism, in other combinations the synergism of two mitogens was reduced by including a third, and if a pair of mitogens did not demonstrate synergism then none was generated when a third mitogen was included. Inclusion of more mitogens to successfully synergistic trios reduced transformation. The system could provide a useful model for in vitro enhancement of responses among lymphocytes from a species with a weak immune system.
Animals↗
Unusual pathology of the vertebrae and dorsal fin rays of the yellow conger pike eel, Congresox talabonoides, from Hong Kong.
Congresox talabonoides, the yellow conger pike eel, caught near Hong Kong, shows a high incidence of abnormal vertebrae and dorsal fin rays. Of 423 C. talabonoides examined during 1967-69, 244 (57.7 per cent) had a total of 999 macroscopically enlarged vertebrae, but 100 of each of the related species Muraenesox bagio and M. cinereus were unaffected. The gross and histological changes were investigated in 20 freshly caught specimens. Small eels (less than 80 cm) were not affected. Bigger specimens showed symmetrically enlarged, densely calcified vertebrae and fin rays, with more bones affected as the fish grew larger. X-rays showed that the calcification was uniform; various degrees of change were seen in X-rays of the fin rays, but the vertebrae appeared either highly radio-dense or normal. Histological examination showed deposition of dense cancellous lamellar bone, which appeared organized rather than random. In the case of the fin rays, the new bone surrounded each ray, but in the vertebrae the normal structure was replaced, then expanded. There is no clearly comparable pathology in mammals. Similar lesions in other species of fish have been attributed to toxins, but the incidence in C. talabonoides seems exceptional.
Animals↗
Duck lymphocytes--III. Transformation responses to some common mitogens.
The lymphocyte transformation (LT) test was performed using duck blood lymphocytes stimulated with phytohaemagglutinin (PHA), concanavalin A (Con A), lentil lectin (LC), Roman snail lectin (HP), peanut agglutinin (PNA), Bandeiraea simplicifolia seed lectin (BSS), wheat germ agglutinin (WGA), horseshoe crab lectin (HSC), pokeweed mitogen (PWM) and E. coli lipopolysaccharide (LPS). Cells were cultured in microtitre trays, at 41.6 degrees C, 8 x 10(5) cells in 200 microliters medium (= 4 x 10(6) cells/ml) supplemented with 10% pooled duck serum. Mitogens were added at final concentrations of 0.1-100 micrograms/ml and triplicate cultures at each concentration were harvested daily for scintillation counting 6 hr after addition of 1 microCi [3H]thymidine. Three patterns of response were observed. The responses to Con A, LC, HP and HSC were greatest at high mitogen concentrations (40-100 micrograms/ml) throughout the 7 days of culture. With PHA, PNA, WGA and LPS maximum stimulation was obtained at 3-5 days, at which time the cells were responding to lower concentrations of mitogen than were required at other times during the experiment. The response to BSS and PWM showed increasing sensitivity to lower concentrations of mitogen during the first 3 days of culture and then stimulated most strongly at 2-10 micrograms/ml in cultures harvested after 4-7 days. Cells from two ducks were cultured for 3 and 5 days with selected concentrations of these mitogens; the results confirmed the variation in response to different mitogens. It is possible that these patterns of response are the outcome of stimulating different populations of duck lymphocytes.
Animals↗
Yolk-sac transmission and post-hatching ontogeny of serum immunoglobulins in the duck (Anas platyrhynchos).
1. To investigate the immunoglobulin (Ig) class which is active in yolk-sac transmission of maternal antibodies in ducks, sera from laying ducks, yolks from their eggs, and sera from ducklings 0-87 days of age were examined by immunoelectrophoresis (IE), and Na2SO4-precipitated Igs from these sera and yolks were run in polyacrylamide gel electrophoresis (PAGE) under reducing conditions. 2. In yolk, 7.8S IgG was greatly enriched compared to 5.7S IgG and IgM, and was the only Ig to reach the sera of newly hatched ducklings. 3. The levels of maternally derived 7.8S IgG in duckling sera decreased after 5 days of age, reaching minimum levels at about 14 days of age. 4. Increases in the serum levels of 7.8S IgG, 5.7S IgG and IgM occurred after 20 days of age, reflecting de novo synthesis by the duckling, and the adult serum profile was achieved by 71 days of age. 5. The involvement of 7.8S rather than 5.7S IgG in yolk-sac transmission was probably determined by the additional heavy chain components of this molecule.
Animals↗
Precipitating antibodies of the duck (Anas platyrhynchos).
1. Ducks do not usually produce precipitating antibodies. However, when hyperimmunized with the dinitrophenyl (DNP)-human IgG (HIgG) conjugate, ducks made precipitating antibodies to the HIgG carrier, though not to the DNP hapten. 2. Precipitation did not require NaCl and occurred over a wide range of molarities and pH. 3. Antigenic and polyacrylamide gel analysis of affinity-purified antibodies, indicated that the major constituent of the antibody population was electrophoretically homogeneous 5.7S IgG. 4. The Ig heavy chains were in two populations, viz MW 37,000 and 41,000; non-precipitating duck 5.7S IgG antibodies to HIgG had only the MW 37,000 heavy chains. 5. It is suggested that duck precipitins belong to a previously unrecognized subclass of duck 5.7S IgG, with minor physical and antigenic differences from their non-precipitating counterparts.
Animals↗
Duck lymphocytes. II. Culture conditions for optimum transformation response to phytohaemagglutinin.
The lymphocyte transformation (LT) test was performed with duck blood lymphocytes in 96-well microtitre trays against nine concentrations (0.1-100 micrograms/ml) of phytohaemagglutinin (PHA). It was found that incubation at 41.6 degrees C (duck body temperature) gave better results than incubation at 37 degrees C, and that a 6 h pulse with [3H]thymidine gave better results than an 18 h pulse. Cell concentration was very critical: successful duck LT required rather high concentrations of cells (approximately 4 X 10(6)/ml, equivalent to approximately 8 X 10(5)/culture) while lower and higher concentrations gave inferior results. Duck serum supported LT optimally when used at a concentration of 10-15%, but a serum pool from adult (approximately 6-month-old) ducks gave superior results to sera from younger birds. Foetal calf serum supported duck LT strongly when used at 20%, but only poorly at 10%, while chicken serum supported duck LT when used at 5-20%. Ultroser G was an ineffective supplement, and the addition of 5% tryptose phosphate broth to other supplements had variable effects. Using optimum culture conditions, maximum LT responses were obtained after 2-3 days' culture, when it was possible to obtain stimulation indices of 500-5000. The addition of PHA to cultures could be delayed for up to 18 h without affecting LT, but thereafter the cells rapidly lost responsiveness.
Animals↗