7S Ig Research Articles

The influence of high dose intravenous immunoglobulins on immunological and metabolic pattern in newly diagnosed type I diabetic patients

In autoimmune disease the functional deficiency of T suppressor cells, also described in Type I diabetes, may be restored through immunoglobulin (Ig) infusion, which increases antigen phagocytosis, NK activity, cell clones and antibody anti-idiotype responses. Sixteen Type I diabetic patients were studied: eight were treated soon after the initial correction of disease-onset glycemic deterioration with intensive intravenous (i.v.) 7S Ig treatment (0.4 g/kg/BW) for 1 week and once per week for 6 months, whilst the remaining patients constituted the control group. All patients were evaluated during the study for metabolic and immunological parameters. A reduction in insulin requirement compared to conventionally treated patients was observed at the third (0.17 +/- 0.06 vs 0.44 +/- 0.08 IU/kg/BW; P less than 0.02) and at the sixth month of therapy (0.19 +/- 0.07 vs 0.54 +/- 0.07 IU/kg/BW; P less than 0.005). Two patients ceased to require insulin therapy within the BW; P less than 0.005). Two patients ceased to require insulin therapy within the first month, showing a prolonged restoration of B-cell function. Serum C-peptide values were also significantly higher in the Ig-treated group compared to the control group after 3 and 6 months. As regards immunological parameters, patients showed a decrease in insulin antibody levels and a reduction in TAC+ cells. Intravenous Ig therapy seems able to affect positively the first phases of metabolic and immunological deterioration of Type I diabetes.

Evolution of low molecular weight immunoglobulins V. Degree of antigenic relationship between the 7S immunoglobulins of mammals, birds, and lower vertebrates to the turkey IgY

There are close antigenic relations between the turkey IgY - the dominant 7S Ig of serum - and the corresponding IgY-like Igs of chicken, duck, goose, tortoise, and frog as well as serum or colostral IgA of man and swine. The RIA-systems used for the determination of immunological cross-reactivity among the Ig types consisted of 125-I-labelled turkey IgY and class-specific rabbit anti-turkey IgY antibodies. The results stand in a good agreement with our findings demonstrating strong antigenic relationships between various serum or colostral Igs of IgY and IgA types, respectively, to the chicken IgY. Therefore, the IgY-like Igs seem to be the precursors for the IgA class of mammals.

Inherited dysgammaglobulinemia of chickens: Reduced incidence of disease in parabiotic chimeras

University of California, Davis (UCD) line 140 chickens develop a dysgammaglobulinemia characterized as selective 7S immunoglobulin (Ig) deficiency with elevated serum IgM levels. To study the role of bursal development on the expression of dysgammaglobulinemia in these birds, we examined the effect of bursacyte transfer to line 140 birds and parabiosis between UCD 140 and a control line of chickens on changes in serm IgM and 7S Ig levels. Bursacyte transfer was performed by injecting 18-day UCD 140 embryos (which had been cyclophosphamide treated on Day 15) with bursacytes from major histocompatability complex B-matched control line (11 × 58) F 1 birds. This transfer produced little change in the incidence of dysgammaglobulinemia in UCD 140 transfer birds (56%) compared to unmanipulated line 140 birds (60%). These data reflect a failure of line 140, rather than technique, because successful reconstitution was seen using line 11 × 58 birds injected with 11 × 58 bursacytes. In contrast, the generation of UCD 140/line 11 × 58 chimeras significantly reduced the incidence of dysgammaglobulinemia in line UCD birds. Indeed, fusion of the chorioallantoic vascular system (parabiosis) of UCD 140 and 11 × 58 embryos on Day 15 decreased the frequency of dysgammaglobulinemia of UCD 140 parabionts to 14% compared to 66% in unmanipulated line 140 controls. The success of parabiosis was 83% as determined by demonstrating chimerism with allogeneic blood groups. Moreover, the frequency of dysgammaglobulinemia in the 17% of parabionts that did not reveal chimerism was similar to unmanipulated UCD 140 chickens.

The phylogenetic relationships of immunoglobulin allotypes and 7S immunoglobulin isotypes of chickens and other phasianoids (turkey, pheasant, quail).

Pheasants, quail and turkeys from different geographical locations were surveyed for the presence of eight 7S Ig and four IgM chicken allotypes. No IgM and only two 7S Ig allotypes were detected. Chicken 7S Ig allotypic specificity G-1.7 cross-reacted with pheasant and turkey isotypic specificities, and was absent in quail. The other determinant (G-1.9) cross-reacted with an allotype found only in turkeys and golden pheasants. These data suggest that G-1.7 and G-1.9 are probably phylogenetically ancient determinants and that polymorphism of chicken immunoglobulins arose after divergence of chickens from other phasianoid birds. Based on the allotypic and isotypic analysis of the 7S Ig antigenic determinants, turkey 7S Ig was as closely related to chicken 7S Ig as was pheasant 7S Ig. Jungle fowl, the ancestor of chickens, had most of the chicken 7S Ig and IgM allotypes present as polymorphic markers.

Structure of chicken 7S immunoglobulin allotypes: Further studies on localization to Fab and Fc fragments

Papain-derived fragments (Fab and Fc) were used to localize previously uncharacterized chicken 7S immunoglobulin (Ig§) allotypic specificities (G-1.7, G-1.8, G-1.9, G-1.10, and G-1.12). Based on the molar amounts of Fab and Fc preparations relative to undigested 7S Ig to inhibit 50% of binding of 125I-7S Ig with homologous alloantiserum, the G-1 allotypes, including some previously reported (G-1.1, G-1.2, G-1.3 and G-1.5), were grouped according to the extent of their modification induced by digestion with papain. The Fab determinants G-1.1 and G-1.12 were considered unmodified and Fab determinant G-1.2 was slightly modified. Although found in an Fab preparation, G-1.8 was greatly modified. Similarly, G-1.3 and G-1.5 were greatly modified, but were found in very low concentrations in Fc preparations. The G-1.10 also was greatly modified but it was found in low concentrations in both Fab and Fc preparations. The G-1.7 and G-1.9 specificities were undetectable (completely destroyed) after papain digestion. No G-1 allotype has been found with high activity in Fc preparations. All allotypes greatly modified or completely destroyed by papain digestion were considered to be papain-sensitive. Most alleles had both Fab and papain-sensitive determinants. A new 7S Ig allotype, G-1.14, was associated with the G-1 a , G-1 b , G-1 c , G-1 f and G-1 g alleles and did not result in the formation of new alleles in inbred chickens homozygous for the allotype loci.

Inherited 7S immunoglobulin deficiency in chickens: presence of suppressor T cells that suppress synthesis of 7S immunoglobulin but not IgM.

University of California (UCD) line 140 chickens, previously described to have an inherited 7S Ig deficiency and dysgammaglobulinemia associated with early bursal defects, and autoimmune phenomena were examined for the presence of suppressor cells. Pokeweed mitogen (PWM) stimulated UCD 140 peripheral blood lymphocytes (PBL) to synthesize IgM but not 7S Ig. In co-culture, UCD 140 PBL specifically inhibited 7S Ig but not IgM synthesis of PWM-stimulated PBL from normal birds. Normal 7S Ig synthesis usually was suppressed 40 to 80%, although PBL from some normal birds were not suppressible. Adoptive transfer of UCD 140 spleen cells to normal chicks resulted in early and transient decreased serum 7S Ig levels. Homology at the B locus (major histocompatibility complex) was not required for suppression. Higher levels of suppressor cells were found in UCD 140 than in normal birds as early as 13 days of age. The suppressor cells were found to be T cells as indicated by inactivation with anti-T antiserum but not with anti-B antiserum, and by suppression associated with T cell fractions obtained by nylon wool fractionation. UCD 140 B cells, obtained by nylon wool fractionation, were stimulated with PWM to synthesize 7S Ig when provided with normal T cells. These findings are discussed with particular reference to early bursal anomalies.

Genetic nomenclature for chicken immunoglobulin allotypes: An extensive survey of inbred lines and antisera

Based on a survey of 36 inbred and 8 partially inbred chicken lines and outbred jungle fowl, and with 29 alloantisera generated in different laboratories, 13 7S Ig and 5 IgM allotypes were designated and a new system of nomenclature for chicken Ig polymorphisms was developed. The survey also revealed considerable genetic polymorphism in the structural gene(s) (G-1) responsible for the production of 7S Ig H chains. IgM H chains, encoded by theM-1 locus were less polymorphic. NineG-1 and fourM-1 gene alleles were delineated in highly inbred lines by the formation of unique combinations ofG-1 orM-1 specificities. Five additionalG-1 alleles were found in chicken lines and jungle fowl segregating for allotypes. Thirty-three percent of theG-1∶M-1 haplotypes theoretically expected, were detected in inbred lines.

Radioimmune analysis of an unexpected mouse allotype.

We have used a radioimmune assay to confirm our earlier findings of an unexpected immunoglobulin allotype in Igb-congenic BALB/c mice. Although these mice were bred to exclude the IgG2a allotype of BALB/c (Ig-la), an Ig-la-like antigen was detected in the 7S Ig fraction of two (of five) pooled serum samples, it represented 0.1--0.3% of the total 7S protein and was indistinguishable from a reference Ig-la. The detection of putative Ig-la in Igb-congenic mice is inconsistent with the notion that allotypes are products of allelic structural genes. It appears rather that expression of Ig-la is controlled by allelic regulator genes and that its low and transient production in Igb-congenic mice results from incomplete negative regulation.

An Allotypic Marker on Chicken Immunoglobulin Light Chains

The first chicken immunoglobulin light (L) chain allotypic specificity (L-1.1) to be described that was present on IgM, 7S Ig, Fab, and L chains was detected by radioimmunoassay. The gene controlling the expression of L-1.1 is inherited in a simple Mendelian fashion at an autosomal locus and is unlinked to a constant region heavy chain locus, four blood group loci and three loci determining lymphocyte cell surface alloantigens.

Immunoglobulin levels in chickens with inherited muscular distrophy

Blood serum levels of 7S Ig appear to be a highly heritable (h(2)=0.76) trait. A possibly weak association of high 7S Ig with the phenotype of inherited muscular dystrophy is noted. In contrast to a previous study (Sanders and Kline 1977), our survey of 4 comparisons in paired lines showed dystrophics with slightly elevated 7S Ig levels and no differences in IgM levels when compared to controls.

Surface membrane changes of T cells induced by syngeneic tumour cells. I. Formation and uptake of complexes of Ig and tumour antigens by T cells.

A large dose of tumour cells (10(7)) from two different tumours produced a significant increase of Ig-bearing spleen cells 6 h after intraperitoneal administration in syngeneic mice, like conventional antigens previously tested. Incubation of normal spleen cells in serum taken 6 h after administration of tumour cells reproduced in vitro the changes observed in the spleen cell population of the serum donors, demonstrating the presence of a cytophilic Ig, which was shown to be taken up by T cells. Serum collected 6 h after tumour cell inoculation contains also a 4S factor which can generate in vitro cytophilic Ig for T cells in the presence of a foreign soluble protein or tumour antigen. Extracts obtained from tumours cells, which were shown to contain tumour antigens, were labelled with 125I and mixed with the 4S factor and normal 7S Ig. Upon fractionation of the mixture, high molecular weight material containing radioactivity and 7S Ig were eluted in the void volume, well ahead of the position of both the tumour cell preparation and the 7S Ig. This material contained Ig cytophilic for splenic T cells and it is likely that it represents cytophilic complexes of Ig and tumour antigens. It is postulated that the cytophilic Ig detected in the serum of animals 6 h after injection of a large number of tumour cells represents cytophilic complexes of Ig and tumour antigens formed through the mediation of a soluble factor.

The simultaneous production of two classes of cytoplasmic immunoglobulins by single cells in Xenopus laevis

The classes of cytoplasmic immunoglobulins of individual lymphoid cells from the spleen and peripheral blood of normal and immunized Xenopus laevis were investigated. Immunofluorescence microscopy and simultaneous double staining of the cytoplasm, using a mixture of class-specific TRITC-anti-19S Ig and FITC-anti-7S Ig conjugated antisera, showed that 70% of the immunoglobulin producing cells are “double producers” and contain the two classes of 19S and 7S immunoglobulins. The remaining 30% are composed of “single producers.” The proportion of splenic cells containing either 19S Ig or 7S Ig, respectively, was unequal, and reversed between two groups of animals, one examined at the primary immune response (29% 19S Ig and 4% 7S Ig) and the second group examined at the secondary immune response (8% 19S Ig and 30% 7S Ig). A spontaneous lymphoid tumor with an increased serum level of 19S Ig was examined in the same way. The tumor cells appear to produce 19S Ig exclusively.

Structural and Genetic Studies on Chicken 7S Immunoglobulin Allotypes

Abstract Low concentrations of allotypic specificity CS-1.1 were detected in the sera of two inbred chicken lines [University of California, Davis (UCD) 7 and Regional Poultry Research Laboratory 15I4] previously reported to lack this specificty. The CS-1.1 alloantigen in 15I4 chickens has the same specificity as the major allotype in a line of chickens (UCD 2) in which it was initially defined. In 15I4 chickens, CS-1.1 allotype is present on a population of molecules distinct from those which carry the major allotype; thus a second 7S Ig H chain locus, CS-2, is proposed. The concentration of CS-1.1-bearing molecules determined by two different methods was 7 µg/ml and 230 µg/ml in 15I4, whereas UCD 2 chickens had 4 mg/ml of CS-1.1 molecules. The levels of CS-1.1 inhibitory activity in 15I4 birds remained relatively constant over a 30-day period. The presence of two 7S Ig populations in 15I4 chickens may be interpreted as evidence either for 7S Ig subclasses with shared allotypes or for a pseudoallelic organization of genes controlling expression of 7S Ig H chains. The results were consistent with the presence of redundant C region genes, differing in allotypes, whose expression is under the control of an as yet undefined regulatory mechanism.

Cross-reaction among immunoglobulins of different families of Amphibia

Immunological cross-reactions between 19S Ig and 7S Ig from Xenopus laevis and those of several other distantly related amphibian species were studied by immunoelectrophoresis using rabbit antisera to purified X. laevis 195 Ig and 7S Ig. Precipitin reactions were detected with sara from members of both orders of Anura and Urodela suggesting a rather slow rate of change during the evolution of the immunoglobulins in these lower vertebrates.

Structural and Genetic Studies on Chicken 7S Immunoglobulin Allotypes

Abstract A survey of 47 inbred or partially inbred chicken lines derived from five sources in the United States and Europe revealed considerable genetic polymorphism in the structural gene (CS-1) responsible for the production of the predominant chicken 7S Ig heavy chain. A minimum of 10 alleles of the CS-1 gene were detected as unique combinations or phenogroups of CS-1 specificities. A system of nomenclature for CS-1 alleles was developed and six homozygous lines were designated as prototype lines. The remaining four CS-1 alleles occurred only in lines that were polymorphic for 7S Ig allotypic specificities.

IMMUNOGLOBULIN GAMMA CHAINS OF A MONOTREME MAMMAL, THE ECHIDNA (TACHYGLOSSUS ACULEATUS): AMINO ACID COMPOSITION AND PARTIAL AMINO ACID SEQUENCE

The echidna represents the lowest stage in phylogeny at which molecules clearly homologous to IgG antibodies appear to occur. We provide evidence that a fraction of gamma chains possess an unblocked N terminal sequence comparable to the VHIII sub-group of human gamma chains and that glycine is the C-terminal residue. Statistical comparison of amino acid composition of the component chains with other immunoglobulin heavy chains suggests that echidna gamma chains are more closely related to eutherian gamma chains than to the 7S Ig heavy chains from amphibia or aves. The results are consistent with our view that true gamma-type heavy chains did not appear in evolution until after the mammalian line diverged from the stem reptiles.

Structural and Genetic Studies on Chicken 7S Immunoglobulin Allotypes

Abstract We have previously reported that chicken 7S immunoglobulin (Ig) heavy (H) chain allotypes (CS-1 locus) segregate as phenogroups in F2 progeny. Specificity CS-1.1 formed a phenogroup with CS-1.4 in inbred chicken line UCD 2, and a second phenogroup with CS-1.3 in line UCD 3. To determine whether these phenogroups were formed by combinations of specificities on the same, or on separate subclasses of 7S Ig, their distribution on the 7S Ig molecules of birds homozygous for 7S Ig allotypes was analyzed by radioimmunoassay. Anti-CS-1.1 and anti-CS-1.3 alloantisera each bound more than 94% of line UCD 3 125I-7S Ig. Similar results were obtained with alloantisera to CS-1.1 and CS-1.4 with 125I-7S Ig from line UCD 2. These results indicate that both phenogroups were formed by combinations of specificities present on the same H chain. Thus, each phenogroup described, probably, is the product of a single structural gene which is responsible for more than 94% of the 7S Ig H chain constant regions. In F1 hybrids with the genotype CS-1.1,1.3/CS-1.2, two populations of serum 7S Ig molecules were detected by direct and sequential binding analysis with specific alloantisera. One population of 7S Ig contained specificities CS-1.1 and CS-1.3, but not CS-1.2; while the second population carried only specificity CS-1.2. Therefore, each population was exclusively the product of one parental allele. Consistent with a genetic regulatory mechanism involving allelic exclusion, no 7S Ig containing allotypes produced by both alleles was detected.

Chicken high molecular weight immunoglobulin (IgM) allotypes: localization on the heavy chains and proposed nomenclature.

An alloantiserum recognizing a genetic marker (CM-1.4) on chicken 17S Ig was generated by immunizing jungle fowl with Salmonella O-anti-Salmonella O (UCD 3) agglutinates. Specificities CM-1.4 and M1a were present on 7S subunits and H chains based on their ability to inhibit in RIA the binding of alloantibody (anti-CM-1.4 or anti-M1a) to UCD 3 125I-17S Ig. CM-1.4 appears to be fully expressed on 7S subunits but is altered on H chains. In contrast, anti-M1a bound both 7S subunits and H chains with decreased avidity indicating that the M1a specificity was altered in both preparations. Since CM-1.4 and M1a are present on 17S Ig H chains, and absent from 7S Ig, they probably represent allotypic markers in the constant region of 17S Ig H chains. Having assigned two 17S Ig allotypic specificities to H chains, we propose that the locus controlling their expression be called CM-1. Based on the distribution of the CM-1.4 and M1a allotypes in inbred lines of chickens, 3 alleles are defined at the CM-1 locus.

A note on unexpected chicken 7S immunoglobulin allotypes.

Allotypes have been detected on both chicken low molecular weight (7S) (1–3) and high molecular weight (17S) (2, 4) immunoglobulins (Ig), and their inheritance is similar to allotype inheritance in mammals. The expression of the 7S heavy (H) chain allotypes and their segregation ratios are indistinguishable from those expected for codominant alleles at a single autosomal locus (3, 5, 6). In addition, genetic analysis of the inheritance of 7S and 17S Ig allotypes is consistent with the presence of alleles at two closely linked loci (7).

Structural and Genetic Studies on Chicken 7S Immunoglobulin Allotypes

Abstract A method was developed for the detection of allotypes on intact, radiolabeled 7S immunoglobulin (Ig) which does not involve insolubilized alloantisera. Binding of dinitrophenylated anti-allotype (DAA) antiserum with radiolabeled alloantigen was demonstrated by the addition of rabbit anti-dinitrophenyl antiserum followed by precipitation of complexes with sheep anti-rabbit γ-globulin antiserum. Dinitrophenylation of alloantiserum up to 8.5 hr had no effect on antibody titer or avidity. Binding inhibition assays with the DAA method detected allotypes on 2 to 5 ng of 7S Ig. Four specificities were detected on 7S Ig heavy (H) chains by binding inhibition with the DAA assay. Specificities CS-1.1 and CS-1.2, located in the Fab fragment, were detected at 3- to 5-fold lower concentrations of reassociated H and light (L) chains than on the isolated H chains. On the basis of regression coefficients calculated from binding inhibition curves, the avidity of isolated H chains was significantly increased following reassociation with L chains, indicating that the conformation of CS-1.1 and CS-1.2 determinants depends in part on H and L chain interactions. In contrast, reassociation of H and L chains did not significantly increase H chain inhibitory activity or avidity for specificities CS-1.3 and CS-1.4.