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C Schiff

Publications and source records attributed to C Schiff.

At least 55 records · Page 3Linked to original sources
PubMed1989

Isolation of early immunoglobulin lambda-like gene transcripts in human fetal liver.

In an attempt to identify early events of human Ig gene expression, we have screened a human fetal liver cDNA library (less than 90 days of gestation) with C mu-, C gamma-, C kappa-, C lambda-specific probes and we report the characterization of two clones, F lambda 1 and F lambda 8, that hybridized with a human C lambda gene. These two clones, which are only 85% homologous to the functional C lambda genes, were shown to be additional nonallelic members of the 14.1/16.1 C lambda-like family. Using pulsed field gel electrophoresis these three C lambda-like genes were shown to be present on a 200-kb DNA fragment, defining a cluster distinct from that of the C lambda one. F lambda 1 and F lambda 8 contained an identical C lambda-like region, and differed from each other by a splicing event which joins a J lambda-like to the C lambda-like exon in the F lambda 1 clone in the absence of any rearrangement. Homologies observed between F lambda 1 and the mouse lambda 5 gene suggest that this human clone may contain the exon 2 and 3 equivalents of lambda 5. Since lambda 5 is selectively expressed in pre-B cells, our proposal is also supported by the early expression of this clone, together with the presence of full-length mu and gamma transcripts and the absence of functional Ig light chain transcripts. The presence of one nucleotide deletion in the C region of F lambda 1 conferring it a pseudogene status, the actual lambda 5 equivalent might be either one of the 14.1 or 16.1 human C lambda-like genes, the function of which is so far unknown.

DNA↗
PubMed1988

Allogeneic manipulation of the GAT idiotypic cascade. Immunization of C57BL/6 mice by BALB/c anti-idiotypes stimulates similar strain-specific V genes as the original antigen.

Antibodies specific for the immunizing Ag (Ab1) (Id+ Ag+) and Ab3 (Id+ Ag+ or Id+ Ag-) of the (Glu60 Tyr10 Ala30) (GAT) idiotypic cascade express similar pGAT public determinants in BALB/c and C57BL/6 strains. These determinants have been shown to be dependent upon both VH and Vkappa encoded segments. The VH of the BALB/c Ab1 (germ-line gene H10) and that of the C57BL/6 Ab1 (germ-line gene V186-2) are only 75% homologous, whereas VK are much more conserved. C57BL/6 mice were immunized with BALB/c Ab2 (anti-idiotypic) antibodies and monoclonal Ab3 were derived after fusion of immunized spleen cells with the nonsecreting hybridoma cell line Sp/2.0-Ag. From 13 cell lines, five clones (four Id+ Ag- and one Id+ Ag+) were isolated and the mRNA V regions sequenced. Immunization with BALB/c anti-idiotypes elicits expression of the same or closely related C57BL/6 VH and Vkappa genes as when C57BL/6 mice were immunized with GAT, although functional VH BALB/c equivalents have been isolated in the B6 strain. Our results suggest that manipulation of the repertoire via antigenic or idiotypic stimulation both lead to the expression of different genes in different strains. They further confirm that the immune system is largely degenerate, for both idiotype expression and Ag recognition.

Amino Acid Sequence↗
PubMed1987

Two V kappa germ-line genes related to the GAT idiotypic network (Ab1 and Ab3/Ab1') account for the major subfamilies of the mouse V kappa-1 variability subgroup.

V kappa Ig germ-line genes have been isolated from recombinant clones prepared in separate libraries constructed from adult BALB/c liver DNA. Three different clones that strongly hybridized with a V kappa-GAT-specific probe were completely characterized and sequenced. All three genes exhibited common characteristic features in their sequences encompassing the 5' to the 3' noncoding region, with coding sections 95% homologous. A comparison with other V kappa genes shows that the size of the first intron is variability subgroup specific. Moreover, a direct correlation exists between the size of this intron and the entire length of the coding region. Nucleotide sequences of these genes were compared with V kappa chains expressed at the Ab1 and Ab1' levels of the GAT idiotypic network: Ag----Ab1----Ab2----Ab3 (Ab1'). K1A5 and K5.1 genes account for V kappa chains in Ab1 and Ab1' hybridomas, respectively. The high conservation of Ab1' sequences in light chain was also recently reported for the heavy chains, suggesting that immunization with Ab2 (anti-idiotypic) antibodies preferentially stimulates the direct expression of germ-line genes. K5.1 and K1A5 genes belong to the V kappa-1 variability subgroup and encode, without any amino acid substitution, V kappa domain in myeloma TEPC 105 and MOPC 467, which are V kappa-1A and V kappa-1C subgroup prototypes, respectively. These genes are extensively used in different mouse strains and in a number of antibodies of discrete specificities, such as anti-GAT, anti-DNP, anti-flagellin, anti-phosphorylcholine, anti-digoxin, anti-phenyloxazolone, and anti-DNA.

Animals↗
PubMed1986

Endocytosis of MHC molecules by B cell-B lymphoma and B cell-T lymphoma hybrids.

Different cells and different cell surface determinants of the same cells take up liposomes, bound to them via monoclonal antibodies, with variable efficiency. We have previously reported that T and B lymphocytes differ in the extent to which they take up liposomes bound to MHC class I molecules; T cells endocytose class I molecules rapidly, but B cells endocytose class I molecules much less efficiently, although their endocytosis of class II molecules is rapid. An approach toward understanding the molecular basis for this difference was made by evaluating the internalization patterns of somatic cell hybrids of B and T cells. Hybrid cells were constructed between LPS-stimulated purified B cell blasts from C57BL/6 mice (H-2b) and the HAT-sensitive AKR T lymphoma BW 5147 (H-2k). Hybrids between the BALB/c B lymphoma M12.4.1 (H-2d) and B cell LPS blasts from B10.BR (H-2k) mice were also evaluated. In all cases, for hybrid tumor cells, liposomes that were bound to class I molecules encoded by genes from the B cell donor were endocytosed as efficiently as liposomes bound to the class I molecules of the recipient lymphoid cell. T cell tumors efficiently internalized their own class I molecules and those donated by B cells; B cell tumors internalized liposomes that were bound to their own and the donor B cell class I molecules poorly. Thus, our results suggest that the internalization of an MHC molecule is not an intrinsic property of the molecule, but rather of the cell in which it is found.

Animals↗
PubMed1986

Genetic basis for expression of the idiotypic network. One unique Ig VH germline gene accounts for the major family of Ab1 and Ab3 (Ab1') antibodies of the GAT system.

Ig germline genes have been isolated from recombinant clones prepared in separate libraries constructed from adult BALB/c liver DNA either in pBR328 plasmid or in EMBL 3 phage. Three clones that gave a very strong positive hybridization signal with a VH anti-GAT-specific probe were completely characterized and sequenced. All three were greater than 95% homologous, with the exception of the 5' noncoding region, which was only 85% homologous but contained characteristic regulatory signals. One of these genes, H10, had a sequence that was completely identical to that of a cDNA derived from a GAT-specific BALB/c hybridoma. Southern blot analysis using Eco RI-digested DNA from rearranged GAT-specific hybridomas revealed that the same gene was used for other GAT-specific VH regions, including one differing from the H10 sequence by 12 nucleotides, which must have been generated by a somatic mechanism. The same H10 germline gene was also used, in most cases without any nucleotide substitution, in hybridomas of the Ab1' set of the GAT idiotypic cascade, suggesting that immunization with Ab2 (antiidiotypic) antibodies preferentially stimulates the direct expression of VH germline genes. Finally, the previous hypothesis that NPa and GAT VH genes were derived from the same germline gene was definitively confirmed, both from sequence data and Southern blot analysis.

Animals↗
PubMed1985

Immune response against poly(Glu60,Ala30,Tyr10) (GAT): immunization with monoclonal anti-idiotypic antibodies leads to the predominant stimulation of idiotypically similar immunoglobulins with anti-GAT activity.

Two monoclonal anti-idiotypic antibodies (HP-Id20 and HP-Id22) recognizing two different public idiotopes expressed in the anti-poly(Glu60,Ala30,Tyr10) (GAT) response were used to immunize BALB/c and C57BL/6 mice. From these animals hybridomas were isolated. From BALB/c and C57BL/6 mice eight and seven monoclonal antibodies were characterized, respectively. The reagents were classified according to the expression of the public idiotypic specificity p.GAT (recognized by a rabbit antiserum). The anti-GAT activity and the expression of the various idiotopes characterized on anti-GAT polyclonal and monoclonal antibodies were also studied. Most of the reagents are Ab1'-type of antibody resembling anti-GAT antibodies. One anti-anti-idiotypic monoclonal antibody (Ab3) was also isolated from BALB/c mice. This suggests that in this experimental model the repertoire induced after HP-Id immunization and antigen stimulation is comparable. The idiotypic analysis of a large number of anti-GAT and of Ab1' monoclonal antibodies suggests that only two public idiotopes are involved in the anti-GAT response.

Animals↗
PubMed1985

Functional and pseudogenes are similarly organized and may equally contribute to the extensive antibody diversity of the IgVHII family.

Eleven germ-line immunoglobulin VH genes have been isolated from a BALB/c genomic library, using a cDNA probe specific for the GAT/NPa variable region. Restriction fragments of all genes were sequenced: two over 800 bp, covering signals of the 5'- and 3'-non-coding regions, three encompassing the complete coding region and part of the 5', the remaining sequences covering most of the V coding region. All sequences pertained to the VHII family, and were compared with the other 13 homologous genes already published. Characteristic features defining the family are clearly visible all along the sequences analyzed, including the 5'-non-coding region, the leader fragment and the intron organization. About half of the compared genes have pseudogene characteristics, defined either by a stop codon in the coding region or the lack of an initiator codon in the leader segment. Analysis of the replacement mutations, as compared with silent ones, indicate that they are highly clustered in complementarity determining regions, for both the functional and the pseudogenes, suggesting that all genes have been submitted to similar selective pressure, and that the pseudogene repertoire may be actively used, by recombination and/or conversion process. Signals that regulate transcription are highly conserved through the family barriers. The VHII group is the largest Ig V genes family, with extreme sequence divergences reaching 22% nucleotide differences. As no two genes were found identical out of the 24 members compared, and as two genes were found to differ by as little as three nucleotides, it seems that the previous estimate of 60 members might be much too low.

Animals↗
PubMed1984

Preoperative combination chemotherapy for advanced stage head and neck cancer. Promising early results.

We treated 19 consecutive patients with cisplatin, bleomycin, and methotrexate before definitive surgery or radiation therapy. Fourteen patients (74 percent) had partial or complete tumor regression after chemotherapy. With a minimum follow-up time of 27 months, none of the 4 patients who had a major histologic response relapsed, and only 2 of the remaining 15 patients continued disease-free. The achievement of a complete histologic response after preoperative chemotherapy may correlate with long-term disease-free survival after surgery and radiation therapy for head and neck cancer.

Aged↗
PubMed1983

Immunoglobulin diversity: analysis of the germ-line VH gene repertoire of the murine anti-GAT response.

A cDNA clone was constructed from a mRNA encoding an anti-GAT (Glu60 Ala30 Tyr10) BALB/c monoclonal antibody heavy chain. Its sequence, covering codons -5 to 162 and therefore encompassing the complete V-D-J region, was determined. Surprisingly, the sequence of the VH gene-encoded region was almost identical with that of the BALB/c VH anti-HNP (4-hydroxy-3-nitrophenyl) acetyl VH region, suggesting that the same VH germ-line might be used to encode two heavy chains contributing to antibodies of discrete specificities. A specific VH probe was derived and annealed to Eco RI and Bg1 II restriction fragments of liver (unrearranged) DNA extracted from the BALB/c, DBA/2 and C57BL/6 mouse strains that differ in their H chain allotypes. Under stringent conditions, only a few bands were identified by Southern blotting. The different patterns observed suggest that the VH anti-GAT repertoire differs between these strains even though their various anti-GAT antibodies express the same public idiotypic specificities.

Amino Acid Sequence↗
PubMed1983

Interstrain conservation of the murine GAT-specific antibody V kappa repertoire as analyzed at the germline gene level.

A cDNA library was constructed in pBR322 from mRNA encoding an anti-GAT (Glu60 Ala30 Tyr10) monoclonal antibody kappa chain. Two cDNA clones were extensively characterized. One, L XI 62, was derived from an aberrant V kappa-J kappa rearrangement which resulted in a frame-shift at position 96, leading to a stop codon at the very beginning of the constant region. The second, L XIX 27, 1150 bp long, was unequivocally assigned to a GAT-specific kappa chain, by comparison of its nucleotide sequence with the previously determined NH2-terminal amino acid sequence of the isolated kappa chain. A specific probe, containing the leader and most of the V kappa gene-encoded region, was prepared from this clone and hybridized to EcoRI and BamHI restriction fragments of liver (unrearranged) DNA extracted from the BALB/c, DBA/2 and C57BL/6 mouse strains. Under stringent conditions, similar patterns were observed for all three strains, and consisted of a small number of bands (3-5). Under nonstringent conditions, patterns were again very similar when the different strains were compared, although 15-20 bands could be identified. These observations support the hypothesis that the GAT-specific kappa chains found in antibodies expressing the public CGAT idiotypes are encoded by a very small number of germline genes. This V kappa repertoire seems extremely conserved between the three strains that were analyzed, an observation which correlates with the interstrain conservation of these public idiotypic specificities.

Alanine↗
PubMed1982

Monoclonal antibodies reveal three types of idiotypic determinants on MOPC 173: H-L-specific private and public idiotopes, and Vh-specific public idiotope(s).

Monoclonal anti-idiotypic antibodies against the IgG2a, K myeloma protein MOPC 173 were raised with A/J- and CBA-immune B-cells. The specificity of the antibodies was studied by hemagglutination and inhibition of a radioimmunoassay (RIA). A series of myeloma proteins, their H- and L-chains, free or reassociated in various combinations, were used as inhibitors. The RIA patterns allow recognition of three types of idiotypic determinants: private conformational idiotope(s), a public conformational idiotope, and public VH-determinant(s). Strain distribution of the public determinant was studied. A tentative correlation between amino acid positions and Id determinants is discussed.

Animals↗
PubMed1976

Deletion of hinge region of human myeloma IgG1 molecule (protein LEC) associated with nonexpression of G1m (3) and Km (1, 2) allotypes. A possible genetic explanation at the DNA level.

In this paper we report the structural basis for the nonexpression of G1m(3) and Km (1,2) allotypes in an IgG1 (kappa) human myeloma protein (protein LEC). Heavy and light chains spontaneously dissociate in sodium dodecyl sulfate polyacrylamide gels. Light chains appear to be covalently S-S bonded. Analysis of cysteine-containing peptides shows that the heavy chain of the IgG protein LEC has a deletion of residues 216-230, thus encompassing the entire hinge region. An arginine residue, characteristic of the G1m(3) marker is present at position 214. An alanine at position 153 and a leucine at position 191 of the light chain, characteristic of the Km (1, 2) allotypes, are present. It is likely that the double Km and Gm lack of expression is the result of the deletion. The genetic implications of the sequence of this protein are discussed.

Amino Acid Sequence↗