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K Meek

Publications and source records attributed to K Meek.

48 records · Page 3Linked to original sources

The influence of V kappa gene polymorphism on the induction of silent idiotypes in the arsonate system.

It has been previously shown that it is possible to modify the expressed repertoire of a given individual using idiotypic manipulation. For example, A/J mice respond to arsonate challenge by synthesizing a dominant idiotype, CRIA, whereas BALB/c mice do not. However, after treatment with rabbit polyclonal anti-CRIA antibodies (Ab2 or anti-idiotypic antibodies) and arsonate, BALB/c mice are able to synthesize a CRIA-like idiotype. To determine whether this modification of repertoire is dependent on the immunoglobulin loci (Ig-h, kappa), we have analyzed the anti-arsonate response after anti-idiotypic treatment of three strains of mice (C58, C.C58, AKR), chosen because they are among a small group of strains which express Kappa V regions not seen in other strains. There are also L chains lacking in these strains which are expressed in other mice. The C58 and C.C58 strains share the same Ig-h locus (Ig-ha) with BALB/c mice but C.C58 are congenic mice, that express the kappa loci on a BALB/c genetic background. AKR mice express the Ig-hd haplotype. AKR, C58 and C.C58 do not produce CRIA positive antibodies in response to arsonate; a defect which has been previously mapped to the kappa locus. These three strains of mice (C58, C.C58 and AKR) were treated with rabbit anti-CRIA and boosted with Ars-KLH. The results show that after such treatment, the C.C58 mice were able to express CRIA-like antibodies which are serologically identical to those of BALB/c.

Animals↗

Identity of the V kappa 10-Ars-A gene segments of the A/J and BALB/c strains.

To characterize the light chain gene segments involved in the murine immune response to keyhole limpet hemocyanin p-azophenylarsonate (Ars), we have determined the amino acid and/or nucleotide sequences of several anti-arsonate antibodies of the Ars-A family in the A/J, C.AL-20, and BALB/c strains. These structures have been compared to certain BALB/c anti-phenyloxazolone and anti-levan antibodies previously sequenced and to the A/J V kappa 10-Ars-A genomic sequence (where V kappa = kappa chain variable). These primary structural studies were complemented by Southern filter hybridization analyses utilizing V kappa and kappa chain joining (J kappa) molecular probes. We found a surprising uniformity of structure among these antibody light chains derived from different murine strains. Thus, in contrast to the heavy chain variable (Vh) regions of the Ars-A antibody family where the BALB/c strain lacks the VH gene segment utilized in the A/J Ars-A response, the light chain variable region gene segments at the V kappa 10-Ars-A locus appear to be identical between the two strains.

Alleles↗

Idiotype-anti-idiotype interactions of VHIX-coded anti-progesterone and anti-arsonate antibodies. Comparison of passive haemagglutination and radioimmunoassays.

The reactivity and specificity of polyclonal and monoclonal anti-idiotypic antibodies raised against monoclonal anti-progesterone and anti-arsonate antibodies have been studied by solid phase radioimmunoassay (RIA) with immobilized idiotype and by passive haemagglutination with idiotype-coupled red cells. The sensitivity of the two methods was comparable, though some cross-reactions were only detected by RIA. Passive haemagglutination was found to be especially suitable in screening for monoclonal anti-idiotypes in hybridoma supernatants and ascites, and had advantages over RIA in detection of syngeneic anti-idiotypes. Demonstration of binding site-associated idiotopes was possible by haemagglutination inhibition. RIA and haemagglutination were used to investigate the idiotypic relationships between BALB/c antiprogesterone and anti-arsonate monoclonal antibodies which share heavy chains encoded by VHIX variable region genes.

Amino Acid Sequence↗

Primary structure of IgE monoclonal antibodies expressing an intrastrain crossreactive idiotype.

We have obtained amino acid sequences (by mRNA and amino acid sequencing) for two IgE kappa mAb that have specificity for the Ars hapten group and are related to the major idiotypic family, CRIA (crossreactive idiotype A), in the A strain of mouse. One mAb, SE20.2, fully expresses CRIA; the other, SE1.3, possesses some but not all of the characteristic idiotopes. Both IgE proteins contain VH and V kappa segments that are closely related to those associated with CRIA. The D segment of SE20.2 is also typical of CRIA+ mAb, but that of SE1.3 is one amino acid residue longer. Chain recombination experiments indicated that the L chain of SE1.3 is fully capable of supporting CRIA expression. Its deficiency with respect to idiotopes of CRIA was attributed to the extra amino acid in the D region and/or substitutions in the VH segment. A major objective was to ascertain the frequency of somatic mutations in IgE. For the VH segment (amino acids 1-98) of SE20.2, there are only three nucleotide differences and one uncertainty with respect to the nucleotide sequence of the germline gene associated with CRIA. A somewhat higher frequency of substitutions is present in the VH segment of SE1.3. The VK amino acid sequences of the IgE proteins are nearly identical to those of a prototype of the CRIA family, mAb R16.7. The results are discussed with reference to the mechanism of the IgM to IgE switch.

Amino Acid Sequence↗

Complete amino acid sequence of heavy chain variable regions derived from two monoclonal anti-p-azophenylarsonate antibodies of BALB/c mice expressing the major cross-reactive idiotype of the A/J strain.

The primary structure of A/J anti-p-azophenylarsonate (anti-Ars) antibodies expressing the major A-strain cross-reactive idiotype (CRIA) has provided important insights into issues of antibody diversity and the molecular basis of idiotypy in this important model system. Until recently, this idiotype was thought to be rarely, if ever, expressed in BALB/c mice. Indeed, it has been reported that BALB/c mice lack the heavy chain variable segment (VH) gene that is utilized by the entire family of anti-Ars antibodies expressing the A/J CRI. Recently, however, it has been possible to elicit CRIA+, Ars binding antibodies in the BALB/c strain by immunizing first with anti-CRI and then with antigen. Such BALB/c, CRIA+ anti-Ars antibodies can be induced occasionally with antigen alone. VH region amino acid sequences are described for two CRIA+ hybridoma products derived from BALB/c mice. While remarkably similar to each other, their VH segments (1-98) differ from the VH segments of A/J CRIA+, anti-Ars antibodies in over 40 positions. Rather than the usual JH2 gene segment used by most A/J CRIA+ anti-Ars antibodies, one BALB/c CRIA+ hybridoma utilizes a JH1 gene segment, while the other uses a JH4. However, the D segments of both of the BALB/c antibodies are remarkably homologous to the D segments of several A/J CRIA+ antibodies sequenced previously, as are the amino terminal amino acid sequences of their light chains. These data imply that BALB/c mice express the A/J CRIA by producing antibodies with very similar, if not identical, light chain and heavy chain D segments, but in the context of different VH and JH gene segments than their A/J counterparts. The results document that molecules that share serologic specificities can have vastly different primary structures.

Amino Acid Sequence↗

Tumoricidal response following perfusion over immobilized protein A: identification of immunoglobulin oligomers in serum after perfusion and their partial characterization.

Previously, we showed that perfusion of plasma from hosts bearing breast adenocarcinoma over immobilized staphylococcal protein A resulted in objective tumor regressions. In the present study, sera perfused in vitro over immobilized staphylococcal protein A were analyzed by physicochemical and immunochemical methods to characterize newly formed products. Sera from normal and breast adenocarcinoma-bearing dogs showed increased levels of C1q-binding IgG after perfusion over a strain of staphylococcus that is protein A rich (Cowan I), but not protein A deficient (Woods 46). C1q binding levels were also increased in normal and tumor-bearing canine or human sera which were perfused over purified protein A immobilized in collodion charcoal (PACC), and this increase was localized in sucrose density gradient fractions ranging from 7S to 19S. Polyacrylamide gel electrophoresis analysis of the high-molecular-weight fraction in postperfusion canine sera, isolated by G-200 fractionation and immunoaffinity chromatography, showed predominantly heavy and light immunoglobulin chains of canine IgG. Furthermore, protein A was released from PACC after perfusion with serum or solutions containing IgG or albumin from humans, dogs, and chickens. After serum perfusion over PACC, protein A was identified in the effluent by additional studies as follows: (a) polyacrylamide gel electrophoresis analysis showed that eluted 125I-protein A comigrated with the protein A marker; (b) postperfusion C1q-binding complexes, isolated by gel filtration under dissociating conditions and affinity chromatography on IgG-Sepharose showed a single precipitin band with normal human (protein A reactive) but not chicken (protein A unreactive) serum. Protein A released from PACC which appeared in postperfusion sera was associated with immunoglobulins in macromolecular complexes since (a) eluted 125I-protein A was largely (NH4)2SO4 and polyethylene glycol precipitable, whereas free protein A was not, and it sedimented in sucrose density gradient fractions distributed beyond the 7S marker, compared to free protein A which localized below 7S; (b) radiolabeled protein A eluting from PACC after serum perfusion showed 8-fold greater binding to C1q-coated tubes compared to free protein A; and (c) increased C1q-binding IgG in postperfusion sucrose density gradient fractions corresponded to the appearance of protein A in parallel gradient fractions.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗

IgA containing immune complexes in dogs bearing a spontaneous mammary adenocarcinoma.

Sera from dogs with mammary adenocarcinoma were assessed for the presence of immune complexes (IC) and the physicochemical composition of these complexes was investigated. Employing 125I-anti-canine IgG as indicator, elevated levels of C1q binding IgG were detected in sera of dogs with mammary adenocarcinoma. Polyacrylamide gel electrophoresis (PAGE) analysis of IC isolated by G-200 fractionation and protein A affinity chromatography revealed the presence of a dense polypeptide band corresponding to the alpha chain of IgA which was present in the mammary adenocarcinoma sera but not in normal dog sera or sera from dogs with other tumours. Employing monospecific radiolabelled anti-canine IgA as indicator in solid phase C1q binding radioimmunoassays, significantly elevated levels of C1q binding IgA were detected in five of eight mammary adenocarcinoma sera but not in sera of normal dogs or other tumour bearing dogs (P less than 0.05). Sera from mammary adenocarcinoma bearing dogs treated with 5% polyethylene glycol (PEG) and subjected to sucrose density gradient ultracentrifugation revealed IgA containing IC in fractions greater than 7S to greater than 19S. Findings suggest that IC are present in sera of dogs with mammary adenocarcinoma and that that IgA is a major and unique component of these complexes and, hence, may play a significant role in the development and evolution of the canine immune response to mammary adenocarcinoma.

Animals↗

Inhibition of intra-abdominal adhesions: a comparison of hemaseel APR and cryoprecipitate fibrin glue.

Our previous studies demonstrated fibrin glue (FG) prepared from cryoprecipitate (cryo) inhibits intra-abdominal adhesions in rats. A new FG, Hemaseel APR, is Food and Drug Administration (FDA) approved for hemostasis during cardiac surgery and splenic trauma. This study was undertaken to determine if Hemaseel FG prevents intra-abdominal adhesions, and to compare it to cryo FG. Forty-five rats underwent laparotomy. Bilateral peritoneal-muscular defects were created. Polypropylene mesh was sewn into each defect with a running silk suture. The bowel was abraded with gauze. The rats were then randomized to mesh covered with Hemaseel FG, cryo FG, or control. On postoperative day 7, the severity of adhesions were graded by percentage of mesh covered by adhesion (0-100%) and degree of adhesion (0-3). The mean percentage of mesh covered by adhesion was 9% for Hemaseel FG, 43% for cryo FG (p = .005), and 65% for the controls (p < .0001). The mean density adhesion score was 0.5 for Hemaseel FG, 1.2 for cryo FG (p = .04), and 2.1 for the controls (p < .0001). In the Hemaseel FG group, 77% of patches had no adhesions, compared with 37% in the cryo FG group (p = .004) and 13% in the controls (p < .0001). Thus, Hemaseel FG significantly decreases intra-abdominal adhesions, and is more effective than cryo FG.

Abdomen↗