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E Lamoyi

Publications and source records attributed to E Lamoyi.

At least 37 records · Page 2Linked to original sources
PubMed1986

Naegleria actin elicits species-specific antibodies.

Actin, the major protein of amebae of Naegleria gruberi, proved to be strongly immunogenic in rabbits. The resulting precipitating antibodies are specific to actin of Naegleria. In a competitive solid-phase radioimmunoassay, these antibodies bound similarly to Naegleria G- and F-actin. Actins from amebae of Acanthamoeba and Dictyostelium, plasmodia of Physarum, sea urchin eggs, and vertebrate muscles gave no competition in the radioimmunoassay. Estimates of the amount of actin in Naegleria amebae ranged from a minimum of 5% of the total cell protein by radioimmunoassay to a maximum of 16% by electrophoresis. The unusual species specificity of these antibodies indicates that Naegleria actin, although conserved in many properties, is different enough to have unique antigenic determinants.

Actins↗
PubMed1985

Lack of K1b9 light chains in Basilea rabbits is probably due to a mutation in an acceptor site for mRNA splicing.

Rabbits of the Basilea strain do not produce normal K1b9 light chains but continue to produce immunoglobulins with light chains of the rare K2 isotype and of lambda type. To understand the molecular basis for this unusual expression of kappa light chains in Basilea rabbits, we undertook an analysis of their kappa genes. We isolated and sequenced the mutant kappa 1b9 gene and found a substitution of A for G in the highly conserved AG dinucleotide of the 3' acceptor splice site. Although we cannot rule out additional alterations of portions of the gene we did not sequence, this spontaneous change of the G found in the normal gene provides a likely molecular explanation for the loss of K1 light chain expression in Basilea rabbits.

Animals↗
PubMed1985

Identification of genes for the constant region of rabbit T-cell receptor beta chains.

We describe cDNA clones from thymus mRNA of a young rabbit that have sequences highly homologous to the human and murine T-cell receptor beta-chain constant region (C beta). In rabbit, man, and mouse there is a conserved extra cysteine in the constant region that could lead to a free thiol group or alternative disulfide bond formation depending on the locations and total numbers of cysteines in assembled receptor molecules. A cDNA clone (CL ANA 11) with 571 bases 5' of the C beta coding sequence has an open reading frame starting at a methionine codon that encodes 141 amino acids in frame with the C beta sequence. The encoded sequence has no resemblance to known immunoglobulin or beta-chain variable regions or other known proteins. An oligonucleotide probe from the 5' end of the encoded protein hybridizes to an approximately equal to 2-kilobase genomic DNA fragment that contains C beta gene sequences and to an approximately equal to 8-kilobase mRNA species in the thymus mRNA preparation from which the clone was derived. Within the 5' coding sequence there is a stretch of 211 bases containing strings of alternating purines and pyrimidines that may form Z-DNA. The sequence of the last 55 base pairs adjacent to C beta resembles the corresponding segment of mouse cDNA clone 86T3 that contains sequence 5' of the mouse C beta 1 gene. Although the function of a potential protein encoded by the 5' end of CL ANA 11 is unknown, it could play a role in regulation of thymocyte growth and differentiation.

Amino Acid Sequence↗
PubMed1984

Crystallization of the fab fragments of monoclonal anti-p-azophenylarsonate antibodies and their complexes with haptens.

We report on the preparation, crystallization, and preliminary x-ray crystallographic study of Fab fragments from monoclonal anti-p-azophenylarsonate antibodies. Several crystalline forms were obtained with the Fab fragment from the R19.9 monoclonal antibody as well as with the complex between the hapten p-aminobenzenearsonic acid and Fab R19.9. The crystals of this hapten-Fab complex are similar to but not always isomorphous with the native Fab crystals. All the native and complex crystals were obtained using polyethylene glycol 6000 as crystallizing agent. Some of these crystalline forms diffract to a 2-A resolution or beyond and are suitable for high resolution x-ray diffraction analysis. A possible interpretation of hapten binding to crystalline Fab fragments from R19.9 and from the R9.3 monoclonal anti-p-azophenylarsonate antibody, implying conformational changes, is discussed.

Animals↗
PubMed1984

Sequence of a cDNA encoding Basilea kappa light chains (K2 isotype) suggests a possible relationship of protein structure to limited expression.

We present the complete sequence of a cDNA encoding rabbit immunoglobulin kappa light chains of the Basilea isotype (K2). Although all rabbits seem to possess a K2 constant region gene, expression of this gene in most rabbits is minimal if present at all. Even in Basilea rabbits the majority of expressed immunoglobulins are of lambda type. We find that the sequence of our Basilea cDNA constant region and the sequence of a "silent" K2 gene from b4 rabbits (bas-N4) are almost identical. The bas (K2) isotype lacks cysteine at position 171 in the constant region that is present in all K1 constant regions and usually forms an interdomain disulfide bond, with a cysteine at position 80 of the variable region. We postulate that one factor contributing to the low expression of the bas (K2) isotype could be a paucity of V kappa regions lacking cysteine at position 80. If a typical rabbit V kappa encoding Cys at position 80 is rearranged and expressed with th K2 isotype. B cells with mRNAs encoding light chains with free sulfhydryl groups would result. These cells may fail to form functional immunoglobulin receptors. Only a small subset of rabbit variable regions that lack the cysteine at position 80 would rearrange and encode K2 light chains lacking a free sulfhydryl group.

Amino Acid Sequence↗
PubMed1983

Idiotype profile of an immune response. II. Reversal of the relative dominance of major and minor cross-reactive idiotypes in arsonate-specific T-independent responses.

Two different cross-reactive idiotype (CRI) groups are distinguishable in the Ab response of A/J mice to the p-azobenzenearsonate (ABA) hapten: CRIA and CRIm. These two groups showed distinct patterns of relative dominance in the ensuing response depending on whether the inducing Ag was a T cell-dependent (TD) form of ABA, such as ABA-KLH or ABA-CGG, or a T-independent type 1 (TI-1) form, such as ABA-Brucella abortus or ABA-lipopolysaccharide (LPS), and on whether the response was elicited in vivo or in vitro. The CRI+ component of primary in vivo plaque-forming cell (PFC) responses to TD ABA Ags was largely (greater than 90%) CRIA+ as was, to a slightly lesser extent (greater than 75%) the CRI+ portion of secondary or hyperimmune serum Ab or PFC responses to the same Ags. In contrast, in vivo primary and hyperimmune PFC responses to ABA-Bru or ABA-LPS showed a significantly lower CRIA/CRI ratio, averaging 0.5-0.6, with some individual mice giving figures as low as 0.2, indicating predominance of CRIm over CRIA. Serological analysis of hyperimmune anti-ABA Abs from a group of 5 A/J mice immunized with ABA-Bru gave a figure of less than 0.5 for the CRIA/CRI ratio. The most striking disparity from the TD pattern was seen in primary in vitro PFC responses to the TI ABA Ags; here ratios of less than 0.2 were generally seen. Since T cell removal did not alter the Id pattern in the TI responses, CRIA-specific Ts cells do not account for the weak expression of CRIA in such responses. We propose a model that explains these results on the basis of differential expression of IdX dominance by two distinct B cell subpopulations--equatable to the Lyb-5+ and Lyb-5- B cell subsets--along with differential relative activation of these subsets in different types of responses. Examination of anti-ABA PFC responses of F1 progeny of CBA/N and A/J mice to ABA-Bru lends support to this hypothesis since CRIA expression was significantly lower in mice with the xid defect.

Animals↗
PubMed1983

Preliminary crystallographic study of the Fab fragment of a monoclonal anti-phenylarsonate antibody.

Preliminary crystallographic data are given for the Fab fragment of a monoclonal anti-p-phenylarsonate antibody. This crystalline Fab fragment was found by screening a number of monoclonal anti-arsonate antibodies obtained from hybrids of A/J immune spleen cells with a non-secreting mouse myeloma line. The protein crystallizes in the monoclinic space group P21 with a = 86.2 +/- 0.1 A, b = 80.4 +/- 0.2 A, c = 75.8 +/- 0.1 A, beta = 90.3 +/- 0.1 degrees. Precession photographs show X-ray reflections extending to a resolution of 3 A.

Antibodies, Monoclonal↗
PubMed1983

Preparation of F(ab')2 fragments from mouse IgG of various subclasses.

We have investigated the effects of peptic digestion on mouse monoclonal immunoglobulins of each subclass of IgG. F(ab')2 fragments were obtained in good yield from IgG1, IgG2a and IgG3 proteins. The relative rates of digestion were IgG3 greater than IgG2a greater than IgG1. Variations in rate of digestion were noted for individual monoclonal IgG3 proteins. Five different IgG2b proteins were degraded very rapidly without the detectable formation of antigen-binding F(ab')2 fragments. One IgG1 protein out of four tested was also rapidly degraded.

Animals↗
PubMed1981

Regulation of expression of a family of cross-reactive idiotypes.

It has recently been shown that anti-p-azophenylarsonate antibodies of A/J mice, which share a common idiotype, are not homogeneous but actually comprise a family of idiotypically related molecules. To obtain additional insight into the degree of relatedness of antibodies within this family, we have determined whether inoculation of any idiotype-positive hybridoma product, conjugated to thymocytes, can activate a regulatory mechanism capable of controlling the entire cross-reactive idiotypic response. In addition anti-idiotypic antibodies were prepared against individual hybridoma products, and their suppressive effects on the idiotypic component of the humoral response were determined. Inoculation of each of the idiotype-positive hybridoma products or anti-idiotypic antisera caused virtually complete suppression of the idiotypic component of the immune response. Furthermore, it was shown that the state of suppression induced by the inoculation of a hybridoma products could be adoptively transferred with T cells to mildly irradiated syngeneic recipients. The results indicate that there are sufficient structural similarities among the family of antibodies comprising the major cross-reactive idiotype to permit their recognition by the same set of elements involved in idiotypic regulation.

Animals↗
PubMed1981

Relationship of idiotypes of the anti-p-azophenylarsonate antibodies of A/J and BALB/c mice.

It has previously been shown that A/J anti-Ar antibodies contain 2 different families of cross-reactive idiotypes, referred to as the major and minor idiotypes populations. The present report shows that the minor A/J idiotype is related to a major idiotype of BALB/c anti-Ar antibodies. Anti-idiotype directed against the minor A/J idiotype binds 5 to 10% of A/J anti-Ar but an average of about 40% of BALB/c anti-Ar. This BALB/c population corresponds to the major BALB/c anti-Ar idiotype. For individual BALB/c anti-Ar preparations the maximum percentages of antibody bound by anti-id directed to A/J or BALB/c anti-Ar are very similar. Anti-id reactive with the minor A/J idiotypic population suppressed the formation of the BALB/c major idiotype when injected into BALB/c mice. Adsorption experiments showed that only about one-third of the minor A/J population is related to the BALB/c idiotype and that the expression of this idiotype is highly variable in individual A/J sera. Several types of evidence, obtained with hybridoma products expressing the major A/J idiotype, revealed no detectable relationship between the major A/J and BALB/c anti-Ar idiotypes.

Animals↗
PubMed1981

Properties of a minor cross-reactive idiotype associated with anti-p-azophenylarsonate antibodies of A/J mice.

Experiments are described that further characterize an A/J anti-phenylarsonate (anti-Ar) antibody population, which is idiotypically cross-reactive within the strain but differs from the family of antibodies expressing the major cross-reactive idiotype (CRI). This population has been designated as expressing a "minor" cross-reactive idiotype. Chain recombination studies with hybridoma products (HP) revealed that 2 of 3 HP expressing minor idiotypic determinants contain L chains that are idiotypically closely related to L chains in anti-Ar antibodies bearing the major CRI. The results indicate the expression of the same or very similar L chains in antibodies that differ in idiotype. The minor idiotypic population in serum was investigated by separating antibodies with minor and major idiotypic determinants by use of an immunoadsorbent containing anti-idiotype directed to an HP expressing the major CRI. Studies with the nonadherent, minor idiotypic population showed that such molecules constitute about 8 to 10% of the anti-Ar antibodies in a pool of serum but that individual sera vary markedly in their content of anti-Ar antibodies bearing minor idiotypes. Preinoculation of mice with conventional anti-idiotypic antiserum before immunization with KLH-Ar was found to suppress the appearance of the minor idiotypes as well as the major CRI upon subsequent immunization. The suppression of the minor idiotypic population is presumably mediated by the small fraction of rabbit anti-id antibodies directed against such molecules.

Animals↗
PubMed1980

Presence of highly conserved idiotypic determinants in a family of antibodies that constitute an intrastrain cross-reactive idiotype.

It has been shown that A/J anti-p-azophenylarsonate antibodies that share a major cross-reactive idiotype (CRI) comprise a family of closely related, but nonidentical, molecules. Our results demonstrate that 12 of 14 monoclonal hybridoma products that express the CRI have in common at least one highly conserved idiotypic determinant. It is proposed that this reflects conservation of a portion of the amino acid sequence, presumably in hypervariable regions. That the conserved determinant(s0 are located in the region of the hapten-binding site is indicated by the ability of haptens to inhibit idiotype-anti-idiotype interactions involving the conserved, or public determinants.

Animals↗
PubMed1980

Structural studies on induced antibodies with defined idiotypic specificities. IX. Framework differences in the heavy- and light-chain-variable regions of monoclonal anti-p-azophenylarsonate antibodies from A/J mice differing with respect to a cross-reactive idiotype.

Amino terminal amino acid sequence analyses have been performed on the heavy and light chains of induced monoclonal antibodies with specificity for the hapten p-azophenylarsonate. Four of the eight antibodies react with conventional antisera to the previously described A/J anti-arsonate cross-reactive idiotype (CRI). Of the 16 chains analyzed, all but one contain sequence differences in their first framework segment (residues 1-30) that distinguish them from the heavy- and light-chain sequences found in anti-arsonate antibodies isolated from A/J serum or ascites fluid. The presence of such framework differences appears to be independent of whether or not the hybridoma antibodies bear the CRI. In spite of the framework substitutions, all four of the CRI-positive hybridoma antibodies have variable (V)-region frameworks that are very similar to each other and to the CRI-positive molecules found in A/J serum. Two of the four CRI-negative molecules are also structurally similar to the serum antibodies. Two others, however, are strikingly different from any serum anti-arsonate antibody thus far described and appear to reflect a completely separate repertoire of anti-arsonate antibodies in the A/J MOUSE. In addition, serological analyses with an anti-idiotypic antiserum generated against a CRI-positive hybridoma product suggest that each monoclonal antibody may possess individual antigenic specificities different from the determinant(s) detected with the conventional rabbit anti-CRI. The consistent appearance of framework substitutions in what has been thought to be a homogeneous antibody population has important implications for our understanding of the generation of antibody diversity and for the precise chemical definition of an idiotype.

Amino Acid Sequence↗