Frequency of lambda light chain subtypes in mouse antibodies to the 2,4-dinitrophenyl (DNP) group

Understanding thymus-independent antigen-induced reduction of thymus-dependent immune responses

Deficiencies in immune responses against polysaccharides can have direct consequences for patients, and therefore, a better understanding of these immune reactions is crucial. We have studied the immune response against the polysaccharide dextran B512 (Dx). Administration of immunogenic doses of thymus-independent (TI) Dx reduces the immunoglobulin G1 response to later challenges with a thymus-dependent (TD) form of Dx. We investigated if this suppression is a general phenomenon caused not only by Dx but also by other TI antigens, and examined possible mechanisms contributing to this unresponsiveness. We show that clonal exhaustion is not involved in modulating subsequent responses, nor is signalling via FcgammaRIIB or other antibody mediated pathways. The reduced TD response is not an exclusive Dx phenomenon; it is also induced by TI antigen oxazolone (Ox). However, responses against the hapten dinitrophenyl (DNP) are not affected, indicating that the TI priming negative effect is not a general process. This may be explained by the restricted immune response to both Dx and Ox, in contrast to the unrestricted DNP response. Our conclusion from these experiments is that the underlying mechanism for the TI-induced reduction of latter TD responses is a property of the TI activation itself.

Elicitation of a predominantly lambda light chain-bearing antibody response in BALB/c mice to a novel bifunctional aminocarboxylate chelating agent

A panel of murine monoclonal antibodies has been raised against the aminocarboxylate bifunctional chelating agent PA-DOTA complexed with Samarium. Ninety percent of the antibodies (43 of 48) used a lambda light chain. The binding specificity of 11 of the antibodies was examined by competition assays using several structurally related aminocarboxylate chelating agents containing different metals. Most of the antibodies are directed against the macrocycle ring of PA-DOTA and require the presence of a metal within the structure for binding.

A unique human IgE-binding epitope on the Bermuda grass pollen recognized by mouse lambda-type monoclonal antibodies

A group of six mouse monoclonal antibodies (MoAbs) with the unusual lambda-type light chain were generated by fusion of NS-1 cells with splenic cells derived from BALB/c mice immunized with crude extracts of Bermuda grass pollen (BGP). Four of them were IgG1, one was IgG2b, and one was IgG3. Binding inhibition assay showed that they recognized the same (or very similar) epitope. Using sera from BGP-allergic patients, it was found that the specific binding between the IgE antibodies and the MoAb 26-11-fixed antigen could be blocked by MoAb 26-11 itself and another MoAb 9-13 in a dose-dependent manner. It appears that the epitope recognized by the lambda-type MoAbs is a human IgE-binding antigenic determinant. Further physico-chemical analyses showed that this epitope was stable under heat but sensitive to treatments of sodium periodate and proteinase K. Results from these studies indicate that this unique epitope which leads to the generation of lambda-type MoAbs is part of a glycoprotein.

Murine anti-TNP antibodies positive for either lambda 1 or lambda 2 light chains express common idiotypic determinants

Although the lambda-bearing antibodies represent only 5% of the total mouse serum immunoglobulins, some antigens such as B1355 dextran (alpha (1-3)Dex), the 4-hydroxy-3-nitrophenyl acetyl (NP) and 2,4-dinitro or 2,4,6-trinitrophenyl (DNP/TNP) antigens can induce lambda-positive immune responses. In contrast to the lambda antibody response against alpha (1-3)Dex and NP antigens which is restricted to the lambda 1 isotype it was shown that the response to the DNP (or TNP) antigen uses lambda 1 and lambda 2 and lambda 3 isotypes. The idiotypy of the alpha (1-3)Dex and NP systems has been well characterized contrary to that of the lambda-positive anti-TNP/DNP response which has been poorly studied. In this paper, we describe two idiotopes (Id C19-3 and Id D11-2) shared by two BALB/c monoclonal anti-TNP antibodies (TNP5 and TNP9) which, respectively, use the lambda 1 and lambda 2 light chains. These idiotopes were independently expressed on other monoclonal anti-TNP/DNP antibodies and appear to require the use of a unique VH gene associated with a particular V lambda region. After TNP-Ficoll immunization, BALB/c mice recurrently express both idiotopes on lambda 1 and (lambda 2 + lambda 3) anti-TNP antibodies. In addition, all the mouse strains immunized against TNP-Ficoll give a lambda 1- and (lambda 2 + lambda 3)-positive immune response with the exception of SJL and SJA strains which present a deficit for the expression of lambda 1 light chain. The expression of Id C19-3 was restricted to the strains with the Igh-Va allotypic haplotype (including SJA) whereas the Id D11-2 was extensively expressed in the various strains.

Maturation of the immune response to (4-hydroxy-3-nitrophenyl)-acetyl (NP) haptens in C57BL/6 mice

Changes with time in specificity and affinity of anti-NP antibodies in C57BL/6 mice after immunization with NP22-chicken gamma-globulin (CGG) were studied by comparing the abilities of the antibodies to bind to NP3-bovine serum albumin (NP3-BSA) at pH 5 and 8. Early anti-NP antibodies (on day 14 after immunization) bound to NP3-BSA at pH 8, but not pH 5. This pH-dependence of binding was explained in terms of the low affinity of the antibody to the phenolic form of NP on the basis of results of fluorescence quenching titration of a monoclonal anti-NP antibody that showed similar specificity to that of the early anti-NP antibodies. Since NP on the CGG molecule ionized with an apparent pK of about 7.4, more than half the NP should be in the unionized (phenolic) form under the immunization conditions. However, early anti-NP antibodies bound preferentially to the ionized (phenolate) form of NP, which was a minor form at neutral pH, whereas later anti-NP antibodies showed ability to bind to both the phenolate and phenolic forms of NP. This change in specificity with time was observed on immunization with T cell-dependent (TD) antigens such as NP-CGG and NP keyhole limpet hemocyanin (KLH), but not with a T cell-independent (TI) antigen such as NP-Ficoll. The heavy (H) chains from the two monoclonal antibodies 3G6 and 3C6, which bound to the phenolate form and both the phenolate and phenolic forms, respectively, were recombined with lambda 1 chains (L3G6 and L3C6) from these antibodies as well as a lambda 1 chain (LHOPC-1) with the amino acid sequence of the germline. Ability to bind to the phenolate form of NP was recovered in all the reconstituted IgGs, while ability to bind to both the phenolate and phenolic form of NP was observed only with IgG reconstituted from H3C6 and L3C6. These results suggest that the specificity corresponding to early anti-NP antibodies were generated even by lambda 1 chains of a germline sequence, but that of late anti-NP antibodies was expressed only by an appropriate pair of H and L chains. The contribution of amino acid substitution by somatic point mutation to the change of specificity with time was discussed.

Repertoire of murine lambda-positive variable domains: polyclonal induction of lambda isotypes and their associated pattern of antibody specificities

The diversity of lambda variable (V lambda) domains is extremely restricted when compared to those of VH and V kappa. In addition, each V lambda domain is determined by the C lambda domain. For these reasons, the lambda system is an excellent model for the study of the associated VH region repertoire. The study of V lambda domain diversity has been limited by the small contribution (approximately 5%) of lambda-bearing proteins to the total Ig pool. We now show that treatment of BALB/c mice with rabbit anti-lambda 1 antibodies coupled to lipopolysaccharide induces a production of polyclonal lambda 1 light chain-bearing Ig whereas, conversely, treatment with rabbit anti-lambda 2 antibodies induces a production of polyclonal lambda 2 + lambda 3 light chain-bearing Ig. The antigenic specificities of these two distinct lambda populations were then studied using B1355 dextran, (4-hydroxy-3-nitrophenyl)acetyl (NP) and 2,4-dinitrophenyl (DNP) as antigens. The anti-alpha(1-3)dextran antibody specificity was found to be mediated exclusively by antibodies bearing the lambda 1 isotype whereas the anti-NP and anti-DNP antibody specificities are mediated by both the lambda 1 and lambda 2 + lambda 3 isotypes. In addition, various mouse strains with the VHa or VHb allotypic haplotype and the rlo lambda 1 or r+ lambda 1 phenotype were treated with rabbit anti-lambda 1 antibodies. The lambda 1 anti-NP and anti-DNP antibody specificities were similar in all strains whereas the lambda 1 anti-alpha(1-3)dextran specificity was linked to the presence of the VHa allotypic haplotype. The mouse strains with the rlo lambda 1 or r+ lambda 1 phenotype did not differ in terms of their patterns of lambda 1 antibody specificities.

The level of lambda 1 light chain expression in the mouse reflects the probability of rearrangement of the relevant gene

The predominance of kappa over lambda light chain expression in mice can either reflect the probability of rearrangement of the relevant locus or be the result of antigen-driven clonal expansion. To discriminate between these two possibilities we determined, by limiting dilution analysis, the frequencies of kappa- and lambda-producing cells in B lymphocytes generated in vitro from bone marrow pre-B cells. The frequencies obtained in these cultures are not significantly different from those obtained with mature spleen cells. In addition, Southern blot analysis of bone marrow-derived and splenic cell DNA revealed that in both populations the extent of B lymphocytes having undergone lambda 1 gene rearrangement does not exceed 4%. These results, therefore, establish that in the mouse the low level of lambda light chain expression directly reflects the probability of rearrangement of the relevant locus.

The antibody paradox: trying on a pair of genes

Rodney Porter's separation of antibody molecules into Fab and Fc fragments engendered the notion that a single antibody polypeptide chain might be coded by two or more genes. This concept profoundly influenced the development of molecular immunology over the past 25 years. Our current knowledge of antibody gene organization has enabled investigators to recombine antibody genes to create 'chimeric' antibodies with a number of potentially useful applications.