Mouse monoclonal antibodies induced by anti-allotype antibody display internal images of the rabbit VHa1 allotype: direct visualization by immunoelectron microscopy

We have previously shown that injection of adult rabbits with anti-immunoglobulin (Ig) antibody (Ab) induces the expression of genetically unexpected Ig markers, i.e., a1 allotypic determinants. We now show that these rabbit Ig markers can also be induced in mice by a similar treatment; in the latter case the a1 determinants are located in the antigen-combining site and thus represent "internal images". Two monoclonal antibodies (mAb) were developed from mice treated with anti-allotype Ab. These mAb were reactive with all homologous and heterologous anti-a1 Ab but not normal Ig; efficiently inhibited the binding of rabbit a1 Ig to anti-a1 Ab; and elicited the production of anti-allotype Ab when injected into normal mice. To determine whether the a1-like determinants on these mAb were located in the antigen-combining site, immunoelectron microscopy was utilized to directly visualize Ab complexes. Complexes composed of intact Ab and anti-a1 Fab fragments yielded uniform binding patterns which were identical to those produced by anti-idiotypic reactions. In each case, an identical tip-to-tip binding configuration was observed with a single Fab fragment attached at an approximate 180 degree angle to the V region terminus of each Ab arm. In contrast, rabbit a1 Ig bound as many as two anti-a1 fragments per Ig arm; these fragments were attached laterally and at right angles to the intact molecule. These mAb thus provide the first direct evidence that Ab2 beta determinants are located in, or near, the antigen-combining site.

[Ir-gene control of rat T-lymphocyte proliferation in response to Ig allotype]

Antigen-induced T-cell proliferation in vitro was adapted to the estimation of antiallotypic response to Igk-Ib immunoglobulin k chain allotype of MSU/b and Fisher rats in WAG, August and FI (WAG X August) rats. August and FI rat T lymphocytes responded to Igk-Ib alloantigen with stimulation indexes (SI) 3.8-5.0 (high responders), while WAG rat T lymphocytes showed practically no response (SI 0.9-1.8--low responders). These results correlate well with our previous findings of Ir-gene-controlled antiallotypic in vitro reactions in these rat strains. Effective antigen presentation to FI anti-Igk-Ib T cells was observed only using Igk-Ib-pulsed antigen-presenting cells (APC) of August responders, but not of WAG non-responders. FI T cells responded well to PPD-pulsed APC of both rat strains. The data confirm Ir-Igk-Ib-gene control and, therefore, MHC-restriction of antiallotypic response in inbred rats.

Familial concurrence of pauciarticular syndrome and systemic sclerosis

We observed a sibship of two children who had the syndrome of early-onset pauciarticular arthritis with anti-nuclear antibodies; their paternal grandmother died of progressive systemic sclerosis. Since the early-onset pauciarticular syndrome is very rare or non-existent in adults, the findings in this kindred pair raise the possibility that this disorder and adult systemic sclerosis may share some genetic or other etiological factors.

Partial amino acid sequence and genetic control of latent a2 allotype induced in rabbits by immunization with anti-a2 antibody

We have shown that after immunization of homozygous a1 rabbits of the B immunoglobulin (Ig) heavy chain haplotype with anti-a2 antibody (Ab) a population of molecules appears that has all of the serologic characteristics of the a2 allotype. We have now isolated these putative latent a2 molecules, have separated the heavy chains, and after enzymatic deblocking, have determined the first 19 N-terminal amino acids. For all eight allotype-associated residues, these putative latent a2 molecules have the amino acid residues typical of a2 allotype. As expected, the preimmune IgG from this a1a1 rabbit has the amino acids typical of the a1 allotype. Thus by partial amino acid sequence analysis, we provide additional evidence that the latent a2 allotype can be induced in a1a1 rabbits of the B heavy chain haplotype by immunization with anti-a2 Ab. Rabbits of other heavy chain haplotypes were also immunized with anti-a2 Ab and were tested for their ability to synthesize latent a2 allotype. Thus far, a1a1 rabbits of the A, B, C, and I heavy chain haplotypes all synthesize latent a2 allotype. In contrast, a3a3 rabbits of the G and H heavy chain haplotypes did not synthesize latent a2 allotype.

A novel idiotopic determinant on phosphorylcholine-binding immunoglobulins restricted to isotype and allotype

A shared idiotopic (Id) determinant, designated B24-50, was detected on phosphorylcholine (PC)-binding myeloma proteins by using a monoclonal antibody. Analysis of immune sera from inbred and congenic strains of mice revealed the presence of this Id determinant on a very small proportion of the PC-binding immunoglobulins (Ig). Hybridoma and myeloma proteins of various classes were analyzed for B24-50 expression, and a clear association of B24-50 with IgA was demonstrated. The Id was found on two distinct idiotypic families, (TEPC15 and McPC603), which share a similar heavy chain but have different light chains; however, isolated heavy chains did not express B24-50. The Id did not require the absolute association of the TEPC15 light chain V kappa 22 with the TEPC15 heavy chain but appeared dependent upon the interaction of the light chain with the TEPC15 heavy chain via quaternary interactions and/or shared amino acid residues of V kappa 8 (M603) and V kappa 22. Furthermore, B24-50 was not found on IgA of strains with the Ighb allotype. Thus B24-50 is a novel isotype-restricted determinant found on two Id families and is influenced by the Igh allotype.

Xid and normal mice express a light chain-associated cross-reactive idiotype in response to (T,G)-A--L and (T,G)-A--L-mBSA

Rabbit anti-idiotypic (Id) antibodies were prepared against purified ascites anti-(T,G)-A--L antibodies (TGB5) that had been absorbed to remove A--L-specific antibodies and were specific for (T,G)-side chain determinants. Purified rabbit anti-TGB5 Id antibodies detected an allotype-independent, light chain-associated cross-reactive Id expressed by the majority of individual mice immunized with (T,G)-A--L, (T,G)-A--L coupled to methylated bovine serum albumin (mBSA), or the linear terpolymer GAT. Primary and secondary monoclonal hybridoma protein (HP) antibodies from X/Xxid heterozygous (wild-type) mice immunized with (T,G)-A--L and/or (T,G)-A--L-mBSA were analyzed for isotypy and were grouped into eight antibody fine specificity sets defined by the patterns of direct binding to the antigens (T,G)-A--L, (Phe,G)-A--L, (T,G)-Pro--L, GT, and A--L. Analysis of these primary and secondary HP for TGB5 idiotypy showed a preferential expression of the TGB5 Id among GT+-binding HP (antibody fine specificity sets 1 through 3). All of the primary GT+-binding HP and the majority of secondary GT+-binding HP (sets 1 through 3) were TGB5 Id+. Most but not all of the TGB5 Id+ HP bound GAT. Of the side-chain-specific HP (sets 1 through 7), 78% of primary HP vs 49% of secondary HP bound GT. By these criteria, the primary HP response appears more restricted than the secondary HP response, consistent with the idea that Id diversification and antibody heterogeneity are regulated and selected events occurring during memory B cell generation. Although xid mice produce less antibody than wild-type mice to (T,G)-A--L, the TGB5 Id was produced early in the primary response by both xid and wild-type mice immunized with (T,G)-A--L or (T,G)-A--L-mBSA, and was maintained as a detectable Id in equivalent amounts in their secondary serum antibody responses. These results support the idea that distinct B cell subsets, including the xid B cell subset, share the same immunoglobulin gene repertoire.

Serologic and biochemical analysis of latent a1 IgG

Immunization of rabbits with anti-allotype antibody (Ab) induces at least two populations of highly cross-reactive molecules. One of these populations bears the nominal VHa allotype of the producing rabbit and is designated the VHa-positive anti-IdX Ab. The other population lacks the expected nominal allotype and thus could represent an induced latent allotype-bearing Ig. To define better the putative latent allotypes, they were subjected to serologic, electron microscopic and biochemical analyses. The induced latent-like population was compared to nominal a1 and found to be indistinguishable in inhibition assays incorporating both rabbit anti-a1 Ab and mouse monoclonal anti-a1 Ab. In contrast, the latent-like Ig was less inhibitory than normal a1 Ig in assays with goat and guinea-pig anti-a1 Ab. The isolated anti-IdX population was less inhibitory than either nominal or latent a1 Ig in all assays. Immunoelectron microscopic analysis indicates that complexes composed of latent-like a1 molecules and Fab anti-a1 ab resemble allotype/anti-allotype (i.e. a1/anti-a1) complexes. Tryptic digests of the putative latent a1 H-chains reveals that these molecules share an a1-specific peptide with digests of nominal a1 H-chain. The peptides from both nominal and latent a1 IgG appear to have blocked N-terminal residues and have a similar though not identical amino acid composition. The composition of these peptides is correlated with the first nine amino acids of the nominal a1 H-chain. The data suggest that the induced latent a1-like molecules share the same major a1 epitope with nominal a1 but may differ in some subtle respects. The possible genetic bases for these observations are discussed.

Allotypy of the rabbit kappa 2 light chain: evidence that the kappa 2 isotype is expressed by all members of the rabbit species

The rabbit kappa 2 light chain subtype was described after isolation of the Basilea mutant strain, which does not express the kappa 1 subtype; antibodies raised in domestic rabbits against the Basilea kappa 2 chain recognized antigenic determinants present in Basilea strain rabbits and in some wild Oryctolagus cuniculus individuals. Some authors have proposed that the kappa 2 isotype is expressed in some individuals and is silent in others. The results presented here provide immunochemical and genetic evidence that the kappa 2 isotype presents at least two allotypic forms, bas 1 (equivalent to bas+) and bas 2 (equivalent to the so-called bas-), which are expressed in low levels in all members of the rabbit species. In addition, preliminary data on the expression of the bas 2 allotype in some hares (Lepus capensis) are reported. On the basis of these results, the rules guiding the selection of kappa 1 and kappa 2 isotypic light chain expression in this species may now be approached.

Selective suppression of allotype expression induced in vitro: maintenance of suppression following adoptive transfer

The question of the ultimate fate of lymphocytes subjected to treatment with anti-allotype antibody (Ab) has been investigated by means of an adoptive transfer system that uses noninbred rabbits matched for major histocompatibility antigens and mismatched for allotype. Suppression of b4 immunoglobulin (Ig) production was induced by incubating lymphocytes from b4b5 rabbits with anti-b4 in culture. Transfer of b4-suppressed cells to newborn recipients of allotype b6b6 resulted in stable chimerism of mixed donor-recipient allotypes, in which b4 Ig production remained suppressed. In recipients of non-Ab-treated cells, b4 Ig production predominated over b5, as had been the case in the intact donor. No evidence for stimulation of b4 Ig synthesis was seen, even when lymphocytes and serum from 1-week-old recipients were examined. When lymphoid cells of antigen-primed b4b5 donors were treated with anti-b4 in vitro and transferred, Ab production of the b4 type was specifically suppressed, with compensatory over-production by Ab-forming cells of the b5 type. The results reported here indicate that although anti-allotype Ab is not directly cytotoxic, a significant proportion of the b4-committed cells were irreversibly inactivated as a result of Ab pulse treatment.

Monoclonal antibodies directed towards the two major cell populations in the bursa of Fabricius of the chicken

Two mouse monoclonal IgM antibodies, B.1 and B.2, have been produced using the mouse myeloma cell line Sp2/0-Ag 14 and spleen cells from mice immunized with chicken bursa cells. The binding of the monoclonal antibodies to cells in suspension or tissue sections was demonstrated by means of the unlabeled peroxidase-antiperoxidase method. B.1 recognizes 61% of the bursa cells, 10-14% of the cells of spleen and of the peripheral mononuclear blood leukocytes and 1% of the thymus cells. The B.1+ cells are regarded as B cells. Their location in tissue sections corresponds with the known B-dependent areas of lymphoid organs. Competitive binding and double marker experiments proved that the B.1 antigen is distinct from surface immunoglobulin (Ig). In the bursa all B.1+ cells are also Ig+, whereas in the thymus, spleen and blood only about 90% of the B.1+ cells show this conformity. B.2 mainly recognizes so called reticular epithelial and reticular cells of the bursa (36%), thymus (20%) and spleen (13%). The B.2+ cells represent the second major cell population of the bursa.

Gamma ray-induced mutants as a tool for the production and characterisation of monoclonal antibodies against HLA-alloantigens

To simplify the screening procedure for murine monoclonal antibodies specific for polymorphic HLA determinants, spleen cells from a mouse immunized with the human cell line BJAB-B95.8.6 were fused with NS1 mouse myeloma cells, and hybridoma supernatants were screened for their reactivity on BJAB-B95.8.6 and two gamma ray-induced HLA-loss mutants of this line. The use of these HLA-loss mutants allowed the rapid identification of two new allospecific MOABs designated TU160 and TU161. Serological as well as biochemical studies revealed TU160 to be specific for HLA-A2, and TU161 for HLA-B13 molecules, respectively. Both MOABs were determined to be antibodies of the IgG class and were able to precipitate their antigens from lysates of radioactively labeled cells.

Genetic markers in rheumatoid arthritis relationship to toxicity from D-penicillamine

In a 3-centre study involving 144 patients with rheumatoid arthritis (RA), a relationship between side effects from D-penicillamine and HLA antigens, allotypic markers of the IgG heavy chain (Gm) and allotypes of complement components Bf, C4A and C4B was sought. There was a significant association between proteinuria induced by D-penicillamine and the antigens DR3 and B8. However, the presence of DR2 seemed to protect against the development of proteinuria. Thrombocytopenia from D-penicillamine was significantly associated with HLA-A1 and DR4; 15 of 23 patients who possessed both antigens developed thrombocytopenia (p less than 0.001 uncorrected, approximate relative risk (RR) = 5.5). A null complement allele located at the C4B locus (C4BQO) was also associated with thrombocytopenia from D-penicillamine (p less than 0.005, RR = 17.3). Our study confirms the findings from other series which indicate that there is a genetic predisposition for the development of proteinuria from D-penicillamine in RA and suggests that this may also be the case in D-penicillamine induced thrombocytopenia.

Assignment of determinants recognized by human alloantisera to HLA-D-subregion molecules by a lysostrip technique

We have used a lysostripping technique to investigate the molecular relationships of the determinants recognized by human alloantisera and murine monoclonal antibodies reactive with HLA-D region products. Cytotoxicity mediated by sera that define the specificities DR1, DR2, DR3, DR4, DR7, DRw11, DRw12, DRw13, DRw14, DRw52 and DRw53 was inhibited by anti-DR but not by anti-DQ Mabs. In contrast, sera that define DQw1, DQw2 and DQw3 were inhibited by anti-DQ but not anti-DR monoclonal antibodies. We found some sera used to define DR specificities that were not inhibited by monoclonal anti-DR. Cytotoxicity mediated by monoclonal antibodies reactive with the recently described specificities TA10 and MC1 was inhibited by anti-DQ and anti-DR monoclonal antibodies, respectively. The lysostripping technique is useful for the assignment of specific determinants to HLA-D subregion molecules.

Studies of monoclonal antibodies specific for major histocompatibility complex products of the rat. IV. Production and characterization of polyclonal and monoclonal anti-anti-idiotypic antibodies

Polyclonal syngeneic, allogeneic, and xenogeneic and monoclonal syngeneic anti-anti-idiotypic antibodies have been produced against previously described monoclonal anti-idiotypic antibodies with specificity for monoclonal RT1 alloantigen-specific antibodies. The anti-anti-idiotypes could again be shown to be highly specific for the monoclonal anti-idiotype used for the induction of the anti-anti-idiotypic antibodies and to carry the same, or a very similar, idiotype as the original monoclonal idiotypic antibody used to induce the monoclonal anti-idiotypic. Among the 30 syngeneic and allogeneic and the five xenogeneic polyclonal anti-anti-idiotypic antisera and the three monoclonal anti-anti-idiotypes, only one polyclonal antiserum showed binding capacity to the corresponding RT1-encoded antigenic determinants on spleen cells. All the other antibodies were idiotypic but not antigen binding.

Suppressor factors generated from human mononuclear cells by means of purified myeloma proteins

Peripheral blood mononuclear cells (PBMC) from normal human donors were cultured in Marbrook flasks in the presence of purified IgG or IgA myeloma proteins. The culture supernatants were tested for their ability to suppress pokeweed mitogen (PWM)- or Epstein-Barr virus (EBV)-driven Ig synthesis by normal PBMC. Two supernatants from PBMC cultured with IgG and one from PBMC cultured with IgA were tested and suppressed PWM-driven Ig synthesis as measured by a reverse haemolytic plaque assay and by quantitation of the Ig secreted into the culture medium of the PWM-driven cells. This suppression was not restricted to the Ig isotype of the 'inducing' myeloma protein, but was extended to IgG, IgA, and IgM. The suppressive effect could be absorbed out with human IgG.

Analysis of the hepatobiliary transport of IgA with monoclonal anti-idiotype and anti-allotype antibodies

The processing and fate of mixed immune complexes is influenced by the antibody isotypes present. The hepatobiliary transport of mixed immune complexes containing the mouse IgA myeloma protein J558 and corresponding monoclonal IgG or IgM anti-J558 idiotype or monoclonal IgG anti-mouse IgA allotype antibodies has been studied. The anti-idiotype or anti-allotype antibodies were radiolabeled and injected into mice with or without mouse polymeric IgA (J558). IgG anti-idiotype antibodies to J558 IgA were selectively transported into bile by J558 IgA. This process occurred with a radiolabeled Fab preparation of the IgG anti-idiotype and was inhibitable with IgA of an irrelevant antigenic specificity. Thus, polymeric IgA influenced the fate of IgA-IgG idiotype-anti-idiotype serum immune complexes. A monoclonal anti-idiotype antibody of the IgM isotype (D8-3) was not selectively transported into bile by itself or as an IgA-IgM complex. A monoclonal IgG antibody (CB5-6) to a mouse allotype determinant in the Fc portion of IgA was not selectively transported into bile. This anti-allotype monoclonal antibody inhibited the hepatobiliary transport of 125I-polymeric J558 IgA and therefore appeared to directly or indirectly block the site in the Fc region of IgA recognized by the hepatic receptor.

Hepatitis B epidemiology and its relation to immunogenetic traits in South American Indians

Serologic tests for hepatitis B prevalence and immunogenetic characterizations were carried out on a sample of 800 persons from several isolated tribes of the lower Amazon basin and the southern Andes. The prevalence of hepatitis B antigen carriers and of antibody to the surface antigen varied from one tribe to another, but were high in all the forest tribes. The serologic evidence indicated high infection rates early in life, but also an increasing proportion showing evidence of infection with increasing age. The frequency of past infections was not differentially associated with the antigen status of the mother or father. A higher proportion of infected males than females had antigenemia. Contrary to published reports, no association of antigenemia was found with any HLA-A, B or C antigen or immunoglobulin allotype, individually or interactively. Antibody prevalence, however, did differ in persons with different HLA haplotypes.

Development of rheumatoid factors and anti-F(ab')2 antibodies in guinea pigs immunized with type II bovine collagen

The purpose of this report is to present results demonstrating for the first time the development of rheumatoid factors to rabbit IgG-Fc as well as antirabbit F(ab')2 antibodies in guinea pigs after chronic sensitization with purified native type II bovine collagen. The sensitized animals also developed antibodies to guinea pig Ig. Antibodies to rabbit Ig arose as early as 3 weeks after bovine type II collagen injection and persisted for as long as 80 weeks when the experiment was terminated. The anti-Ig antibodies did not cross-react with the type II bovine collagen. Despite development and persistence of higher titers of RF and anti-F(ab')2 antibodies in the immunized animals, the animals failed to show clinical evidence of inflammatory polyarthritis. These results indicate that rheumatoid factors as well as antibodies to F(ab')2 arise independently of the clinical expression of disease.

Anti-hapten IgG antibodies bound to cell surface hapten: anti-IgG antibody prevents dissociation as measured with fluid phase hapten

We investigated the dissociation by fluid phase hapten of IgG antibodies bound to cell surface hapten in the presence and absence of anti-IgG antibodies. Dissociation was quantitated with fluid phase hapten, preventing reassociation of the anti-hapten antibodies. More than 90% of the anti-hapten IgG alone was prevented from reassociation by low concentrations of fluid phase hapten (nanogram to microgram range). In contrast, no dissociation of some IgG-anti-IgG complexes could be measured even at 24 hr incubation in the presence of very large excess of fluid phase hapten (100 mg/ml). We excluded aggregate formation between anti-hapten antibodies due to cross-linking by anti-antibodies as a cause for decreased dissociability by 1) performing the experiments in large excess of anti-antibody, 2) showing that the phenomenon was independent of anti-hapten antibody density, 3) showing that decreased dissociation also occurred at 4 degrees C, and 4) showing that aggregation by protein A did induce decreased dissociability, albeit three orders of magnitude lower than the anti-antibody. It was concluded that anti-antibody directly affected the "avidity" of cell hapten bound anti-hapten IgG in an unknown manner.

Antibodies to lipoteichoic acid from Staphylococcus aureus. Specificity of murine monoclonal and human antibodies

Two monoclonal antibodies against staphylococcal lipoteichoic acid (LTA) were made by fusing P3X63Ag8 myeloma cells and splenocytes from mice immunized with purified LTA. Both were isotyped as being IgM kappa. Their specificities were determined by enzyme-linked immunosorbent assays indicating that both antibodies reacted with the glycerol-phosphate backbone, while one of them also had some affinity for the alanyl substituent. Antibodies in serum from 7 multiple sclerosis (MS) patients and serum and cerebrospinal fluid (CSF) from 7 non-MS patients apparently reacted with the sugar moiety of LTA. In contrast, CSF antibodies from 6 of the 7 MS patients and 1 of the 7 non-MS patients had affinity for the alanine residue. This non-MS patient also had serum antibodies against the alanine residue. None of the other sera tested appeared to contain such antibodies.

Suppression of IgE secretion from hybridoma cells in allotype congenic mice: suppression of allotype 7a by T cells in allotype b mice

Anti-2,4-dinitrophenyl (DNP) IgE producing hybridoma B 53 when injected subcutaneously is established equally well in syngeneic BALB/c (heavy-chain allotype a) and congenic CB20 (heavy-chain allotype b) mice. However, secretion of anti-DNP IgE monoclonal antibody is greatly suppressed in CB20 mice. B 53 cells taken from the subcutaneous tumors of CB20 mice produce anti-DNP IgE in vivo in BALB/c mice and in vitro. No difference was observed in IgE production between these cells and the controls taken from BALB/c mice. The suppression of IgE production was due to T cells and/or their product(s) of CB20 mice.

Autoanti-allotype antibodies and idiotypic network regulating allotype production in rabbits

Anti-idiotype sera were prepared by immunization of inbred B/J as well as random-bred rabbits with anti-b4 antibodies from a syngeneic rabbit. These antisera inhibited the binding between b4 and anti-b4 from different animals to various degrees. Anti-anti-idiotype sera prepared in syngeneic rabbits also inhibited the binding between anti-b4 and anti-idiotype from different animals, and did not contain anti-b4 antibodies. These results suggest that at least some anti-b4 and anti-idiotype antibodies could carry the same or similar idiotypes, respectively. Treatment of b4b5 F1(B/J X Chbb:HM) hybrids at birth with these anti-idiotype sera from B/J rabbits resulted in a modulated production of the allelic allotypes in the serum. Anti-idiotype serum against anti-b4 induced an elevated production of b4 with little effect on the production of b5 in the same serum. In F1 hybrids born from a doe immunized with anti-idiotype antibodies against anti-b4, there was a decreased production of b4, followed by a gradual recovery to normal levels. Serum b5 levels in F1 offspring of one particular Chbb:HM doe were extremely low, as compared with those in other F1 hybrids and the b4/b5 ratio in the serum was unusually high. Such low b5 levels were no longer observed when offspring of this doe were given normal b5 serum at birth. Anti-b5 activity was not detected in the serum of this doe. These observations strongly suggest the presence in normal rabbits of the autoanti-allotype antibody and of the idiotypic network involving this antibody and regulating allotype production.

Failure to detect antihuman-immunoglobulinallotype-active antibodies in diagnostic sera directed against some enterobacteria

Diagnostic sera to determine antigenic properties of bacteria were tested to clarify the question whether these sera also contain antibodies being active against human immunoglobulin allotypes. Sera directed against various strains of Escherichia coli, Salmonella, and Shigella were found to be negative for anti-Ig-allotype activity.

Activation of immunoglobulin allotype-specific T cells by B cells

To investigate the role of Ia and immunoglobulin (Ig) molecules of B cells in alloantigen-specific and nominal antigen-specific T-cell activations, the ability of B cells to stimulate Ig allotype-specific T cells was examined. T15-primed B10.BR T cells responded to MOPC 315 (IgA myeloma protein derived from BALB/c) as well as T15 but not to MOPC31c (IgG1 myeloma protein). These T cells were stimulated by papain-digested Fc fragment of T15. Thus, T15-primed B10.BR T cells were shown to be specific for Ig allotype of T15, that is, Igh-2a. T15-specific B10.BR T cells were selected by 10-day cultures with T15 in vitro. They responded to BALB.K spleen cells without addition of soluble T15 antigen to the assay culture. Stimulator cells in this mixed lymphocyte reaction (MLR)-like response between T15-specific B10.BR T cells and BALB.K spleen cells were Thy-1-, Ia+ cells and these responses were blocked by anti-Iak antibodies. Furthermore, Sephadex G-10-passed BALB.K B cells stimulated the proliferation of T15-specific B10.BR T cells, while they failed to stimulate allogeneic BALB/c spleen cells. The stimulating ability of B cells in this MLR-like response of T15-specific B10.BR T cells was shown to be genetically restricted, namely, both H-2 and non-H-2 genes are involved in the manifestation of the stimulating ability. This system will provide a useful model for studying the role of B-cell surface Ig and Ia molecules in the activation of antigen-specific T cells and alloreactive T cells.

Double precipitin arcs of IgA myeloma sera on immunoelectrophoresis. Origin and suggestion of IgA2m(2) allotype

The serum from two patients with IgA myeloma displayed double precipitin arcs upon immunoelectrophoresis with class-specific (light chain absorbed) anti-IgA antisera obtained by immunization with monoclonal IgA1, but not IgA2 proteins. Both sera contained large amounts of monoclonal IgA2m(2) together with some polyclonal IgA1. No incomplete IgA molecules were found. The double precipitin arcs resulted from the reaction of large amounts of monoclonal IgA2m(2) with class-specific antibodies, and of small amounts of polyclonal IgA1 with subclass-specific anti-IgA1 antibodies of the same antiserum. Such double arcs, if not due to incomplete IgA molecules, could indicate the IgA2m(2) nature of the monoclonal IgA in these rare sera.

Analysis of rheumatoid factors by a biotin-avidin based isotype-specific ELISA

A one day enzyme immunoassay for the detection of rheumatoid factors of the IgG, IgM, and IgA class is described. The assay utilizes rabbit IgG as solid-phase reactant and the biotin-avidin interaction for the coupling of enzyme to indicator antibody. Three different indicator antibodies discriminated effectively between rheumatoid arthritis patients and normal subjects. F(ab')2 fragments of goat antibodies were found best suited for the test. Rheumatoid factor activity was expressed in U/ml by comparing samples to an internal standard, which was related to the WHO international reference serum for rheumatoid arthritis. Rheumatoid factor activity (U/ml) in the IgM-specific assay showed a close correlation to the latex agglutination titer. Avidity indices estimated from the slopes of the dose response curves of test sera were significantly higher for rheumatoid arthritis patients than for a group of healthy persons, indicating a higher avidity of the rheumatoid factors in the patients' sera.

Broad phylogenetic expression of heavy-chain determinants detected by rabbit antisera to VHa allotypes

Immunoglobulin molecules from diverse vertebrate species were examined, using an enzyme-linked immunosorbent assay (ELISA), for the expression of determinants detectable by rabbit antisera to VHa allotypes. The data indicate that immunoglobulins of elasmobranchs, teleosts, amphibians and birds express determinants cross-reactive with those specified by the a1, a2 and a3 alleles in the domestic rabbit. We localize VHa cross-reactive specificity to the denatured heavy chain of a primitive vertebrate, the Galapagos shark (Carcharhinus galapagensis). Furthermore, the N-terminal amino acid sequence of the shark heavy chain shows significant homology with rabbit heavy chains of known VHa type at positions where allotype-correlated differences have been implicated. VHa-related determinants are shared by immunoglobulins of a wide range of vertebrates from sharks to man and thus seem to be epitopes which have been conserved during vertebrate evolution. The determinants detected on immunoglobulins of lower vertebrates by rabbit anti-VHa allotype sera most probably are VH-subgroup rather than allotypic markers. Their distribution demonstrates a strong phylogenetic conservation of VH-regions.

[Possible common partial antigens in human Ig allotype structure and ubiquitous bacteria, studied with the example of Escherichia coli]

As can be learned from the literature, bovine serum may contain antibodies directed against human immunoglobulin allotypes. This gave rise to the question of what the origin of those antibodies is. We tested bacteria (E. coli) by means of the haemagglutination inhibition assay, which is used to type either Gm or Km factors. Anti-G1m(2) and anti-G3m(10)-specific antibodies were inhibited by the bacteria in a clear-cut manner, as was anti-Km(1), albeit less significantly. In contrast, the bacteria tested almost totally failed to inhibit anti-G3m(21) serum. The results lead to the assumption that E. coli may carry both Gm- and Km-like antigenic structures, which are presumably the antigenic material leading to immunization of cattle. Furthermore, new attention is drawn to a mechanism for immunization which is discussed regarding the genesis of either AB0 isoagglutinins in man or other "naturally occurring" antibodies.

Enhancement of IgG anti-carrier responses by IgG2 anti-hapten antibodies in mice

Isologous IgG2a and IgG2b anti-hapten antibodies injected along with trinitrophenylated or fluoresceinated keyhole limpet hemocyanin (KLH) were found to considerably stimulate primary IgG responses to the carrier protein in mice. No such stimulation was observed with IgG1, IgM and IgA anti-hapten antibodies. Depending on the antigen antibody combination, the amplification obtained after a single injection of IgG2-complexed haptenated KLH ranged from 20- to 1000-fold. By comparison, secondary responses were only marginally enhanced (approximately 3-fold) when IgG2-complexed rather than free antigen was used to boost irradiated recipients previously reconstituted with primed spleen cells. The IgG2-mediated enhancement was effective over a wide range of antigen/antibody ratios, did not require the use of high affinity antibodies and occurred whatever the route of injection. The stimulation was specific for the complexed antigen and developed to the same extent whether complexes were formed in vitro or in vivo. A comparable stimulation of the anti-carrier response was obtained with several other haptenated proteins but with formaldehyde-treated diphtheria and tetanus toxoids inhibition rather than stimulation was observed.

Immunoglobulin allotypes in patients in end-stage renal failure

In a population of 282 Caucasoid patients in end-stage renal failure (ESRF) Gm and Km typing has confirmed a significant increase in the frequency of the Gm1,2,17;21 haplotype. This was confined to an increase in the number of heterozygous Gm(1,2,3,17;21,5,10,13,14) individuals. A concomitant decrease in the frequency of presumptive Gm(3,5,10,13,14) heterozygotes was also confirmed. Analysis of individual renal diseases revealed significant immunoglobulin allotype, phenotype and haplotype frequency deviations in those patients presenting with hypertension, glomerulonephritis or pyelonephritis. The allotype distribution in patients with physical abnormalities of the urinary-genital tract, whether congenital or acquired, was normal.

Relation of age, race, and allotype to immunoglobulin subclass concentrations

Concentrations of IgG1, IgG2, and total IgG were measured by a solid phase radioimmunoassay in sera from 36 healthy adults and 114 healthy children. As expected, IgG2 and total IgG had a positive correlation with age in children. In addition to age, several other factors were associated with significant differences in serum subclass concentrations. Female children had higher concentrations of IgG1 than males, and black subjects had significantly higher concentrations of IgG1, IgG2, and total IgG than whites. Although Km(1) and Gm(23) immunoglobulin allotypes had no relation to subclass concentrations when tested as single factors, the Km(1) allotype interacted significantly with race so that Km(1)-positive black children had higher IgG2 concentrations than other subjects. Our findings may explain, in part, recent observations of an association of the Km(1) allotype with altered immune responses of blacks to certain vaccines containing bacterial polysaccharides. In addition, our data indicate the need to control factors such as sex, race, and allotype in studies of subclass concentrations or immune responses.

Presence of kappa 2 light chain in normal rabbits and as induced auto anti-allotype antibody in kappa 1 light chain suppressed subjects

Using an antiserum raised in b(bas)/b(bas)-suppressed rabbits to kappa 2 light chain we have shown that the kappa 2 light chain is an isotype of kappa 1, present in the majority of, if not all, rabbits. It probably exists in at least 2 allelic forms. It is capable of producing a functional antibody molecule (auto anti-b6) and compensates for the absence of kappa 1 light chain in homozygous b6-suppressed rabbits.

Isotypes of antibodies induced by plain dextran or a dextran-protein conjugate

Mice were immunized with alpha (1----6) dextran or its protein conjugate with monthly intervals, and their antibodies were quantitated with an isotype-resolved radioimmunoassay. Plain dextran (molecular weight = 5-40 million) induced antibody concentrations varying from 20 to 80 micrograms/ml (primary response). The response to a booster injection was weaker than the response to the first injection. More than 90% of anti-dextran antibodies were IgM but IgG and IgA responses could be unequivocally demonstrated. IgG1 and IgG3 were the predominant subclasses of IgG. Dextran antibody responses to a conjugate of dextran (molecular weight approximately equal to 10000) and chicken serum albumin (CSA) were stronger (80-300 micrograms/ml) than responses to plain dextran, and anti-CSA responses to the conjugate were even stronger (up to 900 micrograms/ml). Three distinctly different isotype patterns were observed. A pattern IgM much greater than IgG1 = IgG3 greater than IgG2a prevailed in responses to the plain dextran and in primary anti-dextran responses to dextran-CSA. Another pattern IgG1 greater than IgG3 greater than IgM greater than IgG2a was observed in late anti-dextran responses to dextran-CSA. The third pattern IgG1 much greater than IgG2a greater than IgG3 approximately equal to IgM was characteristic of anti-CSA antibodies. Little IgG2b or IgA antibodies were found. Different isotype patterns can best be explained on the basis of secondary factors such as T cell help.

RISH V. Application to monoclonal antibody production

RISH considers that cell surface components involved in like cell identification are not involved in the structure of the plasma membrane per se and are attached to a part of their mRNA. The mRNA then acts as a template for the synthesis of DNA. Thus the component at the cell surface is attached to an RNA/DNA receptor. If there is a conformational change in the component (antigen) this will cause a distortion in its RNA/DNA receptor. This distortion is then detected by a tissue specific T lymphocyte which removes all or part of the RNA/DNA receptor from the aberrant cell and the lymphocyte then undergoes replication. During this process receptor RNA/DNA is incorporated into the daughter lymphocyte which becomes a B lymphocyte/plasma cell producing immunoglobulin. The initial tissue specific T lymphocyte becomes a dual functional helper/suppressor cell. The plasma cell after the initial immune response becomes a circulating memory B cell displaying IgM or IgD. If this cell complexes an antigen with its surface IgM or IgD a humoral immune response will be developed as previously described, but in this case the antibodies produced will be anti-idiotypic antibodies. The anti-idiotypic antibodies will regulate the production of the antibody directed against the antigen per se. The anti-idiotypic antibodies will in turn be regulated by a second anti-idiotypic antibody. In RISH five such anti-idiotypic systems may be involved in regulating the immune response to the initial non-immunoglobulin antigen. Based on the RISH anti-idiotypic mechanism a system is briefly described whereby human memory B cells, to a particular antigen, may be isolated. These B cells may then be activated to secrete immunoglobulin with autologous isolated anti-idiotypic antibodies. These activated cells may then be infected with E.B. virus to establish an immortal cell line of B cells secreting the immunoglobulin of interest.

A comparison between Fc receptors for IgG1 and IgG3 on human monocytes and lymphocytes using anti-Rh antibodies

In a rosette assay with human erythrocytes equally sensitized with anti-Rh antibodies, the Fc receptor-bearing (FcR) cells are much more numerous among monocytes than among lymphocytes. FcR monocytes could be detected using IgG1 and/or IgG3 antibodies although a higher percentage of FcR cells is observed with sera containing IgG3. FcR lymphocytes are detectable almost only with sera containing IgG3 antibodies. If the anti-Rh antibodies are restricted to IgG1 none or single FcR cells could be found. The application of mixed rosette assay with fluorescein-stained erythrocytes sensitized with IgG3 and unstained red cells sensitized with IgG1 allowed documentation of the presence of receptors for both subclasses on monocytes as well as on lymphocytes although some differences between these cells were observed. Almost all FcR monocytes bind both IgG subclasses, although in different proportions. On the contrary, most FcR lymphocytes bind only or mainly IgG3, but receptors for IgG1 can also be detected.

Evaluation of antisera for bloodstain grouping. II. Ss, Kell, Duffy, Kidd, and Gm/Km

Thirty-one different examples of commercially available blood grouping antisera specific for the S, s, K, k, Fya, Fyb, Jka, and Jkb antigens and anti-human globulin sera were serologically evaluated with red cells and in absorption-elution tests to determine their applicability to bloodstain antigen determinations. Nineteen examples of commercially available antisera specific for various Gm and Km antigens and their corresponding anti-D reagents were likewise evaluated in inhibition tests with sera and bloodstains. Elution tests with the blood grouping antisera and inhibition tests with the Gm/Km antisera on a series of aging bloodstains on cotton cloth, and on bloodstains on a number of different substrata, demonstrated that properly evaluated commercial antisera are useful reagents for bloodstain grouping in forensic serology.

The nature of antiidiotype molecules induced by antiallotype. Presence of both latent allotype and allotypic internal images

Previously (9), I found that immunization of rabbits with antibody directed against variable region heavy chain VH polypeptides of a1 allotype induced the production of antiidiotype (anti-Id) molecules that appeared to bear images of the original a1 allotype. I now show that these anti-Id molecules can be fractionated into two populations: one population (a2a3- anti-Id) that lacks the nominal VH a2 or a3 allotype of the rabbit from which it was derived, and another population (a2a3+ anti-Id) that expresses these allotypes. Both anti-Id populations display epitopes that resemble a1 since: (a) they were capable of inhibiting 125I-a1 Ig binding to rabbit anti-a1, goat anti-a1, and mouse anti-a1 mAb; and (b) immunization of normal a2a3 rabbits with either anti-Id fraction led to the formation of specific anti-a1 antibody. Reductive cleavage of the anti-Id molecules showed that the a1 determinants in the a2a3- population were fully displayed on isolated H chains, consistent with the presence of latent a1 Ig. On the other hand, as expected for internal images encoded by the antigen-combining site, the a2a3+ anti-Id population required intact H and L chains for maximal a1 expression. The a1-like images within the a2a3+ anti-Id population do not appear to be identical to nominal or latent a1, however, since a2a3- anti-Id was invariably a more efficient inhibitor of a 1 Ig-anti-a1 binding than a a2a3+ anti-Id. These results indicate that immunization with antiallotype can result in the simultaneous production of both latent allotypes and allotypic internal images.

Correlation between G2m(n) immunoglobulin allotype and human antibody response and susceptibility to polysaccharide encapsulated bacteria

To determine whether genetic factors influence the human antibody response to polysaccharides, we correlated Ig allotypes with the concentrations of antibody to 14 bacterial capsular antigens in 130 actively immunized Caucasian adults. The 88 individuals possessing G2m(n), an allotype antigen of IgG2 subclass heavy chains, had significantly higher postimmunization antibody levels to Haemophilus influenzae type b (Hib) and 8 of 11 pneumococcal types (P less than 0.05) than the 42 lacking this antigen. For Hib, pneumococcus type 14, and meningococcus group C, an increased response was observed in IgG class but not in IgM or IgA classes of antibody. The G2m(n) positive individuals also had higher preimmunization antibody levels to most polysaccharide antigens. Total IgG2 concentrations were correlated with the mean postimmunization antibody concentrations to pneumococci (P = 0.005), but this correlation was independent of G2m(n) by multiple regression analysis. To determine if the lack of G2m(n) was associated with increased susceptibility to infection, we compared the frequencies of various Ig allotypes in 98 children infected with Hib and 98 matched controls. Caucasian children with Hib infections other than epiglottitis were significantly more likely to lack the G2m(n) allotype than controls (P less than 0.05). G2m(n) negative Caucasian children less than or equal to 18 mo old have a 5.1-fold higher risk of nonepiglottitic Hib infections than G2m(n) positive children (P less than 0.01). We conclude that allotypic variants of the gamma-2 heavy chain genes, or genes in linkage equilibrium with them, exert a regulatory influence on the caucasian antibody response to a variety of immunologically distinct bacterial polysaccharide antigens. Young Caucasian children of the low responder phenotype, i.e., those lacking the G2m(n) allotype, are genetically predisposed to Hib and perhaps other bacterial infections.

Immunoglobulin-bearing stem cells for clones of B (bursa-derived) lymphocytes

Treatment of neonatal chickens with cyclophosphamide depletes bursal lymphocytes while maintaining the bursal epithelium intact. The bursae of normal young chickens contain "bursal stem cells" which can reconstitute the lymphoid compartment in the bursa of the cyclophosphamide-treated recipient. Using bursal stem cells from IgM allotype-heterozygous donors we show that most bursal follicles in the reconstituted host are colonized by single stem cells which are committed to the expression of one or other IgM allotype. In addition we show that the reconstituting bursal stem cells express allelically excluded surface IgM at the time of transfer. Our results suggest that B lymphocyte numbers in hatched chickens are maintained by self-renewal of committed precursors rather than by de novo production from multipotential stem cells.

Migration and differentiation of bone marrow lymphocytes: development of surface immunoglobulin, Fc receptor, complement receptor, and functional responsiveness as studied with anti-allotype serum

Immunofluorescent studies using fluorescein isothiocyanate-conjugated mouse anti-allotype antibody were carried out to study the migration pattern and the development of surface Ig (SIg), Fc receptor for IgG (FcR gamma), and complement receptor (CR) or mouse bone marrow lymphocytes following intravenous injection into congenic mice. After transfer of bone marrow cells from CSW mice into untreated congenic CWB mice, the absolute number of donor-type SIg-bearing (SIg+) cells and the proportion of either FcR gamma- or CR-bearing (FcR gamma+ or CR+) cells in donor-type SIg+ cells were evaluated in the recipient spleen and the results were compared with those obtained after the transfer of CSW spleen cells. After injection of donor bone marrow cells, detectable donor-type SIg+ cells, although few initially, increased from day 1 to Day 2 and reached a plateau thereafter. The proportion of FcR gamma+ cells in donor-type SIg+ cells, although very low in the donor marrow inoculum, increased progressively after 1 day to reach a maximum at Day 5 (90%). On the other hand, following the transfer of spleen cells, the proportion of FcR gamma+ cells remained at high levels (90%) for 5 days after transfer. Likewise, the proportion of CR+ cells in donor-type SIg+ cells was very low (less than 1%) in the original donor bone marrow cells but high (60%) in the donor spleen cells. However, in transferring bone marrow cells this proportion also increased in the recipient spleen to reach a maximum (49%) at Day 5 although it was lower compared to the percentage of FcR gamma+ cells in donor SIg+ cells. Furthermore, the ability of functional responsiveness to antigen was also examined in the same system by detecting plaque-forming cells (PFC) from donor origin. In transferring donor bone marrow cells into recipient, the participation of donor cells in the PFC response was very low when the recipients were primed with sheep red blood cells at Day 3 after transfer. However, when the recipients were primed at Days 7 to 21 after transfer, increasing numbers of the donor marrow-derived cells were involved in the PFC response. Thus, the present study demonstrates that the bone marrow-derived lymphocytes, albeit lacking both distinctive surface receptors (IgM, FcR gamma, CR) and the functional responsiveness to antigen, continue their development along the B-cell lineage after migrating into the spleen, as evidenced by the surface receptor expression and participation in the antibody response.

IgG subclass antibodies to herpes simplex virus

Several mouse monoclonal antibodies specific for human IgG1, IgG2, IgG3, and IgG4 were evaluated by enzyme-linked immunosorbent assay to detect human IgG subclass antibodies to herpes simplex virus (HSV) antigens. The variable results with different monoclonal antibodies point to the need for well-characterized reagents in the study of antibody responses to infectious agents. The 204 sera tested were obtained from 157 patients with various forms of clinically manifest HSV infections and from several controls. IgG1 antibodies were demonstrated in almost all HSV-infected subjects and were the first antibodies to appear in primary genital infections. IgG2, IgG3, and IgG4 antibodies were detected in acute-phase sera, most often in patients with recurrent genital herpes but in none of those with primary infections. IgG4 antibodies occurred significantly more frequently in sera from men than in those from women with recurrent genital infections.

Cosuppression of latent and nominal allotypes in individual rabbit lymphocytes

Endogenous synthesis of latent and nominal allotype was observed in vitro in rabbit peripheral blood lymphocytes (PBL). PBL from rabbits displaying the nominal b4 specificity, as well as the latent b5 and b6 either on the cell surface or in the serum or both, were treated with pronase to remove surface latent and nominal allotypes and cultured in serum-free medium to regenerate the nominal and latent markers. Rosette formation using the mixed anti-globulin assay demonstrated that the nominal b4 and latent b5 and b6 specificities were displayed in the same cell. Cells were seen bearing the b4 + b5, b4 + b6, or b4 + b5 + b6, as double or triple expressors. No latent allotype-bearing cells were detectable in the absence of the nominal allotype. In vitro suppression of nominal surface b4 with anti-b4 antibodies resulted in the cosuppression of the latent b5 and b6. In contrast, in vitro suppression of latent b5 and b6 with anti-b5 and anti-b6 antibodies, respectively, did not cause the cosuppression of the nominal b4 allotype. Cosuppression of latent and nominal markers in the same cell confirms that the biosynthetic machinery for latent and nominal allotypes lies within the same cell.

Autoantibodies to anti-DNA with anti-allotypic and anti-idiotypic specificities in (NZB X NZW)F1 mice

The monoclonal A52 (IgG2b, kappa) anti-DNA autoantibody represents a major cross-reactive idiotype in the murine and human autoimmune response to DNA. Examination of sera and purified IgG derived from (NZB X NZW)F1 mice showed that these mice develop an age-dependent binding reactivity with the pure anti-DNA IgG. Three monoclonal antibodies possessing this reactivity were prepared from unprimed female (NZB X NZW)F1 mice. One of these monoclonal antibodies appeared to be directed against allotypic determinants present in the NZB IgG2b; the other two antibodies exhibited a marked preference for idiotypic determinants of the A52 IgG. The IgG anti-allotype and anti-idiotype activities in (NZB X NZW)F1 mice may, therefore, represent the products of a deregulated immune system and/or constitute the normal elements of a functional immune regulation system.

Structural polymorphism of murine complement factor H controlled by a locus located between the Hc and the beta 2M locus on the second chromosome of the mouse

Structural polymorphism of murine factor H protein was demonstrated by using three different methods. 1) By prolonged agarose electrophoresis and immunofixation, factor H protein was visualized in the beta region as a single, distinct protein band in freshly bled EDTA-plasmas from many laboratory and wild mice. Two variants were detected among a large number of tested strains; one, referred to as H.1, moved faster to the anodal region (type strain, BALB/c), and the other, referred to as H.2, moved more slowly to the anodal region (type strain, STR). The F1 hybrid between BALB/c and STR exhibited a combining type of factor H protein, which was observed in each parent. 2) Two-dimensional peptide mapping analysis was carried out with tryptic peptides of these two factor H allotypes. Almost all of the spots in the maps of tryptic peptides were common to both allotypes. However, three distinct spots among the 57 spots detected in the map of tryptic peptides of the H.1 allotypes were not detected in that of H.2 allotype, whereas two spots among the 56 spots in the map of H.2 allotype were unique for this allotype. The F1 hybrid between BALB/c and STR showed a combining type of the map of parent. 3) Alloantisera against each of H allotypes were successfully produced in BALB/c or BALB/c-H.2 (a congenic strain with H.2 allotype) by repeated injection of each purified factor H protein either from the BALB/c or the STR strain. These findings indicated that the observed variants of factor H represent antigenically and structurally distinguishable allotypes. The allotypes of murine factor H protein are controlled by a single codominant locus located between the Hc locus and the beta 2M locus on the second chromosome of the mouse. This was shown by phenotyping the Hc locus and H locus with backcross progenies between A/J (one of strain with H.1) and MoA (one of strain with H.2). The recombination frequency between these two loci was 0.17 +/- 0.046.

Quantitative and spectrotypic analysis of paternal IgG2a expression in normal and allotype-suppressed mice

The synthesis and clonal diversity of IgG2a molecules bearing the paternally inherited immunoglobulin allotype have been examined in the offspring of matings between BALB/c mothers (Igh-1a) and SJL or C57BL/10 males (both Igh-1b) using a sensitive quantitative single radial immunodiffusion in gel assay and isoelectric focusing with autoradiography. In normal litters, the first detectable paternally-marked IgG2a is extensively polyclonal in both F1 crosses (i.e. diversity precedes expression); however, there is a delay of 2-3 weeks in the first appearance of the clonally diverse set of molecules when these are coded by the SJL genome, compared with the C57BL/10. Delayed maturation of allelically-excluded Igh-1b-expressing B cells in the (BALB/c X SJL)F1 may explain the unique susceptibility of these offspring to chronic allotype suppression when exposed to maternal anti-Igh-1b antibodies in early life. We find that, although such suppressed mice may begin life with a (delayed) synthesis of polyclonal IgG2a of paternal allele (Igh-1b), the condition of chronic suppression later imposed in the majority of mice is associated with spectrotype (clonal) simplicity.

Immunogenic and antigenic epitopes of immunoglobulins. X: Monoclonal antibodies specific for human IgA, the IgA1 and IgA2 subclasses and an nA2m(2) iso-allotypic epitope

Monoclonal antibodies (McAb) specific for human IgA, the IgA1 and IgA2 subclasses and the iso-allotypic epitope nA2m(2) have been produced. Three distinct McAb recognize an IgA1-specific epitope expressed in the C alpha 2 domain or the hinge region whilst a further McAb is directed possibly to an IgA1 hinge region epitope. The McAb having nA2m(2) specificity recognizes an iso-allotypic epitope expressed within the Fab region. IgA1 and IgA2 epitopes were detected in gorilla but not rhesus or baboon sera suggesting that the IgA subclasses represent a recent gene duplication even. However, these epitopes were also detected in some non-primate sera.

Monoclonal antibodies specific for the mouse IgG1 allotypic determinants: reactivity with inbred and outbred mice

C57BL/6J mice were immunized with an affinity purified monoclonal antibody (IgG1) derived from BALB/c mice and their spleen cells were fused with the mouse myeloma X63.Ag8.653. Two monoclonal antibodies (3A9, gamma 1,kappa and 1C10, gamma 1,kappa) derived from separate fusions were originally found to react with BALB/c monoclonal antibodies expressing a gamma 1 heavy chain isotype but not with other heavy chain isotypes. The results from strain distribution reactivity patterns indicate that these antibodies recognize determinants coded by the allotype locus designated Igh-4a. In a survey of 22 different inbred or congenic strains of mice, no additional polymorphism associated with this locus has been detected. However, allelic polymorphism of the gamma 1 heavy chain allotype does exist in the wild mouse population. The 3A9 and 1C10 antibodies recognize the same determinants (i.e., specificity 1) associated with Igh-4a allotype.

Monoclonal antibodies against common and Igk-1a allotypic determinants of rat immunoglobulin kappa chain constant domain

SJL/J mice were immunized with polyclonal rat Ig light chains of two allotypes and immune spleen cells were fused with P3-Ag8.653 myeloma cells. 17 cell populations producing antirat Ig AB were cloned. Four clones, 1G9, L3E8, L2B2 and L2C5 have been characterized in detail. All MABs are of the IgG1, kappa isotype. Using monoclonal rat kappa chains it was demonstrated that all the AB react with rat Ig kappa chains. Further localization of antigenic determinants was performed using isolated L chain C domain. It was shown that all MABs are directed against C domain epitopes. L2C5 MAB binds selectively to August rat L chains, thus showing specificity for Igk-1a determinants. The remaining three clones bind equally well to L chains of different allotypes, but 1G9 clone binds preferentially to isolated L chains as compared to intact IgG molecules.