Intraperitoneal immunization of human subjects with tetanus toxoid induces specific antibody-secreting cells in the peritoneal cavity and in the circulation, but fails to elicit a secretory IgA response

Five patients on continuous ambulatory peritoneal dialysis (CAPD) were immunized intraperitoneally with tetanus toxoid (TT) through an indwelling catheter. Four control patients on CAPD received the same dose of TT intramuscularly. Before immunization, virtually no anti-TT antibody-secreting cells (AbSC) were detected by the enzyme-linked immunospot (ELISPOT) assay in peripheral blood or peritoneal fluid from patients of either group. One to 2 weeks after immunization, high frequencies of TT-specific AbSC were detected in the circulation and peritoneal cavity. More than 80% of those cells were of the IgG isotype, with IgA accounting for most of the remainder. Patients receiving TT by the i.p. route showed significantly higher frequencies of specific IgG and IgA AbSC in the peritoneal cavity than patients immunized intramuscularly. Frequencies of AbSC in peripheral blood did not significantly differ between the two groups. Immunization with TT by both routes resulted in a significant increase of IgG anti-TT antibodies in serum, saliva and peritoneal fluid. A significant IgA antibody response was seen only in serum and peritoneal effluents. Therefore, i.p. immunization of human subjects with TT elicited both a localized response in the peritoneal cavity as well as a systemic response in serum, but did not induce a salivary IgA response.

Switch recombination in normal IgA1+ B lymphocytes

Most B lymphocytes in normal individuals express two classes of cell-surface immunoglobulins, IgM and IgD. The specificity of the two antigen receptors is identical since they are produced by transcription and differential splicing of the same variable region gene segment to the heavy-chain constant region gene segments for both mu and delta heavy chains. B lymphocytes expressing other immunoglobulin isotypes, IgG, IgA, or IgE, are rare and not well characterized. Particularly controversial is the molecular mechanism of their isotype switch. Here we use high-gradient magnetic cell sorting and fluorescence-activated cell sorting to purify surface IgA1-bearing B lymphocytes from human blood for cellular and molecular analysis. These cells express no immunoglobulin class other than IgA1 and are a relatively uniform population with regard to expression of other cell-surface molecules. They are resting cells in terms of cell cycle and activation marker analysis. The molecular basis for class switching in the IgA1+ cells is not differential transcription or splicing. Rather, switch recombination involving deletion of DNA has occurred on both immunoglobulin heavy-chain gene loci, including the allelically excluded one, and appears to have been directed to IgA1 under normal physiological conditions.

Immunoglobulin levels and monoclonal gammopathies in children after bone marrow transplantation

Bone marrow graft recipients suffer profound immunodeficiency during at least 3 months after transplantation. B-cell reconstitution following allogeneic bone marrow transplantation (BMT) in children was studied longitudinally by quantification of Ig (sub)class levels in serum and by investigation of numbers and characteristics of homogeneous Ig components (H-Ig); ie, monoclonal gammopathies (MG). For the latter purpose, a sensitive immunoblotting technique capable of detecting H-Ig of a concentration as low as 0.5 microgram/mL was used. Sera of 40 children grafted for a variety of diseases were investigated and followed up for 5 years. It was found that Ig (sub)classes reached normal levels from 3 months after BMT onward. The sequential increase of the different Ig isotypes was in accordance with that seen in normal ontogeny. This was especially clear following BMT for severe congenital immunodeficiency. H-Ig appeared from as early as 6 weeks after BMT in increasing numbers, beginning within IgM, IgG3, and IgG1, and afterward within other isotypes. After an initial increase of serum Ig levels, "overshooting" occurred accompanied by high frequency of H-Ig. H-Ig were still present at 5 years after BMT, when Ig levels normalized. Our data indicate that B-cell reconstitution after allogeneic BMT recapitulates normal ontogeny but in a clonally dysregulated fashion; that is, with overexpression of some clones and underexpression of others.

Gastrointestinal AAPOAII and systemic AA-amyloidosis in aged C57BL/Ka mice. Amyloid-type dependent effect of long-term immunosuppressive treatment

The light microscopic and immunohistochemical features of a novel localized senile amyloidosis in the gastrointestinal tract of C57BL/Ka mice are described. Senile gastrointestinal amyloidosis was predominantly found in the lamina propria of the ileum, cecum and stomach and infrequently in other segments of the gastrointestinal tract. The Congo red affinity of the senile amyloid was sensitive to potassium permanganate pretreatment. The amyloid did not react with anti-AA and anti-immunoglobulin antisera, but stained positively for apoAII, a major apolipoprotein of high density lipoproteins. A similar type of amyloid, termed AApoAII, has recently been described in a systemic form of senile amyloidosis in mice. In the present study, we investigated the effect of long-term immunosuppressive treatment on the incidence of systemic AA-amyloidosis and gastrointestinal AApoAII-amyloidosis in aged C57BL/Ka mice. Gastrointestinal amyloidosis occurred in 60% of the control mice, but significantly less in mice of the immunosuppressed groups. In contrast, systemic AA-immunoreactive amyloidosis was only found in mice that were given immunosuppressive treatment. There was no codeposition of AA and AApoAII-amyloid. These findings indicate that immunosuppressive drugs have a profound effect on the incidence as well as the type of amyloidosis in C57BL/Ka mice.

Evidence for selective pressure in the appearance of monoclonal immunoglobulins during aging: studies in M54 mu-transgenic mice

Serum monoclonal immunoglobulins (M-Ig) appear during aging but little is known about the immunological factors which lead to their development. We have investigated whether such M-Ig occur as a clonally random process or result from V-region-directed selective pressures. We have analyzed a mu-transgenic mouse strain in which over 95% of all splenic B cells express the transgenic mu chain. All endogenous repertoire and mu-chain diversity are generated from the 5% of the B cells which express endogenous mu chains. Not one of the M-Ig detected in these mice were of transgene origin alone; 11 of the 14 M-Ig did not express a mu chain and none of the mu chain containing M-Ig expressed the transgene allotype alone. This observation suggests that the B cells giving rise to M-Ig are heavily selected from among the small number of B cells which express endogenous Ig. The selective factors that might act on the endogenous B cell pools are discussed.

Serum immunoglobulin class and IgG subclass levels and the occurrence of homogeneous immunoglobulins during the course of ageing in humans

Serum levels of IgM and IgA classes and of IgG subclasses were determined and related to the presence of homogeneous immunoglobulin components (H-Ig) in volunteers equally distributed in age groups from 25 to 98 years, who all met the Senieur admission criteria for immunogerontological studies. In addition, sera of non-Senieur volunteers aged 75 years and older were included. Furthermore, the amount of IgD was determined in sera of Senieur individuals equally distributed in age groups from 15 to 98 years. In the Senieur persons, the contribution of the IgG subclasses and the IgM and IgA classes to the pool of serum immunoglobulins remained relatively unchanged during the course of ageing. In comparison with Senieur individuals aged 25-34 years, a slight increase in IgM and IgA levels was observed from the age 35 to 44 onwards and in IgG1 from the age 55 to 64 onwards. The variability of the immunoglobulin concentrations increased during ageing. The most prominent observation was the continuous decline of serum IgD starting in young adults. The non-Senieur persons differed from their Senieur age-matched counterparts mainly by the elevated IgG2 and IgA levels. During the course of ageing, H-Ig mainly of low concentration were detected at an increasing frequency in the Senieur persons and even more frequently in the elderly non-Senieur volunteers. Although in some individuals the elevation of immunoglobulin levels correlated with the appearance of H-Ig within the corresponding isotype, this relationship was not conclusive for all sera investigated. These results suggest that the rise of serum levels of individual immunoglobulin isotypes associated with ageing is usually the consequence of a polyclonal B cell activation. The occurrence of H-Ig and the decline of serum IgD in aged Senieur persons indicate that these are, at least partly, true phenomena of ageing and not always the consequence of disease.

Development of aging-associated monoclonal gammapathies with antibody activity to the antigen used for immunization of young mice

The influence of immunization with dinitrophenylated human serum albumin (DNP-HSA) at a young age on the development of age-related monoclonal gammapathies (MG) was investigated in a longitudinal study in intact and neonatally thymectomized (NTx) C57BL/KaLwRij and CBA/BrARij mice. Three-month-old mice were immunized four times in monthly intervals with DNP-HSA. Control mice received saline and adjuvant only. Mice immunized with DNP-HSA responded with heterogeneous antibodies, occasionally with some clonal dominance. The antibody levels further declined and were hardly detectable when the mice were 21 months old. Eighteen of 87 experimental mice developed homogeneous antibody components (H-Ab) to DNP-HSA with aging. Their frequencies per individual groups were 5, 22, 24, and 29% for intact CBA, NTx-CBA, NTx-C57BL, and intact C57BL mice, respectively. Some H-Ab had the same mobility and similar spectrotypes as dominant clonal products at the peak of the response. However, the majority of H-Ab appearing at old age were "new" H-Ab. While most of H-Ab in the CBA mice were transient and of a low concentration, the majority of H-Ab in the C57BL mice had all characteristics of a benign monoclonal gammapathy. The results indicate that memory cells of the B cell clones involved in the original specific response may in a susceptible strain become targets for events leading to the development of benign monoclonal gammapathy.

Evaluation of monoclonal antibodies having specificity for human IgG subclasses: results of the 2nd IUIS/WHO collaborative study

Following the 1st IUIS/WHO Collaborative Study of monoclonal anti-IgG subclass antibodies, a panel of WHO Specificity Reference Reagents (SRR) was established [Jefferis, R., et al. (1985) Immunol. Lett., 10, 223]. At the time, the hope was expressed that further reagents particularly for IgG2, and other allotypic specificities would become available which could be applied in a wide range of assay protocols. The 2nd study reports the evaluation of nineteen anti-subclass and seven anti-allotype monoclonal antibodies. The anti-IgG1 antibody HP6187 was equivalent in performance to the SRR. Others, that were not of the mouse IgG1 isotype, may be useful for particular applications. The anti-IgG2 antibody HP6200 could be a valuable addition to the WHO SRR; it is specific for an epitope in the Fab region but does not have the light chain bias of HP6014. Antibodies of putative allotype specificity exhibited the claimed specificity when used within protocols similar to those employed by the originating laboratory. It appears to be inherent in the nature of the epitopes (allotopes) recognized that it will take several years before reagents applicable to a wide range of techniques will become available.

Cleavage of human immunoglobulins by serine proteinase from Staphylococcus aureus

The serine proteinase (SP) released into the environment by most strains of S. aureus cleaves human IgG, IgM and IgA of both subclasses--IgA 1 and IgA 2. SP cleaves H chains of all immunoglobulin classes and the SC of S-IgA, the L chains are degraded partially. The SP-induced cleavage results in a large spectrum of fragments under reducing conditions within a broad range of Mr (approx. 41,000 to less than 12,400). This indicates that the enzyme does not affect the Ig molecule in the hinge region only. The degree of cleavage depends on the enzyme:substrate ratio and on the duration of incubation. The generation of small fragments is associated with the loss of antigenic determinants that results from the decreased binding of the cleaved material in the ELISA method. Partial cleavage of L chains suggests that the enzyme alters part of the molecule that is involved in antigen binding. Even if the ability of antigen binding remains preserved after cleaving Ig with SP, the antibody function is disturbed by splitting off the Fc region or by its degradation into small fragments. SP has to be considered as one of the virulence factors of S. aureus that may protect bacteria against the defence mechanisms of the host.

Monoclonal gammapathies in long-term surviving rhesus monkeys after lethal irradiation and bone marrow transplantation

Late effects of total body irradiation and subsequent autologous bone marrow transplantation on the development of age-related monoclonal gammapathies (MG) were studied in 14 long-term surviving Rhesus monkeys. Together with 27 untreated control monkeys, they have been followed up for more than 20 years. In contrast with the control group, the experimental monkeys developed MG with aging in higher frequencies, earlier and mainly of the benign MG category. One experimental monkey developed a multiple myeloma, the first observed in the nonhuman primates so far. These results indicate an accelerated senescence of the immune system in the experimental monkeys as a late consequence of tissue or cell damage during irradiation.

Cellular origins of human polymeric and monomeric IgA: enumeration of single cells secreting polymeric IgA1 and IgA2 in peripheral blood, bone marrow, spleen, gingiva and synovial tissue

Using modified ELISA and spot-ELISA, which permit the parallel determination of heavy chain subclass and the presence of covalently linked J chain, we analysed IgA found in cell culture supernatants or secreted by individual cells from peripheral blood, spleen, bone marrow, gingiva and synovial tissue, with respect to its polymeric or monomeric IgA form (pIgA, mIgA) and IgA1 or IgA2 subclass. The ELISA for determination of J chain in tissue culture supernatants was specific and highly sensitive (detection limit in pg). The results demonstrated that IgA1-producing cells predominated in the tissues examined, and that J chain could be detected in association with the majority of IgA1 and IgA2 secreted by individual cells. With respect to the frequency of cells secreting polymeric, J chain-containing IgA, only 20-30% of cells from the bone marrow were engaged in the synthesis of PIgA. In other tissues the frequency of cells secreting pIgA1 and pIgA2 was considerably higher. Peripheral blood mononuclear cells secreting pIgA2 were easily inducible during stimulation with T cell-dependent pokeweed mitogen, whereas Epstein-Barr virus-transformed cells secreted preferentially mIgA1. When the frequencies of pIgA-, pIgA1- or pIgA2-secreting cells (determined by spot-ELISA technique) from different tissues were correlated with the proportion of pIgA to mIgA (and IgA subclasses) secreted in tissue culture supernatants, data obtained suggest that many individual IgA-producing cells could be engaged in simultaneous secretion of mIgA and pIgA.

Isolation and molecular characterization of the B cells producing the paraprotein in a case of benign monoclonal gammapathy in C57BL mice

Benign monoclonal gammapathy (BMG) is defined as a benign monoclonal B cell proliferative disorder characterized by the presence of a persisting component of homogenous immunoglobulins (H-Ig) in the serum. A possible role of antigenic stimulation in the development of BMG has been suggested. From a C57BL mouse, a murine model for BMG, we have isolated clonally related B cells in order to investigate the occurrence of somatic mutations in the variable heavy chain (VH) region of the genes of H-Ig-producing B cell clones. Therefore, B cells were immortalized by hybridoma technology. The hybridomas were screened for resemblance of the serum H-Ig component by Wieme agar electrophoresis, followed by immunoblotting and isoelectrofocusing. Clonal relationship was investigated by Southern blot analysis using a JH probe. In this way we isolated five hybridomas producing an IgG2a, kappa that was identical to the original serum H-Ig component according to testing with anti-idiotypic antisera. mRNA sequencing of four hybridomas showed only one base pair difference in the VH genes. This particular gene belonged to the J558 VH gene family. When compared to the most closely related known VH sequence, three base pair differences were found. The almost complete absence of base pair differences in the VH genes of the four sequenced hybridomas, compared with an independently derived hybridoma, suggests that the same germ-line VH gene has been used and that somatic mutations were infrequent in our BMG clone.

Both IgA subclasses are reduced in parotid saliva from patients with AIDS

Secretory IgA (SIgA), the isotypes IgA1 and IgA2, and IgM were measured by ELISA in stimulated parotid saliva from patients with AIDS (n = 16), subjects with asymptomatic HIV infection (n = 28), and HIV-seronegative healthy controls (n = 19). SIgA was significantly reduced in the AIDS group (10.4 micrograms/ml) compared with the asymptomatic HIV-infected subjects (17.1 micrograms/ml) and the controls (23.0 micrograms/ml). This decrease comprised both IgA1 and IgA2 to a similar extent on a relative basis. The SIgA decrease in AIDS patients was in striking contrast to their serum IgA level, which was significantly increased (6.9 g/l) compared with the asymptomatic HIV-infected subjects (2.9 g/l) as well as the controls (2.8 g/l). Low parotid output of SIgA in patients with HIV infection was associated with low numbers of CD4+ lymphocytes in peripheral blood as well as the presence of oral infections. The parotid output of IgM was similar in all groups. A low level of SIgA in the external secretions of patients with AIDS may well contribute to their frequent mucosal infections of opportunistic microorganisms.

Immunoblotting techniques for the detection of low level homogeneous immunoglobulin components in serum

Because of the increasing demand for simple and reliable techniques for the detection of low concentrations of paraproteins against a highly heterogeneous serum background, two techniques were investigated for their sensitivity: isoelectric focusing (IEF) and Wieme high resolution electrophoresis, each with subsequent blotting by diffusion. The techniques were compared using isolated mouse monoclonal antibodies (mAb) of known concentration and specificity. Wieme electrophoresis in combination with immunoblotting (IBL) or antigen-specific immunoblotting (ABL) has a detection limit of 100 ng/ml and 10 ng/ml, respectively. For IEF in combination with IBL or ABL these limits were 1000 and 30 ng/ml, respectively. For ABL, polyvinylidene difluoride (PVDF) and nylon-supported nitrocellulose (NSNC) membranes gave similar detection limits, although for IBL, PVDF is preferred to NSNC. While IEF is essential for investigating the spectrum of the antibody repertoire. Wieme electrophoresis is the most powerful technique for the detection of homogeneous immunoglobulin components (H-Ig). After separation of the proteins. IBL is fast, simple and sensitive enough for routine detection and characterization of H-Ig. However, when the antibody specificity is known, ABL should be chosen for its superior sensitivity.

Site of catabolism of autologous and heterologous IgA in non-human primates

Because of similarities between the human and monkey immune systems, we considered the monkey a suitable model for studies on the catabolism of various molecular forms of IgA, for which little information is available. The residualizing label dilactitol-[125I]tyramine was coupled to monkey (Macaca fuscata) IgA and IgG, as well as to human monomeric and polymeric myeloma IgA1 and IgA2 proteins. When labelled proteins were injected intravenously into monkeys, the non-metabolizable radioiodinated tracer accumulated at the cellular site of protein degradation, allowing identification of the catabolic sites. To determine the uptake of injected proteins by various tissues, monkeys were sacrificed 6-7 days after injection of labelled proteins, when blood-associated radioactivity was less than or equal to 10% of the injected dose, as measured by plasma clearance. When monkey or human monomeric IgA, as well as human polymeric IgA, irrespective of subclass, was administered to monkeys, the liver showed the greatest tissue uptake relative to total dose injected and to organ weight, and the highest acid soluble radioactivity (degraded protein). Although both hepatocytes and non-parenchymal liver cells were involved in IgA uptake, the hepatocytes were more active. Therefore, it appears that the liver is the major site of uptake and catabolism of IgA in monkeys and possibly in humans.

Do infections induce monoclonal immunoglobulin components?

The incidental finding of monoclonal immunoglobulin components (MC) in some infections prompted us to study this phenomenon more systematically. Using isoelectric focusing with immunoblotting (detection limit for MC 0.1 mg/ml), the following infections were studied for the presence of MC: visceral leishmaniasis, cytomegalovirus (CMV) infection, echinococcosis and infectious mononucleosis. MC were found in 16 of 20 leishmania patients and in eight of 18 CMV patients, but in only one of 20 echinococcosis patients and in none of 30 infectious mononucleosis patients. The MC were mostly transient, where tested. A minority of the MC found in the leishmaniasis patients was shown to bind to leishmania antigens. The specificity of the majority of the MC remains unknown. Further study is required to explain the high incidence of MC in CMV infection and visceral leishmaniasis.

Age-related monoclonal gammapathies: clinical lessons from the aging C57BL mouse

In this article the long-held notion that benign monoclonal gammapathy (BMG) is a premalignant stage in the development of multiple myeloma (MM) is attacked. Jiri Radl argues that clinical and experimental observations indicate that they are separate entities which may be distinguished in the laboratory and which should be managed in radically different ways.

Monoclonal gammopathies in human aging: increased occurrence with age and correlation with health status

To determine the incidence of monoclonal gammopathies (MG) in relation to the aging process as such, and to evaluate the influence of disease on the occurrence of MG, we studied 439 elderly subjects aged 75-84 years. These individuals were categorized into 4 groups on the basis of their health status. There was a group of "optimally healthy" elderly, a group of "apparently healthy" residents of homes for the aged, a group of geriatric outpatients and a group of randomly chosen inpatients from a general hospital. Whereas no MG were detected in a control group of healthy young subjects aged 25-34 years, the frequency of MG in the aged groups ranged from 11% in the "optimally healthy" aged group to 38% in the inpatients group. In a tentative classification according to possible cause, most of the MG belonged to the pathogenetic category of immunodeficiency. There was a clear association of the occurrence of monoclonal gammopathies of this category with the health status.

The 5T mouse multiple myeloma model: absence of c-myc oncogene rearrangement in early transplant generations

Consistent chromosomal translocations involving the c-myc cellular oncogene and one of the three immunoglobin loci are typical for human Burkitt's lymphoma, induced mouse plasmacytoma (MPC) and spontaneously arising rat immunocytoma (RIC). Another plasma cell malignancy, multiple myeloma (MM), arising spontaneously in the ageing C57BL/KaLwRij mice, was investigated in order to see whether the MM cells contain c-myc abnormalities of the MPC or RIC type. Rearrangement of the c-myc oncogene was found in the bone marrow cells only in 5T2 MM transplantation line in a mouse of the 24th generation and in none of the seven other MM of the 5T series which were of earlier generations. Since the mouse 5T MM resembles the human MM very closely, including the absence of consistent structural c-myc oncogene abnormalities, it can serve as a useful experimental model for studies on the aetiopathogenesis of this disease.

Inflammatory demyelinating neuropathy in C57BL/KaLwRij mice

Neuropathies associated with monoclonal gammopathy (MG) in humans have been extensively studied in the past few years, but experimental models have proved difficult to create. C57BL mice are prone to develop benign MG and it has been reported that some of these mice with benign IgG MG present an inflammatory demyelinating neuropathy (IDN). In order to verify such findings, the serum and the sciatic nerve of the first group of 28 C57BL/KaLwRij mice were examined: none of 10 mice with normal serum showed ultrastructural abnormalities in the sciatic nerve, while lesions of IDN were present in three out of 10 mice with benign IgG MD, in two out of seven with benign IgM MG, and in a mouse with Waldenström-like lymphoma. The second group of animals was studied in the same way; it was composed of seven C57BL mice with transplanted multiple myeloma, and six C57BL mice with Morbus Waldenström-like lymphoma. In none of these animals, which were younger than those of the first group, was any lesion of IDN observed.

Antibodies to a short synthetic peptide related to the hinge segment of human IgG3 recognizes thermally or fixative induced conformational changes in the human IgG3 molecule

A synthetic decapeptide (SP) was used to produce a murine monoclonal antibody specific for the human IgG3 molecule. Recognition of the IgG3 determinant is heat- and fixation-sensitive in ELISA and immunoenzyme cytology, respectively. The antibody specifically recognizes a sequence from the hinge region of IgG3, but only when subtle alterations in the conformation are induced by mild heating (greater than 40 degrees) and subsequent stabilization by means of electrostatic interactions in solid-phase assays or by fixation with formalin acetic acid mercury chloride. The structure of the human IgG3 molecule is especially sensitive to microenvironmental influences, as can be concluded from its behaviour under various physicochemical conditions. To this, we add that the immunogenic determinants in the structure of relatively flexible parts of this protein can be severely altered by the routine application of fixation methods. It is shown that these changes can also be of importance in the recognition of antigen by monoclonal antibodies.