Indirect double sandwich ELISA for the specific and quantitative measurement of mouse IgM, IgA and IgG subclasses

Descriptive Comparison of ELISAs for the Detection of Toxoplasma gondii Antibodies in Animals: A Systematic Review

Toxoplasma gondii is the zoonotic parasite responsible for toxoplasmosis in warm-blooded vertebrates. This systematic review compares and evaluates the available knowledge on enzyme-linked immunosorbent assays (ELISAs), their components, and performance in detecting T. gondii antibodies in animals. Four databases were searched for published scientific studies on T. gondii and ELISA, and 57 articles were included. Overall, indirect (95%) and in-house (67%) ELISAs were the most used types of test among the studies examined, but the 'ID Screen® Toxoplasmosis Indirect Multi-species' was common among commercially available tests. Varying diagnostic performance (sensitivity and specificity) and Kappa agreements were observed depending on the type of sample (serum, meat juice, milk), antigen (native, recombinant, chimeric) and antibody-binding reagents used. Combinations of recombinant and chimeric antigens resulted in better performance than native or single recombinant antigens. Protein A/G appeared to be useful in detecting IgG antibodies in a wide range of animal species due to its non-species-specific binding. One study reported cross-reactivity, with Hammondia hammondi and Eimeria spp. This is the first systematic review to descriptively compare ELISAs for the detection of T. gondii antibodies across different animal species.

Towards middle-up analysis of polyclonal antibodies: subclass-specific N-glycosylation profiling of murine immunoglobulin G (IgG) by means of HPLC-MS

In recent years, advanced HPLC-MS strategies based on intact protein (“top-down”) or protein subunit (“middle-up/middle-down”) analysis have been implemented for the characterization of therapeutic monoclonal antibodies. Here, we assess feasibility of middle-up/middle-down analysis for polyclonal IgGs exhibiting extensive sequence variability. Specifically, we addressed IgGs from mouse, representing an important model system in immunological investigations. To obtain Fc/2 portions as conserved subunits of IgGs, we made use of the bacterial protease SpeB. For this purpose, we initially determined SpeB cleavage sites in murine IgGs. The resulting Fc/2 portions characteristic of different subclasses were subsequently analysed by ion-pair reversed-phase HPLC hyphenated to high-resolution mass spectrometry. This enabled simultaneous relative quantification of IgG subclasses and their N-glycosylation variants, both of which influence IgG effector functions. To assess method capabilities in an immunological context, we applied the analytical workflow to polyclonal antibodies obtained from BALB/c mice immunized with the grass pollen allergen Phl p 6. The study revealed a shift in IgG subclasses and Fc-glycosylation patterns in total and antigen-specific IgGs from different mouse cohorts, respectively. Eventually, Fc/2 characterization may reveal other protein modifications including oxidation, amino acid exchanges, and C-terminal lysine, and may thus be implemented for quality control of functional antibodies.

Exogenous insulin enhances humoural immune responses in short-day, but not long-day, Siberian hamsters (Phodopus sungorus)

Many animals experience marked seasonal fluctuations in environmental conditions. In response, animals display adaptive alterations in physiology and behaviour, including seasonal changes in immune function. During winter, animals must reallocate finite energy stores from relatively costly, less exigent systems (e.g. reproduction and immunity) to systems critical for immediate survival (e.g. thermoregulation). Seasonal changes in immunity are probably mediated by neuroendocrine factors signalling current energetic state. One potential hormonal candidate is insulin, a metabolic hormone released in response to elevated blood glucose levels. The aim of the present study was to explore the potential role of insulin in signalling energy status to the immune system in a seasonally breeding animal, the Siberian hamster (Phodopus sungorus). Specifically, exogenous insulin was administered to male hamsters housed in either long 'summer-like' or short 'winter-like' days. Animals were then challenged with an innocuous antigen and immune responses were measured. Insulin treatment significantly enhanced humoural immune responses in short, but not long days. In addition, insulin treatment increased food intake and decreased blood glucose levels across photoperiodic treatments. Collectively, these data support the hypothesis that insulin acts as an endocrine signal integrating seasonal energetic changes and immune responses in seasonally breeding rodents.

Antibody-mediated protection against infection with Helicobacter pylori in a suckling mouse model of passive immunity

Studies of active immunization against Helicobacter pylori indicate that antibodies play a minor role in immunity. There is also evidence, however, that the translocation of antibodies in the stomach may be insufficient to achieve functional antibody levels in the gastric lumen. We have used a suckling mouse model of passive immunity to determine if perorally delivered antibodies can protect against infection with H. pylori. Female C57BL/6 mice were immunized parenterally with formalin-fixed cells of three clinical isolates of H. pylori (3HP) or the mouse-adapted H. pylori strain SS1 before mating. Their pups were challenged with the SS1 strain at 4 days of age and left to suckle before determination of bacterial loads 14 days later. Compared to age-matched controls, pups suckled by 3HP-vaccinated dams were significantly protected against infection (>95% reduction in median bacterial load; P<0.0001). Pups suckled by SS1-vaccinated dams were also significantly protected in terms of both median bacterial load (>99.5% reduction; P<0.0001) and the number of culture-negative pups (28% versus 2% for immune and nonimmune cohorts, respectively; P<0.0001). Similar results were obtained with pups suckled by dams immunized with a urease-deficient mutant of SS1. Fostering experiments demonstrated that protection was entirely attributable to suckling from an immunized dam, and antibody isotype analysis suggested that protection was mediated by the immunoglobulin G fraction of immune milk. Analysis of the bacterial loads in pups sampled before and after weaning confirmed that infection had been prevented in culture-negative animals. These data indicate that antibodies can prevent colonization by H. pylori and suppress the bacterial loads in animals that are colonized.

Development of immunoglobulin A nephropathy- like disease in beta-1,4-galactosyltransferase-I-deficient mice

Beta4 galactosylation of glycoproteins plays important roles in protein conformation, stability, transport, and clearance from the circulation. Recent studies have revealed that aberrant glycosylation causes various human diseases. Here we report that mice lacking beta-1,4-galactosyltransferase (beta4GalT)-I, which transfers galactose to the terminal N-acetylglucosamine of N- and O-linked glycans in a beta-1,4 linkage, spontaneously developed human immunoglobulin A nephropathy (IgAN)-like glomerular lesions with IgA deposition and expanded mesangial matrix. beta4GalT-I-deficient mice also showed high serum IgA levels with increased polymeric forms as in human IgAN. IgAN is the most common form of glomerulonephritis, and a significant proportion of patients progress to renal failure. However, pathological molecular mechanisms of IgAN are poorly understood. In humans, abnormal character of serum IgA, especially serum IgA1 with aberrant galactosylation and sialylation of O-glycans in its hinge region is thought to contribute to the pathogenesis of IgAN. Mouse IgA has N-glycans but not O-glycans, and beta4-galactosylation and sialylation of the N-glycans on the serum IgA from beta4GalT-I-deficient mice was completely absent. This is the first report demonstrating that genetic remodeling of protein glycosylation causes IgAN. We propose that carbohydrates of serum IgA are involved in the development of IgAN, whether the carbohydrates are O-glycans or N-glycans.

FK778 and FK506 Combination Therapy to Control Acute Rejection after Rat Liver Allotransplantation

BACKGROUND

In organ transplantation, several immunosuppressants are currently used to control graft rejection. Clinically, no single immunosuppressive agent can completely prevent posttransplantation immunoreaction; thus, combination therapy is usually performed. Novel agents with more powerful immunosuppressive activity and less toxicity need to be developed.

METHODS

Lewis rat livers were orthotopically transplanted into Brown-Norway recipients. FK778 was administered orally from day 0 to day 6 to prevent acute rejection and from day 7 to day 13 to rescue ongoing rejection. To assess the combined effects, recipients were treated with intramuscular injection of FK506 and oral administration of FK778 from day 0 to day 6. Blood chemistry and histopathologic findings were measured to determine the patient's general condition and the graft condition. Allospecific antibodies were measured using enzyme-linked immunosorbent assays. The FK778 trough concentration was examined by using high-performance liquid chromatography.

RESULTS

The acute immune response was suppressed by FK778 alone in a dose-dependent manner. The optimal FK778 dosage was determined to be 20 mg/kg per day, because adverse effects (weight loss and intestinal bleeding) occurred at 30 mg/kg per day. FK778 treatment from day 7 to day 13 rescued liver grafts from ongoing rejection. The intramuscular FK506 (0.125 mg/kg per day) injection and the oral FK778 (20 mg/kg per day) gavages suppressed acute liver graft rejection effectively and maintained better graft condition compared with monotherapy. CONCLUSIONS.: FK778 treatment effectively prevented acute rejection and rescued ongoing rejection after liver transplantation. The optimal dosage was determined to be 20 mg/kg per day. Combination therapy with FK506 was more beneficial than FK778 monotherapy.

Incomplete block of B cell development and immunoglobulin production in mice carrying the muMT mutation on the BALB/c background

The expression of the preB cell receptor (preBCR), composed of the mu chain, surrogate light chains and the Igalpha /Igbeta signal transduction unit, permits further differentiation of Bcell precursors. C57BL/6 mice homozygous for an inactivating mutation of the membrane exon of the mu chain gene (C57BL/6muMT/muMT)) cannot form a preBCR and are, consequently, devoid of mature B lymphocytes. Here we present evidence that the block of B cell development by the muMT mutation is incomplete in BALB/c mice. Unlike C57BL/6muMT/muMT), BALB/cmuMT/muMT) mice generate small numbers of mature B cells, accumulate plasma cells and produce high levels of all immunoglobulin isotypes, except IgM. The observed phenomenon seems to be controlled by a single genetic locus that is not linked to IgH.

Heminephrectomy causes the progression of glomerulosclerosis and apoptosis in high IgA strain ddY mice

BACKGROUND

The reduction in nephrons in IgA nephropathy is critical to the prognosis of this disease. However, the immunopathological mechanism of the modifications seen in glomerular lesions is not clear. We thus investigated the influence of nephron reduction by heminephrectomy on renal lesions in a high immunoglobulin A inbred strain of ddY mouse (HIGA mouse), which shows progressive mesangial sclerosis with elevated renal expression of transforming growth factor (TGF)-beta.

METHODS

Five-week-old HIGA mice were heminephrectomized (Nx), and were evaluated in comparison with a sham-operated group (S) at 40 weeks old. Histological findings, immunoglobulin depositions (IgG, IgA, and IgM), and expressions of cytokine and extracellular matrix proteins (TGF-beta, fibronectin, collagen type I and IV) were analysed. PCNA and TUNEL stainings were performed with electron microscopic detection of apoptosis. Tissue renin-angiotensin systems (RAS) were also investigated by real-time quantitative RT-PCR.

RESULTS

In the Nx group, the glomerular tuft area and ratio of mesangial matrix area per tuft were significantly increased, and the glomerular cell count per tuft area was significantly decreased. Glomerular immunoglobulin deposits of IgG, IgA, and IgM in Nx were all significantly expanded in the paramesangium. The glomerular expressions of TGF-beta and the extracellular matrix proteins were significantly increased in Nx mice. In contrast to the significant decrease of PCNA-positive cells, TUNEL-positive cells were significantly increased in Nx. Angiotensin-converting enzyme (ACE) was significantly increased in the renal cortex of Nx.

CONCLUSION

Simple heminephrectomy, other than 5/6 renal ablation, of HIGA mice may be a potential model for research into the progressive glomerulosclerosis of human IgA nephropathy. The pathological role of apoptosis is apparently involved in these disease processes, possibly through upregulated RAS.

Interleukin 12 induces crescentic glomerular lesions in a high IgA strain of ddY mice, independently of changes in IgA deposition

BACKGROUND

Our recently established high immunoglobulin (Ig)A inbred strain (HIGA) of ddY mice showed constantly high serum IgA levels, progressive mesangial sclerosis accompanied by IgA deposits, and elevated renal expression of transforming growth factor (TGF)-beta, mimicking IgA nephropathy. In the present study, we assessed the role of the immune system, especially of T cells, in this strain.

METHODS

The in vitro production of interferon (IFN)-gamma, interleukin (IL)-4 and TGF-beta1 by splenic CD4+ T cells was assessed in HIGA mice at 14 and 28 weeks of age by comparison with age-matched C57BL/6 and BALB/c mice, T-helper (Th) 1, and Th2 prone controls respectively. Moreover, recombinant murine IL-12 was administered intraperitoneally to HIGA mice and serum IgA and renal lesions were analysed.

RESULTS

The production of IFN-gamma by splenic CD4+ T cells was markedly upregulated in HIGA mice at both ages as compared with age-matched C57BL/6 and BALB/c mice. Although splenic CD4+ T cells from HIGA mice produced less IL-4 than those from BALB/c mice at both ages, the former produced significantly more IL-4 with age, which contrasted with the age-associated decrease in the latter. Moreover, TGF-beta1 production of these cells in HIGA mice was equal to or greater than that in the two groups of control mice at both ages. Daily intraperitoneal administration of IL-12 for 1 week significantly enhanced crescent formation with glomerular macrophage accumulation and interstitial cell infiltration, whereas it reduced the serum IgA level.

CONCLUSIONS

In HIGA mice, Th1 is markedly upregulated from a young age and there is an age-associated Th2 increase with TGF-beta1 upregulation in helper T cells. The former may be related to the exacerbation of inflammatory renal lesions on IL-12 administration, while the latter may contribute to increased IgA production, leading to glomerular IgA deposition and progressive glomerulosclerosis in HIGA mice. The pathogenic role of T cell function and fluctuation of these subsets, especially the Th1/Th2 balance, is crucial to the immunopathological phenotype of the renal lesions in HIGA mice.

Alymphoplasia (aly)-type nuclear factor kappaB-inducing kinase (NIK) causes defects in secondary lymphoid tissue chemokine receptor signaling and homing of peritoneal cells to the gut-associated lymphatic tissue system

Alymphoplasia (aly) mice, which carry a point mutation in the nuclear factor kappaB-inducing kinase (NIK) gene, are characterized by the systemic absence of lymph nodes and Peyer's patches, disorganized splenic and thymic architectures, and immunodeficiency. Another unique feature of aly/aly mice is that their peritoneal cavity contains more B1 cells than normal and aly/+ mice. Transfer experiments of peritoneal lymphocytes from aly/aly mice into recombination activating gene (RAG)-2(-/-) mice revealed that B and T cells fail to migrate to other lymphoid tissues, particularly to the gut-associated lymphatic tissue system. In vivo homing defects of aly/aly peritoneal cells correlated with reduction of their in vitro chemotactic responses to secondary lymphoid tissue chemokine (SLC) and B lymphocyte chemoattractant (BLC). The migration defect of aly/aly lymphocytes was not due to a lack of expression of chemokines and their receptors, but rather to impaired signal transduction downstream of the receptors for SLC, indicating that NIK is involved in the chemokine signaling pathway known to couple only with G proteins. The results showed that the reduced serum levels of immunoglobulins (Igs) and the absence of class switch to IgA in aly/aly mice are due, at least in part, to a migration defect of lymphocytes to the proper microenvironment where B cells proliferate and differentiate into Ig-producing cells.

An ELISA for quantification of murine IgG in rat plasma: application to the pharmacokinetic characterization of AP-3, a murine anti-glycoprotein IIIa monoclonal antibody, in the rat

An enzyme-linked immunosorbent assay (ELISA) has been developed to determine concentrations of murine IgG in rat plasma. Specifically, the assay was developed to measure a murine anti-glycoprotein IIIa antibody (AP-3) in rat plasma to facilitate future investigations of AP-3 pharmacokinetics and pharmacodynamics in the rat. The working range of the assay is 15-100 ng ml(-1), corresponding to a limit of quantification of 1.5 microg ml(-1) in rat plasma. The assay was validated with respect to accuracy, precision, and cross-reactivity with both pooled rat and mouse IgG. Intra-assay recoveries of AP-3 in rat plasma ranged from 93 to 103%, with CV% values ranging from 5.2 to 8.5%. Inter-assay recoveries of the plasma AP-3 samples ranged from 107 to 119% with CV% values ranging from 17.7 to 25.1%. The assay has no appreciable cross reactivity with pooled rat IgG and full cross reactivity with pooled mouse IgG, making this an ideal assay to determine plasma pharmacokinetics of mouse antibodies in the rat. The assay was used to determine the pharmacokinetics of AP-3 in a Sprague-Dawley rat.

The immunoevasive function encoded by the mouse cytomegalovirus gene m152 protects the virus against T cell control in vivo

Cytomegaloviruses encode numerous functions that inhibit antigen presentation in the major histocompatibility complex (MHC) class I pathway in vitro. One example is the mouse cytomegalovirus (MCMV) glycoprotein gp40, encoded by the m152 gene, which selectively retains murine but not human MHC class I complexes in the endoplasmic reticulum-Golgi intermediate compartment/cis-Golgi compartment (Ziegler, H., R. Thäle, P. Lucin, W. Muranyi, T. Flohr, H. Hengel, H. Farrell, W. Rawlinson, and U.H. Koszinowski. 1997. Immunity. 6:57-66). To investigate the in vivo significance of this gene function during MCMV infection of the natural host, we constructed recombinants of MCMV in which the m152 gene was deleted, as were the corresponding virus revertants. We report on the following findings: Deletion of the m152 gene has no effect on virus replication in cell culture, whereas after infection of mice, the m152-deficient virus replicates to significantly lower virus titers. This attenuating effect is lifted by reinsertion of the gene into the mutant. Mutants and revertants grow to the same titer in animals deprived of the function targeted by the viral gene function, namely in mice deficient in beta2-microglobulin, mice deficient in the CD8 molecule, and mice depleted of T cells. Upon adoptive transfer of naive lymphocytes into infected mice, the absence of the m152 gene function sensitizes the virus to primary lymphocyte control. These results prove that MHC-reactive functions protect CMVs against attack by CD8(+) T lymphocytes in vivo.

Uteroglobin is essential in preventing immunoglobulin A nephropathy in mice

The molecular mechanism(s) of immunoglobulin A (IgA) nephropathy, the most common primary renal glomerular disease worldwide, is unknown. Its pathologic features include hematuria, high levels of circulating IgA-fibronectin (Fn) complexes, and glomerular deposition of IgA, complement C3, Fn and collagen. We report here that two independent mouse models (gene knockout and antisense transgenic), both manifesting deficiency of an anti-inflammatory protein, uteroglobin (UG), develop almost all of the pathologic features of human IgA nephropathy. We further demonstrate that Fn-UG heteromerization, reported to prevent abnormal glomerular deposition of Fn and collagen, also abrogates both the formation of IgA-Fn complexes and their binding to glomerular cells. Moreover, UG prevents glomerular accumulation of exogenous IgA in UG-null mice. These results define an essential role for UG in preventing mouse IgA nephropathy and warrant further studies to determine if a similar mechanism(s) underlies the human disease.

Quantitative ELISA for mouse monoclonal antibody determination in culture supernatants and in human serum

An ELISA has been set up for quantifying mouse monoclonal antibodies in culture supernatant. The assay includes rabbit anti-mouse IgG antibodies chromatographycally purified. This preparation was used as coating and as conjugated antibodies in the ELISA. The assay can detect IgG1 with sensitivity of 0.2 ng/mL, IgG2a (0.85 ng/mL), IgG2b (0.13 ng/mL), and IgG3 (3.19 ng/mL) in culture supernatants. The effective working range was from subnanogram per mL quantities to 30 ng/mL by using a computer statistical program. Variation coefficient of ELISA was below 7%. Correlation estimates with a similar ELISA using commercial reagents were performed for each mouse antibody subclass. The assay was able to detect the four mouse monoclonal antibody subclasses in pure human serum as compared with the same ELISA using commercial antibodies. A 24-h pharmacokinetic profile of 1 patient treated with an IgG2a monoclonal antibody is presented.

Administration of anti-IL-12 antibody in vivo inhibits rejection of a rat histiocytoma and suppresses cytokine response in a tumour-bearing host

Activated macrophages are the major producers of heterodimeric cytokine interleukin-12 (IL-12). Earlier evidence suggested that early rejection of AK-5 tumours is mediated by IL-12 through interferon-gamma (IFN-gamma) production, involving activation of natural killer (NK) cells and upregulation of T-helper 1 (Th1)-type cytokine response. Injection of anti-IL-12 antibody into AK-5 tumour-bearing animals resulted in a large number of changes in the host immune response towards the tumour. These animals showed diminished NK-mediated antibody-dependent cell-mediated cellular cytotoxicity (ADCC) activity, down-regulation of Th1-type cytokine response, decreased anti-tumour antibody response ultimately leading to either delay or inhibition of the tumour-regression process. There was also increased production of IL-10 in the animals that had received anti-IL-12 antibody thereby resulting in the down-regulation of IL-2 and IFN-gamma production. IL-12 plays a major role in the activation of the different immune parameters responsible for early rejection of AK-5 tumour. We also studied the activation status of macrophages from tumour-transplanted animals and their ability to produce IL-12. Monocytes/macrophages from antibody-injected animals were less active and produced lower quantities of IL-12, IL-1 beta and tumour necrosis factor-alpha (TNF-alpha) as compared with the macrophages from AK-5 tumour-bearing animals.

The neonatal Fc receptor is not required for mucosal infection by mouse mammary tumor virus

The milk-borne mouse mammary tumor virus (MMTV) infects newborn mice via the intestine. Infection is initially restricted to Peyer's patches and later spreads to the epithelial cells of the mammary gland. The receptor that mediates uptake and transport of MMTV across the intestinal barrier has not yet been identified, The neonatal Fc receptor (nFcR), which is expressed by enterocytes during the first two weeks of life, is downregulated at weaning, and its disappearance correlates with the onset of intestinal resistance to MMTV. To test whether the nFcR mediates transport and allows infection, we foster nursed on infected MMTV mothers beta2 microglobulin-deficient (beta2m-deficient) newborn mice that are unable to express the nFcR at the surface of their enterocytes. Exposure of beta2m-deficient mice to milk-borne virus resulted in the deletion of peripheral blood T cells reactive to the superantigen encoded by MMTV. Since beta2m-deficient newborn mice are susceptible to MMTV infection despite the lack of the nFcR, we conclude that the nFcR is not required for MMTV transport.

Interactions of B6 wild and B6 gld cells engrafted within athymic nude beige recipients

The murine gld mutation is targetted to the gene coding for the ligand of the Fas receptor for apoptosis. Gld mice display a lymphoproliferative and autoimmune syndrome that can be transferred in both irradiated euthymic wild and athymic beige (nubg) recipients. In order to test whether a supply of normal wild cells could correct the development of the gld syndrome, nubg mice were grafted with mixtures of gld and wild spleen cells from congenic donors which differed for the allotypes of the T-cell Thy1 membrane glycoprotein and/or of the B-cell Ig heavy chain. In the nubg chimeras, the wild spleen cells could down-regulate the hyperactivation of the B cells and the proliferation of the gld T cells, but this was not due to total eradication of the gld T-cell subset. Since this occurred in an athymic recipient, the correction of the gld syndrome did not require wild stem cell differentiation within a thymic environment, but should only depend on a sufficient Fas ligand supply by normal wild cells. Since the gld cells could proliferate in the nubg environment, the nubg environment could not provide sufficient Fas ligand to regulate the gld cell proliferation. Thus, the nubg B cells might lack Fas ligand expression, or express it but to a lower extent that T cells.

Serological abnormalities induced by engraftment of viable motheaten hematopoietic cells in nude beige recipients

C57BL/6J (B6) mice homozygous for the viable motheaten (mev) mutation are short-lived and display severe immunodeficiency, autoimmunity and inflammatory disease. B6 mice doubly homozygous for the nude (nu) and beige (bg) mutations (nubg mice) are also short-lived and immunodeficient. Nevertheless, grafts of mev lympho-hematopoietic cells increased life expectancy of nubg recipients. Such [mev --> nubg] chimeras did not develop any mev-like inflammatory pathology but showed autoimmunity features, particularly hyperglobulinemia which, unlike the mev one, was due to IgG rather than IgM. Serological studies of [mev IgHb --> nubg Igha] chimeras surprisingly revealed the exclusive host B-cell origin of the IgG2a overproduced by these chimeras. Yet, about half of such chimera serum IgM being IgMb, mev B cells had actually engrafted the nubg hosts. Together with the lack of transfer of the inflammatory pathology, this suggests that a non-mev environment might succeed acting as a regulator of some mev-induced dysfunctions.

Interactions of the scid or beige mutations with the viable motheaten mutation

The viable motheaten (mev) mice are characterized by a moth-eaten appearance of the coat, immunodeficiency, autoimmunity, generalized inflammatory disease, paws necroses, and early death. The target of the single point mev mutation is PTP1C, a protein tyrosine phosphatase whose deficient expression in hematopoietic cells should explain all phenotypic features of mev mice, particularly their autoimmune and inflammatory pathologies. In order to evaluate their role in the development of the mev mouse disease, we constructed mevscid congenics to probe the impact of autoimmunity and mevbeige congenics to probe the impact of elastase and cathepsine G neutrophil activities. Both mevscid and mevbeige mice were nearly equivalent to mev mice with regards to moth-eaten appearance, paw necroses and early death. Thus, autoimmunity does neither initiate nor substantially enhance the mev mouse syndrome. Moreover, the beige mutation-linked deficiency of protease activity of neutrophils is unable to significantly reduce the mev mutation-dependent inflammatory pathology.

Antibodies are not essential for the resolution of primary cytomegalovirus infection but limit dissemination of recurrent virus

Virus shedding from the epithelial cells of the serous acini of salivary glands is a major source for the horizontal transmission of cytomegalovirus. These cells are, different to other tissues, exempt from CD8 T lymphocyte control. CD4 T lymphocytes are essential to terminate the productive infection. Here, we prove that T-B cooperation and the production of antibodies are not required for this process. For the infection with murine cytomegalovirus, mutant mice were used which do not produce antibodies because of a disrupted membrane exon of the immunoglobulin mu chain gene. Also, in these mice the virus clearance from salivary glands is a function of CD4 T lymphocytes. However, these mice clear the virus and establish viral latency with a kinetics that is distinguishable from normal mice. Reactivation from virus latency is the only stage at which the absence of antibodies alters the phenotype of infection. In immunoglobulin-deficient mice, virus recurrence results in higher virus titers. The adoptive serum transfer proved that antibody is the limited factor that prevents virus dissemination in the immunodeficient host.

A new mutation, aly, that induces a generalized lack of lymph nodes accompanied by immunodeficiency in mice

We have found a new spontaneous autosomal recessive mutation in mice that causes a systemic absence of lymph nodes and Peyer's patches. The name "alymphoplasia", with the gene symbol "aly", is proposed for this mutant. The spleen of aly/aly mice is devoid of well-defined lymphoid follicles, and the thymus does not show a clear cortical-medullary distinction. The mutant homozygotes are deficient in both humoral and cell-mediated immune functions, and are highly susceptible to infections. They have a reduced level of IgM and severely depressed levels of IgG and IgA in their sera, and do not reject allogeneic skin grafts. However, they have mature T and B cells as determined from their cell surface antigens. The results of bone marrow transplantation experiments suggest a mesenchymal disorder as a possible cause of the lack of lymph nodes and of immunodeficiency in the aly mouse. The aly mutant mouse may be a useful animal model of primary immunodeficiency, as are the nu (nude) and scid (severe combined immunodeficiency) mice.

Determination of immunoglobulin M concentration by piezoelectric crystal immunobiosensor coated with protamine

In the present study, the specific binding between protamine and immunoglobulin M (IgM) has been exploited to construct a piezoelectric crystal based immunobiosensor for the determination of concentration of IgM. The system consisted of highly stable IC based oscillator, 8-digit frequency counter and modified piezoelectric crystal device. The crystal surface was physically modified and chemically treated (refluxed) with strong acid to produce stable hydroxylic groups of silicon oxide. This modified surface reacted strongly with coupling reagents for binding of protein molecules. The protamine was immobilized by using either gamma-aminopropyltriethoxy silane (gamma-APTES) or 2.2.2-trifluoroethanesulfonyl chloride (tresyl chloride). Scanning electron microscope images of piezo crystal revealed that tresyl activated surface presented more surface area for binding than gamma-APTES modified surface and showed better sensitivity. This immobilization technique also improved the reproducibility and long term stability of the detection system. Using the system described, the IgM concentration up to the level of 10 ng/ml could be detected without interference of IgG.

Amiodarone pulmonary toxicity in the rat is associated with increased lavage immunoglobulin and alveolar macrophages primed for increased interleukin-1 secretion

To determine whether a hypersensitivity reaction played a role in amiodarone-induced pulmonary inflammation and affected humoral immunity, we examined pulmonary immunoglobulin (Ig) levels, alveolar macrophage release of interleukin-1 (IL-1)-like activity, and the ability to generate both systemic and pulmonary humoral immune responses after immunization. Levels of IgG, IgM, and albumin in lavage fluid were measured by enzyme-linked immunosorbent assay (ELISA) in control rats and rats fed drug for 3, 8, 11, and 30 wk. Control rats showed no change in lavage Ig levels at any time point. However, drug-fed rats had a significant increase in IgG/albumin at 11 and 30 wk and IgM/albumin at 30 wk. To determine whether alveolar macrophages were in an activated state, the amount of IL-1-like activity released by cells from control rats was compared with drug-fed rats, using the standard C3H/HeJ thymocyte proliferation assay. We found no difference in the spontaneous release of IL-1 activity, but lipopolysaccharide-stimulated macrophages from the drug-fed rats produced significantly more IL-1 than did control macrophages. Finally, to examine antibody responses, control and drug-fed rats were immunized and boosted with 1 mg/ml of ovalbumin (OA) in adjuvant followed by an intratracheal immunization of OA. There was no difference in antibody titers measured by ELISA. In conclusion, although there is some suggestion of an immune-mediated component in amiodarone-induced pulmonary inflammation, the increase in lymphocytes and lavage Ig appears too late to be the sole cause.

Quantitation of monoclonal antibodies by ELISA. The use of purified mouse IgG and mouse IgM monoclonal antibodies as standards in a quantitative ELISA measuring monoclonal antibodies produced by cell culture

Murine monoclonal antibodies (MAbs) of IgG1, IgG2a and IgG2b subclasses and IgM class in hybridoma culture supernatants were quantified using a sensitive, reliable, optimized indirect double antibody sandwich ELISA. In the ELISA, the MAb in the culture supernatants was sandwiched between affinity isolated heavy chain specific polyclonal antibodies used for capture and detection. Quantitation was achieved by comparison with a standard curve produced by a purified MAb of the same class, subclass or ideally the same clone as the MAb to be quantified. These quantitative results were compared with those obtained using purified IgG and IgM polyclonal serum samples as standards and those obtained by total protein estimation using measurement at OD280nm. The IgG subclass MAbs used as standards were purified using protein G and the IgM class MAb was purified by ion exchange followed by gel filtration chromatography. Bovine IgG contamination of the MAb supernatants and the purified MAbs was also measured by a double antibody sandwich ELISA.

Measurement and computation of murine interleukin-4 and interferon-gamma by exploiting the unique abilities of these lymphokines to induce the secretion of IgG1 and IgG2a

A specific and new method for measuring Interleukin-4 and Interferon-gamma, based on the estimation of IgG1 and IgG2a isotypes secretion from B cells is described. An antagonizing effect of Interferon-gamma in the production of IgG1 induced by Interleukin-4 was neutralized by using antibody to Interferon-gamma. Similarly, the interference of Interleukin-4 in the Interferon-gamma mediated enhancement of IgG2a production was blocked by anti-Interleukin-4 antibody. The high concentrations of Interleukin-4 and Interferon gamma inhibited the secretion of IgG1 and IgG2a respectively. Therefore, in the assay described, the samples containing the cytokines were so diluted that their activity fell into the non-inhibitory zone. A computer program has also been developed for determining the concentrations of lymphokines.

Adoptive transfer of the entire gld (generalized lymphoproliferative disease) syndrome in nude beige mice by a single gld thymocyte graft

C57BL/6 nude beige mice (B6 nubq; no T cell, no NK activity) were used as recipients for the adoptive transfer of thymocytes from B6 gld mice (generalized lymphoproliferative disease) which are a model of systemic lupus erythematous. The [gld----nubg] chimeras showed several similarities with gld control mice including the T cell disorders (lymphoproliferation and Con A-response deficiency of splenocytes) and B cell disorders (hyperglobulinemia and elevated anti-single-stranded DNA antibody titers). This suggests that the gld lymphoproliferative disorder has a thymic origin (and does not result from an abnormally extrathymic T cell development) and that the gld T cells have an essential role for the emergence of the disorders of both the T and B cells.

Serum immunoglobulin isotype profile of viable and non viable lymphoid cell chimaeras made with nude athymic lpr (lymphoproliferation) mouse recipients

C57BL/6 mice (B6) which are homozygous at the nu (nude, athymic) and lpr (lymphoproliferation) locus (B6 nulpr) are short-lived. We showed previously that increased survival could be obtained by grafting lymphoid cells from euthymic lpr-homozygous B6 mice (B6 lpr) mice ([lpr----nulpr] chimaeras), but curiously enough not from normal (B6 wild) mice ([wild----nulpr] chimaeras). Moreover female, but not male, [lpr----nulpr] chimaeras developed spleen and lymph node enlargement. In the present paper the distribution and absolute concentrations of all serum immunoglobulin (Ig) isotypes have been determined in these chimaeras and their controls. All chimaeras displayed whole serum Ig levels higher than those of B6 wild mice, suggesting a successful reconstitution of the athymic recipients by the grafted lymphoid cells, but two types of chimaeras were peculiar. The short-lived [wild----nulpr] chimaeras showed a proportion of IgM as high as ungrafted B6 nulpr mice, suggesting a deficient down-regulation of IgM production by the grafted B6 wild-type lymphoid cells. The [lpr----nulpr] female chimaeras recovered a long lasting overexpression of all Ig isotypes, like B6 lpr mice, while all the other chimaeras showed a transient overexpression only. Since neither lymphadenopathy nor persistent increase of serum Ig levels were observed in [lpr----nu] chimaeras, our data confirmed the need for a genetically lpr host to allow the significant development of the lpr syndrome.

Adoptive transfer of the gld syndrome in double congenic nude lpr mice

Homozygosity for either the lymphoproliferation (lpr) or the generalized lymphoproliferative disease (gld) mutation of mice causes the development of strikingly similar autoimmune and lymphoproliferative syndromes. The relationship between the lpr and gld mutations was studied by grafting B6 gld spleen cells (SC) to athymic B6 nude lpr mice (B6 nulpr) or to B6 nude (B6 nu) mice as controls. The injection of B6 gld SC, but not of B6 wild SC, to B6 nulpr mice caused a prolongation of survival of the short living B6 nulpr recipients. This was associated with elevated anti-single stranded DNA antibody titers and a serum hyperglobulinemia, as well as by a splenomegaly which was nearly as high as in genetically B6 gld mice, and by a marked lymphadenopathy (though milder than that of B6 gld mice). In contrast the [gld----nu] chimaeras showed a more attenuated form of gld-induced syndrome. These results suggest that the lpr environment supplied in athymic lpr recipients is compatible with--and may even favour--the development of the gld-induced syndrome.

A quick procedure for identifying doubly homozygous immunodeficient scid beige mice

This article describes a rapid and reliable procedure for identifying mice which are doubly homozygous at the scid and beige (bg) loci starting from CB17 scid (no T and B cells) and B6 bg mice (no NK activity). The [scid, bg] mice are directly identified in the F2 progeny by monitoring (1) the hypogammaglobulinemia for the scid gene and (2) the prolonged bleeding associated with the bg gene. Like CB17 scid mice, the [scid, bg] mice show a high susceptibility to infections and die early in life unless they are protected against potential infections. This is achieved by a graft of splenocytes plus bone marrow cells from (B6 bg x CB17 scid) F1 mice. These [scid, bg] mice combine the bg and scid immunodeficiencies and should be better recipients for xenografts than classical scid mice.

Immunoglobulin isotypes of C57BL/6 nu/nu, lpr/lpr mice. Lack of direct intrinsic effect of the lpr gene on B cell hyperactivity

The absolute concentrations of mouse immunoglobulin (Ig) heavy chain isotypes were determined by specific ELISAs in the serum of C57BL/6 (B6) mice doubly homozygous at the nude (nu) and the lymphoproliferation (lpr) locus (B6 nu, lpr mice), and compared with normal B6 nu mice. The distribution and the absolute concentrations of all Ig isotypes were found to be very similar in B6 nu, lpr and B6 nu mice, for both sexes and with similar increases in titers with ageing. Thus, the major part of the severe autoimmunity and hyperglobulinemia characteristic of the lpr syndrome of euthymic B6 lpr mice, including their elevated titers of thymus-independent IgM and IgG3 isotypes, is abrogated by the nude mutation, an effect of which is the lack of thymus differentiation. Though a postulated intrinsic activity of the lpr gene directly on B cell hyperactivity cannot be discarded, its expression would then require the presence of either the thymus or of T cells or of other cells or factors whose expression is also abrogated by the homozygosity at the nude locus.

Partial expression of the viable motheaten (mev) mutation in the heterozygous state: abnormal levels of serum immunoglobulins and natural anti-ssDNA antibodies

The 'viable motheaten' (mev) mutation in the C57BL/6 (B6) mouse causes a rapidly progressive and fatal autoimmune syndrome in mev-homozygous B6 mice, combined with generalized immunodeficiency, whereas the mev-heterozygous B6 mice look phenotypically normal. However, serological analyses of the levels of some spontaneously occurring, natural antibodies and of the levels and distribution of the different classes of immunoglobulins revealed mild but evident dysregulation of the natural humoral immunity of +/mev individuals.

Common and individual features of the humoral immunity dysregulation of mice homozygous at the viable motheaten (mev) mutation

The "viable motheaten" (mev) mutation in the C57BL/6 (B6) mouse causes in mev-homozygous B6 mice a rapidly progressing and fatal autoimmune syndrome, combined with a generalized immunodeficiency. Serological analyses of a large number of mev/mev individual mice revealed profound abnormalities of the levels of various spontaneously occurring, natural antibodies and of the levels and distribution of the different classes of immunoglobulins, some common to all mev/mev mice and some specific to individual mice. Although very high serum IgM levels (70X the normal B6 mouse serum level) and high anti-ssDNA titers are common features, the increases in the other immunoglobulin isotypes are not so marked (4.7X for IgG3, 2.7X for IgA, 1.6X for IgG1 and IgG2b, and even 0.6X for IgG2a), and the occurrence of other natural antibody specificities shows more individual variability.

An indirect asymmetrical sandwich ELISA using anti-allotype antibodies for the specific and quantitative measurement of mouse IgG2a of Igh-1b allotype

We recently described an indirect double sandwich ELISA (Klein-Schneegans et al., J. Immunol. Methods (1989) 119, 117) which permits the specific and quantitative measurement of mouse IgM, IgA and IgG subclasses with one major exception: IgG2a of the b allotype (Igh-1b in mouse strains such as C57BL/6) could not be reliably quantitated even by a very specific and sensitive asymmetrical sandwich ELISA (using two different anti-IgG2a isotype antibodies for capture and for detection). We now describe a similar method based on the use of two different anti-IgG2a allotype antibodies for the capture and detection of IgG2a in the serum of Igh-1b mouse strains.

Serum concentrations of IgM, IgG1, IgG2b, IgG3 and IgA in C57BL/6 mice and their congenics at the lpr (lymphoproliferation) locus

The serum concentrations of IgM, IgG1, IgG2b, IgG3 and IgA were determined in mice of C57BL/6 background, from weaning to one year of age, by quantitative isotype-specific, indirect double sandwich enzyme-linked immunosorbent assays (ELISAs). Only limited data could be obtained for the IgG2a isotype in the present study. The mean serum Ig levels found for 6-month-old B6 mice were 0.22 mg/ml for IgM, 0.28 mg/ml for IgG1, 1.22 mg/ml for IgG2b, 0.18 mg/ml for IgG3, 0.075 mg/ml for IgA and about 0.7 mg/ml for IgG2a. In comparison with mice of the wild strain, C57BL/6 mice homozygous at the lpr (lymphoproliferation) locus showed very high increases in serum Ig levels when older than 20 weeks. With 6-month-old B6 lpr mice, increases in concentration were found for all tested heavy chain isotypes: 6 to 6.5-fold for IgA (0.45 mg/ml) and IgG1 (1.82 mg/ml), 9-fold for IgG3 (1.6 mg/ml), 11 to 11.5-fold for IgM (2.44 mg/ml) and IgG2b (13.8 mg/ml) and about 8-fold for IgG2a (5.5 mg/ml). Therefore homozygosity at the lpr locus provides the conditions for generalized, poly-isotypic rather than isotype-specific restricted Ig enhancement. This observation may be more compatible with hyperinducibility of all B-cell subclasses than with excessive production of T-cell-derived factors whose activity would be expected to be restricted to some T-dependent subclasses, and at least to affect IgM-committed B cells to a lesser extent than other B-cell classes.