Number Of IgG Research Articles

Effects of the oral administration of the exopolysaccharide produced by Lactobacillus kefiranofaciens on the gut mucosal immunity

The probiotic effects ascribed to lactic acid bacteria (LAB) and their fermented dairy products arise not only from whole microorganisms and cell wall components but also from peptides and extracellular polysaccharides (exopolysaccharides) produced during the fermentation of milk. There is a lack of knowledge concerning the immune mechanisms induced by exopolysaccharides produced by lactic acid bacteria, which would allow a better understanding of the functional effects described to them. The aim of this study was to investigate the in vivo immunomodulating capacity of the exopolysaccharide produced by Lactobacillus kefiranofaciens by analyzing the profile of cytokines and immunoglobulins induced at the intestinal mucosa level, in the intestinal fluid and blood serum. BALB/c mice received the exopolysaccharide produced by L. kefiranofaciens for 2, 5 or 7 consecutive days. At the end of each period of administration, control and treated mice were sacrificed and the numbers of IgA+ and IgG+ cells were determined on histological slices of the small and large intestine by immunofluorescence. Cytokines (IL-4, IL-6, IL-10, IL-12, IFNγ and TNFα) were also determined in the gut lamina propria as well as in the intestinal fluid and blood serum. There was an increase of IgA+ cells in the small and large intestine lamina propria, without change in the number of IgG+ cells in the small intestine. This study reports the effects of the oral administration of the exopolysaccharide produced by L. kefiranofaciens in the number of IgA+ cells in the small and large intestine, comparing simultaneously the production of cytokines by cells of the lamina propria and in the intestinal fluid and blood serum. The increase in the number of IgA+ cells was not simultaneously accompanied by an enhance of the number of IL-4+ cells in the small intestine. This finding would be in accordance with the fact that, in general, polysaccharide antigens elicit a T-independent immune response. For IL-10+, IL-6+ and IL-12+ cells, the values found were slightly increased compared to control values, while IFNγ+ and TNFα+ cells did not change compared to control values. The effects observed on immunoglobulins and in all the cytokines assayed in the large intestine after kefiran administration were of greater magnitude than the ones observed in the small intestine lamina propria, which may be due to the saccharolytic action of the colonic microflora. In the intestinal fluid, only IL-4 and IL-12 increased compared to control values. In blood serum, all the cytokines assayed followed a pattern of production quite similar to the one found for them in the small intestine lamina propria. We observed that the exopolysaccharide induced a gut mucosal response and it was able to up and down regulate it for protective immunity, maintaining intestinal homeostasis, enhancing the IgA production at both the small and large intestine level and influencing the systemic immunity through the cytokines released to the circulating blood.

Modulation of immune responses and suppression of experimental autoimmune myasthenia gravis by surgical denervation of the spleen

Critical interactions between the nervous system and the immune system during experimental autoimmune myasthenia gravis (EAMG) were examined in an animal model for human MG after immunization of adult female Lewis rats with Torpedo acetylcholine receptor (AChR) and complete Freund's adjuvant. Immunized rats depicted marked clinical severity of the disease. Using enzyme-linked immunospot (ELISPOT) assay and in situ hybridization techniques, immune responses in these animals were examined and showed elevated numbers of anti-AChR IgG secreting B cells and AChR reactive interferon (IFN)-gamma-secreting cells, enhanced mRNA expression of the proinflammatory cytokines IFN-gamma and tumour necrosis factor (TNF)-alpha as Th1 subset and the anti-inflammatory cytokines interleukin (IL)-4 and IL-10 as a Th2 subset, and transforming growth factor (TGF)-beta as a Th3 cytokine. Corticosterone and prostaglandin E(2) (PGE(2)) levels were measured by radioimmunoassay and illustrated increased production after immunization. Surgical denervation of the spleen reduced significantly the clinical severity of the disease, suppressed the numbers of IgG and IFN-gamma-secreting cells, down-regulated the mRNA expression for cytokines and reduced corticosterone and PGE(2) production. As controls, sham-operated rats were used and showed results as the EAMG non-denervated control rats. The data present herein, and for the first time, substantial effects of the nervous system on immune responses that may influence the outcome of EAMG. These effects were not dependent on cytokine inhibitory mediators such as prostaglandins or stress hormones. IL-10 and TGF-beta, the two potent immunosuppressive cytokines, were also suppressed, indicating a general suppression by splenic denervation. More investigations are initiated at our laboratories to understand the evident neural control over the immune system during challenges leading to the break of tolerance and development of autoimmunity, which may assist in innovative therapeutic approaches.

Morphological Findings in Lymphatic Tissues of Sheep Following Oral Application of the Immunosuppressive Mycotoxin Mycophenolic Acid

Mycophenolic acid (MPA) is applied in immunosuppressive therapy after organ transplantation. As a common contaminant in silage, this substance is also frequently fed to sheep unintentionally. In this study, the effect of MPA on the immune system of sheep was examined. Four groups of 9 sheep each were fed 0, 0.5, 1.2, or 5 mg of MPA per kg body weight per day for 6 weeks. Then, the animals were slaughtered and various organs were examined macroscopically, histologically, and immunohistochemically. No effect of MPA on general health was detected. With increasing dose of MPA, germinal centres in the retropharyngeal lymph nodes displayed an activated morphology with numerous centroblasts. In the highest dose group, the sheep showed shrinkage of thymic lobules. The numbers of IgG or IgM positive plasma cells decreased in the ileum with increasing MPA-doses. These results suggest, that MPA in a high concentration may affect the morphology of immune organs of sheep.

Spontaneous immunoglobulin-producing capacity of cultures from lupus patients and normal donors following depletion of cells expressing CD19 or CD38.

Cells spontaneously secreting IgG or IgM (ISC) are present at a high level in the blood of patients with systemic lupus erythematosus (SLE). By use of magnetic-bead techniques, mononuclear cells from such patients and healthy donors were fractionated according to expression of CD19 or CD38 and the cell fractions were then cultured in the absence of added mitogen/antigen for 5/6 days. Supernatant IgG and IgM were determined and, in addition, in the CD38 experiments ISC were enumerated both before and after culture. Much of the immunoglobulin-producing capacity of unfractionated cells (UFC) from both donor groups was recovered in the CD19- fraction, and no immunoglobulin was produced by CD19+ cells suggesting, unexpectedly, that ISC were not expressing CD19. By contrast, CD38 fractionation resulted in nearly all ISC passing to the CD38+ fraction which produced levels of immunoglobulin approaching 50% that of UFC. On culture of CD38- cells there was a build up in the number of IgG and IgM ISC, this being particularly striking in the controls with numbers well in excess of those in UFC. Not all these new ISC became CD38+, but the maturation process was more efficient in the SLE patients. The possibility is discussed that the spontaneous response in the CD38- populations is due to removal of CD38+ natural killer (NK) cells. Removal of ISC that are present preculture is a helpful initial step in studying ISC generation in the disease.

B-cell activation in the mesenteric lymph nodes of resistant BALB/c mice infected with the murine nematode parasite Trichuris muris.

Immune responses in resistant BALB/c mice infected with the murine nematode parasite Trichuris muris were examined. Following the establishment of infection, worm burdens of T. muris were expelled by BALB/c mice by day 21 postinfection (p.i.). Specific immunoglobulin G1 (IgG1) antibodies to T. muris excretory/secretory (E/S) antigens were detected in sera from infected mice, though specific IgG2a antibodies were not observed during infection. Ig-producing cells increased in the mesenteric lymph nodes (MLN) of infected mice on days 7, 14, and 21 p.i., with the greatest increase in numbers of IgG- and IgA-producing cells occurring on day 14. Marked increases in the relative percentages of B220+ and surface Ig+ (sIg+) cells were observed in the MLN of infected mice on days 14 and 21 p.i. Furthermore, cellular expansion of the MLN in infected mice resulted in an increase in the absolute numbers of B220+ and sIg+ cells. The levels of interleukin 2 (IL-2), IL-4, and interferon-gamma (IFN-gamma) detected in the supernatants from concanavalin A-stimulated MLN cells of infected mice were higher than those found in normal mice. Consequently, the expulsion of T. muris in resistant BALB/c mice was concomitant with cytokine production and B-cell activation in the MLN of infected mice. These results suggest the involvement of B-cell responses in protective immunity to T. muris infection.

Effects of ageing and oestrogen on the localization of immunoglobulin-containing cells in the chicken ovary.

Immunoglobulins in the chicken ovary are important for transfer of immunity to chicks through the egg and for protection of the ovary from infection. The aim of this study was to examine the effects of ageing and oestrogen on the population of Ig-containing cells in the chicken ovary. The ovarian tissue of immature, young laying and old laying hens and that of immature birds treated with diethylstilboestrol (DES), progesterone or sesame oil (vehicle) was processed for paraffin wax sections. The sections were stained for IgG, IgM and IgA by an indirect immunostaining method and the population of cells positive for each Ig was analysed under a light microscope. The number of cells positive for IgG, IgM and IgA was significantly greater in the ovarian stromal tissue of young laying hens than in immature or old laying hens (P < 0.01). The number of IgG- and IgM-positive cells in the thecal layer of primary follicles of young laying hens was significantly greater than that in immature and old laying hens (P < 0.01) and there were significantly more (P < 0.05) IgA-positive cells in young laying hens than in immature birds. The number of IgG-, IgM- and IgA-positive cells was significantly (P < 0.01) greater in both the stromal tissue and the thecal layer of DES-treated birds than in the vehicle-treated birds. Progesterone had no significant effect (P < 0.05) on the population of Ig-positive cells. These results indicate that the number of Ig-positive cells increases as chickens mature and decreases with ageing, and that oestrogen may be involved in this process.

Effects of sexual maturation and gonadal steroids on the localization of IgG-, IgM- and IgA-positive cells in the chicken oviduct.

The effects of sexual maturation and gonadal steroids on the localization of immunoglobulin-positive cells in chicken oviducts were studied. Oviductal tissues were collected from laying hens and chicks treated with stilboestrol (DES, an analogue of oestrogen) or progesterone. Paraffin wax sections of the tissues were immunostained for IgG, IgM and IgA, and the frequency of cells staining positive was examined using an image analysis system. Some of the cells in the mucosal epithelium and plasma cell-like cells in the stroma of the oviduct stained positive for IgG, IgM or IgA. In the mucosal epithelium of laying hens, there was a significantly greater number of IgG-positive (IgG+) cells in the shell gland than in the infundibulum, magnum and isthmus, more IgM+ cells in the magnum than in the infundibulum, and more IgA+ cells in the magnum than in the other segments of the oviduct with the exception of the vagina. The frequency of IgG+ and IgM+ cells in the mucosal epithelium of all oviductal segments and IgA+ cells in the magnum, isthmus and vagina was significantly higher in laying hens than in immature birds. In the subepithelial stroma of laying hens, there was a significantly greater population of IgG+ cells in the infundibulum and vagina than in the magnum and isthmus, more IgM+ cells in the infundibulum than in the magnum, and more IgA+ cells in the uterovaginal junction and vagina than in the magnum and isthmus. The frequency of IgG+, IgM+ and IgA+ cells in the subepithelium of infundibulum, uterovaginal junction and vagina was significantly greater in laying hens than in immature birds. The number of IgM+ cells in all oviductal segments and of IgA+ cells in the magnum of the mucosal epithelium of the chicks treated with DES increased significantly compared with those of control chicks. In addition, the number of IgG+ cells in the shell gland and vagina and of IgM+ cells in the vagina of the stroma of DES-treated birds were increased. Treatment of immature birds with progesterone had no effect on the localization of Ig+ cells in the oviduct except for a decrease in the number of IgM+ cells in the shell gland. These results suggest that the local immunity in the oviduct develops during sexual maturation, possibly under the control of oestrogen.

Early expansion of secondary B cells after primary immunization with antigen complexed with IgE.

IgE antibodies have potent immunoregulatory effects in vivo, and mice immunized with IgE-antigen (IgE/ Ag) complexes exhibit a several hundred-fold higher humoral Ag-specific response than mice immunized with non-complexed Ag. In vitro studies indicate that this is a result of efficient endocytosis of the IgE/Ag complexes via the low-affinity receptor for IgE (CD23) on B cells, leading to efficient antigen presentation to T cells. Previous studies of IgE-induced Ab responses in vivo have only measured serum responses. The authors have now studied the up-regulated response as the number of IgG-, IgA-, IgE- and IgM-secreting single B cells in spleen, lymph nodes and bone marrow of mice immunized with IgE-anti-TNF+BSA-TNP (2,4,6-trinitrophenylated bovine serum albumin). IgE and Ag induced a greater than 500-fold increase of specific IgG-secreting spleen cells with the peak of the response 6 days after primary immunization. The response of other Ab isotypes and the response in other lymphoid organs was marginal. The rapid increase in the number of IgG-secreting cells in the spleen suggests that IgE/Ag complexes induce a secondary type of antibody response without requirement for conventional priming.

Selective thymocyte depletion and immunoglobulin coating in the thymus of cats infected with feline immunodeficiency virus.

Thymus alterations associated with feline immunodeficiency virus (FIV), an AIDS animal model, were investigated by measuring phenotypic composition of thymocytes, structure of thymic epithelial cells, and transcription of viral RNA in the thymus of FIV-infected juvenile kittens. These kittens either acquired infection by natural vertical transmission or were experimentally inoculated with the virus at defined times of fetal or neonatal life. Thymocytes from FIV-infected cats were analyzed by flow cytometry for the differential expression of CD4, CD8, Pan T, and IgG and subpopulation percentages were compared to values from uninfected littermates. Infected cats demonstrated a decrease in the percentage of CD4+/CD8+ lymphocytes and a concurrent increase in the percentage of CD4-/CD8-, CD4-/CD8+, and IgG+ lymphocytes. Absolute numbers of IgG+ cells were increased with FIV infection. On bivariate distribution scatter plots generated by two-color flow cytometry, this population of IgG+ cells overlapped extensively with cells having low to minimally detectable levels of a pan-T lymphocyte marker, suggesting that thymocytes were coated with IgG. Immunohistochemical detection of feline IgG defined a broad zone of IgG+ cells within the residual cortex but outside lymphoid follicles. However, cells stained with B5, a feline B lymphocyte marker, localized almost exclusively to the centers of lymphoid follicles that were also characterized by a lack of internal cytokeratin staining. FIV RNA transcripts detected by in situ hybridization using an FIVgag RNA probe were evenly distributed throughout the thymic parenchyma except in lymphoid follicles, which were generally devoid of FIV expression. Despite these phenotypic and structural changes, thymus weight, expressed as a percentage of body weight, was not significantly reduced. From these data, we conclude that the clinically asymptomatic stage of FIV infection is associated with two distinct B cell-related phenomena within the thymus-the formation of germinal centers and the coating of thymocytes with IgG. These changes accompany a distorted thymocyte distribution characterized by a reduced percentage of CD4+/CD8+ lymphocytes and a relative increase in CD4-/CD8+ and CD4-/CD8- lymphocytes. Together, these findings suggest that degenerative thymic changes after lentivirus infection may involve humoral immune mechanisms.

Effect of physical defenses of the respiratory tract on the development of pneumonia in pigs inoculated endobronchially with Actinobacillus pleuropneumoniae.

Seven pigs inoculated endobronchially with Actinobacillus pleuropneumoniae (App) serotype 1 developed acute and subacute necrotizing pleuropneumonia. When treated with high doses of atropine (0.25 mg per kg) and/or xylocaine spray using a bronchoscope, which suppressed mucus secretion and ciliary activity, the pigs showed severe pleuropneumonia and 2 treated pigs died within 36 hr after inoculating 320 colony forming units (CFU)/2ml of App serotype 1. Histopathologically, their lungs had alveolar and interlobular edema and intravascular fibrinous thrombosis. In the surviving pigs, the lymph nodes had App antigens in the germinal centers corresponding closely with activated follicular dendritic cells and increased in the number of IgG- and IgM-containing cells. The bacterial antigens were also observed as small sized granules in the cytoplasm of bronchoalveolar macrophages. These findings suggest that the attachment of App to the mucosal surface may be crucial in the development of pneumonic lesions.

In vivo effect of chronic administration of vasoactive intestinal peptide on gut-associated lymphoid tissues in rats.

The in vivo effects of chronic administration of vasoactive intestinal peptides (VIP) on the lymphoid cell traffic and the population and function of cells in intestinal lymph and gut-associated lymphoid tissues were examined in rats. VIP was continuously infused from the superior mesenteric artery in rats at a dose of 10 ng/min/kg body weight for 96 h. Lymphocyte transport through intestinal lymph was significantly reduced by VIP without any changes in lymph flow. When lymphocyte subpopulation was examined in intestinal lymph, T cell subsets were decreased with a dominant reduction in the population of helper T cells. T cell subsets were also decreased in mesenteric lymph nodes, but in this case suppressor/cytotoxic T cell subsets were mainly reduced. Despite of the decrease in lymphocyte transport through intestinal lymph and changes of lymphocyte subpopulation, proliferative response of lymphocytes from intestinal lymph and mesenteric lymph nodes to phytohemagglutinin did not show any significant alteration after administration of VIP. By histochemical study on the lamina propria of the small intestine, the population of pan T cells, especially helper T cells, was demonstrated to be significantly decreased after VIP treatment. There was also a marked decrease in the number of immunoglobulin (Ig) A-containing cells in the lamina propria of the small intestine in VIP-treated rats, while no significant changes were seen in the number of IgG and IgM-containing cells. Our present results showed the possibility that a long-term alteration of serum VIP levels could affect the dynamics of immune effector cells and IgA production in gut-associated lymphoid tissues.

Antibody-containing cells in the abomasal mucosa of sheep with genetic resistance to Haemonchus contortus

The frequency distribution of parasite-specific antibody-containing cells ( ACC) and total immunoglobulin-containing cells ( ICC) in the abomasal mucosa was examined in genetically resistant and random-bred sheep, following infection with Haemonchus contortus, to determine whether the two genotypes differed in the development of a local immune response. Immunofluorescence staining was used to detect ACC and ICC of IgA, IgG 1, IgG 2 and IgM classes. No ACC were found in the abomasum of any of the sheep before infection. ACC were first detected in the abomasal mucosa of both the resistant and susceptible sheep seven days after infection, reached a peak level on day 21 and then declined. At all observation times, the majority of ACC in both genotypes were of the IgA isotype, followed by IgG 1 and IgM. The IgG 2-ACC response was negligible compared with the IgA and IgG 1 response. The comparison of genotypes showed that the resistant sheep had significantly more IgA- ACC on days 14, 21, 28 and 35, and significantly more IgG 1-ACC than random-bred sheep on days 14, 21 and 28. The numbers of IgG 2- and IgM- ACC did not differ between the genotypes. The abomasal mucosa of the resistant sheep was also found to have significantly more ICC than the mucosa of random-bred sheep; IgA- ICC predominated at all the observation times followed by IgG, and IgM. These results suggest that IgA and IgG 1 antibodies, produced locally in response to infection, may play a role in mediating genetic resistance to haemonchosis in sheep.

Mechanisms of Rabies Virus Neutralization

The number of immunoglobulins necessary to neutralize rabies virus (CVS strain) was estimated using IgG and IgM monoclonal antibodies (MAb) specific to the three antigenic sites of the glycoprotein. It was estimated that below 130 IgG or 30 IgM bound per virions, infectivity was totally preserved. Neutralization occurred for an average of 1 or 2 IgG for 3 spikes and 1 IgM for 9 to 10 spikes on the virus surface. Saturation was obtained for 1 to 3 IgG per spike, depending on the antibody, and 1 IgM for 4 to 5 spikes. This result was confirmed by electron microscopy. Neutralization-resisting mutants which continued to fix the selecting MAb in ELISA were also investigated. In two cases, the lack of neutralization was due to the fact that the maximum number of immunoglobulins bound per virion was below the neutralizing dose. In one case, however, the mutant was able to fix the same number of IgG as the parental strain and was not neutralized, even at saturation. The capacity of the antibodies to reduce the attachment of the virus onto BSR cells was also examined. Every intermediate between no inhibition of the attachment and inhibition by a factor of 20 was found; even in this last case, inhibition of attachment was insufficient to explain the extent of neutralization. No correlation was found between the antigenic site recognized by the antibody and the level of inhibition. IgM inhibited attachment more than IgG and one IgG2b antibody did not inhibit attachment at all. The fusion of virions saturated with this antibody with artificial liposomes was totally inhibited, either specifically or because virus-antibody complexes did not attached to the liposomes.

Immunopathology in Aujeszky's disease virus-infected pigs exposed to fluctuating temperatures

Pigs exposed to fluctuating temperatures (high, 30±2°C; low, 4±1°C) were intranasally inoculated with Aujeszky's disease virus (ADV). ADV-infected pigs, exposed to the fluctuating temperatures, showed severe clinical signs and ADV in the nasal secretions persisted longer than in the ADV-infected control pigs kept at the normal temperature (20±2°C). High concentrations of ADV were isolated from nasal secretions on the 1st day after inoculation of the virus. Pathologically, all ADV-infected pigs had non-suppurative encephalitis and trigeminal ganglionitis. The lesions were more widely distributed in pigs exposed to fluctuating temperatures than in infected control pigs. Two infected pigs given the stress had severe malacic foci in the frontal lobe and four of them had prominent interstitial pneumonia. In the pigs exposed to fluctuating temperatures, a significant number of immunoglobulin-containing cells, especially IgM-containing cells, did not respond to ADV infection. A significant ( P<0·01) difference in the number of IgG- and IgM-containing cells was observed between the ADV-infected pigs exposed to the fluctuating temperature and ADV-infected control pigs, respectively. These results demonstrated that the stress of fluctuating temperatures enhanced the susceptibility to ADV infection.

温式自己免疫性溶血性貧血患者における赤血球結合ＩｇＧ量の測定とその意義

A sensitive immunoradiometric assay (IRMA) was used to quantitate the amount of red blood cell-associated IgG (RBC-IgG). The mean RBC-IgG of 91 healthy volunteers was 33±13 (SD) molecules per one RBC. The correlation between the agglutination strength in antiglobulin test and the number of IgG were very satisfactry. We also tested the amount of RBC-IgG of 27 patients with immune hemolytic anemia of warm type (AIHA). (AIHA, n=17; RBCs with positive antiglobulin test, n=2; RBCs with negative antiglobulin test, n=8; eluates from patients' RBCs). The mean RBC-IgG of 17 patients with antiglobulin test positive AIHA was 998±930 (SD) molecules per one RBC. It was ranged from 257 to 3000 molecules per one RBC. Two patients with antiglobulin test negative AIHA (7.4%, 2/27) had 138 and 172 IgG molecules per one RBC, respectively. The indirect antiglobulin tests of RBCs sensitized with 8 eluates showed positive. The RBC-IgG of sensitized RBCs was higher than that of RBCs from healthy volunteers. Using this assay, quantitative studies of RBC-IgG was extremely useful for the detection of small amount of IgG on RBC in case of the antiglobulin test negative AIHA.

Phenotyping of immunocompetent cells in normal labial and palatal salivary glands and in non‐autoimmune sialadenitis

Different types of inflammatory cells in healthy major and minor salivary glands (SG), including those in labial and palatal non-autoimmune sialadenitis, were quantified immunohistochemically. Plasma cells, mainly IgA type predominated in all SG types, with the smallest number seen in the palatal glands. The numbers of common leukocyte antigen (CLA) reactive lymphocytes were greater in major SGs than in minor ones and were predominantly UCHL1 positive T cell type. Macrophages and neutrophils were absent in palatal glands, rarely present in labial ones and usually present in major SGs. Increases in the number of IgG and IgM plasma cells and lymphocytes (CLA+) which include both UCHL1+ T and L26+ B cell types, were found in non-autoimmune labial and palatal sialadenitis. There was no significant correlation between the number of the inflammatory cells and the degree of glandular atrophy in both labial and palatal non-autoimmune sialadenitis. Increase in their number represents a protective response of these glands in contrast to the inflammatory cells in major autoimmune sialadenitis playing there a pathogenetic role.

Analysis of human IgG and IgA subclass antibody-secreting cells from localized chronic inflammatory tissue.

The chronic inflammatory diseases in humans have been intensively investigated, however the immune mechanisms underlying diseases such as rheumatoid arthritis (RA), inflammatory bowel disease, and periodontal disease (PD) remain elusive. In this study, we have analyzed the distribution of IgM, IgG, and IgA secreting cells with emphasis on the IgG and IgA subclasses among mononuclear cell populations isolated from gingiva at different stages of PD. Surgically removed tissues were treated with Dispase to gently dissociate cells and the Ficoll-Hypaque gradient centrifugation was used to enrich for viable mononuclear cells rich in lymphocytes, macrophages, and plasma cells. The total numbers of plasma cells increased with the severity of disease. Immunofluorescence analysis showed that most Ig-containing cells were of the IgG isotype; however, significant numbers of IgA-positive cells but few IgM-positive cells were seen. This isolation procedure allowed analysis, at the single cell level, of the distribution of IgG and IgA subclasses of antibody-secreting cells with monoclonal antibodies to human IgG and IgA subclasses. For this, we selected four monoclonal anti-IgG subclass (anti-gamma 1, -gamma 2, -gamma 3, and -gamma 4) antibodies with no subclass cross reactivity for use in the enzyme-linked immunospot assay. Analysis of slight, moderate, and advanced stages of PD showed a progressive increase in spotforming cells (SFC) numbers, and the major isotype of SFC was IgG followed by IgA. The major IgG subclass SFC seen was IgG1 followed by IgG2 whereas similar numbers of IgG3 and IgG4 SFC were observed, a pattern also seen with cells from synovium of RA patients and in mitogen-triggered spleen and PBMC. In terms of the IgA subclass distribution, IgA1 predominated in moderate stages, whereas a selective increase in IgA2 SFC were seen in the more advanced stage of PD. These results show that significant numbers of viable plasma cells/Ig-secreting cells can be isolated from inflamed gingival tissues. Further, careful analysis has shown that IgG subclass responses in gingiva are similar to those found in synovia of RA subjects, and in stimulated PBMC and spleen. However, it should be noted that the number of IgG4- and IgA2-secreting cells increased in the advanced stage of PD.

Quantification of IgG-containing plasma cells as an adjunct to histopathology in distinguishing acute self-limited colitis from active idiopathic inflammatory bowel disease.

ASLC is clinically and endoscopically similar to active idiopathic IBD, especially ulcerative colitis. While several histopathologic criteria have been described which are useful in distinguishing these conditions, the diagnosis can still be difficult. In this study, we review the use of immunofluorescence on formalin-fixed paraffin-embedded biopsies from patients with ASLC. While tissues from active IBD have a striking increase in the number of IgG- and a lesser increase in the IgA- and IgM-containing plasma cells in the lamina propria, tissues from ASLC have normal numbers of IgG-containing cells with only a slight increase in IgA- and IgM-containing cells. The use of immunofluorescence on these tissues can provide quantifiable information which may be a helpful diagnostic adjunct in distinguishing these alternatives if histopathologic evaluation is equivocal.

Spontaneous immunoglobulin synthesis by peripheral mononuclear cells in active rheumatoid arthritis.

Spontaneous production of immunoglobulins (Igs) by peripheral blood mononuclear cells (PBMC) in vitro was investigated to assess B cell activity in a group of 24 patients with rheumatoid arthritis (RA) with or without active joint disease and with or without rheumatoid vasculitis (RV) at the time of study. PBMC of patients with active arthritis (Ritchie index above 16) produced significantly more IgG and IgA than those of patients with inactive joint disease or those of 12 healthy controls. Enhanced production of IgG was found mainly among RA patients with concomitant RV, whereas markedly enhanced IgA production could also be found in patients without symptoms of RV. IgM production was only enhanced in two patients who had both active arthritis and RV. High production of IgG and IgA was probably due to increased numbers of Ig-secreting cells among freshly isolated PBMC, since the concentrations of Ig produced in vitro rose steadily, starting on day 0 and persisting throughout the entire culture period. Moreover, IgG and IgA concentrations measured after 7 days of culture showed significant correlations with the numbers of IgG- and IgA-containing plasma cells in PBMC on day 0. Comparison of the spontaneous production of Igs by PBMC with the levels of circulating immune complexes (CIC), showed that CIC levels were also significantly higher in active arthritis and in RV, but that there was no correlation between the CIC levels in individual patients and Ig production by their PBMC in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoglobulin isotypes and antibody specificity repertoire of "spontaneously" occurring ("background") immunoglobulin-secreting cells in germfree mice fed chemically defined ultrafiltered "antigen-free" diet.

“Spontaneously” occurring (“background”) immunoglobulin (Ig)-secreting cells have been observed in all lymphoid organs of non-immunized mice. Their frequency was found to depend on the genetic background, age and antigenic load of the mice studied (Benner et al., 1982). Even in germfree (GF) mice “background” antibody-secreting cells occur, as has been assessed in antigen-specific plaque assays with sheep red blood cells (SRBC) as targets (Nordin, 1968; Hof et al., 1975; Benner et al., 1981b). The total number of IgM-secreting cells as detected with the protein A plaque assay is virtually normal in GF mice, but the numbers of IgG- and IgA-secreting cells are severely decreased as compared to conventionally raised mice (Benner et al., 1981b). The latter indicates that exogenous antigenic and mitogenic stimulation is a major driving force for the “background” IgG- and IgA-synthesis. For IgM this is unclear, because of the crucial question whether the GF animals used in those experiments can really be regarded as devoid of exogenous stimuli. It has been shown that a substantial mitogenic and/or antigenic activity can be exerted by food substances or dead bacteria in the diet (Wostman et al., 1971). With the successful breeding of GF mice fed an ultrafiltered solution of chemically defined (CD) low molecular weight nutrients, these exogenous stimuli are reduced to the presently achievable minimum (Pleasants et al., 1981; Wostmann et al., 1982; Pleasants, 1984).