Double immunocytochemistry of vasoactive intestinal peptide and cGnRH-I in male quail: photoperiodic effects

Reproduction in Japanese quail is primarily regulated by photoperiod. Vasoactive intestinal peptide (VIP) has been suggested as a transducer of environmental information, especially photoperiodic cues, to the hypothalamo-pituitary-gonadal axis. To investigate the possible interaction of VIP and the reproductive (gonadotropin-releasing hormone, GnRH) system, double-immunocytochemical staining for VIP and cGnRH-I was conducted in sexually mature male quail held under a long-day photoperiod (16L:8D; LD) and in sexually quiescent males held under a short-day photoperiod (8L:16D; SD). VIP-immunoreactive (ir) cells were found primarily in three locations: lateral septal organ (LSO) in nucleus accumbens (Ac), ventral hypothalamus, and infundibular area. VIP-ir cells in LSO displayed characteristics typical of cerebrospinal fluid (CSF)-contacting cells, and co-existed with cGnRH-I-ir cells and beaded fibers. In contrast, VIP-ir cells in the infundibular area did not co-exist with cGnRH-I-ir structures. The number of visible VIP-ir cells in the infundibular area of SD males was significantly lower than that of LD males, while the number of visible VIP-ir cells in Ac/LSO was not altered by photoperiod. A cluster of cGnRH-I-ir cells in the caudalmost septal area was heavily innervated by VIP-ir fibers, which appeared to contact cGnRH-I-ir cells directly at this location. Both VIP- and cGnRH-I-ir fibers heavily innervated the external layer of the median eminence (ME). These data suggest that Ac/LSO, the caudalmost septal area, and ME are possible sites of interaction between the VIP and the GnRH systems.

Cutting edge: the mucosal adjuvant cholera toxin redirects vaccine proteins into olfactory tissues

We tested the notion that the mucosal adjuvant cholera toxin (CT) could target, in addition to nasal-associated lymphoreticular tissues, the olfactory nerves/epithelium (ON/E) and olfactory bulbs (OBs) when given intranasally. Radiolabeled CT ((125)I-CT) or CT-B subunit ((125)I-CT-B), when given intranasally to mice, entered the ON/E and OB and persisted for 6 days; however, neither molecule was present in nasal-associated lymphoreticular tissues beyond 24 h. This uptake into olfactory regions was monosialoganglioside (GM1) dependent. Intranasal vaccination with (125)I-tetanus toxoid together with unlabeled CT as adjuvant resulted in uptake into the ON/E but not the OB, whereas (125)I-tetanus toxoid alone did not penetrate into the CNS. We conclude that GM1-binding molecules like CT target the ON/E and are retrograde transported to the OB and may promote uptake of vaccine proteins into olfactory neurons. This raises concerns about the role of GM1-binding molecules that target neuronal tissues in mucosal immunity.

Administration of IgG Fc fragments prevents glomerular injury in experimental immune complex nephritis

Most human nephritis is due to glomerular deposition and/or formation of immune complexes (IC). In cultured mesangial cells, Fc receptor stimulation induces proliferation, matrix synthesis, and release of several mediators implicated in the initiation and progression of glomerular injury. Since Ig Fc fragments in vitro modified these phenomena, we studied the effects of systemic administration of IgG Fc fragments on the evolution of experimental IC nephritis. Fc fragment injection (1 mg/day i.p.) to rats with ongoing nephritis (proteinuria 20-50 mg/24 h vs 9 +/- 0.2 mg/24 h in controls) markedly ameliorates proteinuria, renal function, and morphological renal lesions. This was accompanied by a reduction in the renal synthesis of chemokines (monocyte chemoattractant protein-1, IFN-inducible protein-10, and cytokine-induced neutrophil chemoattractant-1), matrix proteins, and growth factors (platelet-derived growth factor, and TGF-beta), and in the activity of transcription factors. The treatment did not affect the glomerular deposition of IgG IC and complement C1q. In contrast, a decrease in the renal expression and production of C3 was observed without changes in serum complement levels. In vitro, very low complement consumption and no C3b covalent interaction were observed with Fc fragments, confirming that they did not modify systemic complement activity. These results indicate that the administration of Fc fragments prevents the development of glomerular damage in an aggressive model of proliferative glomerulonephritis through mechanisms involving a reduced local generation of complement, chemokines and growth factors. Modulation of IC-mesangial cell interaction by Fc fragment administration could represent a new approach to the treatment of severe immune nephritis.

Cross-presentation of tumour antigens: evaluation of threshold, duration, distribution and regulation

The development of technology to measure antigen presentation in the secondary lymphoid system has provided the opportunity of analysing components of the host antitumour immune response that have, until now, been unavailable for study. In particular, this technology has enabled us to evaluate threshold levels of tumour antigen required for cross-presentation in draining lymph nodes, the duration of this antigen presentation and processes that regulate tumour antigen presentation. Thus, we have been able to dissect out the relationship between antigen presentation and the resultant development of effector function in class I-restricted T cells, as well as the role of regulatory CD4 cells. We have also used this technology to evaluate the effects of antitumour therapy on local antigen cross-presentation.

Distribution fate and mechanism of immune modulation following mucosal delivery of plasmid DNA encoding IL-10

DNA vaccination has been widely studied in several models of vaccination and in the treatment of inflammatory diseases, even though the mechanism involved is still unclear. This report demonstrates that mucosal administration of plasmid DNA leads to rapid and widespread distribution around the body. Dissemination likely occurred via the bloodstream because plasmid DNA was present in blood plasma. The plasmid DNA was also detectable in several tissues including draining lymph nodes, spleen, liver, bone marrow, and even the dermis of ear pinnae. Except for the site of administration, plasmid DNA was no longer detectable in tissues after 3 wk postadministration. RNA and protein expression was also found in the tissues and bloodstream. Animals previously primed by HSV infection and subsequently given IL-10 DNA via the nasal mucosa, showed diminished Ag-induced delayed type hypersensitivity reactions for up to 5 wk posttreatment. The mechanism of modulation involved diminished the Ag-specific proliferation and production of Th1 cytokines. The Ag-specific silencing effects persisted beyond the duration of detectable plasmid encoded protein and was maintained upon adoptive transfer of T cells into a plasmid-free environment. The silenced T cells were not a source of IL-10, and their anergic state was reversible by exposure to Ag in the presence of exogenous IL-2.

Enhanced antigen transport across rat tracheal epithelium induced by sensitization and mast cell activation

Ag challenge to the apical surface of tracheal epithelium results in a rapid ion secretory response due to the activation of mast cells. The aim of this study was to examine the impact of sensitization and specific Ag challenge on the timing, route, and quantity of Ag transported across tracheal epithelium. After sensitization of rats to a model protein, HRP, tracheal tissues were excised and mounted in Ussing chambers. Tracheas from HRP-sensitized rats, but not naive or OVA-sensitized rats, responded to apical HRP challenge with a rise in short-circuit current (beginning at approximately 2 min). Photomicrographs of tissues fixed at 2 min showed that initial transepithelial HRP transport occurred via endosomes and was significantly enhanced in HRP-sensitized rats compared with both control groups. In addition, nonciliated cells, the proportion of which increased after sensitization, contained significantly more HRP than ciliated cells. The hypersensitivity response occurred only in HRP-sensitized and challenged rats and was associated with increased conductance of tracheal epithelium and overall flux of HRP across the tissue. This increased flux of Ag and elevated conductance was not observed in mast cell-deficient Ws/Ws rats. Photomicrographs of tissues fixed 90 min after challenge also showed HRP in the paracellular spaces between adjacent epithelial cells. We conclude that sensitization increases uptake of specific Ag initially via an endosomal transcellular pathway across tracheal epithelium and that, after the hypersensitivity reaction, mast cell-dependent recruitment of the paracellular pathway further augments Ag influx into airway tissue.

Rabbit IgG distribution in skin, spinal cord and DRG following systemic injection in rat

In order to determine the distribution of antibodies such as anti-NGF following systemic injection in neonates, immunocytochemical techniques were used to examine the localization of rabbit IgG in rat skin, DRG, and spinal cord after treatments with normal rabbit serum or purified rabbit IgG. Daily subcutaneous injections beginning on postnatal day 2 or on day 15 were given for three days. On the fourth day the animals were sacrificed and tissues were processed for rabbit IgG-IR. In the dorsal and ventral spinal cord, staining intensities suggest a substantial increase in the blood-brain barrier during the first two weeks after birth. Staining intensity in the epidermis of the glabrous skin from the hindpaw was substantially lower than in the adjacent dermis. In addition, IgG infrequently accumulated intracellularly in intensely stained patches in the epidermis. IgG was also able to reach relatively high intracellular concentrations in a small number of sensory neurons. The IgG staining pattern in the skin was similar when anti-NGF itself was administered to the animals. The results are discussed in the context of the effects of anti-NGF on the development of nociceptive afferents.

A monoclonal antibody, DL10, which recognizes a sugar moiety of MHC class I antigens expressed on NK cells, NK+ T cells, and granulocytes in humans

One mAb, DL10, was established from mice injected with dolphin lymphocytes. In addition to its reactivity against all dolphin lymphocytes, it reacted with some human leukocytes, including NK cells, NK+ T cells, and granulocytes. When its reactivity was examined in various animals, bovine, ovine, and equine leukocytes were DL10+. Murine, rat, and canine leukocytes were DL10-. Although the reactivity of DL10+ was similar to those of CD56 and CD57 antigens in humans, the actual molecules it recognized were different. Thus, all reactivity of DL10 disappeared after treatment of cells with glycopeptidase or after culture of cells with tunicamycin. Furthermore, the immunoprecipitation method revealed that DL10 indirectly recognized the heavy chain (45kD) of MHC class I antigen in humans and animals. Considering data from analysis of the N-terminal amino acid sequence of the DL10 molecule and the HLA typing of reactive cells, DL10 recognized a sugar moiety of some monomorphic MHC antigens and polymorphic MHC antigens such as HLA-B60 and -B61. If the donors are HLA-B60- and -B61 (> 80% in Japan and > 95% in the United States), DL10 would appear to be a very useful agent for the detection of pan-NK+ T cells.

Cellular environments and apoptosis: tissue microenvironments control activated T-cell death

Activated T cells must be removed by apoptosis at the end of an immune response in order to maintain cellular homeostasis. Although recent attention has focused on the role of CD95 (Fas/APO-1) in the elimination of activated T cells, apoptosis can also be induced by cytokine deprivation. Here, Arne Akbar and Mike Salmon describe how both death pathways interact in activated T cells and are profoundly influenced by different tissue microenvironments.

Determination of tissue distribution of an intramuscular plasmid vaccine using PCR and in situ DNA hybridization

The increasing use of nucleic acid-based therapeutics has created a need for new methods of determining tissue distribution and levels. Radiolabel methods may not always be appropriate because nucleic acids are easily degraded. Quantitation using the polymerase chain reaction (PCR) has the advantage that only continuous stretches of DNA will be amplified. In situ hybridization allows detection of specific sequences in histological preparations. We have used quantitative PCR and in situ hybridization techniques to study the pharmacokinetics and distribution of PGagPol (a potential anti-HIV plasmid vaccine) in rabbits. Samples were obtained 4 hr, 24 hr, 7 days, and 28 days after intramuscular injection of 100 micrograms or 400 micrograms of plasmid. A simplified procedure for collecting and processing tissues for PCR that minimizes the risk of contamination was developed. Using PCR, plasmid was found principally in the skin and muscle of the injection site and in blood plasma. At 4 hr after dosing with 400 micrograms, the plasmid was detected at the injection site with mean copy numbers of 10(6) (in muscle) and 4 x 10(4) (in skin) per microgram of tissue. Plasmid copy number declined rapidly in muscle during the first 24 hr and was undetectable at 7 and 28 days after injection. The decline was slower in the skin, and the plasmid was still detectable at 28 days. With in situ hybridization, plasmid was detected in muscle, mainly in the perimysium and to a lesser degree in the endomysium and within the muscle fibers. These data indicate that quantitative PCR and in situ hybridization are sensitive methods for examining tissue distribution of DNA used for gene therapy.

Role of the eosinophil in allergic reactions

The eosinophil may have several functions in health and in the pathogenesis of allergic and other diseases. Some roles of the eosinophil are based on the acute, effector responses of this cell, its capacity to generate biologically active lipid mediators and release its granule contents, including its distinctive cationic proteins. Whilst the effector responses of eosinophils are important for their contribution to the acute pathogenesis of allergic diseases, a fuller understanding of the eosinophil requires evaluation of the role this cell may play at tissue sites, especially submucosal sites, where the cell is normally localized in the absence of disease. Moreover, for the long-lived, tissue-resident eosinophil, definition of the interactions that occur between the eosinophil and other immune cells is germane to understanding the functions of eosinophils both in acute and chronic diseases. Many allergic diseases are characterized by heightened accumulation of eosinophils and are chronic ongoing diseases.

Novel monoclonal antibody, SO-MU1, against human gastric MUC5AC apomucin

Human gastric mucins were chemically deglycosylated with trifluoromethanesulfonic acid. A mouse monoclonal antibody (MoAb), SO-MU1, was established against the deglycosylated mucins. SO-MU1 recognized not only the deglycosylated mucins but also the native gastric mucins. Periodate treatment of the native mucins increased the SO-MU1 reactivity. Trypsin digestion abolished the antigenicity. Human gastric cDNA expression library was screened with SO-MU1 and a mucin cDNA clone was obtained. Its sequence contained the MUC5AC tandem repeat domain. We studied gastrointestinal distribution of the SO-MU1-reactive antigen immunohistochemically. Gastric surface epithelial cells and parietal cells expressed the antigen, but the glandular cells did not. The antigen was also detected in the small intestine and biliary tract but not in the colon and pancreas. In summary, (1) MoAb SO-MU1 was raised against human gastric mucins, (2) it recognized human gastric MUC5AC apomucin, and (3) the SO-MU1-reactive antigen showed characteristic distribution in the organs of endodermal origin. MoAb SO-MU1 is the first MoAb against MUC5AC.

A pathological and immunohistochemical study of caprine pleuropneumonia induced by subspecies of Mycoplasma mycoides

In a population of 700 goats, 150 died; of these, 29 were necropsied. Ten of the 29 goats had pleuropneumonia. Mycoplasma mycoides subsp. mycoides (Large Colony) (MmmLC), Mycoplasma mycoides subsp. capri (Mmc), and Pasteurella multocida were isolated from five of the pleuropneumonic goats. Gross and microscopical lesions were typical of caprine pleuropneumonia (CPP), with bronchopneumonia, fibrinopurulent or fibrinonecrotic pleuropneumonia and dilatation of the interlobular septa and pleura. Immunohistochemical examination with antisera against MmmLC and Mmc showed mycoplasma antigens in all 10 goats with CPP. In all cases, both MmmLC and Mmc antigens were detected together. Mycoplasma antigens were present in the lumina of the airways and alveoli, mainly inside the cytoplasm of neutrophils and macrophages, but extracellular antigen was demonstrated in areas of necrosis. Pasteurella antigens were detected in four of the 10 animals with CPP. From the histological, immunohistochemical and microbiological results it was concluded that the two mycoplasmas, acting together, caused the pleuropneumonia, with P. multocida playing a subsidiary synergistic role.

Detection of MHC class II transcripts in lymphoid tissues of the common carp (Cyprinus carpio L.)

In all vertebrates studied to date, the expression of MHC class II genes is known to be restricted to a limited number of tissues and cell types. In order to have a better understanding of the function of the equivalent genes in teleost fish, the distribution of MHC class II beta transcripts (Cyca-DAB) in the common carp (Cyprinus carpio L.) was investigated. RNA was isolated from tissues and leucocytes, cDNA was produced, and amplification of the Cyca-DAB genes was carried out by PCR. Of the organs with known immunological function, the highest level of Cyca-DAB transcription was found in the thymus. Despite their expected different cellular organization, total blood, head kidney, spleen and the second segment of the gut had similar Cyca-DAB expression levels. No class II transcripts were detected in the skeletal muscle. The studies carried out with leucocytes isolated from the lymphoid tissues point to a direct correlation between the levels of expression and the amounts of surface immunoglobulin positive (sIg+) cells present in the different cell fractions. However, thymus leucocytes did not follow this correlation since the highest level of class II expression was found in a thymocyte fraction that contained very low numbers of Ig+ cells. In PBL the Ig+ cells were highly positive whereas the Ig- were weakly positive. Adherent leucocytes shown to be class II positive, although adherent cells from PBL show a lower level of expression compared to those from the spleen and head kidney.

Expression and inducibility of antigens in severe combined immunodeficient mice recognized by human anti-P450 antibodies

Engrafting components of human immune systems in severe combined immunodeficient (SCID) mice has been utilized to investigate the pathogenesis of several human autoimmune diseases and may provide a model for studying idiosyncratic drug toxicity. The purpose of this investigation was to examine in SCID mice the tissue distribution and inducibility of antigens recognized by anti-cytochrome P450 (CYP) antibodies in sera from patients with hypersensitivity reactions to the aromatic anticonvulsants phenytoin, phenobarbital, and carbamazepine. Microsomal proteins were prepared from liver, skin, kidney, intestine, and lung of SCID mice pretreated with vehicle (50% propylene glycol/DMSO), phenytoin, carbamazepine, phenobarbital, or dexamethasone. Proteins immunoreactive with anti-CYP2C and anti-CYP3A antisera were detected in all organs examined. Antibodies in patient sera recognized a 53-kDa hepatic microsomal protein that was expressed to a limited extent in vehicle-pretreated microsomes, but which was induced by dexamethasone, phenytoin, and phenobarbital, but not carbamazepine. This antigen was very similar to a 52.5-kDa protein immunoreactive with anti-CYP3A polyclonal antibody. The expression and inducibility of the 53-kDa antigen correlated significantly with testosterone 6 beta-, 2 beta-, and 15 beta-hydroxylation and erythromycin N-demethylase activity, all markers of CYP3A activity, and is tentatively identified as CYP3A11. No immunoreactivity was observed in murine extrahepatic organs including skin, kidney, intestine, and lung. Therefore, further development of the SCID mouse model may require xenotransplantation of human target organs like skin together with transfer of patient immune systems to reproduce the serological and pathological features of human anticonvulsant hypersensitivity reactions.

Characterization of a new antigen expressed by B and myeloid lineage cells identified by the monoclonal antibody LIP-6

The LIP-6 MAb was produced against the undifferentiated cell line bh2-1 and recognizes an antigen expressed on all pre-B and B cell lines tested and some myeloid lineage lines. FACS analysis of normal tissues showed that LIP-6 is expressed on B lineage cells at all stages of differentiation, from bone marrow pre-B to plasma cells. T cells and thymocytes are LIP-6-, and splenic CD11b+ cells are heterogeneous for LIP-6 expression. The LIP-6 MAb was shown to precipitate a major 75-kDa and a minor 85-kDa protein under reducing conditions and a large protein of > 240 kDa under nonreducing conditions. Removal of N-linked sugars from the reduced lysates resulted in a single 65-kDa protein, suggesting that there is differential glycosylation of a single 65-kDa protein that forms disulfide-linked multimers. Finally, the LIP-6 antigen was shown not to be linked to the cell surface via a GPI linkage.

Investigation into the origin of the antigens of Mycoplasma arthritidis cross-reacting with host tissue antigens

The electrophoretical separations of Mycoplasma arthritidis and the serum used in the cultivation medium show a high number of protein bands with identical molecular weights. Proteins with molecular weights of 84, 72 and 52 kDa also appeared to be identical with proteins of Mycoplasma arthritidis in their antigenic properties as demonstrated by Western blotting with rat-anti-Mycoplasma arthritidis serum. The autoradiography of electrophoretically separated Mycoplasma arthritidis cells metabolically labeled with 35S-methionine and 35S-cysteine revealed that the proteins of Mycoplasma arthiritidis identical in molecular weight and antigenic structure with serum proteins are synthesized by Mycoplasma arthritidis, and represent true translation products.

Gamma delta T-cell subset distribution in human semen from fertile donors

PROBLEM

Gamma delta T-cell subset distribution has not been fully investigated in normal human semen.

METHODS

We therefore carried out experiments by using a direct immunofluorescence staining technique followed by two-color cytofluorimetric analysis on mononuclear cell (MC) suspensions from ejaculates of ten healthy, fertile volunteers. Autologous peripheral blood MC were simultaneously analyzed and the results used for statistical comparison.

RESULTS

The proportion of normal human semen lymphocytes bearing the gamma delta T-cell receptor for antigen was greatly increased compared with autologous circulating counterparts. Interestingly, the rise was mainly due to an overexpansion of cells expressing V delta 1 gene-encoded determinants on their surface. This contrasts with the normal blood picture, where most gamma delta T cells express V delta 2 conformational epitopes.

CONCLUSIONS

The numerical and phenotypical differences in semen gamma delta T lymphocytes provide further evidence of a defined migrating lymphocyte subset balance in anatomically and physiologically distinct areas of the body. Their functional role, in terms of both helper and suppressor-cytotoxic activities in the nonsterile proximal portions of the male genital tract, now needs to be explored in detail.

Novel monoclonal antibody reactive with thrombin-sensitive 74-kDa glycoproteins present on platelets and megakaryocytes both from mouse and rat

A monoclonal antibody (designated 1C2) that reacts only with mouse platelets and megakaryocytes among hematopoietic cells was established by immunizing mouse platelets to an Armenian hamster. 1C2 reactive mouse molecule (1C2 antigen) was a surface glycoprotein with molecular weight of 74 kDa. Side by side comparison revealed that 4A5, a rat monoclonal antibody against mouse platelet, immunoprecipitated the identical molecule to 1C2 antigen. Of particular interest, 1C2 also labeled rat tissues with an identical pattern to that of mouse tissues and recognized a 74-kDa protein from rat platelets. Reactivity of 1C2 to mouse and rat platelets decreased when they were treated with thrombin. Following thrombin treatment of mouse platelets, 1C2 reactive 69-kDa protein appeared in the supernatants. Mouse and rat 1C2 antigens purified on 1C2-coated beads were cleaved by thrombin to generate 69-kDa fragments, establishing that 1C2 antigen is a direct substrate for thrombin. 1C2 is the first antibody to platelets and megakaryocytes of mouse and rat whose reactive molecule is well characterized, i.e., substrate for thrombin. 1C2 can be a useful tool in studying megakaryocytopoiesis and thrombopoiesis in rodent systems.

Tissue expression, structure and function of the murine Ly-6 family of molecules

Murine Ly-6 molecules are a family of cell surface glycoproteins which have interesting patterns of tissue expression during haematopoiesis from multipotential stem cells to lineage committed precursor cells, and on specific leucocyte subpopulations in the peripheral lymphoid tissues. These interesting patterns of tissue expression suggest an intimate association between the regulation of Ly-6 expression and the development and homeostasis of the immune system. Ly-6 molecules are low molecular weight phosphatidyl inositol anchored glycoproteins with remarkable amino acid homology throughout a distinctive cysteine rich protein domain that is associated predominantly with O-linked carbohydrate. These molecules are encoded by multiple tightly linked genes located on Chr. 15 which have conserved geneomic organization. The in vivo functions of Ly-6 molecules are not known although in vitro studies suggest a role in cellular activation. This review will summarize our understanding of Ly-6 with regard to tissue expression, molecular structure, gene organization and function.

Distribution of the major xenoantigen (gal (alpha 1-3)gal) for pig to human xenografts

We have previously demonstrated that the major epitope in pig tissues detected by naturally occurring human IgM antibodies is galactose (alpha 1-3)galactose. Subsequent biochemical studies demonstrated this epitope to be present on molecules (Mr40-220kDa) on both endothelial cells and lymphocytes. The objective of the present study was to define the distribution of gal(alpha 1-3)gal in different pig tissues, concentrating on those of relevance for the potential transplantation of pig organs or tissues to humans. Adult pig tissues were obtained fresh, fixed, and stained by the immunoperoxidase technique using biotinylated Griffonia simplicifolia lectin (IB4) which binds only to gal(alpha 1-3)gal, and examined histologically. Endothelial cells in all small vessels (capillaries, arterioles and venules) had a unifrom and dense expression of gal(alpha 1-3)gal; in larger vessels, like the aorta, they were less reactive. The highest concentrations were found in the liver parenchyma which stained uniformly, and in the kidney, where the highest amounts were found in the brush border of the proximal convoluted tubules. There was no staining of collecting ducts or glomeruli (except for endothelium) and moderate staining of the distal convoluted tubules. Heart muscle was nonreactive, although the high density of capillaries indicated a reasonable content of gal(alpha 1-3)gal. In contrast to these tissues was the distribution in the pancreas, which, apart from vessels and the lining of ducts, was nonreactive, i.e. islet cells were essentially lacking in gal(alpha 1-3)gal. Other tissues such as the lung contained moderate amounts of material lining the alveoli and bronchioles.(ABSTRACT TRUNCATED AT 250 WORDS)

Distribution of anti-CD68 (EBM11) immunoreactivity in formalin-fixed, paraffin-embedded bovine tissues

A commercially acquired anti-human macrophage antibody (anti-CD68; EBM11) was used in an immunocytochemical technique to detect macrophages in formalin-fixed, paraffin-embedded tissues from cattle, pigs, humans, rats, turkeys, dogs, and cats. In healthy cattle, the antibody labeled alveolar macrophages, pulmonary intravascular cells (presumably intravascular macrophages), and macrophage-like cells in other tissues. In bovine lungs infected with Pasteurella haemolytica, EBM11 antibody labeled 95% of alveolar macrophages and macrophages within alveolar septa but only 0-2% of streaming or "oat" leukocytes. Alveolar macrophages were also stained by EBM11 in pigs but not in rats, turkeys, dogs, and cats. The antibody also stained macrophage aggregates in the mesenteric lymph nodes and intestinal lamina propria of Mycobacterium paratuberculosis-infected cattle. This study shows that the anti-CD68 (EBM11) antibody is a useful marker of macrophages in normal bovine tissues or tissues from areas of acute or chronic inflammation that have been routinely processed. The study also adds strength to the growing evidence suggesting that streaming leukocytes seen in pneumonic pasteurellosis are neutrophils.

Identification of a target cell antigen recognized by nonspecific cytotoxic cells using an anti-idiotype monoclonal antibody

Nonspecific cytotoxic cells (NCC) are the teleost equivalent of mammalian natural killer (NK) cells. In the present study an anti-idiotypic monoclonal antibody (mAb 7D12) was generated against idiotopes on an mAb (mAb 6D3.2) that recognizes a putative receptor on NCC. The idiotypic specificity of mAb 7D12 was determined in competition assays by incubating biotinylated mAb 7D12 with mAb 6D3.2 hybridoma cells following preincubation with combinations of biotinylated 7D12 with either nonbiotinylated homologous or heterologous mAb. The ligand recognized by mAb 7D12 (determined by flow cytometry) was found on cells from the anterior kidney, spleen, thymus, PBL, liver, and brain. NCC lysis of IM-9 targets was inhibited 76% following preincubation of the target cells with different concentrations of mAb 7D12. The involvement of the ligand recognized by mAb 7D12 in the NCC lytic cycle was determined by showing that this mAb produced 50% inhibition of NCC conjugate formation with NC-37 target cells. Biochemical analysis using SDS-PAGE and Western blotting revealed that mAb 7D12 recognized 54 and 65 M(r) proteins in IM-9 target cell lysates. These studies demonstrated that an idiotope on a NCC specific anti-receptor mAb was an "internal image" of a target cell ligand. The anti-id mAb generated against this image (idiotope) inhibited NCC cytotoxicity and thus was equivalent to an NCC receptor that binds to a target cell ligand involved in NCC recognition.

Differentiation antigens of human articular chondrocytes and their tissue distribution as assessed by monoclonal antibodies

Five monoclonal antibodies (HuMC1, HuMC2, HuMC3, HuMC4 and HuMC5) raised against intact human articular chondrocytes were tested with chondrocyte samples from arthritic and non-arthritic patients by surface immunofluorescence and by immunoperoxidase labeling of fixed cells. All acetone-fixed samples reacted strongly with the monoclonal antibodies but some variation in the percentages of intact chondrocytes positive by immunofluorescence was noted. Under culturing conditions which induced de-differentiation, epitopes recognized by HuMC1, HuMC3 and HuMC4 disappeared with time in culture. In contrast, reactivities to HuMC2 and HuMC5 either persisted or increased as the culture became more fibroblastic and these antibodies bound to antigens on human fibroblast cell lines. HuMC1, HuMC3 and HuMC4 reacted with purified adult and fetal proteoglycan. HuMC2 and HuMC5 exhibited only slight or no reactivity to either proteoglycan. All five monoclonal antibodies reacted with chondrocytes in frozen articular cartilage but HuMC2 and HuMC5 failed to react to chondrocytes in paraffin-embedded cartilage sections. Only HuMC1, HuMC3 and HuMC4 recognized matrix components in both frozen and paraffin-embedded cartilage. When tested against 29 different non-cartilaginous tissues, each of the monoclonal antibodies had distinctive reactivity patterns, suggesting that each reacted to different epitopes. HuMC3 reacted with neurons in the cerebral cortex and cerebellum, indicating that it may recognize epitopes shared on the S-100 protein. HuMC1 showed the greatest specificity for chondrosarcomas. These antibodies are useful for identifying differentiated chondrocytes, providing information on the distribution of chondrocyte antigens shared by other human tissue, assessing the extent of chondrocyte heterogeneity in a population and aiding in the classification of chondrosarcomas.