A hemolytic plaque assay for the detection of direct and indirect antibody-forming cells to keyhole limpet hemocyanin

The impact of long-term reduced access to cleaner fish on health indicators of resident client fish

In many mutualisms, benefits in the form of food are exchanged for services such as transport or protection. In the marine cleaning mutualism, a variety of 'client' reef fishes offer 'cleaner' fish Labroides dimidiatus access to food in the form of their ectoparasites, where parasite removal supposedly protects the clients. Yet, the health benefits individual clients obtain in the long term from repeated ectoparasite removal remain relatively unknown. Here, we tested whether long-term reduced access to cleaning services alters indicators of health status such as body condition, immunity and the steroids cortisol and testosterone in four client damselfish species Pomacentrus amboinensis, Amblyglyphidodon curacao, Acanthochromis polyacanthus and Dischistodus perspicillatus To do so, we took advantage of a long-term experimental project in which several small reefs around Lizard Island (Great Barrier Reef, Australia) have been maintained cleaner-free since the year 2000, while control reefs had their cleaner presence continuously monitored. We found that the four damselfish species from reef sites without cleaners for 13 years had lower body condition than fish from reefs with cleaners. However, immunity measurements and cortisol and testosterone levels did not differ between experimental groups. Our findings suggest that clients use the energetic benefits derived from long-term access to cleaning services to selectively increase body condition, rather than altering hormonal or immune system functions.

Distribution and characterization of rhogocyte cell types in the mantle tissue of Haliotis laevigata

Molluscan rhogocytes are known to be the only cells able to synthesize hemocyanin that is one of the largest respiratory proteins in nature. However, investigation of rhogocyte cells in vitro is limited due to difficulty in isolating and establishing marine cell culture. The aim of this study was to investigate the nature and distribution of rhogocyte cells of Haliotis laevigata in the mantle tissue with respect to the expression of the two known isoforms of hemocyanin. Rhogocyte cells were identified using immunofluorescence-fluorescence in situ hybridization (IF-FISH) that involved simultaneous staining of localized hemocyanin by a polyclonal antibody while the mRNA was hybridized with FISH probes. The distribution of rhogocyte cells was demonstrated using flow cytometry, followed by cell sorting with fluorescence-activated cell sorter (FACS) and confocal microscope imaging for further characterization. Our results suggested that the mantle tissue is dominated by two distinct populations of rhogocyte cells that synthesize hemocyanin type 1. Observation with confocal microscopy of both populations revealed hemocyanin localization in the periphery of the cell membrane. Cell population with higher antibody signal had irregular and elongated cell morphology with punctate mRNA probe signals. The second population with lower antibody signal had ovoid morphology and wide distribution of mRNA probe signals. We suggest that these populations represent two distinct phases of hemocyanin biosynthesis of a single isoform, which is closely related to Haliotis tuberculata type 1 hemocyanin (HtH1). The knowledge acquired in this study enhances the understanding of the biology of rhogocyte cells and biosynthesis of hemocyanin.

Analysis of immunotoxicity by enumeration of antibody-producing B cells

The plaque-forming cell (PFC) assay measures the humoral immune response mediated by the concerted actions of antigen-presenting cells, T lymphocytes, and B lymphocytes. The most common form of the plaque method is used for the detection of murine primary IgM antibodies directed against the T cell-dependent sheep red blood cell (sRBC) surface antigens. Research has shown that the PFC response to sRBC is not only an excellent monitor of the primary effector function of the B cell, but that it may be the most sensitive immune parameter currently available to identify chemical perturbation. Several modifications and variations of the PFC assay are described in detail in this unit.

Does access to the bluestreak cleaner wrasse Labroides dimidiatus affect indicators of stress and health in resident reef fishes in the Red Sea?

Interactions between the bluestreak cleaner wrasse Labroides dimidiatus and its client reef fish are a textbook example of interspecific mutualism. The fact that clients actively visit cleaners and invite inspection, together with evidence that cleaners eat many client ectoparasites per day, indeed strongly suggests a mutualistic relationship. What remains unknown is how parasite removal affects the physiology of clients and thereby their body condition, health, and immune function. Here we addressed these issues in a field study in Ras Mohammed National Park, Egypt. In our study area, small reef patches are inter-spaced with areas of sandy substrate, thereby preventing many species (i.e., residents, including cleaner wrasses) from travelling between the reef patches. This habitat structure leads to a mosaic of resident clients with and without access to bluestreak cleaner wrasses, further referred to as "cleaner access", on which we focused our study. We found that residents with cleaner access had higher body condition than residents without cleaner access. However, indicators of stress like variation in cortisol levels corrected for handling time and various immune parameters were apparently unaffected by cleaner access. In fact antibody responses were significantly higher in fishes without cleaner access. This suggests that cleaner access decreases the need for active immunity and that this releases resources that might be allocated to other functions such as somatic growth and reproduction.

In situ (mesocosm) assessment of immunotoxicity risks to small mammals inhabiting petrochemical waste sites

Oil refineries inadvertently deposit a variety of complex mixtures of organic hydrocarbons and heavy metals in the soil, many of which are thought to be potent immunotoxicants. Terrestrial ecosystems such as this have not been adequately investigated with respect to wild rodent populations. The primary objective of this study was to use mesocosms to assess the immunotoxicity risks to feral small mammal populations associated with soils contaminated with petroleum refinery wastes. A series of 4-week and 8-week exposure trials using laboratory raised cotton rats (Sigmodon hispidus) were conducted in situ on three contaminated and three reference sites on the Oklahoma Refining Company Superfund Waste Site, Cyril, Oklahoma. Cotton rats exposed to these soils showed significant alterations in selected morphological traits, in vivo humoral immune responses, complement activity, and macrophage activity. However, immune alterations were not great, suggesting that resident small mammals may be a better biomonitoring choice than using mesocosms.

T cell-dependent immune response in C1q-deficient mice: defective interferon gamma production by antigen-specific T cells

The role of the classical complement pathway in humoral immune responses was investigated in gene-targeted C1q-deficient mice (C1qA-/-). Production of antigen-specific immunoglobulin (Ig)G2a and IgG3 in primary and secondary responses to T cell-dependent antigen was significantly reduced, whereas IgM, IgG1, and IgG2b responses were similar in control and C1qA-/- mice. Despite abnormal humoral responses, B cells from C1qA-/- mice proliferated normally to a number of stimuli in vitro. Immune complex localization to follicular dendritic cells within splenic follicles was lacking in C1qA-/- mice. The precursor frequency of antigen-specific T cells was similar in C1qA-/- and wild-type mice. However, analysis of cytokine production by primed T cells in response to keyhole limpet hemocyanin revealed a significant reduction in interferon-gamma production in C1qA-/- mice compared with control mice, whereas interleukin 4 secretion was equivalent. These data suggest that the classical pathway of complement may influence the cytokine profile of antigen-specific T lymphocytes and the subsequent immune response.

The purification and characterisation of cervine IgM and IgG

A procedure is described for the isolation of immunoglobulin G (IgG) and immunoglobulin M (IgM) from hyperimmune cervine serum. Hybrids of red deer (Cervus elaphus) and wapiti (Cervus canadensis) were immunised with keyhole limpet hemocyanin (KLH). An immunoglobulin-containing fraction was precipitated from the hyperimmune serum using ammonium sulphate. The antigen-specific immunoglobulins were purified by KLH-conjugated sepharose affinity chromatography and further separated into IgM and IgG by gel-filtration chromatography. Purified immunoglobulin was analysed by polyacrylamide gel electrophoresis and isoelectric focusing. The molecular weights and isoelectric points of the composite chains of cervine IgG and IgM are presented.

Delayed-type hypersensitivity to hen egg-white lysozyme. I. The surface phenotypes of suppressor T cells induced by intravenous injection of lysozyme-modified spleen cells, and their molecular interactions

Suppressor T cells (Ts) induced by lysozyme-modified syngeneic lymphocytes were characterized. Hen egg-white lysozyme (HEL)-specific delayed-type hypersensitivity (DTH) was suppressed when HEL-induced Ts were transferred into naive mice. These HEL-induced Ts had surface markers of both Thy-1 antigen, and I-J gene products. The suppression of HEL-specific DTH was greatly increased, when these Ts had been enriched with HEL-coated petri dishes. Isolated anti-HEL antibodies from B10.BR or A/Sn mice were inoculated into rabbits to induce anti-cross-reactive idiotype (CRI) antibodies. The rabbit antisera were extensively absorbed with normal B10.BR or A/Sn immunoglobulins (Igs) and MOPC 104E ascites Igs to render them idiotype (Id) specific. Using these anti-CRI antibodies, we observed that these Ts possessed Id receptors on their cell surface. Results of both fluorescence techniques and cytotoxicity tests revealed that about 10% of the enriched T cells containing these Ts were Id positive. Moreover, these enriched T cells were substantially killed by anti-I-J antiserum plus complement. However, this killing was completely blocked by HEL antigen. These results suggest that both Id receptors and I-J gene products might be forming the same molecular complexes or might coexist in the vicinity of the molecule.

Genetic control of the immune response to hen's egg-white lysozyme in mice. I. Antibody and T-lymphocyte proliferative responses to the native protein

We have initiated studies to determine whether the antibody and T-lymphocyte proliferative responses to lysozyme and its antigenic sites is genetically controlled in mice. Mice of the H-2f, H-2k and H-2p were high responders, while haplotypes H-2b, H-2d, H-2r and H-2s were low responders. Studies with recombinants indicated that the immune response is controlled by two H-2I region loci, one being in the I-A subregion and the other may be in the I-C subregions.

Microtubular proteins in pigeon erythrocyte membranes

[3H]Colchicine binds in a concentration and temperature dependent, saturatable and noncooperative manner to cytoplasmic proteins from pigeon erythrocytes: Kd = 3.5 x 10(-7) M at 37 degrees C. Binding of [3H] colchicine at 0 degrees C and of [3H]lumicolchicine at 37 degrees C was significantly reduced. Hence microtubular proteins are present in the cytoplasm of pigeon erythrocytes. Antibody against bovine brain tubulin was raised in rabbits and confirmed by immunodiffusion, passive immunohaemolysis and in radioimmunoassay. Pigeon erythrocyte membrane proteins solubilized with 2% sodium cholate competed with 125I-labelled tubulin in the radioimmununoassay although much higher concentrations of membrane proteins than of purified bovine brain tubulin were required for effective competition. No binding to antibody occurred with boiled solubilized membrane preparations. Similar results were obtained with antitubulin-dependent passive immunohaemolysis of tubulin-coated sheep erythrocytes in the presence of complement. The presence of tubulin in membranes was verified by binding intact pigeon erythrocytes to colchicine-Sepharose beads at 37 degrees C. Free colchicine (5mM) or incubation at 0 degrees C prevented binding. Lumicolchicine-Sepharose beads did not attach to erythrocytes at 37 degrees S. Thus pigeon erythrocyte membranes contain microtubular protein.