Claude Brillouet

Properties of Cell Subpopulations of Starfish Axial Organ: In Vitro Effect of Pokeweed Mitogen and Evidence of Lymphokine‐like Substances

The in vitro effects of pokeweed mitogen (PWM) on axial organ (AO) cells of the echinoderm starfish Asteria rubens have been studied. PWM stimulates 3H‐thymidine incorporation by the whole population of AO cells (index of stimulation 4–5). On the basis of surface adherence to nylon wool the AO cell population can be fractionated into adherent and non‐adherent subpopulations. PWM strongly stimulates the non‐adherent cells (index 14) but not the adherent cells (index 1.2–1.8). Specific soluble mediators obtained from stimulated non‐adherent cells were able to stimulate the whole AO cell population but not the fractionated adherent or non‐adherent cells.

In vitro effect of various mitogens on starfish (Asterias rubens) axial organ cells

Abstract The effects of various mitogens on axial organ (AO) cells of the sea star have been studied. Pokeweed mitogen (PWM) stimulates [ 3 H]thymidine incorporation by the whole population of axial organ cells of the sea star. This effect occurs 24 hr after the addition of PWM and is maximal at 40 μg/ml. In contrast, no stimulation is observed when coelomocytes are treated with PWM under the same conditions. No stimulation of the whole AO cell population is observed in the presence of Con A or LPS. However, the AO cell population can be divided, on the basis of surface adherence properties, into two subpopulations, adherent and nonadherent. Con A stimulates the nonadherent cells, but not the adherent cells: The stimulating effect is maximal 24 hr after addition of Con A and at 0.2–0.5 μg/ml. In contrast, LPS stimulates the adherent but not the nonadherent cells and the stimulating effect is maximal at 24 hr and at 45 μg/ml.

Correlation between the injection of specific proteins in starfishes and the appearance of binding sites for the same proteins in cell populations of their axial organ

Abstract Sea stars were injected with two different proteins (bovine serum albumin and whale myoglobin). Cell suspensions were prepared from the axial organ of injected and untreated animals. After exposure of these suspensions to soybean agglutinin (SBA), agglutinable and nonagglutinable cell subpopulations were obtained and compared as to their binding to fluorescent conjugates of the same proteins: FITC-serum albumin and FITC-myoglobin. The SBA-agglutinable subpopulation from injected animals showed a significantly higher number of membrane fluorescent cells than the nonagglutinable subpopulation. No significant membrane fluorescence was observed in the cell subpopulations obtained from untreated animals. The membrane fluorescence appeared mainly when the protein of the fluorescent conjugate was the same as that used for injecting the animal.

Immunocompetent cells in the starfish Asterias rubens. An ultrastructural study

Cells from the axial organ of the starfish Asterias rubens were fractionated into two populations, adherent and non-adherent to nylon wool. In both populations the ultrastructural study revealed the presence of cells resembling the lymphocytes of the vertebrates, as well as phagocytic, peroxidase positive cells. The lymphocyte-like cells in the non-adherent population (average diameter 4 mu) have a high nucleo-cytoplasmatic ratio and are morphologically similar to Th lymphocytes while the adherent cells (average diameter 5.5 mu) are more similar to Bm lymphocytes. These observations are in line with the hypothesis that there exist, in the starfish, a primitive immune system with characteristics resembling those of the immune system of vertebrates.

In vitro effect of rabbit anti sea star lymphocyte serum on axial organ cells

The axial organ (AO-cells) of the sea star Asterias rubens is a primitive immune organ. The total population was fractionated or not into two populations: adherent (B-like) and non adherent (T-like) to nylon wool. Rabbit anti sea star lymphocyte serum induces the proliferation of axial organ cells. The T-like antiserum stimulates the T-like cells exclusively; the whole axial organ cell antiserum only stimulates the whole axial organ cell population.

MLR-like reaction between axial organ cells from asterids

The uptake of [3H]thymidine by axial organ (AO) cells arising from two starfishes and mixed together, in a ratio of 50/50 was studied. Mixed leucocyte reaction (MLR) combinations gave a positive response at the fifth day of culture in about 20% of the tested combination (index: 1.8-6.7). No positive reaction was observed in an allogeneic system. More significant results seem to be obtained with the nonadherent nylon-wool subpopulation cells from the two species, rather than with the whole axial organ cells.

The heterogeneity of antibody-like membrane receptors in subpopulations of sea star axial organ cells

Abstract The sea star Asterias rubens plays a fundamental role in the phylogeny of the immune response. It was recently reported that sea star axial organ cells cultured and stimulated with hapten carrier conjugates release an antibody-like protein. In particular, B-like cells were shown to have a specific role when compared to T-like cells. We have examined membrane antibody-like receptors in axial organ cell-subpopulations by the use of flow cytofluorometry. Our results indicate that the binding distribution in B-like cells differs from that found in T-like cells which present no antibody-like receptors. This is new evidence suggesting a possible comparison between sea star B-like cells and vertebrate B lymphocytes.

Mitogens induced regulation of sea star axial organ cell humoral immune response in vitro

Abstract A specific anamnestic response occurs in the sea star, Asterias rubens after in vivo and in vitro stimulation of axial organ cells, with hapten-carrier conjugates. The effect of the mitogenic lectin Con.A on the in vitro production of antibody like factors is studied by means of a haemolytic assay. It appears that Con.A produces a modulating effect on the secondary in vitro response of sea star axial organ cells. I.O-Methyl-α-D-Mannopyranoside inhibits the modulating effect of Con.A in controls. On the other hand it appears clearly that LPS has no action on the synthesis and/or the activity of the “antibody-like” factors secreted by axial organ cells.

Production of an antibody-like factor in the sea star asterias rubens: role of the gastric haemal tufts

Abstract Cells from the axial organ (AO) of sea stars stimulated “in vivo” with TNP coupled to polyacrylamide beads and subsequently cultured “in vitro” were able to produce an antibody-like factor which induced the lysis of mammalian red cells sensitized with TNP. Three types of cells at least are involved in the production of the antibody-like factor. The addition of 2-mercapto-ethanol to the cultures including these 3 populations was essential but what is a novelty is the fact that cells from the gastric haemal tufts (G.H.T.), probably phagocytes, are able to replace it. Otherwise G.H.T. contain cells playing the role of nylon wool- non adherent AO cells or T like cells.

IN VITRO EFFECT OF MITOGENS ON STARFISH AXIAL ORGAN CELLS EVIDENCE OF LYMPHOKINE-LIKE SUBSTANCES

ABSTRACT In this paper we have investigated the in vitro effect of various mitogens on the axial organ (A.O.) cells of the Starfish Asterias rubens. We have isolated two cell subpopulations whose responses to mitogens strongly resemble to those of Vertebrates T and B lymphocytes. When stimulated by P.W.M. these cells appear to product a soluble mitogenic factor that can be called lymphokine-like substance.