Gilles Luquet

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.

Spontaneous and induced cytotoxicity of axial organ cells from Asterias rubens (asterid - echinoderm)

Spontaneously occurring cytotoxicity of starfish axial organ cells on target cells has been studied. It appears that in an allogeneic system no cytotoxic phenomenon occurs after 4 or 6 h of culture, whereas spontaneous cytotoxicity toward malignant vertebrate target cells is shown and reaches its maximum at 37 degrees C. In a certain way, the axial organ cell population includes cells, which may be compared with vertebrate natural killer cells. On the other hand, it must also be noted that axial organ cells are able to exert in a few cases, an induced cytotoxicity on MBL2 cells. This phenomenon appears at the end of the fourth day of culture.

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.

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.

In vitro effect of silica on axial organ cells in the presence and absence of mitogens

Abstract The axial organ (AO-cells) of the sea star Asterias rubens is a primitive immune organ. The total population was fractionated into two populations: adherent (B-like) and non-adherent (T-like) to nylon wool. Mitogenic responses were tested in the presence or absence of silica. Silica inhibits specifically the action of phagocytes contained in T-like and B-like subpopulations. Mitogenic responses do not occur in the presence of silica.

Effect of in vivo inoculation of bacteria on the spontaneous cytotoxicity of axial organ cells from Asterias rubens

In vivo inoculation of heat-killed bacteria in the coelomic cavity of starfish induces an increase of spontaneous cytotoxicity developed by axial organ (an ancestral lymphoid organ) cells, phenomenon demonstrated by an in vitro [51Cr]-release assay. This observation corroborates the existence of a sophisticated immune system in the echinoderms, a first-rate model for phylogenic study of the immune response.

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.