Interleukin-2 and phytohaemagglutinin stimulate the proliferation of tunicate cells.
Proliferative responses of cells in tunicate pharyngeal explants to human interleukins and mitogenic lectins were tested. Increased tritiated-thymidine [( 3H]-TdR) uptake was detected among pharyngeal cells incubated with recombinant human interleukin-2 (IL-2), and phytohaemagglutinin-P (PHA-P). Responses to IL-2 were dose-dependent and affected lymphocyte-like cells. Enhanced proliferation was stimulated by IL-2 in the absence of co-stimulants and was not synergized by co-incubation with human interleukin-1 (IL-1) or PHA-P. Anti-IL-2 polyclonal antibody inhibited the stimulatory activity of recombinant human interleukin-2 (rhIL-2). Of three lectins tested (concanavalin-A [Con-A], pokeweed mitogen [PWM] and PHA-P), only PHA-P proved to be mitogenic. Con-A and PWM did not significantly increase proliferative activity even though both lectins were capable of binding pharyngeal cells as revealed by flow cytometry and fluorescence microscopy. Similarly, human IL-1 had no effect on [3H]-TdR uptake either alone or in combination with IL-2 and PHA-P. These data suggest that the functions of some interleukin-like cytokines have been conserved during evolution.
Raftos
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DA
Department of Anatomy and Cell Biology, School of Medicine, University of California, Los Angeles 90024-1763.
Stillman
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DL
Cooper
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EL
D000818:Animals; D005075:Biological Evolution; D002455:Cell Division / Q000187:drug effects; D007375:Interleukin-1 / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology*; D037102:Lectins / Q000276:immunology; D010835:Phytohemagglutinins / Q000276:immunology*; D013936:Thymidine / Q000378:metabolism; D014561:Urochordata / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
D007375:Interleukin-1; D007376:Interleukin-2; D037102:Lectins; D010835:Phytohemagglutinins; C028784:phytohemagglutinin-P; D013936:Thymidine