Differential effects of temperature on macrophages of ectothermic vertebrates

Abstract

The role of macrophages in vertebrate defense reactions is especially important at low temperatures, which commonly affect representatives of ectothermic species. The aim of this work was to compare the effects of in vivo thermal acclimation and in vitro assay temperatures on peritoneal macrophages (PMs) from fish (carp and goldfish) and amphibians (salamanders and toads). The substratum adherence of PMs was undisturbed over the wide range of temperatures experienced by animals in nature. Dehydrogenases and endocytosis were sensitive to temperature fluctuations in a species-specific manner, more or less dependent on the previous thermal history of animals. The MTT reduction, inhibited by low assay temperatures, was slightly improved in PMs from cold-acclimated amphibians but not fishes. Endocytosis by the amphibian PMs, very efficient over the wide range of assay temperatures, was additionally improved by previous in vivo cold exposure. Contrasting effects of thermal acclimation were most evident in the case of endocytic properties of fish PMs; endocytosis by PMs from cold-acclimated fishes was extraordinarily efficient at a temperature just above zero, which almost completely inhibited cells from fishes adapted to warmth.

Winter syndrome in the gilthead sea breamSparus aurata. Immunological and histopathological features

“…Similarly, Plytycz & Jurewicz (1994) observed much more e$cient endocytosis and phagocytosis when fish were first adapted to cold temperatures. Besides direct e#ects of temperature, an important concurrent factor is the e#ect of stress.…”

Linking global climate and temperature variability to widespread amphibian declines putatively caused by disease

“…Drops in temperature on a monthly or seasonal time scale might also be particularly important, because ectotherms seem to take longer to acclimate to a temperature decrease than to a temperature increase (35). For a variety of immune cells and proteins, low temperatures can dramatically reduce their production and/or activity levels, including (but probably not limited to) peripheral leukocyte levels (32,34), T and B cell proliferation (35), macrophage endocytosis (36), and abundance of antimicrobial skin peptides (37), the latter of which are known to be important for defending against Bd (22). Potential increases in host susceptibility with drops in temperature are of particular concern for Bd epidemics because decreases in temperature might benefit this relatively cold-tolerant pathogen (22,32,38).…”

Strain differences in some immune parameters can be obscured by circadian variations and laboratory routines: studies of male C57BL/6J, Balb/c and CB6 F1 mice

“…For investigations of interactions between the immune and the neurohormonal systems, we have used a model of experimental peritoneal in¯am mation which is easy to induce and monitor in various vertebrat es like ®sh (Gruca e t a l. 1996), am phibians (Plytycz & Jozkowicz 1994 ), and mam mals (Chadzinska e t a l. 1999 ) and is strongly affec ted by several factors like ambient temperature (Menaszek e t a l. 1999 ), handling stress (Plytycz e t a l. 1998), and morphine treatm ent (Chadzinska e t a l. 1997(Chadzinska e t a l. , 1999. Some of these experiments (Chadzinska e t a l. 1999) were performed on CB6 F1 mice.…”