Aluminum is a powerful adjuvant in teleost fish despite failing to induce interleukin-1β release.

Although aluminum salts (Alum) have been extensively used in human vaccination for decades, its mechanism of action is controversial. In fish, the use of Alum as a vaccine adjuvant is scarce and there are no studies aimed at identifying its mechanism of action. In the present study we report that Alum is a powerful adjuvant in the gilthead seabream (Sparus aurata L.

Aluminum adjuvant potentiates gilthead seabream immune responses but induces toxicity in splenic melanomacrophage centers.

A key goal of a successful vaccine formulation is the strong induction of persistent protective immune responses without producing side-effects. Adjuvants have been proved to be successful in several species at inducing increased immune responses against poorly immunogenic antigens. Fish are not the exception and promising results of adjuvanted vaccine formulations in many species are needed.

Histamine and mast cell activator compound 48/80 are safe but inefficient systemic adjuvants for gilthead seabream vaccination.

Histamine has a key role in the regulation of inflammatory and innate immune responses in vertebrates. Gilthead seabream (Sparus aurata L.), a marine hermaphrodite teleost of great commercial value, was the first fish species shown to possess histamine-containing mast cells (MCs) at mucosal tissues.

Cimetidine disrupts the renewal of testicular cells and the steroidogenesis in a hermaphrodite fish.

The importance of histamine in the physiology of the testis in mammals and reptiles has been recently shown. Histamine receptors (Hrs) are well conserved in fish and are functional in several fish species. We report here for the first time that histamine and the mRNA of Hrh1, Hrh2 and Hrh3 are all present in the gonad of the hermaphrodite teleost fish gilthead seabream.

Selective estrogen receptor modulators differentially alter the immune response of gilthead seabream juveniles.

17α-ethynylestradiol (EE2), a synthetic estrogen used in oral contraceptives and hormone replacement therapy, tamoxifen (Tmx), a selective estrogen-receptor modulator used in hormone replacement therapy, and G1, a G protein-coupled estrogen receptor (GPER) selective agonist, differentially increased the hepatic vitellogenin (vtg) gene expression and altered the immune response in adult gilthead seabream (Sparus aurata L.) males. However, no information exists on the effects of these compounds on the immune response of juveniles.