In vitro elicitation of intestinal immune Responses in Teleost Fish: evidence for a type IV hypersensitivity reaction in Rainbow Trout.

In fish the gut immune system has been the subject of few investigations until now. Here, we provide novel morphological and immunological data on the gut isolated from rainbow trout Salmo gairdneri. The pyloric (P) and terminal (T) segments of trout gut, when morphologically examined, evidenced lymphocytes and macrophages (MO) loosely dispersed in the intestinal mucosa and in the lamina propria in the absence of typical Peyer's patches-like structures. Furthermore, incubation of P and T sections with Candida albicans (Ca) and functional analysis of supernatants generated some interesting results. In fact, active supernatants, when compared with controls, exhibited cytokine-like activities attributable to the presence of interferon (IFN)-gamma and migration inhibiting factor (MIF), respectively. In particular, IFN-gamma-like activity gave rise to an enhancement of Ca phagocytosis by MO, whereas MIF inhibited MO migration in agarose. Taken together, these in vitro data suggest that the gut-associated lymphoreticular tissue in fish possesses the appropriate armamentarium to mount a type IV hypersensitivity response when challenged by microbial antigens

Do fish thrombocytes play an immunological role? Their cytoenzymatic profiles and function during an accidental piscine candidiasis in aquarium

Fish (F) thrombocytes (THRs) from healthy trouts were studied in terms of cytoenzyme expression. FTHRs were positive to acid periodic of shiff (PAS) and acid phosphatase (ac. phos.) without tartaric acid (-TA) stainings, as well to alkaline phosphatase. However, when compared with autologous macrophages (MOs), they were negative to naphthol cloroacetate esterase (AS-D), alpha-naphthyl acetate esterase (Anae), peroxidase (perox) and control ac. phos. with tartaric acid (+TA) stainings, thus indicating a lack of typical lysosomial enzymes. This evidence supports the notion that FTHRs are not true digesting cells. Quite interestingly, trouts and human MOs were positive for PAS, AS-D, Anae, and perox stainings, thus confirming that cellular cytochemistries are maintained across evolution as their phagocytic functions. Additionally, blood films from trouts, accidentally infected with Candida albicans in aquarium, were morphologically analyzed. Actually, FTHRs interact with erythrocytes, potentiating the formation of rosettes around a central MO. Polymorph nuclear cells and lymphocytes are present in these cellular aggregates, thus suggesting that FTHRs may represent a link between innate and adaptive immunity

Cystitises in the equine species: pathogenetic causes, histomorphological aspects and analogies with the human species

Reports in literature of urinary bladder alterations in the equine species are few and far between Most excretory urinary tract inflammation pathologies are triggered by some sort of infection, although chemical and physical causes have also been evidenced, particularly in human medicine. Infrequent cases of phlogosis caused by toxins in the bloodstream (Cantharidin and Mycotoxin in the horse) have, however, been observed in veterinary medicine. The aim of this paper is to present a comparative study of equine cystitises and their analogies with the human species. To this end, the authors have examined 235 urine bladders taken from regularly slaughtered horsesReports in literature of urinary bladder alterations in the equine species are few and far between Most excretory urinary tract inflammation pathologies are triggered by some sort of infection, although chemical and physical causes have also been evidenced, particularly in human medicine. Infrequent cases of phlogosis caused by toxins in the bloodstream (Cantharidin and Mycotoxin in the horse) have, however, been observed in veterinary medicine. The aim of this paper is to present a comparative study of equine cystitises and their analogies with the human species. To this end, the authors have examined 235 urine bladders taken from regularly slaughtered horses