Evaluation of immunological parameters in farmed gilthead sea bream, Sparus aurata L., before and during outbreaks of 'winter syndrome'

In recent years, 'winter syndrome' has caused severe economic losses in many marine farms in southern Europe. This study compared the activity of the immune system in healthy, asymptomatic and diseased gilthead sea bream. Serum protein and immunoglobulin content were evaluated as well as serum complement activity from these groups of fish. Differential leucocyte counts were also determined. Immunological assays were performed to determine intra- and extracellular 'respiratory burst' activity as non-specific immune response parameters. Diseased fish showed a significant reduction in haemolytic activity (90%), and in serum proteins and immunoglobulins in comparison with the other groups. A significant increase in the lymphocyte percentage (50%) and a decrease in the granulocyte percentage (over 70%) was found in asymptomatic fish. Respiratory burst activity was reduced in both the clinical and preclinical stages of the disease, compared with the controls. These observations confirm a severe immunodeficiency in diseased fish but also the presence of a cellular immune dysfunction in fish without clinical signs, before the onset of the disease

ELASTASE IS THE HUMAN NEUTROPHIL GRANULE PROTEIN RESPONSIBLE FOR THE IN VItro ete Borrelia burgdorferilling of the Lyme dusease spirochre

INFECTION AND IMMUNTIT

Valutazione della protezione indotta da frazioni antigeniche di Lactococcus garvieae in trota iridea (Oncorhynchus mykiss)

SUMMARY \u2013 Effective procedures of vaccination against lactococcosis in rainbow trout (Oncorhynchus mykiss) are still under investigation and the methods currently employed are based on \u201cautovaccines\u201d that are injected intraperitoneally to fish. These vaccines allow a protection for 8 months, when integrated with adjuvants. The bacterial antigenic components involved in the protection are only partially considered by the literature. This investigation concerns the effect of some fractions of Lactococcus garvieae in the development of a protective immune response to the infection. Extracellular products (ECPs), bacterial whole cells (WCs) and membrane antigens (AM) were injected intraperitoneum to 90 g. rainbow trouts. Fish were subsequently submitted to an intraperitoneal challenge with L. garvieae (2.6 7105 cfu/individual). The treatments allowed the following relative percentages of survival (RPS): 95% for WCs; 35% for ECPs, 33% for AM. These results suggest that WCs give the best protection, but also ECPs and AM are effective. Samples of serum collected from immunized and control fish were analysed by immunoblotting against the SDS-PAGE/Western Blotting protein profile of each bacterial fraction. The control and immunized fish sera contained immunoglobulins able to bind aspecifically the proteins having a molecular weight of 23, 48 and 102 kDa respectively

Vaccination trials of sea bass (Dicentrarchus labrax, L.) against Photobacterium damsela subsp. piscicida, using antigens prepared in novel media

Bacterial cells of the marine fish pathogen Photobacterium damsela subsp. piscicida were grown in novel culture media. A mixture of whole cells and extracellular components was inactivated and used in bath, intraperitoneal (i.p.) and oral vaccination of sea bass, Dicentrarchus labrax, employing two sizes of fish. A commercial vaccine was used for comparative purposes. Control and immunized fish were either bath or intraperitoneally challenged 6 and 12 weeks post-vaccination. Small fish had significantly higher relative percentage survival with the novel vaccine mixture both at 6 and 12 weeks post-vaccination by bath, in comparison with the commercial vaccine. No protection was afforded at 6 or 12 weeks post-immunization by either vaccine after challenge via i.p. injection. Sea bass (1.5-2 g) intraperitoneally vaccinated with various adjuvanted vaccine mixtures were not protected against pasteurellosis. In contrast, larger sea bass (20 g) benefited from vaccination with the novel vaccine mixtures. Intraperitoneal challenge with the pathogen resulted in protection in both fish groups vaccinated with novel vaccine mixtures, whereas control fish suffered high mortalities (> 80%). Orally vaccinated fish were immersion challenged with the pathogen. At 6 and 12 weeks post-vaccination the control fish had a high mortality and the fish vaccinated with the novel vaccine mixture achieved good protection

Valutazione della risposta anticorpale e della protezione indotta da un vaccino per immersione anti Yersinia ruckeri in trota iridea (Oncorhynchus mykiss)

Vaccini costituiti da batteri della specie Yersinia ruckeri, inattivati con formalina e somministrabili tramite immersione, sono disponibili in USA e in Europa a partire dalla fine degli anni \u201970, per la profilassi della bocca rossa o \u201cEnteric Redmouth Disease\u201d (ERM). Nonostante siano state affrontate numerose prove sperimentali per indagare l\u2019esito di questo intervento di profilassi in trota iridea (Oncorhynchus mykiss) risulta ancora poco definita la correlazione fra titoli anticorpali specifici e protezione indotta dal vaccino. L\u2019obiettivo di questa indagine \ue8 stato quello di valutare in vivo la protezione indotta da un vaccino commerciale somministrato per immersione (30 secondi) a trote iridee di 5 grammi, tramite infezione sperimentale con un ceppo virulento di Yersinia ruckeri e di studiare la risposta anticorpale specifica indotta dal medesimo vaccino nelle settimane successive alla somministrazione. Tramite la tecnica di agglutinazione in micropiastra \ue8 stato possibile evidenziare la presenza di anticorpi agglutinanti nel siero dei soggetti trattati a partire da 7 settimane dopo la vaccinazione. La tecnica ELISA indiretta ha dimostrato una maggiore sensibilit\ue0, evidenziando titoli anticorpali significativamente pi\uf9 elevati rispetto ai controlli, a partire da 5 settimane dopo la vaccinazione. La percentuale relativa di sopravvivenza o RPS, collegata all\u2019efficacia protettiva conferita dal vaccino commerciale, \ue8 risultata pari al 77% in seguito a prova di infezione intraperitoneale con 3x106 UFC/sogg., effettuata a 7 settimane dalla vaccinazione. Tale riscontro consente di ipotizzare che gli anticorpi sierici prodotti in seguito alla immunizzazione tramite immersione siano protettivi nei confronti della malattia

Investigation of media formulations promoting Photobacterium damsela subsp. piscicida natural and novel antigen expression and recognition by sea bass (Dicentrarchus labrax, L.) immune sera

Photobacterium damsela ssp. piscicida (Phdp) isolates were grown in various bacteriological media, in eukaryotic cell culture media and in the presence of fish cells (resembling some aspects of in vivo growth environments). Bacterial cells, extracellular products (ECPs) and crude capsular polysaccharide were isolated and analysed by electrophoresis and Western blot using sea bass sera. Growth in bacteriological media conserved the synthesis of cell and extracellular components when these were compared with those prepared under near-in vivo growth conditions. In fact, synthesis of a larger range of cell components was induced after growth in bacteriological media. Certain media based on yeast extract and peptones from various sources and a specific salt formulation induced the synthesis of novel cell components at approximately 21.3 and 14 kDa. These antigens were recognized by sea bass sera collected after natural pasteurellosis outbreaks and other sea bass sera raised against live or inactivated Phdp cells. The ECPs of the pathogen were not good immunogens in their soluble form despite various treatments prior to immunization. The results are discussed with respect to vaccine development