Early innate immune response and redistribution of inflammatory cells in the bony fish gilthead seabream experimentally infected with Vibrio anguillarum

Abstract

An obvious difference between the immune system of fish and mammals is that fish lack both bone marrow and lymph nodes; in their place, the head-kidney acts as a major haematopoietic and lymphoid organ in adult fish, whereas the thymus, spleen and mucosa-associated lymphoid tissues are common to both fish and mammals. This suggests that differences exist in antigen presentation and naive lymphocyte stimulation, a prerequisite for the initiation of adaptive immune responses. Intraperitoneal injection of the bony fish gilthead seabream (Sparus aurata L.) with intact Vibrio anguillarum, as a particulate bacterial antigen, results in the mobilisation of head-kidney leucocytes to the peritoneal cavity and priming of their respiratory burst activity. We have also observed the rapid infiltration of acidophilic granulocytes, which are leucocytes functionally equivalent to mammalian neutrophils, into the spleen. These cells may be involved in antigen capture and transport to the spleen, since an apparent association between mobilised acidophilic granulocytes, bacterial antigens and proliferating lymphocytes has been seen in this organ. Collectively, these results suggest that, in addition to being actively involved in bacterial clearance, fish phagocytic granulocytes play a role in the initiation and support of the adaptive immune response.

Professional phagocytic granulocytes of the bony fish gilthead seabream display functional adaptation to testicular microenvironment

“…We used a mAb, G7, which is specific to sbNLCs [5], to determine, by flow cytometry, the percentage of these cells in the testis of the gilthead seabream throughout its reproductive cycle. The results show that approximately 80% of the granulated cells (R2 region) of the testis were sbNLCs (G7 ϩ cells; Fig.…”

“…The acidophilic granulocytes of the teleost gilthead seabream, despite their staining pattern, display similar functions to human neutrophils. For example, they are the most abundant circulating granulocytes and are recruited rapidly from the head-kidney, the main hematopoietic organ in fish, to the infection site [5]. In addition, their main role is the phagocytosis of bacteria, which is accomplished by coordinating their attachment and internalization to the release of reactive oxygen intermediates (ROIs) into the phagocytic vacuole [5][6][7].…”

“…For example, they are the most abundant circulating granulocytes and are recruited rapidly from the head-kidney, the main hematopoietic organ in fish, to the infection site [5]. In addition, their main role is the phagocytosis of bacteria, which is accomplished by coordinating their attachment and internalization to the release of reactive oxygen intermediates (ROIs) into the phagocytic vacuole [5][6][7]. Bearing all this in mind, henceforth, we will use the term "neutrophil-like cells" (sbNLCs) to refer to the professional phagocytic granulocytes of the gilthead seabream.…”

Transcriptome analysis of soiny mullet (Liza haematocheila) spleen in response to Streptococcus dysgalactiae

“…Within the molecular function category, the five most abundant subcategories were binding (14,870,66.05%), catalytic activity (9,274, 38.17%), enzyme regulator activity (1,450, 5.97%), transporter activity (1,332, 5.48%), and molecular transducer activity (1,313, 5.4%). In the cellular component category, cell (17,212,70.83%), cell part (17,211, 70.83%), organelle (12,859, 52.92), membrane (8,461,34.82%) and organelle part (7,957,32.75%) were the most common subcategories. While in the biological process category, most unigenes were assigned into cellular process (18,323,75.4%), single-organism process (15,185,62.49%), metabolic process (14,025, 57.72%), biological regulation (11,709, 48.19%) and regulation of biological process (11,047, 45.46%) subcategories (Fig.…”

“…T and B cells are expressed. During bacterial infections, fish spleen act as a second lymphoid organ to prevent further lesions by adaptive immune responses [8,9]. Thus, it is reasonable to choose the spleen as a major target tissue and investigate fish immune responses.…”